detailed description of project components...detailed description of project components 1. the...
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Supporting Electricity Supply Reliability Improvement Project (RRP SRI 49216)
DETAILED DESCRIPTION OF PROJECT COMPONENTS 1. The Supporting Electricity Supply Reliability Improvement Project consists of the following components:
a. Component 1: Renewable energy development: (i) Hybrid renewable energy systems in small isolated islands; (ii) Productive energy use for small isolated islands and rural communities; (iii) Renewable energy based micro-grid pilot subproject;
b. Component 2: Reliability improvement of the medium voltage network; c. Component 3: Rural electrification and distribution performance monitoring; and d. Component 4: Reactive power management in the transmission system.
I. Renewable Energy Development 2. This component consists of three subcomponents: (i) hybrid renewable energy systems in small isolated islands off the coast of Jaffna (Analaitivu, Delft and Nainativu); (ii) productive use of electricity by the communities of the above three islands to be financed by grant proceeds; and (iii) an innovative pilot micro-grid served with renewable energy to demonstrate the use of modern technology to establish economically efficient stand-alone energy systems. Subcomponents (i) and (ii) will be implemented in the three islands in the Jaffna district of the Northern province, whereas subcomponent (iii) will be implemented in an urban area of the Western Province. A. Hybrid Renewable Energy Systems in Small Isolated Islands 3. Setting up hybrid renewable energy based power systems in the small islands is a part of the loan package offered by the Asian Development Bank (ADB) to support Sri Lanka in achieving 100% electrification and to improve electricity supply reliability. Hybrid power plants use a combination of complementary electricity generation systems to meet a customer demand. Ceylon Electricity Board (CEB) has decided to implement hybrid power plants initially in three selected islands off the Jaffna Peninsula, namely Analaitivu, Delft and Nainativu. The energy sources to be tapped for this purpose are wind and solar resources that are found in abundance in the three islands. 4. The three islands are presently served by CEB-owned diesel generating plants through a distribution network that covers parts of each island. Diesel fuel is transported by boat from the mainland resulting in additional costs. Diesel generators used in the islands are small, and they have to cater to the varying and relatively small customer demand in each island. As such, the fuel cost incurred in producing electricity and other maintenance costs and overheads exceed SLRs50 per kilowatt-hour (kWh), which is about three times the national average cost of supply of electricity. Diversification of the energy supply base in these islands is expected to improve the power plant reliability and reduce the electricity production costs, owing to the high wind and solar resource potential in the islands and the declining capital expenditure on renewable energy-based power generating systems (especially of solar photovoltaic).
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A.1 Proposed Hybrid Renewable Energy System 5. Basic structure of a renewable energy-based hybrid power plant is schematically shown in Figure 1. It consists of an alternating current bus bar connected to the outgoing transmission line via a step-up 400 volt(V)/11kilovolt (kV) transformer. The solar photovoltaic system generates direct current that is transformed to alternating current by the direct current/alternating current converter (inverter). Variable frequency alternating current generated by a variable speed wind turbine is converted to alternating current at 50 hertz (Hz) using a back-to-back converter (alternating current/alternating current converter). Output from the diesel generators is fed directly to the bus bar at 400 V. The system incorporates a lithium ion battery bank to store excess energy delivered by the uncontrolled sources–wind and solar, as well as to feed the bus bar in case of short-term frequency drop.
Figure 1: Structure of a Hybrid Power Plant using Renewable Energy
1. Baseline Situation in the Islands
6. Analaitivu is a small island located about 5 km off the mainland of the Jaffna Peninsula (Figure 2). The island is approximately 4 kilometer (km) long with an approximate land area of 6 square kilometres (km2). The total population in Analaitivu is 1,804 comprising of 516 families (2015). Average employment level is around 34%, while the main livelihoods of the people in the island are fishery and agriculture. Monthly average income of the households is about SLRs3,000–SLRs7,000, and presently no major industrial activities are carried out in Analaitivu. Analaitvu belongs to the Islands North (Kayts) Divisional Secretariat while there are two Grama Niladhari1 Divisions (GNDs) in the islands.
1 Village administrative officer.
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Figure 2: Islands Located off Jaffna Peninsula
7. Delft is the second largest island in Sri Lanka, located 10 km off the mainland of the Jaffna Peninsula. The island is approximately 8 km long and 6 km wide with an approximate land area of 47 km2. The population in Delft is 4,502 comprising of 1,328 families. Tourism in the island is growing due to different attractions such as Dutch history, its temples and wild horses. The main livelihood of the people is fishery, while people also engage in agriculture and livestock. Delft Divisional Secretariat is divided in to six GNDs. Delft East and Delft Central East GNDs have the highest population. 8. Nainativu is one of the islands in Islands South (Velanai) Divisional Secretariat. There are three GNDs in the island with a total population of 2,861 (874 families). Nainativu is located about 2 km off the mainland (Kurikattuwan) of Jaffna Peninsula and the total land area of the island is 5.6 km2. The main livelihood of the people in Nainativu is fishery and the present employment level is around 42%. Average income of the households is about SLRs3,000. 9. The present electrification level in Analaitivu is 38% with 208 electricity consumers. Annual total electricity consumption of the island is 124,824 kWh with an annual revenue of SLRs1.18 million. The largest island, Delft has an electrification level of 47% with 949 consumers as of 2015. Annual total electricity consumption of the island is 346,087 kWh and the annual total revenue is SLRs4.19 million. Nainativu has a comparatively high electrification level when compared with the other two islands. Its present electrification level is 60% with a consumer base of 751. Annual total electricity consumption in Nainativu is 474,472 kWh and the total annual revenue is SLRs6.39 million. Table 1 summarizes the annual electricity consumption in the three islands.
Delft
Nainativu
Analaitivu
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Table 1: Annual Electricity Consumption of the Islands by Consumer Categories
Consumer Category Analaitivu Delft Nainativu
Domestic Consumers
No. of consumers 182 856 665
Total electricity consumption (kWh)
95,870 250,444 269,244
Revenue (SLRs) 845,797 2,142,078 2,499,072
Religious Consumers
No. of consumers 10 19 21
Total electricity consumption (kWh)
21,544 17,362 64,204
Revenue (SLRs) 151,565 117,883 545,775
Industrial Consumers
No. of consumers - 1 1
Total electricity consumption (kWh)
- 1,466 564
Revenue (SLRs) - 24,782 13,450
General Purpose Consumers
No. of consumers 16 73 64
Total electricity consumption (kWh)
7,410 76,815 140,460
Revenue (SLRs) 178,874 1,902,757 3,329,746
Total Number of Consumers 208 949 751
Total Annual Electricity Consumption (kWh) 124,824 346,087 474,472
Total Annual Revenue (SLRs) 1,176,237 4,187,501 6,388,044 kWh = kilowatt-hour, SLRs = Sri Lanka rupee. Source: Ceylon Electricity Board estimates.
10. Presently, 11 kV medium voltage distribution is available only in Delft and Nainativu islands, but the existing network covers only certain parts of these islands (Figure 3). CEB is in the process of extending the medium voltage network in Delft and Nainativu, to fully serve each island. However, there is no medium voltage network in Analaitivu island, and the generated electricity is distributed only through the 400 V low voltage network. A new medium voltage network is being presently constructed by CEB in the Analaitivu Island. Table 2 summarizes the present status of the medium voltage and low voltage networks of the three islands.
Table 2: Existing MV and LV Network of the Islands
Component Analaitivu Delft Nainativu
Existing MV (11 kV) lines (km)
- 7.5 3.5
Existing distribution substations
- 4×100 kVA 1×160 kVA 1×250 kVA
Existing bulk supply substations
- 1×100 kVA -
Existing LV Lines (km) 14.11 15.2 25.78 km = kilometer, kV = kilovolt, kVA = kilovolt-ampere, LV= low voltage, MV = medium voltage.
Source: Ceylon Electricity Board estimates.
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Figure 3: Existing Medium Voltage and Low Voltage Networks of the Islands 11. Present electricity demand in the islands is served by diesel generators. Table 3 provides the details of the existing generators. Condition of these generators is poor due to long operational hours and lack of maintenance. None of these power stations have the synchronizing facility. In peak hours, generators with higher capacities supply the demand and during off-peak, generators with lower capacities supply the demand. This operating mechanism requires power interruptions to switch the supply lines between generators. Photographs of the power stations are shown in Figure 4. Since the present condition of the power stations is poor, the proposed renewable energy-based hybrid power plants will be equipped with new diesel generator sets and switchgear with matching features and characteristics.
Analaitivu Nainativu
Delft
LV (400 V) Lines
MV (11 kV) Lines
Power House
Bulk Supply Transformer
Distribution Transformer
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Table 3: Details of the Existing Diesel Generators in the Islands
Island Diesel Generators Capacity (kVA) Year of Manufacture
Analaitivu
DG 1 250 1999
DG 2 180 1993
DG 3 100 1993
Delft
DG 1 250 1999
DG 2 250 1999
DG 3 250 1995
Nainativu
DG 1 500 1986
DG 2 250 1999
DG 3 250 1986 DG = diesel generator, kVA =kilovolt-ampere. Source: Ceylon Electricity Board estimates.
Figure 4: Existing Power Stations and Switch Boards
12. Operating costs of the power stations in the islands are comparatively high. Diesel and lube oil are transported by boats from mainland to the islands. Most of the time, these old diesel generators are partly loaded. This leads to inefficient operations, with higher consumption of fuel. Per unit costs of the three islands are shown in Table 4, and monthly diesel and lube oil consumption in year 2015 is shown in Table 5.
Analaitivu Delft
Nainativu Switch boards
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Table 4: Cost of Electricity Generation in the Islands
Island
Cost of maintenance and repair (SLRs/kWh)
Cost of labour
(SLRs/kWh)
Cost of diesel
(SLRs/kWh)
Cost of lube oil
(SLRs/kWh)
Cost of transport (SLRs/kW
h)
Total cost (SLRs/kW
h)
Analaitivu 27.25 13.86 47.16 3.02 1.06 92.35
Delft 16.60 3.04 34.90 1.14 1.06 56.75
Nainativu 3.27 3.24 33.91 1.13 0.76 42.33 kWh = kilowatt-hour, SLRs = Sri Lanka Rupee. Source: Ceylon Electricity Board estimates.
Table 5: Monthly Diesel and Lube Oil Consumption in Year 2015
Month
Analaitivu Delft Nainativu
Diesel (l) Lube oil (l) Diesel (l) Lube oil (l) Diesel (l) Lube oil (l)
January 8,000 20 23,575 135 17,535 25
February 5,730 55 18,195 135 15,295 165
March 6,110 25 21,910 170 17,370 20
April 6,190 105 20,275 25 18,200 155
May 6,040 115 21,450 155 17,875 165
June 5,875 25 20,210 35 21,215 100
July 6,605 70 20,915 115 21,025 100
August 6,395 25 21,675 35 19,455 145
September 5,340 85 20,575 140 18,775 25
October 5,605 90 20,725 160 19,475 145
November 5,598 70 19,270 95 19,535 140
December 5,910 60 19,350 85 19,995 15 l = liter. Source: Ceylon Electricity Board estimates.
13. The present peak demand in Analaitivu, Delft and Nainativu are 45 kilowatt (kW), 145 kW and 151 kW respectively. Load data averaged over the period from 17 to 30 July 2015 for the three islands are presented in Figure 5, Figure 6 and Figure 7. The peak demand of all the three islands occurs between 7.00 pm and 8.00 pm. Day time demand variation is very low and it is about half of the peak demand. In these islands, electricity demand is mainly due to household activities. There are no major industrial activities which consume electricity. In Delft, there is a water desalination plant which is in operation for 10 hours per day and its demand is 35 kW. Seasonal variation of the electricity demand can be observed in Nainativu due to the annual religious festivals. The demand growth of the islands is less than 5% per year, which is below the demand growth of the Jaffna peninsula.
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Figure 5: Daily Load Profile of Analaitivu (July 2015)
Figure 6: Daily Load Profile of Delft (July 2015)
Figure 7: Daily Load Profile of Nainativu (July 2015)
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2. Selection of Sites for Hybrid Power Plants
a. Criteria for Site Selection 14. Following criteria were used to select sites for the proposed hybrid power plants:
(i) compliance with the power plant configurations; (ii) exposure of the sites to wind and solar resources; (iii) compliance with regulations of the coast conservation department; (iv) availability of sufficient land area; (v) ease of acquiring the required amount of land; and (vi) proximity of the site to load centres.
b. Description of the Selected Sites
15. Analaitivu: Approximate extent of land to accommodate the complete power plant facility comprising wind turbines and solar photovoltaic was estimated at 2 hectares (ha). This was based on 5D crosswind spacing for a single row of wind turbine generators (WTGs) and land area of 20 m2/kilowatt peak (kWp) for solar photovoltaic (including internal walkways, buildings, open areas, etc.). The selected location lies on the south eastern coast of the island. Area earmarked for the project was tentatively estimated as a block of land approximately 200 m x 100 m (Figure 8).
Figure 8: Proposed Site for the Hybrid Power Plant in Analaitivu
16. Delft: Approximate extent of land to accommodate the complete power plant facility comprising wind turbines and solar photovoltaic was estimated at 3 ha. This was based on 5D crosswind / 8D downwind spacing for two rows of WTGs, land area of 20 m2/kWp for solar photovoltaic (including internal walkways, buildings, open areas etc.). Area earmarked for the project was tentatively estimated as a block of land approximately 300 m x 100 m (Figure 9). The site lies outside the recently declared wild life park.
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Figure 9: Proposed Alternative Sites for the Hybrid Power Plants in Delft
17. Nainativu: Nainativu has a uniformly distributed vegetation cover across the island. Hence, the exposure to wind is generally restricted in most parts of the island. The only site that offers potential for siting the proposed hybrid power plant lies on the south western coast. There are two problems with this site: (i) the site gets water logged during the rainy season due to the existence of a long barrage along the coastline; and (ii) when the 95 meter (m) coastal set back distance is applied, the area for siting wind turbines get highly restricted. GNDs claimed that the artificial water retention area was created to recharge ground water in the area. In view of these limitations, it was decided to adopt only a solar – diesel configuration for this island, and to exclude wind power. 18. Approximate extent of land to accommodate the complete power plant facility comprising solar photovoltaic and two diesel generator sets was estimated to be 0.5 ha. This was based on land area of 20 m2/kWp for solar photovoltaic (including internal walkways, buildings, open areas, etc.). Area earmarked for the project was tentatively estimated as a block of land approximately 100 m x 50 m (Figure 10).
Figure 10: Area Proposed for the Hybrid Power Plant in Nainativu
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3. Configuration of Proposed Hybrid Renewable Energy Systems for the Islands
19. Wide variety of variables come to play when designing hybrid power plants and selecting the optimum plant configuration that involves the analysis of large number of technically feasible scenarios. One of the software tools being used widely for optimization of a hybrid power plant design is known as HOMER developed by the National Renewable Energy Laboratory (NREL) of the United States Department of Energy. 20. The software can model photovoltaic modules, wind turbines, biomass power, hydropower, generators driven by internal combustion engines, micro turbines, storage batteries, grid connections, fuel cells and even electrolysers. It can be used to design grid-connected and off-grid renewable energy based power systems. Primary inputs to the software are the load data, resource data (e.g., wind speed, solar radiation, etc.), technologies to be considered for the power plant, cost data and user-defined conditions. HOMER examines all possible combinations of system components and capacities, and then sorts the cases according to the optimisation methodology. Key outputs of the analysis are a series of power plant configurations and the levelized cost of energy for each configuration.
a. Demand Forecasting Methodology 21. Power demand that is met by the currently operating diesel power plants in each island was taken to define the baseline load curve. This data was provided by the CEB office in Jaffna. The load curve was then modified assuming 100% electrification level in all three islands after setting up the hybrid power plants. Annual demand growth of each island is assumed to be equivalent to national electricity demand growth rate of 6% per annum, and the demand was assumed to be totally saturated at the end of five years. The forecast demand profile was then modified to include the operation of a water desalination plant in the Nainativu Islands. 22. As on-site wind and solar data do not exist in any of the islands, relevant wind speed data and global horizontal irradiance data were extracted from different sources. The wind speed data was obtained from the Pooneryn wind measuring station data (Figure 11) and the monthly average irradiance data for the islands were obtained from the Geospatial Toolkit developed by NREL (Figure 12).
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Figure 11: Monthly Average Wind Speeds Obtained at Pooneryn Measuring Station
Figure 12: Monthly Average Global Horizontal Irradiance (GHI) in Delft
b. Modelling Scenarios 23. Three scenarios were developed to analyze the economic benefit of each hybrid renewable energy system:
(i) Baseline scenario: In this scenario, the present load profile and the existing diesel generator sets are taken into account.
(ii) Diesel generator sets only scenario: This scenario was modelled for the forecast demand, which will be served by existing diesel generator sets.
(iii) Hybrid renewable energy system scenario: This is the hybrid scenario, which contains renewable components along with new diesel generator sets. In this scenario, the forecast demand was taken into account.
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c. System Constraints 24. Finding a suitable bare land for wind turbines in Nainativu island was difficult and therefore, the hybrid system in Nainativu island was limited to solar photovoltaic, diesel generator sets and storage batteries. The solar photovoltaic system capacity for Nainativu was restricted to 250 kW because of space constraints at the available site.
d. Cost Structure 25. Free on Board (FOB) prices of system components were adjusted according to the insurance and freight charges, duties and taxes, and the supply costs of the components were used for HOMER simulations (Table 6).
Table 6: Supply Cost of System Components (ex port of Colombo)
Solar PV System
(US$/kW)
Wind Turbine System
(US$/kW)
Battery Storage
(US$/kWh) Converter (US$/kW)
Diesel Genset
(US$/kW)
Unit FOB price 750 4,000 720 350 450
Insurance and freight charges per unit
75 400 72 35 45
Duty, taxes & levies
- 836 - - 168
Supply cost 825 5,236 792 385 663 FOB = free on board, kW = kilowatt, PV = photovoltaic. Source: Asian Development Bank and Ceylon Electricity Board estimates.
26. Other costs related to the project are, clearing and transportation charges, cost of building construction, civil works, installation and commissioning and step-up transformer costs. Summary of these for the three islands are given in Table 7.
Table 7: Other Capital Costs for Islands
Other Capital Costs Analaitivu
($) Delft ($) Nainativu ($)
Clearing & transportation charges
70,000 160,000 55,000
Land acquisition cost - - -
Cost of buildings 150m2
area 60,000 60,000 60,000
Civil works ,installation and commissioning at 20%
148,478 389,125 163,867
Step-up Transformer cost 16,680 8,340 11,120
Total other capital costs 286,818 625,805 289,987
Total other capital costs- rounded to nearest ‘000
287,000 626,000 290,000
m2 = square
meter.
Source: Asian Development Bank and Ceylon Electricity Board estimates.
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e. Results
(i) Optimum System Capacities
27. Considering the results of economic optimization as well as renewable penetration, the following system capacities were selected. (Table 8)
Table 8: System Capacities for Islands
Component Analaitivu Delft Nainativu
Solar PV 200 kW 400 kW 250 kW
Wind 60 kW 160 kW -
Battery Storage 200 kWh 400kWh 300 kWh
Converter 200 kW 400 kW 250 kW
Diesel Genset 1 100 kW 200 kW 150 kW
Diesel Genset 2 100 kW 350 kW 300 kW kW = kilowatt, kilowatt-hour, PV = photovoltaic.
Source: Asian Development Bank and Ceylon Electricity Board estimates.
(ii) HOMER Output for the Optimum System Capacities
28. Based on the optimum system capacities, HOMER provides the levelized cost of energy, initial investment, operational cost, annual fuel consumption, renewable energy penetration, carbon dioxide (CO2) emissions, etc. These were obtained for all the three scenarios and shown in Table 9, Table 10 and Table 11.
Table 9: HOMER Outputs for Analaitivu Island
Baseline Scenario
Diesel Genset Only Scenario
Hybrid Renewable
Energy System Scenario
Net present cost over 25 years at 12% discount rate
$ 820,582 $ 2,884,472 $ 2,618,492
Initial Investment 0 0 $ 1,133,960 Operational cost $ 69,593 $ 244,631 $ 125,903 Annual fuel consumption
73,266 l/year 253,266 l/year 113,355 l/year
RE penetration 0% 0% 38% CO2 emissions 192,934 kg/year 666,930 kg/year 298,501 kg/year Levelized cost of energy
0.39 0.39 0.35
CO2 = carbon dioxide, kg/year = kilogram per year, l/year = liter per year, RE = renewable energy. Source: Asian Development Bank estimates
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Table 10: HOMER Outputs for Delft Island
Baseline Scenario
Diesel Genset Only Scenario
Hybrid Renewable
Energy System Scenario
Net present cost over 25 years at 12% discount rate
$ 3,377,484 $ 9,011,389 $ 7,167,749
Initial Investment 0 0 $ 2,629,010 Operational cost $ 286,444 $ 764,254 $ 384,929 Annual fuel consumption
293,418 l/year 804,534 l/year 363,354 l/year
RE penetration 0% 0% 38% CO2 emissions 772,667 kg/year 2,118,603 kg/year 956,832 kg/year Levelized cost of energy
0.41 0.39 0.31
CO2 = carbon dioxide, kg/year = kilogram per year, l/year = liter per year, RE = renewable energy. Source: Asian Development Bank estimates.
Table 11: HOMER Outputs for Nainativu Island
Baseline Scenario
Diesel Genset Only Scenario
Hybrid Renewable
Energy System Scenario
Net present cost over 25 years at 12% discount rate
$ 3,209,818 $ 9,500,308 $ 5,143,658
Initial Investment 0 0 $ 970,050 Operational cost $ 272,224 $ 545,350 $ 353,962 Annual fuel consumption
275,160 l/year 581,341 l/year 362,148 l/year
RE penetration 0% 0% 21% CO2 emissions 724,588 kg/year 1,530,861 kg/year 953,655 kg/year Levelized cost of energy
0.42 0.38 0.29
CO2 = carbon dioxide, kg/year = kilogram per year, l/year = liter per year, RE = renewable energy. Source: Asian Development Bank estimates.
4. Operation and Maintenance Arrangement 29. Operation and maintenance work of power generation facilities in the three islands is headed by the Electrical Engineer (Small Island Generation). The Electrical Engineer is assisted by an Engineering Assistant who directly supervises the work of the Electrical Superintendent and Mechanical Superintendent. All these officials operate from the office of the Deputy General Manager–Northern Province based in the Jaffna mainland. Operation of the island-based diesel generator sets are carried out by two plant operators in each island, who operate in shifts. Up to now CEB has not developed any new operation and maintenance (O&M) arrangements for the proposed hybrid power plants, but it is most likely that the on-site staff will be strengthened with additional expertise to cope with demands of the newly introduced technologies.
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5. Project Benefits 30. Project benefits would largely be economic and environmental. In economic terms, it could be expected that the cost of generation would be reduced by 28% due to addition of solar and wind generated electricity. Major contribution in this regards comes from solar photovoltaic technology, the price of which has been falling dramatically during the past 5–8 years. In environmental terms, the design analysis indicates a reduction of CO2 emissions of the order of 800 tons per year due to reduced fuel burning. The proposed hybrid power plant also has the potential to improve the system reliability because of the synchronizing facility and new switchgears. B. Productive Energy Use for Small Isolated Islands and Rural Communities 31. The project will promote and strengthen energy-based livelihoods through access to electrical appliances and technologies, emerging with the availability of electricity for production and marketing of traditional crafts and other similar local manufacturing activities in the Analaitivu, Delft and Nainativu islands. The project aims to provide:
(i) energy-based livelihoods with focus on women’s microenterprises developed with a target of 50 microenterprises established, 100% below-poverty-line and at least 20% women headed households participating;
(ii) renewable energy technology (RET)-based local infrastructure development (a sea water desalination plant in Nainativu Island, small water storage tanks, an ice-making factory, refrigeration facilities, public and street lighting);
(iii) end-user education for the safe and efficient use of electricity and electrical equipment with a target of at least 50% women’s participation; and
(iv) technical and skills training to avail of employment and livelihood opportunities targeting 100% below-poverty-line households and at least 50% women’s participation.
32. The Ministry of Power and Renewable Energy (MPRE) will be the executing agency for this subcomponent. The implementing agency for subcomponent item (ii) will be the National Water Supply and Drainage Board, and subcomponent items (i), (iii) and (iv) will be implemented by Sri Lanka Sustainable Energy Authority. The detailed description of this subcomponents is available in a relevant supplementary linked document. C. Renewable Energy based Micro-grid Pilot Project
1. Introduction 33. Owing to the rapid depletion of conventional energy resources and the environmental costs associated with the use of fossil fuels for electricity generation, electric utilities are now under increased pressure to include distributed renewable energy resources into their networks. In addition, energy efficiency, demand side management and load control are becoming integral parts of modern electricity distribution operations. Customer expectations and regulatory environments also demand improved power quality, reliability, and operational flexibility. In these conditions, increasing the supply capacity by investing on traditional infrastructure alone would not be sufficient. Smart grids, micro-grids and demand response schemes are some of the initiatives distribution utilities can take to meet these future challenges. 34. Micro-grid is an emerging concept, which has gained significant attention and popularity in the power industry owing to its contribution to improvements in efficiency, reliability, resilience
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and independence over the traditional utility grid. A micro-grid is a self-contained energy system which has the ability to operate independent of the grid and supply electricity to the loads connected to it. There can be micro-grids served with electricity generated from different forms of primary sources; fossil fuel, renewable or a mix of fossil fuel and renewables. However, this evolving concept can be complex and needs further study and analysis on its adaptability to a particular distribution utility eco-system. 35. In this context, Lanka Electricity Company (Private) Limited (LECO), which is a benchmarked utility in the region, has proposed to implement a micro-grid as a pilot subproject within its franchised area. Objectives of the subproject include: (i) develop a renewable energy micro-grid to establish and examine its feasibility as an extension to the conventional utility distribution system; (ii) catalyse adoption of distributed generation as a means of improving network efficiency and demand side management; and (iii) validate the effectiveness of direct current electricity supply as an energy efficiency measure.
2. Project Scope 36. A renewable energy based micro-grid will be developed by LECO at the premises of one of its large scale electricity customers. In order to supply alternating current and direct current loads separately, instead of a conventional micro-grid, an alternating current-direct current hybrid micro-grid will be implemented.
3. Rationale 37. With the introduction of the Net Metering Scheme2 in Sri Lanka, followed by a rapid reduction in global solar photovoltaic prices, a large number of customers installed solar photovoltaic systems at their premises to partly offset their electricity bills. However, owing to technical and commercial reasons, if the grid is not available, these solar photovoltaic systems are not allowed to supply electricity even to the same premises they are installed at. 38. When a distributed energy resource such as solar photovoltaic is available at the premises of an electricity customer, allowing it to operate independent of the grid (i.e., in an islanded mode) would be beneficial both to the customer as well as for the grid. While the supply reliability of the customer is improved, the grid can make use of this capability to off-load part of its demand during peak and network constrained periods. 39. By integrating the solar photovoltaic, battery storage and a standby diesel generator in to a single control system, a simple micro-grid can be set up, which can be operated both in grid-tied and islanded modes. Furthermore, since majority of modern loads such as light-emitting diode (LED) lighting, computers, televisions and other consumer electronics operate on a direct current supply, in supplying electricity from a micro-grid, it is more efficient to connect these loads directly to the direct current bus of the micro-grid.
4. Project Location 40. For successful implementation, micro-grids need a considerable amount of controllable power demand and sufficient amount of energy resources. Upon evaluating several potential
2 Sri Lanka introduced net metering option to all customers, where electricity generation from renewable energy
resources can be connected in parallel with grid supply. Any surplus sent to the grid can be taken back anytime over a 10-year contract period.
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sites, LECO has selected a public sector location3 within its franchised area for the development of the pilot project. In addition to the suitability of the loads and the energy resources available at the location, the prospects of demonstrating the project over a wider community have been the factors considered in selecting the particular location.
5. System Configuration 41. Figure 13 depicts the configuration proposed for the micro-grid. As illustrated in Figure 13, the overall system proposed comprises of customer loads, the grid supply and the micro-grid.
Figure 13: Configuration of the Proposed Micro-grid
a. Customer Loads 42. Existing: While a mix of alternating current and direct current loads would most-likely exist at the selected location, currently the entire load is typically connected and supplied through an alternating current supply system. The maximum demand of the loads is expected to be about 200 kW, out of which a chiller (air conditioning) accounts for a substantial portion. Several non-essential loads would also be available, providing the opportunity to reduce the demand, if controlled properly. 43. Proposed: Considering that a large amount of appliances used in this location are most-likely direct current loads, and most of the lighting can also be converted to LED lamps, it is
3 The location would most likely be a government-owned university, but the final selection of location would be part
of the feasibility study during implementation.
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proposed that a separate direct current supply be provided to the buildings, which can then be served directly by a direct current source, which in this particular case can be the direct current bus of the micro-grid. A static converter (rectifier) will be used between the alternating current and direct current busses to supply the direct current loads from the grid. Also, the pilot subproject will install a chilled-water storage system for the chiller, allowing the air conditioning system to be used as a deferrable load, providing additional flexibility in supplying this large load.
b. Grid Supply 44. Existing: Currently, electricity for the location is supplied by LECO via an 11 kV/400 V step down transformer. 45. Proposed: No upstream changes to the existing supply are proposed. However, at the point of interconnection, a dual synchronising panel will be installed to enable seamless synchronisation of the micro-grid with the grid.
c. Micro-grid 46. Existing: A diesel generator rated around 250 kVA is considered to be available as a standby power supply option. 47. Proposed: Due to resource and space limitations at the selected location, the micro-grid may consist only of solar photovoltaic, battery storage and a diesel generator. In order to provide a continuous power supply to the customer load independent of the grid, the following capacity ratings are proposed: (i) System Capacity: 300 kW (leaving provisions for future demand growth and to enable continuous islanded operation); (ii) Solar photovoltaic: 300 kWp; (iii) Inverter: 300 kW; (iv) Battery Storage: 120 kWh (with on-line operation and frequency control capabilities); (v) Diesel Generator: 400 kVA (frequency and voltage control, prime rating: 300 kW); and (vi) Micro-grid Central Management System.
6. Proposed Operation of Micro-grid 48. It is expected that the micro-grid will be able to operate both in the islanded mode and grid connected mode. During normal operation, the micro-grid will operate in grid connected mode, providing renewable energy generated by the solar photovoltaic primarily to serve the loads within the premises (via alternating current and direct current buses) and any excess to the grid. However, the micro-grid can seamlessly switch over to the islanded mode during grid interruptions and also when requested by the distribution system controller, mainly as a demand response measure. In the islanded mode, the micro-grid is fully disconnected from the grid and the necessary frequency and voltage references are provided by the micro-grid inverter. While the real time energy balance immediately after shifting into the islanded mode will be maintained by the battery storage, the steady state energy requirement is expected to be provided by the solar photovoltaic itself, backed up by the diesel generator.
7. Mode of Implementation 49. The implementing agency of the micro-grid pilot subproject will be LECO. With the assistance of a team of consultants (one local and one international), LECO will prepare the feasibility study and the detailed design of the micro-grid. Procurement of a turnkey contractor will be through competitive bidding. The necessary modifications to the load side, such as
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changing of lamps to LEDs, a chilled water storage system and any changes to the building wiring, will be carried out by LECO using own contractors. Once commissioned, the pilot micro-grid will be operated and maintained by LECO as part of its distribution network. Through metering at appropriate alternating current and direct current nodes, an electricity bill consistent with the applicable tariffs will be raised to the customer. These would effectively shield the customer from the complexities of operating a micro-grid. At the inception, LECO staff will be trained on implementing, operating and maintaining micro-grid, which will enable LECO to develop its own capacity to replicate the concept throughout the network. Furthermore, the pilot micro-grid will be used for study and research purposes.
8. Cost Estimates 50. The expected investment of the pilot project is $1.8 million. Table 12 provides a break-up of the costs estimated for the project.
Table 12: Cost Break-up of the Proposed Renewable-based Pilot Micro-grid Project
Item Cost
(USD)
Support for feasibility study and detailed design, and procurement:
International consultant - 6 person months 150,000 National consultant (s) - 5 person months 75,000
Staff capacity building through training and workshops 75,000 Sub total 300,000
Procurement and installation micro-grid equipment (EPC) Civil and electrical works 100,000
Solar PV and inverter 600,000
Battery storage 300,000
Diesel Generator 150,000
Micro-grid controller, software and SCADA system 100,000
Interconnection facilities 200,000
Sub total 1,450,000
Load side modifications
Chiller modification 25,000
Conversion of dc loads + converter 25,000
Sub total 50,000
Total 1,800,000 dc = direct current, EPC = engineering, procurement and construction, PV = photovoltaic, SCADA =
Supervisory Control and Data Acquisition. Source: Lanka Electricity Company Limited estimates.
9. Expected Outcomes 51. The following key outcomes are expected from the pilot subproject: (i) capacity building in the design, implementation, O&M of the micro-grid in the distribution system; (ii) optimized operation of loads and resources, leading to cost savings on electricity supply to the customer; (iii) reduced burden on thermal dominant national grid and lower environmental impact; (iv) development of interconnection standards and operation guidelines for micro-grids to facilitate replication; (v) contribution to improved reliability and energy security to the customer; (vi) establishment of a workable business and operational model for distribution network integrated micro-grids; and (vii) scalable, educational and research supported micro-grid platform.
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10. Modalities for Replication and Sustainability
52. After the successful implementation of the pilot project, both the CEB and LECO can look in to replication of the project in the country. Capital investments for these projects can be raised either through commercial loans or through soft financing obtained from international development agencies. The utilities are allowed to absorb project investments to their capital expenditure (CAPEX), which generates 2% profit to the allowed revenue and depreciate the asset over the expected project duration. Further, the interest payback and operation and maintenance costs can be incorporated into the operational expenditure, which can be included within the annual allowed revenue calculation.
II. Reliability Improvement of the Medium Voltage Network
53. This component consists of: (i) construction of 270.5 km new 33 kV tower lines using bare conductors, and associated 13 gantries, (ii) construction of 80 km of new 33 kV aerial bundled conductor (ABC) lines in areas with special environmental constraints, and (iii) installation of 25 of 33 kV auto reclosers and 175 of 33 kV load break switches. A. Construction of New 33 kV Tower Lines using Bare Conductors and
Associated Gantries 54. Lines to be built under this subcomponent are listed in Table 13. Some of the gantries listed as new are to be built under this project, and the justification in subsequent paragraphs include the combined project of line and gantry, where relevant.
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Table 13: New 33 kV Lines to be Built
Item CEB DD
Line Starting Point End Point Line
Length (km)
1 DD1 33 kV Lynx DC line from Puttalam GS to Keeriyankeliya
Puttalam GS (Existing)
Switching gantry at Keeriyankalliya (New)
27
2 DD1 33 kV Lynx DC line from Mallawapitiya GS to Ratmalgoda
Mallawapitiya GS (Existing)
Switching gantry at Ratmalgoda (New)
16
3 DD1 33 kV Lynx DC line from Maho GS to Ma-Eliya
Maho GS (Exisiting)
Switching gantry at Ma-Eliya (New)
24
4 DD2 33 kV Lynx DC line from Wimalasurendra GS to Maskeliya
Wimalasurendra GS (Existing)
Switching gantry at Maskeliya (New)
10
5 DD2 33 kV Lynx DC line from the switching gantry at Choisy to Thawalantenna
Switching gantry at Choisy (Existing)
Switching gantry at Thawalantenna (Existing)
5
6 DD2 33 kV Lynx DC line from Kegalle GS to switching gantry at Gevilipitiya
Kegalle GS (Under construction)
Switching gantry at Gevilipitiya (Proposed)
11
7 DD2 33 kV Lynx DC line from Ampara GS to Uhana
Ampara GS (Existing)
Switching gantry at Uhana (New)
10
8 DD2 33 kV Lynx DC line from Kappalthurai to the switching gantry at 6th mile post
Kappalthurai GS (Under construction)
Switching gantry at 6
th mile post
(Existing) 15
9 DD2 33 kV Lynx DC line from Irakkandy to Kumburupitiya
Switching gantry at Irakkandy (New)
Switching gantry at Kumburupitiya (New)
6.5
10 DD3 33 kV Lynx DC line from Badulla GS to Ella and a switching Gantry at Ella
Badulla GS (Existing)
Switching gantry at Ella (New)
16
11 DD3 33 kV Lynx DC line from Mahiyanganaya GS to Bible
Mahiyanganaya GS (Existing)
Switching gantry at Bibile (New)
30
12 DD3 33 kV Lynx DC Line from Monaragala GS to Wellawaya
Monaragala GS (Existing)
Switching gantry at Wellawaya (New)
34
13 DD3 33 kV Lynx DC line from Ratnapura GS to Idangoda
Existing Ratnapura GS (Existing)
Switching gantry at Idangoda (Proposed)
19
14 DD4 33 kV Lynx DC line from Warukandeniya to Morawaka
Switching gantry at Warukandeniya (New)
Switching gantry at Morawaka (New)
18
15 DD4 33 kV Lynx DC line from switching gantry Elpitiya 11th mile post to Mattaka
Switching gantry at Elpitiya 11
th
mile post (Existing)
Switching gantry at Mattaka (New)
11
16 DD4 33kV Lynx DC line from Matara GS to switching gantry at Yakabedda
Matara GS (Existing)
Switching gantry at Yakabedda (Existing)
18
CEB = Ceylon Electricity Board, DC = double circuit, DD = Distribution Division, GS = grid substation, km = kilometer, kV = kilovolt.
55. Line 1: A new 33 kV line from Puttalam grid substation to Keeriyankalliya and a new switching gantry at Keeriyankalliya. The work includes (i) construction of a 27 km 33 kV Lynx double circuit tower line from existing Puttalam grid substation to the new two section single bus
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bar (2SSBB) gantry at Keeriyankalliya, and (ii) construction of a new 2SSBB gantry at Keeriyankalliya. 56. Project Justification: The proposed line will connect the existing medium voltage system in Keeriyankalliya area of the North Western Province (NWP) to the existing Puttalam grid substation. Load growth in the NWP is forecast to be at an average of 6.4% per year over the two year planning period 2015–2017. The electrification level of NWP as at mid-2014 was 95% and the energy loss in the medium voltage system was 1.7%. Construction of this express line provides power injection to 33 kV systems in Keeriyankalliya area that will improve reliability, line end voltages and system operation flexibility, reduce medium voltage losses, and increase line capacities. The proposed 33 kV 2SSBB switching gantry at Keeriyankalliya is required to connect the above 33 kV backbone line from Puttalam grid substationto the existing medium voltage system in the area, to improve the operational flexibility of the medium voltage system. Details of the medium and low voltage systems improved by the introduction of the new line and the gantry are given below.
33 kV Lines (km) Low Voltage lines
(km) Distribution Substations
Number of Consumers
223 880 255 50,212 57. After implementation, the peak-time voltage at the worst affected point of the medium voltage system is expected to improve to 97.7% from the current level of 92.3% in 2016, and to 97.1% in 2020. The estimated annual energy savings through loss reduction will be 1.08 gigawatt-hour (GWh) in 2016 and 1.73 GWh in 2020. Estimated annual energy flow through the new double circuit line is 19.45 GWh and 24.23 GWh in 2016 and 2020, respectively. 58. Line 2: A new 33 kV line from Mallawapitiya grid substation to Rathmalgoda and a new switching gantry at Rathmalgoda. The work includes (i) construction of a 16 km 33 kV Lynx double circuit tower line from existing Mallawapitiya grid substation to the new 2SSBB gantry at Rathmalgoda, and (ii) construction of a new 2SSBB gantry at Rathmalgoda. 59. Project Justification: The proposed line will connect the existing medium voltage system in Rathmalgoda area of the NWP to the existing Mallwapitiya grid substation. Load growth in the NWP is forecast to be at an average of 6.4% per year over the two-year planning period 2015–2017. The electrification level of NWP as at mid-2014 was 95% and the energy loss in the medium voltage system was 1.7%. Construction of this express line provides power injection to 33 kV systems in Rathmalgoda area that will improve reliability, line end voltages and system operation flexibility, reduce medium voltage losses, and increase line capacities. The proposed 33 kV 2SSBB switching gantry at Rathmalagoda is required to connect the above 33 kV backbone line from Mallawapitiya grid substationto the existing medium voltage system in the area, to improve the operational flexibility of the medium voltage system. Details of the medium and low voltage systems improved by the introduction of the new line and the gantry are given below.
33 kV Lines (km) Low Voltage lines
(km) Distribution Substations
Number of Consumers
140 866 251 59,425 60. After implementation, the peak-time voltage at the worst affected point of the medium voltage system is expected to improve to 98.8% from the current level of 96.5% in 2016 and to 98.3% in 2020. The estimated annual energy savings through loss reduction will be 0.37 GWh
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and 0.58 GWh in 2016 and 2020, respectively. Estimated annual energy flow through the new double circuit line is 5.16 GWh and 18.4 GWh in 2016 and 2020, respectively. 61. Line 3: A new 33 kV line from Maho grid substation to Ma-Eliya and a new switching gantry at Ma-Eliya. The work includes (i) construction of a 24 km 33 kV Lynx double circuit tower line from existing Maho grid substation to the new 2SSBB gantry at Ma-Eliya, and (ii) construction of a new 2SSBB gantry at Ma-Eliya. 62. Project Justification: The proposed line will connect the existing medium voltage system in Ma-Eliya area of the NWP to the existing Maho grid substation. Load growth in the NWP is forecast to be at an average of 6.4% per year over the two-year planning period 2015–2017. The electrification level of NWP as of mid-2014 was 95% and the energy loss in the medium voltage system was 1.7%. Construction of this express line provides power injection to 33 kV systems in Ma-Eliya area that will improve reliability, line end voltages and system operation flexibility, reduce medium voltage losses, and increase line capacities. The proposed 33 kV 2SSBB switching gantry at Ma-Eliya is required to connect the above 33 kV backbone line from Maho grid substation to the existing medium voltage system in the area, to improve the operational flexibility of the medium voltage system. Details of the medium and low voltage systems improved by the introduction of the new line and the gantry are given below.
33 kV Lines (km) Low Voltage lines
(km) Distribution Substations
Number of Consumers
420 1291 374 73,645 63. After implementation, the peak-time voltage at the worst affected point of the medium voltage system is expected to improve to 97.5% from the current level of 94.8% in 2016 and to 96.8% in 2020.The estimated annual energy savings through loss reduction will be 0.57 GWh and 0.9 GWh in 2016 and 2020, respectively. Estimated annual energy flow through the new double circuit line is 6.36 GWh and 7.94 GWh in 2016 and 2020, respectively. 64. Line 4: A new 33 kV line from Wimalasurendra grid substation to Maskeliya and a new switching gantry at Maskeliya. The work includes (i) construction of a 10 km 33 kV Lynx double circuit tower line from existing Wimalasurendra grid substation to the new 2SSBB gantry at Maskeliya, and (ii) construction of a new 2SSBB gantry at Maskeliya. 65. Project Justification: The proposed line will connect the existing medium voltage system in Maskeliya area of the Central Province to the existing Wimalasurendra grid substation. In the Central Province, load growth of domestic and commercial retail sector and industrial and bulk supply sector is forecast to be 6% and 4%, respectively, over the 10-year planning period 2015–2024. The electrification level in the Central Province as of end of 2014 was 98% and the energy loss in the medium voltage system was 1.9%. Construction of this express line provides power injection to 33 kV systems in Maskeliya area that will improve reliability, line end voltages and system operation flexibility, reduce medium voltage losses, and increase line capacities. The proposed 33 kV 2SSBB switching gantry at Maskeliya is required to connect the above 33 kV backbone line from Wimalasurendra grid substation to the existing medium voltage system in the area, to improve the operational flexibility of the medium voltage system. Details of the medium and low voltage systems improved by the introduction of the new line and the gantry are given below.
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33 kV Lines (km) Low Voltage lines
(km) Distribution Substations
Number of Consumers
95 235 80 17,525 66. After implementation, the peak-time voltage at the worst affected point of the medium voltage system is expected to improve to 98% from the current level of 96.5% in 2016 and to 97% in 2020. The estimated annual energy savings through loss reduction will be 0.63 GWh and 1.73 GWh in 2016 and 2020, respectively. Estimated annual energy flow through the new double circuit line is 31.06 GWh and 39.21 GWh in 2016 and 2020, respectively. 67. Line 5: A new 33 kV line from switching gantry at Choisy to switching gantry at Thawalantenna. The work includes construction of a 5 km 33 kV Lynx double circuit tower line from existing switching gantry at Choisy to existing switching gantry at Thawalantenna. 68. Project Justification: The proposed line will connect the existing medium voltage system in Thawalantenna area of the Central Province to the existing gantry at Choisy. In the Central Province, load growth of domestic and commercial retail sector and industrial and bulk supply sector is forecasted to be 6% and 4%, respectively, over the 10-year planning period 2015–2024. The electrification level of the Central Province as of the end of 2014 was 98% and the energy loss in the medium voltage system was 1.9%. Construction of this express line provides power injection to 33 kV systems in Thawalantenna area that will improve reliability, line end voltages and system operation flexibility, reduce medium voltage losses, and increase line capacities. Details of the medium and low voltage systems improved by the introduction of the new line and the gantry are given below.
33 kV Lines (km) Low Voltage lines
(km) Distribution Substations
Number of Consumers
130 395 105 24,400 69. After implementation, the peak-time voltage at the worst affected point of the medium voltage system is expected to improve to 96.9% from the current level of 94.9% in 2016 and to 96% in 2020. The estimated annual energy savings through loss reduction will be 1.24 GWh and 1.73 GWh in 2016 and 2020, respectively. Estimated annual energy flow through the new double circuit line is 16.74 GWh and 21.14 GWh in 2016 and 2020, respectively. 70. Line 6: A new 33kV line from Kegalle grid substation to switching gantry at Thawalantenna. The work includes construction of 11 km 33 kV Lynx double circuit tower line from Kegalle grid substation, which is under construction to proposed switching gantry at Gevilipitiya. 71. Project Justification: The proposed line will connect the existing medium voltage system in Gevilipitiya area of the Central Province to the Kegalle grid substation, which is under construction. In the Central Province, load growth of domestic and commercial retail sector and industrial and bulk supply sector is forecasted to be 6% and 4%, respectively, over the 10-year planning period 2015–2024. The electrification level of the Central Province as of the end of 2014 was 98% and the energy loss in the medium voltage system was 1.9%. Construction of this express line provides power injection to 33 kV systems in Gevilipitiya area that will improve reliability, line end voltages and system operation flexibility, reduce medium voltage losses, and increase line capacities. Details of the medium and low voltage systems improved by the introduction of the new line and the gantry are given below.
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33 kV Lines (km) Low Voltage lines
(km) Distribution Substations
Number of Consumers
72 350 51 19,400 72. After implementation, the peak-time voltage at the worst affected point of the medium voltage system is expected to improve to 97.6% from the current level of 96.1% in 2016 and to 96.5% in 2020. The estimated annual energy savings through loss reduction will be 0.85 GWh and 1.2 GWh in 2016 and 2020, respectively. Estimated annual energy flow through the new double circuit line is 27.32 GWh and 34.49 GWh in 2016 and 2020, respectively. 73. Line 7: A new 33 kV line from Ampara grid substation to Uhana and a new switching gantry at Uhana. The work includes (i) construction of a 10 km 33 kV Lynx double circuit tower line from existing Ampara grid substation to the new 2SSBB gantry at Uhana, and (ii) construction of a new 2SSBB gantry at Uhana. 74. Project Justification: The proposed line will connect the existing medium voltage system in Uhana area of the Eastern Province to the existing Ampara grid substation. In the Eastern Province, load growth of domestic and commercial retail sector and industrial and bulk supply sector is forecast to be 7.% and 3.7%, respectively, over the 10-year planning period 2015–2024. The electrification level of the Eastern Province as of the end of 2014 was 88% and the energy loss in the medium voltage system was 2.9%. Construction of this express line provides power injection to 33 kV systems in Uhana area that will improve reliability, line end voltages and system operation flexibility, reduce medium voltage losses, and increase line capacities. The proposed 33 kV 2SSBB switching gantry at Uhana is required to connect the above 33 kV backbone line from Ampara grid substation to the existing medium voltage system in the area, to improve the operational flexibility of the medium voltage system. Details of the medium and low voltage systems improved by the introduction of the new line and the gantry are given below.
33 kV Lines (km) Low Voltage lines
(km) Distribution Substations
Number of Consumers
264 118 14,600 75. After implementation, the peak-time voltage at the worst affected point of the medium voltage system is expected to improve to 95% from the current level of 90.5% in 2016 and to 92% in 2020. The estimated annual energy savings through loss reduction will be 0.23 GWh and 1.1 GWh in 2016 and 2020, respectively. Estimated annual energy flow through the new double circuit line is 19.54 GWh and 26.87 GWh in 2016 and 2020, respectively. 76. Line 8 and Line 9: A new 33kV line from Kapplthurai grid substation to switching gantry at 6th mile post and a new 33 kV line from switching gantry at Irakkandy to switching gantry at Kumburupitiya. The work includes (i) construction of a 15 km 33 kV Lynx double circuit tower line from Kapplthurai grid substation, which is under construction to the existing switching gantry at 6th mile post; (ii) construction of a 6.5 km 33 kV Lynx double circuit tower line from new switching gantry at Irakkandy to new switching gantry at Kumburupitiya; (iii) construction of a new 2SSBB gantry at Irakkandy; and (iv) construction of a new 2SSBB gantry at Kumburupitiya. 77. Project Justification: These proposed two lines will connect the existing medium voltage system in Nilaveli area of the Eastern Province to the Kappalthurai grid substation, which is under construction. In the Eastern Province load growth of domestic and commercial retail sector and industrial and bulk supply sector is forecast to be 7% and 3.7%, respectively,
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over the 10-year planning period 2015–2024. The electrification level of the Eastern Province as of the end of 2014 was 88% and the energy loss in the medium voltage system was 2.9%. Construction of these express lines provides power injection to 33 kV systems in Nilaveli area that will improve reliability, line end voltages and system operation flexibility, reduce medium voltage losses, and increase line capacities. The proposed 33kV 2SSBB switching gantries at Irakkandy and Kumburupitiya are required to connect the above 33 kV backbone lines to the existing medium voltage systems in the two areas, to improve the operational flexibility of the medium voltage systems. From switching gantry at 6th mile post to switching gantry at Irakkandy energy will flow through existing 33kV double circuit tower lines. Details of the medium and low voltage systems improved by the introduction of the new lines and the gantries are given below:
33 kV Lines (km) Low Voltage lines
(km) Distribution
Substations (Nos) Number of Consumers
282 - 155 15586 78. Load flow study output drawings of the medium voltage system without and with the proposed project in 2016 and 2020 are given in Annex 1. After implementation, the peak-time voltage at the worst affected point of the medium voltage system is expected to improve to 97.3% from the current level of 83% in 2016 and to 96% in 2020. The estimated annual energy savings through loss reduction will be 6.04 GWh and 0.61 GWh in 2016 and 2020, respectively. Estimated annual Energy Flow through the new double circuit line is 17.91 GWh and 22.55 GWh in 2016 and 2020, respectively. 79. In connection with lines 8 and 9, which feeds the medium voltage systems off Kappalthurai grid substation, CEB has received a request for additional 30 MW supply to a Board of Investment (BOI) hotel project in Kumburupitiya area. A load flow analysis has been done with line 8 and 9 together feeding the entire system, including anticipated demand due to the BOI hotel project. It is observed that even with the two lines voltage at worst affected point in 2016 is 92% and in 2020 the voltage will go down further to 90.3%, indicating a need for major supply injection in this area. CEB is proposing a grid substation (2×31.5 MVA) at Kumburupitiya to be commissioned in 2017 if the proposed load requirement is confirmed by BOI. 80. Line 10: A new 33 kV line from Badulla grid substation to Ella and a new switching gantry at Ella. The work includes (i) construction of a 16 km 33 kV Lynx double circuit tower line from existing Badulla grid substation to the new 2SSBB gantry at Ella, and (ii) construction of a new 2SSBB gantry at Ella. 81. Project Justification: The proposed line will connect the existing medium voltage system in Ella area of the Uva Province (Uva) to the existing Badulla grid substation. In Uva, load growth of domestic and commercial retail sector and industrial and bulk supply sector is forecast to be 8.2% and 3%, respectively, over the 10-year planning period 2015–2024. The electrification level of Uva as of mid-2014 was 95% and the energy loss in the medium voltage system was 2.6%. Construction of this express line provides power injection to 33 kV systems in Ella area that will improve reliability, line end voltages and system operation flexibility, reduce medium voltage losses, and increase line capacities. The proposed 33 kV 2SSBB switching gantry at Ella is required to connect the above 33 kV backbone line from Badulla grid substation to the existing medium voltage system in the area, to improve the operational flexibility of the medium voltage system. Details of the medium and low voltage systems improved by the introduction of the new line and the gantry are given below.
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33 kV Lines (km) Low Voltage lines
(km) Distribution Substations
Number of Consumers
327.7 1,323 199 41,658 82. After implementation, the peak-time voltage at the worst affected point of the medium voltage system is expected to improve to 94.7% from the current level of 93.3% in 2016 and to 93.1% in 2020. The estimated annual energy savings through loss reduction will be 0.54 GWh and 0.91 GWh in 2016 and 2020, respectively. Estimated annual energy flow through the new double circuit line is 19.09 GWh and 24.54 GWh in 2016 and 2020, respectively. 83. Line 11: A new 33kV line from Mahiyangana grid substation to Bibile and a new switching gantry at Bibile. The work includes (i) construction of a 30 km 33 kV Lynx double circuit tower line from existing Mahiyangana grid substation to the new 2SSBB gantry at Bibile, and (ii) construction of a new 2SSBB gantry at Bibile. 84. Project Justification: The proposed line will connect the existing medium voltage system in Bibile area of the Uva Province (Uva) to the existing Mahiyangana grid substation. In Uva, load growth of domestic and commercial retail sector and industrial and bulk supply sector is forecasted to be 8.2% and 3%, respectively, over the 10-year planning period 2015–2024. The electrification level of Uva as of mid-2014 was 95% and the energy loss in the medium voltage system was 2.6%. Construction of this express line provides power injection to 33kV systems in Bibile area that will improve reliability, line end voltages and system operation flexibility, reduce medium voltage losses, and increase line capacities. The proposed 33 kV 2SSBB switching gantry at Bibile is required to connect the above 33kV backbone line from Mahiyangana grid substation to the existing medium voltage system in the area, to improve the operational flexibility of the medium voltage system. Details of the medium and low voltage systems improved by the introduction of the new line and the gantry are given below.
33 kV Lines (km) Low Voltage lines
(km) Distribution Substations
Number of Consumers
491.9 1,343 202 42,286 85. After implementation, the peak-time voltage at the worst affected point of the medium voltage system is expected to improve to 97.4% from the current level of 95.7% in 2016 and to 96.8% in 2020. The estimated annual energy savings through loss reduction will be 0.10 GWh and 0.10 GWh in 2016 and 2020, respectively. Estimated annual energy flow through the new double circuit line is 17.60 GWh and 22.97 GWh in 2016 and 2020, respectively. 86. Line 12: A new 33 kV line from Monaragala grid substation to Wellawaya and a new switching gantry at Wellawaya. The work includes (i) construction of a 34 km 33 kV Lynx double circuit tower line from existing Monaragala grid substation to the new 2SSBB gantry at Wellawaya, and (ii) construction of a new 2SSBB gantry at Wellawaya. 87. Project Justification: The proposed line will connect the existing medium voltage system in Wellawaya area of the Uva Province (Uva) to the existing Monaragala grid substation. In Uva, load growth of domestic and commercial retail sector and industrial and bulk supply sector is forecasted to be 8.2% and 3.0%, respectively, over the 10-year planning period 2015–2024. The electrification level of Uva as at mid-2014 was 95% and the energy loss in the medium voltage system was 2.6%. Construction of this express line provides power injection to 33 kV systems in Wellawaya area that will improve reliability, line end voltages and system
29
operation flexibility, reduce medium voltage losses, and increase line capacities. The proposed 33 kV 2SSBB switching gantry at Wellawaya is required to connect the above 33 kV backbone line from Monaragala grid substation to the existing medium voltage system in the area, to improve the operational flexibility of the medium voltage system. Details of the medium and low voltage systems improved by the introduction of the new line and the gantry are given below.
33 kV Lines (km) Low Voltage lines
(km) Distribution Substations
Number of Consumers
569.9 1,297 195 40,820 88. After implementation, the peak-time voltage at the worst affected point of the medium voltage system is expected to improve to 96.5% from the current level of 91.8% in 2016 and to 95.3% in 2020. The estimated annual energy savings through loss reduction will be 0.54 GWh and 0.91 GWh in 2016 and 2020, respectively. Estimated annual energy flow through the new double circuit line is 22.67 GWh and 29.12 GWh in 2016 and 2020, respectively. 89. Line 13: A new 33 kV line from Ratnapura grid substation to Idangoda. The work includes construction of a 19 km 33 kV Lynx double circuit tower line from existing Ratnapura grid substation to proposed switching gantry at Idangoda. 90. Project Justification: The proposed line will connect the existing medium voltage system in Idangoda area of the Sabaragamuva Province (Sabaragamuva) to the existing Ratnapura grid substation. In Sabaragamuva, load growth of domestic and commercial retail sector and industrial and bulk supply sector is forecasted to be 7.1% and 3.5%, respectively, over the 10-year planning period 2015–2024. The electrification level of Sabaragamuva as of mid-2014 was 99% and the energy loss in the medium voltage system was 1.3%. Construction of this express line provides power injection to 33 kV systems in Idangoda area that will improve reliability, line end voltages and system operation flexibility, reduce medium voltage losses, and increase line capacities. Details of the medium and low voltage systems improved by the introduction of the new double circuit line and the gantry are given below.
33 kV Lines (km)
Low Voltage lines (km)
Distribution Substations
Number of Consumers
253.2 804 104 26,500 91. After implementation, the peak-time voltage at the worst affected point of the medium voltage system is expected to improve to 97% from the current level of 93.86% in 2016 and to 96.4% in 2020. The estimated annual energy savings through loss reduction will be 0.12 GWh and 0.17 GWh in 2016 and 2020, respectively. Estimated annual energy flow through the new double circuit line is 16.78 GWh and 20.40 GWh in 2016 and 2020, respectively. 92. Line 14: A new 33 kV line from switching gantry at Warukandeniya to switching gantry at Morawaka. The work includes (i) construction of a 18 km 33 kV Lynx double circuit tower line from new switching gantry at Warukandeniya to new switching gantry at Morawaka, (ii) construction of a new 2SSBB gantry at Warukandeniya, and (iii) construction of a new 2SSBB gantry at Morawaka. 93. Project Justification: The proposed line will connect the existing medium voltage systems in Warukandeniya and Morawaka of the Southern Province. In the Southern Province, load growth of domestic and commercial retail sector and industrial and bulk supply sector is forecasted to be 8.1% and 3.3%, respectively, over the 10-year planning period 2015–2024.
30
The electrification level of Southern Province as of the end of 2013 was 99.5% and the energy loss in the medium voltage system was 1.66%. Construction of this express line provides power injection to 33 kV systems in Warukandeniya area that will improve reliability, line end voltages and system operation flexibility, reduce medium voltage losses, and increase line capacities. The proposed 33 kV 2SSBB switching gantries at Warukandneiya and Morawaka are required to connect the above 33 kV backbone line to the existing medium voltage systems in the two areas, to improve the operational flexibility of the medium voltage system. Details of the medium and low voltage systems improved by the introduction of the new line and the gantry are below.
33 kV Lines (km) Low Voltage lines
(km) Distribution Substations
Number of Consumers
181 695 107 20,541 94. After implementation, the peak-time voltage at the worst affected point of the medium voltage system is expected to improve to 95% from the current level of 94.4% in 2016 and to 93.7% in 2020. The estimated annual energy savings through loss reduction will be 0.49 GWh and 0.73 GWh in 2016 and 2020, respectively. Estimated annual energy flow through the new double circuit line is 123 GWh and 153.27 GWh in 2016 and 2020, respectively. 95. Line 15: A new 33 kV line from switching gantry at Elpitiya 11th mile post to a new switching gantry at Mattaka. The work includes (i) construction of a 11 km 33 kV Lynx double circuit tower line from proposed switching gantry at Elpitiya 11th mile post to the new 2SSBB gantry at Mattaka, and (ii) construction of the new 2SSBB gantry at Mattaka. 96. Project Justification: The proposed line will connect the existing medium voltage system in Mattaka and Elpitiya areas of the Southern Province. In Southern Province, load growth of domestic and commercial retail sector and industrial and bulk supply sector is forecasted to be 8.1% and 3.3%, respectively, over the 10-year planning period 2015–2024. The electrification level of Southern Province as of the end of 2013 was 99.5% and the energy loss in the medium voltage system was 1.66%. Construction of this express line provides power injection to 33 kV systems in Mattaka area that will improve reliability, line end voltages and system operation flexibility, reduce medium voltage losses, and increase line capacities. The proposed 33 kV 2SSBB switching gantry at Mattaka is required to connect the above 33 kV backbone line from Elpitiya 11th mile post to the existing medium voltage system in the area, to improve the operational flexibility of the medium voltage system. Details of the medium and low voltage systems improved by the introduction of the new line and the gantry are given below.
33 kV Lines (km) Low Voltage lines
(km) Distribution Substations
Number of Consumers
156 364 56 12,840 97. After implementation, the peak-time voltage at the worst affected point of the medium voltage system is expected to improve to 96.2% from the current level of 94.5% in 2016 and to 95.4% in 2020. The estimated annual energy savings through loss reduction will be 3.08 GWh and 4.20 GWh in 2016 and 2020, respectively. Estimated annual energy flow through the new double circuit line is 176.35 GWh and 213.77 GWh in 2016 and 2020, respectively. 98. Line 16: A new 33 kV line from Matara grid substation to Yakabedda. The work includes construction of 18 km 33 kV Lynx double circuit tower line from existing Matara grid substation to existing switching gantry at Yakabedda.
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99. Project Justification: The proposed line will connect the existing medium voltage system in Yakabedda area of the Southern Province to existing Matara grid substation. In Southern Province, load growth of domestic and commercial retail sector and industrial and bulk supply sector is forecasted to be 8.1% and 3.3%, respectively, over the 10-year planning period 2015–2024. The electrification level of Southern Province as of the end of 2013 was 99.5% and the energy loss in the medium voltage system was 1.66%. Construction of this express line provides power injection to 33 kV systems in Yakabedda area that will improve reliability, line end voltages and system operation flexibility, reduce medium voltage losses, and increase line capacities. Details of the medium and low voltage systems improved by the introduction of the new double circuit line and the gantry are given below.
33 kV Lines (km) Low Voltage lines
(km) Distribution Substations
Number of Consumers
180 903.5 139 33,783 100. After implementation, the peak-time voltage at the worst affected point of the medium voltage system is expected to improve to 97.2% from the current level of 93.4% in 2016 and to 96.5% in 2020. The estimated annual energy savings through loss reduction will be 1.10 GWh and 1.46 GWh in 2016 and 2020, respectively. Estimated annual energy flow through the new double circuit line is 271.08 GWh and 329.93 GWh in 2016 and 2020, respectively. B. Construction of new 33 kV Aerial Bundled Conductor (ABC) Lines 101. Proposed 33kV ABC lines will help to eliminate frequent failures that occur due to heavy salt accumulation on bare conductor lines in coastal areas. Further, insulated ABC lines, which require minimum clearance of existing vegetation, are proposed as a more economical solution, for locations where there are difficulties in maintaining clearances for overhead bare-conductor lines in populated areas. 102. Construction of 35 km of 33 kV ABC lines is proposed in Distribution Division 1 to eliminate failures due to salt contamination. Construction of 30 km and 15 km of ABC lines are proposed in Distribution Division 3 and Distribution Division 4, respectively, for locations where statutory minimum clearances could not be maintained due to obstructions to existing lines. Details of the ABC lines to be constructed are given in Table 14.
Table 14: Details of New ABC Lines
CEB DD
Province Proposal Length
(km)
DD1 NWP Norachcholai GS to Kalpitiya PS 20.0 NP Mannar GS to Sunny Village PS 15.0
DD3
Uvaa Badulla Town Feeder 4.0 Uva From 4 Pole gantry to Welimada Town 5.0 Uva From Welimada Gantry to Welimada Town 3.0
WPS Several locations in Avissawella, Bandaragama and Horana areas
8.0
Sabb Deraniyagala Miyanawita Kosgahakanda 10.0
DD4
WPS New Lynx feeder from Panadura GS to Pallimulla PS and new switching arrangement
5.2
WPS New Lynx feeder to proposed PSS at Mt. Lavania bus station from Maliban Junction
1.8
WPS 5MVA New Transformer at Galvihara Road close to the Zoo 0.6
32
CEB DD
Province Proposal Length
(km)
WPS Replacing road crossing 33 kV OH lines in urban areas 2.0
WPS Replacing 33 kV OH lines with ABC lines which doesn't have safety clearances
2.0
WPS Interconnection lines between Panadura GS Feeder 5 & 3 0.4 SP Galle GS to Holcim RCW 1.0 SP Tangalle Bay Hotel to Sams Lanka Ice Factory 0.6 SP Dickwella New Rd to Dickwella Town 0.5 SP Hambanthota Oil bunkering facility line 1.0
ABC = aerial bundled conductor, CEB = Ceylon Electricity Board, DD = Distribution Division, GS = grid substation, km = kilometer, kV = kilovolt, MVA = megavolt-ampere, NP = Northern Province, NWP = North Western Province OH = overhead , PS = power station, PSS = power substation RCW = Ruhunu Cement Works, SP = Southern Province, WPS = Western Province South. a
Uva Province b
Sabaragamuva Province
C. Installation of 33 kV Auto Reclosers and 33 kV Load Break Switches 103. For distribution system operation coordination, 33 kV auto reclosers and load break switches, with remote control facilities, are proposed to be installed in the 33 kV network in order to provide efficient fault isolation and restoration, and improve operational flexibility of the system. The auto reclosers will provide automatic fault detection and restoration on transient faults and isolation of permanent faults, covering a large area of the network. The load break switches are proposed to be installed at locations to isolate smaller sections of the system under fault conditions limiting the number of consumers affected. Number of the auto reclosers and load break switches proposed to be installed in the CEB distribution divisions are given in Table 15. Location of each auto recloser and load break switch are given in Annex 2 and Annex 3 respectively.
Table 15: Proposed Number of Auto Reclosers and Load Break Switches
Distribution Division Auto Reclosers Load Break Switches
DD1 7 40 DD2 7 65 DD3 6 40 DD4 5 30 Total 25 175
DD = Distribution Division. Source: Ceylon Electricity Board estimates.
III. Rural Electrification and Distribution Performance Monitoring 104. The component has two main purposes: (i) expansion of the distribution network in rural areas, and (ii) installation of meters at distribution transformers to monitor performance of the low voltage network.
A. Expansion of the Distribution Network in Rural Areas 105. Unavailability of the national grid in the far away villages is one of the major reasons for the low electrification level in certain locations, and the high cost of the grid extensions had been the main barrier to supply electricity to such locations. Under this project, 106 rural electrification schemes including 198 km of medium voltage lines and 406 km of low voltage
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lines are proposed to be implemented, as summarized in Table 16. The project includes low voltage line extensions as given in Table 17. There will be around 35,700 customers of the rural electrification schemes and extensions among which, the majority (99%) would be household consumers.
Table 16: Summary of Rural Electrification Schemes
CEB DD
No of RE Schemes
Line Length (km)
No of customers HT
LT (Fly)a
LT (ABC)
1p>3p
CR (ABC)
Total LT Line
length
DD1 19 47.33 0.00 111.71 0.29 1.25 113.25 1,650
DD2 61 83.34 0.00 161.92 2.55 30.46 194.93 3,228
DD3 24 64.80 0.00 83.92 0.00 7.10 91.02 795
DD4 02 2.70 0.30 6.92 0.00 0.00 7.22 32
Total 106 198.17 0.30 364.47 2.84 38.81 406.42 5,705 ABC = aerial bundled conductor, CEB =Ceylon Electricity Board, CR = Conductor Replacement, DD = Distribution Division, HT = high tension, km = kilometer, LT = low tension, p = phase, RE = rural electrification. a
Fly is aluminium bare conductor type.
Source: Ceylon Electricity Board estimates.
Table 17: Summary of Low Voltage Extensions
CEB DD
Line Length (km) Total Line Length
(km)
Number of Customers LT (Fly)
a LT
(ABC) 1p>3p 2p>3p
CR (ABC)
DD1 0 996.37 72.91 0.00 3.56 1,072.84 13,384
DD2 0 654.42 56.97 1.49 16.80 729.68 10,609
DD3 12 38.98 0.15 0.00 0.00 51.13 1,093
DD4 0 120.00 0.00 0.00 0.00 120.00 4,919
Total 12 1,809.77 130.02 1.49 20.36 1,973.64 30,005 ABC = aerial bundled conductor, CEB =Ceylon Electricity Board, CR = Conductor Replacement, DD = Distribution Division, HT = high tension, km = kilometer, LV = low voltage, LT = low tension, p = phase . a
Fly is aluminium bare conductor type.
Source: Ceylon Electricity Board estimates.
106. A typical new rural electrification scheme to be built under the project consists of (i) extension of an existing 33 kV line or building a new spur line off an existing 33kV line, (ii) installation of a 33 kV/400 V, 100 kVA 3-phase transformer, and (iii) drawing 400 V 3-phase distribution feeder lines in at least two directions from the transformer, to reach potential customers. Maximum number of feeders from a transformer will be five. Initial demand from these transformers is in the range of 10-15 kVA. All the 33 kV/400 V, 100 kVA 3-phase transformers of the rural electrification schemes will be bought by CEB in a separate mechanism and hence do not fall under this project. 107. Allowed maximum length of a feeder from a CEB distribution transformer is 1.8 km. Average length of a feeder of the proposed rural electrification schemes is 1.2 km. This will ensure that the voltage level at the end of the feeder will be within the allowed range. Majority of the customers, who will be supplied electricity in these schemes, falls to domestic tariff category.
34
B. Installation of Meters at Distribution Transformers to Monitor Performance 108. Metering and monitoring of distribution performance would fulfil the objective of the project as CEB will be able to monitor and report medium voltage and low voltage system performance separately, leading to improved reliability. 109. With Sri Lanka covering about 98% households, the focus is on (i) reliability improvement, (ii) energy efficiency, and (iii) reporting performance to the regulator. Energy losses in the CEB distribution divisions in the year 2014 are given in Table 18. Segregation of medium voltage and low voltage losses in distribution systems is not possible yet.
Table 18: Energy Loss in Distribution Divisions (2014)
Licensee Loss
% Allowed Loss %
Loss (GWh)
DD1 9.4 8.3 366.4 DD2 9.4 10.4 395.8 DD3 7.1 8.3 155.8 DD4 9.4 9.2 175.2
LECO 4.2 5.2 55.2 DD = Distribution Division, GWh = gigawatt-hour, LECO = Lanka Electricity Company Limited.
Source: Ceylon Electricity Board and Lanka Electricity Company Limited estimates.
110. Present Distribution System Control position in the CEB: Setting up of Distribution Control Centres (DCC), at the Provincial offices of CEB, to direct system operations and monitor system performance, and issue regular monthly reports, are at different stages of development. Except for a few provinces, CEB is not in the position to report its distribution licensee performance indicators to Public Utilities Comission of Sri Lanka (PUCSL). Distribution licensee performance regulations are not issued as yet by PUCSL. Draft performance regulations have been developed for PUCSL in 2011 under ADB TA 7265-SRI.4 Summary reliability indices System Average Interruption Duration Index (SAIDI) and System Average Interruption Frequency Index (SAIFI) details of distribution systems, present level of development of DCCs are given in Annex 4 .These performance indices indicate a need for investments in the medium voltage systems and a need to reduce interruptions in low voltage systems. 111. By installing programmable meters with remote reading and communicating facilities at distribution substations, it will be possible to achieve the following to monitor, improve and report on system performance expeditiously: (i) all distribution substations could be connected to DCC distribution automation systems and monitored online, facilitating distribution system performance reporting; (ii) substation wise loss calculation (energy auditing) is facilitated; (iii) substations with high losses are easily identified for concentrated low voltage loss reduction activities with responsibilities assigned; (iv) segregation of medium voltage and low voltage energy losses is facilitated with added advantage of energy costing at different levels of supply system; (v) overloaded transformers could be easily identified avoiding transformer failures due to overloading; (vi) losses due to load un-balance could be identified, to take corrective action; (vii) substation load profiles could be developed online, from which load profile of a Distribution Division can be developed; (viii) for distribution planning studies, coincident substation data collection would be possible, with the added advantage of finalising reports expeditiously; (ix)
4 ADB. 2009. Capacity Development for Power Sector Regulation. Manila (TA7265-SRI).
35
triggering alarms at DCC in the event of loss of supply, or drop in load below set thresholds; and (x) contribution of Non-conventional renewable energy and distributed generation can be monitored online. 112. According to CEB, the number of distribution substations in all four DDs in 2014 was 24,283. It is proposed to install 25,000 programmable low voltage, Current Transformers connected, meters with remote reading and communicating facilities at distribution substations, covering all four DDs. Typical connection scheme together with communication links to DCC is shown in Figure 14. Allocation of new meters to DDs is given in Table 19.
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Figure 14: Integrating Distribution Substation Energy Meters to SCADA at CEB Distribution Control Centre
SCADA host at Distribution Control Centre
Other smart grid devices (auto reclosers, load break switches, fault path indicators, etc.)
CP
CP
CP
Cellular Network
Communication Protocol (CP)
Energy Meter
Distribution Transformer
37
Table 19: Allocation of New Meters to Distribution Divisions
CEB Distribution
Division
Number of 33 kV/ 400 V
substations
Number of 11 kV/ 400 V
substations
Number of total substations
Allocation of new meters
DD1 6,803 2,388 9,191 9,460 DD2 5,799 551 6,350 6,540 DD3 5,352 53 5,405 5,560 DD4 2,866 471 3,337 3,440 Total 20,820 3,463 24,283 25,000
CEB = Ceylon Electricity Board, DD = Distribution Division, kV = kilovolt, V = volt. Source: Ceylon Electricity Board estimates.
IV. Reactive Power Management in the Transmission System 113. The Long Term Transmission Development (LTTDP) study conducted by CEB recommends several transmission development proposals to be implemented to strengthen the transmission network of the country. These include the development of new transmission lines and grid substations augmentation of existing grid substations, and the addition of special equipment to improve the quality of service delivery, efficiency and reliability of the system. 114. In addition to active power that converts electrical energy to another useful form of energy, reactive power is also required to establish and maintain the magnetic fields in electrical equipment and appliances used by customers. Additionally, transmission and distribution lines as well as transformers require reactive power for their operations. Such reactive power requirements may either be supplied from power generating plants, or supplied from capacitors fixed at various locations in the system. To improve the provision of reactive power closer to the load centers in the Western Province, and to improve reliability of the transmission system in the event of disturbances in the transmission system, respectively, CEB proposes the following:
(i) Installation of 100 megavolt-ampere reactive (Mvar) breaker-switched capacitors (BSC) at the 132 kV bus bar of the existing Pannipitiya grid substation (including a new 132 kV BSC bay), to control the voltage of the 220 kV bus bar; and
(ii) Installation of a +100/-50 Mvar static var compensator (SVC) at the 220 kV bus bar
of the existing Biyagama grid substation (including a new 220 kV SVC bay), to control the voltage of the 220 kV bus bar during dynamic conditions.
115. Breaker switched capacitors primarily assist in improving the voltage profile in an electric power system, which helps maintain the quality of supply to customers. Further, when reactive power is generated at points of use, current flows in transmission lines reduce and thereby, energy loses are reduced. Sri Lanka’s transmission voltages are 220 kV and 132 kV, and the operating voltage range specified is ±5% and ±10%, respectively. If the transmission plan of CEB is implemented without the installation of the BSC proposed to be installed at the Pannipitiya grid substation, the system performance and voltages would be as shown in Table 20.
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Table 20: Power Losses and Voltage Criteria Violations in 2020
Demand and Dispatch Scenario (Year 2020)
Power Loss
Voltage Criteria Violations without the proposed BSC at
Pannipitiya GS
Without BSC
Real Power (MW)
Reactive Power (MVAr)
Thermal Maximum Night Peak (TMNP) 58.21 938.37 Nil
Thermal Maximum Day Peak(TMDP) 54.37 839.19 Nil
Hydro Maximum Night Peak (HMNP) 79.6 1074.89 BUSES WITH VOLTAGE LESS THAN 0.9500: BUS# X-- NAME --X BASKV V(PU) V(kV) 2300 KELAN-2 220.00 0.9373 206.21 2305 KERAWALA_2 220.00 0.9394 206.66 2350 COL-L-2 220.00 0.9352 205.75 2355 PORT CITY-2 220.00 0.9352 205.74 2560 PANNI-2 220.00 0.9415 207.13 2570 BIYAG-2 220.00 0.9424 207.32 2580 KOTUG-2 220.00 0.9447 207.83
Hydro Maximum Day Peak(HMDP) 59.85 823.86 BUSES WITH VOLTAGE LESS THAN 0.9500: BUS# X-- NAME --X BASKV V(PU) V(kV) 2300 KELAN-2 220.00 0.9479 208.54 2305 KERAWALA_2 220.00 0.9500 208.99 2350 COL-L-2 220.00 0.9458 208.08 2355 PORT CITY-2 220.00 0.9458 208.07
Hydro Maximum Off Peak(HMOP) 17.49 239.5 Nil
Thermal Maximum Off Peak(TMOP) 27.27 334.53 Nil
BSC = breaker switched capacitors, GS = grid substation, kV = kilovolt, MW = megawatt, MVAr = megavolt-ampere reactive. Source: Ceylon Electricity Board estimates.
116. When the Pannipitiya BSC is installed, CEB studies show that the system losses decrease, while all the voltage criteria violations are contained within the stipulated levels. The reduction in power losses is given in Table 21. Accordingly, the voltage violations are resolved, and there would be power savings, which would in turn save energy lost in the system.
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Table 21: Reduction in power losses with the installation of the BSC at Pannipitiya GS
(2020)
Demand and Dispatch Scenario (Year 2020)
Power Loss
Without BSC With BSC
Real Power (MW)
Reactive Power (MVAr)
Real Power (MW)
Reactive Power (MVAr)
Saving in Real
Power (MW)
Thermal Maximum Night Peak (TMNP)
58.21 938.37 56.95 918.43 1.26
Thermal Maximum Day Peak(TMDP)
54.37 839.19 52.85 816.12 1.52
Hydro Maximum Night Peak (HMNP)
79.6 1074.89 76.25 1031.66 3.35
Hydro Maximum Day Peak(HMDP) 59.85 823.86 56.66 782.31 3.19 Hydro Maximum Off Peak(HMOP) 17.49 239.5 17.49 239.5 0 Thermal Maximum Off Peak(TMOP)
27.27 334.53 27.13 333.3 0.14
BSC = breaker switched capacitors, GS = grid substation, MW = megawatt, MVAr = megavolt-ampere reactive. Source: Ceylon Electricity Board estimates.
117. SVCs are used in system transient conditions. Reactive power requirements of customer loads, system components and transmission lines, are generally provided by generators and BSCs, if any, during normal operations. Under emergency conditions, the system voltage may swing in a wide range, and capacity limitations and limited response times of generators and BSCs would require other fast acting compensators to manage the voltage in the system. Such dynamic voltage management can be achieved either through injection or removal of reactive power from the system. SVCs have the capability to provide reactive power or remove reactive power from the system. Through a process of scenario analysis, CEB has derived the capacity requirements for capacity and inductive reactive power requirements, to improve dynamic voltage variations at the Biyagama grid substation, to be 100 Mvar and 50 Mvar, respectively.
40 Annex 1
List of Auto Reclosers
CEB DD
Province Location Quantity
DD1
NWP Between PU-P-054 & PU-P-840 1 NWP Anamaduwa Gantry, Nikaweratiya Feeder 1 NWP Anamaduwa Gantry, Puttalam Feeder 1 NWP Between PU-B-06 & D-1925 1 NWP Galgamuwa Gantry, Thambuttegama Feeder 1 NWP Galgamuwa Gantry, Nanneriya Feeder 1 NWP Galgamuwa Gantry, Diwulgane Feeder 1
DD2
WPN New at SR Steela (DP03) tapping 1 WPN Replace DDLO near Arangalakanda Boundary Meter 1 WPN Replace ABS at Haddamulla 1 WPN New near Hanwella Bridge 1
WPN New at Kadawatha Town for the spur line to Mankada Road
1
CP New near Brooke side 1 CP Replace ABS at Summera Hill 1
DD3
WPSII Nawagamuwa Junction towards Hanwella 1 WPSII IT Park Gantry 1 Sab b Godakawela 1 Sab Madampe 1 Uva c Kelburne, Balangoda F7 1 Uva Neluwa, Badulla F4 1
DD4 WPS I
At Agalawatta new 33 kV Lynx feeder from Mathugama GS to Agalawatta
2
WPS I New Lynx Line from Kithulgoda gantry to Lathpadura. 2 SP At Lunugamwehera (To Katharagama Line) 1
ABS = air break switch, CEB = Ceylon Electricity Board, CP = Central Province, DD = Distribution Division, DDLO = drop down lift off, GS = grid substation, IT = information technology, kV = kilovolt, NWP = North Western Province, WPN = Western Province North, WPS = Western Province South, SP = Southern Province. a
SR Steel is the name of the steel company b Sabaragamuva Province
c Uva Province
Annex 2 41
List of load break switches
CEB DD
Province Location Quantity
DD1
NP Puthukudiyiruppu 1 NP Vattapalai 1 NP Mullaithivu 1 NP Depot Junction 1 NP Uyilankulam 1 NP Mahakachikodiya 1
NWP D-950 1 NWP Between WN-B-24 & WN-B-393 1 NWP CH-B-46 (Hatharaman Handiya) 1 NWP Kalaoya Boundary Meter 1 NWP PU-B-08 1 NWP PU-B-22 1 NWP Between D-1424 & PU-B-28 1 NWP Between WP-G-111 & WP-B-38 1 NWP WP-B-22 1 NWP WP-B-10 1 NWP KR-B-33, Wehera Gantry 1 NWP KR-B-34, Wehera Gantry 1 NWP KR-B-73 1 NWP Between KR-L-62 & KR-G-027 1 NWP KR-B-59, Kawisigamuwa Gantry 1 NWP NA-B-24 1 NWP NA-B-26 1 NWP NA-B-27, Alawwa Gantry 1 NWP NA-B-28, Alawwa Gantry 1
DD2
WPN Replace ABS at Hapuwalana 1 WPN Replace DDLO near P070 S/S 1 WPN New between P107 S/S & P076 S/S for spur line 1 WPN New before P046 S/S 1 WPN New before SR Steel Tapping 1
WPN Replace DDLO near C018 S/S for spur line along Negombo Giriulla Road
1
WPN New for Badalgama Junction to Pannala F06 spur line
1
WPN New near C041 S/S for spur line along Negombo to Aluthepola Road
1
WPN Replace DDLO near P012 S/S for spur line along Negombo to Meerigama road
1
WPN Replace ABS near B008 S/S 1 CP Replace DDLO near Ranwala Ayurweda Hospital 1 CP Replace DDLO at Horagasmankada 1 CP Rplace DDLO at Yakulla Walgama 1 CP Replace ABS at Moragoda B/B Line at Mawanella Gantry 1
CP Replace ABS at Kiribathkumbura H14 B/B at Mawanella Gantry
1
CP Replace DDLO at Deewala Ahasliyadda 1 CP Replace DDLO at Kambi Adiya - Kaikawela 1 CP Replace DDLO at imbulandanda 1 CP Replace DDLO at Slaught House 1 CP Replace DDLO at Mandandawela Gantry 1 CP New LBS at Mandandawela to Aluvihare line 1
CP New LBS at Palapathwela to Mathale line 1 CP Replace DDLO at Nagala 1 CP Replace DDLO at Karagastenna 1 CP New LBS between Kambiadiaya & Thibbotukanatta S/S 1
DD3
WPSII Oruwala 1 WPSII Pittugala junction 1 WPSII Habanhenawatta DDLO 1 WPSII Depanama Havi Sectionalizer 1
42 Annex 1
CEB DD
Province Location Quantity
WPSII Watareka Somarathne Mawatha 1 WPSII Gamanayaka tapping point 1 WPSII Olaboduwa 1 WPSII Installation of LBS at old ABS Horana area 1 WPSII At Arangala junction on Athurugiriya F6 1 WPSII Nearby Highway crossing at Isurupura 1
Sabaragamuwa Middeniya Boundary Meter 1 Sabaragamuwa Kepock (Balangoda) 1 Sabaragamuwa Delgashandiya 1 Sabaragamuwa Thibolketiya (Udawalawa Feeder 1) 1 Sabaragamuwa Bopeththa Spur line 1 Sabaragamuwa Egoda Nivithigala 1 Sabaragamuwa Wewalkandura 1
Uvaa Badulla town (DM Office) Badulla F1 1
Uva Karametiya Badulla F6 1 Uva Dunuwangiya Badulla F1 1 Uva Vineethagam SP Badulla F5 1 Uva Poojanagaraya Mahiyangana F2 1 Uva Kahagolla Balangoda F7 1 Uva Ettampitiya Badulla F4 1 Uva Haggala (Boundary) Nuwaraeliya F2 1
DD4
WPS1 New 33kV Lynx D/C line from Mathugama GS to Beruwala PS and Payagala PS
3
WPS1 New 33 kV Lynx feeder from Kukuleganga Power Station 1
WPS1 New 33 kV Lynx feeder from Mathugama GS to Agalawatta 1 WPS1 New Lynx Line from Kithulgoda gantry to Lathpadura on Poles 2
WPS1 New GS at Kalutara with 2 x 31.5 MVA (feeder Rearrangements with new GS at Fullerton)
5
WPS1 New 5 MVA unmanned PSS at Kothalawala Pura 2
WPS1 1 X 5 MVA New Transformer at Galvihara Road close to the Zoo
2
WPS1 New Lynx feeder from Panadura GS to Pallimulla PS and new switching arrangement
3
WPS1 Load sharing from from Mathugama GS and proposed New GS at Fullerton (2 LBSs at Thebuwana side and Malaboda Junction )
2
WPS1 convertion of existing DDLOs to LBSs at Bolosagama and Remanagoda
2
SP Ambalangoda F6 -Near Uragaha Susil Garaj 1 SP Replace Sandagirigoda ABS with an LBS 1
ABS = air break switch, CEB = Ceylon Electricity Board, CP = Central Province, DD = Distribution Division, DDLO = drop down lift off, GS = grid substation, kV = kilovolt, LBS = load break switch, MVA = megavolt-ampere, NP = Northern Province, NWP = North Western Province, PSS = power substation, SP = Southern Province, WPN = Western Province North, WPS = Western Province South. a
Uva Province
* Locations are not available for 75 number of load-break switches.
Annex 3 43
Summary of SAIDI and SAIFI Details
CEB DD DD1 DD2
Distribution Province
North Central North Western Northern Colombo
City Western North
Cen-tral
Eas-tern
DCC Development
OP OP OP OP PC OP DS
SAIDI/SAIFI SAIDI
% SAIFI
SAIDI
% SAIFI
SAIDI
% SAIFI
SAIDI
SAIFI
SAIDI
% SAIFI
MV Systems 37 7% 0.18 48 8% 1.4
8 109 24% 1.0
756 73% 1.3 NR NR
LV Systems 158 32% 0.71 405 70% 0.4
6 87 19% 0.47
237 23% 0.4
Interruptions 306 61% 0.61 122 21% 0.2
7 256 57% 0.1
36 3% 0.1
Total 501 100
% 1.5 575
100%
2.22
453 100
% 1.58 14 0.16 1029
100%
1.8
Total less Interruptions
195 39% 0.89 453 79% 1.8
6 197 43% 1.47
993 97% 1.7
Report month Oct'15 May'15 Oct'15 Oct'15 Oct'15
CEB = Ceylon Electricity Board, DD = Distribution Division, DCC = distribution control center, DS = design stage, LV = low voltage, MV = medium voltage, OP = operational, PC = partially complete, NR = no reports, SAIDI = System Average Interruption Duration Index, SAIFI = System Average Interruption Frequency Index.
DCC = Distribution control center development, DS = design stage, LV = low voltage, MV = medium voltage, OP = Operational, PC = Partially Complete, NR = no reports, SAIDI = System Average Interruption Duration Index, SAIFI = System Average Interruption Frequency Index. a
Uva Province
Distribution DD DD3 DD4
Distribution Province
Western South II Uvaa
Sabarag-amuwa
Western South I Southern
DCC Development DS
DS DS DS DS
SAIDI/SAIFI SAIDI SAIFI
SAIDI % SAIFI SAIDI % SAIFI
MV Systems
NR NR 63 66% 0.34 58 10% 0.74
LV Systems
31 33% 0.17 340 57% 0.44
Interruptions
1 1% 0.01 203 34% o.38
Total 360 2.82
95 100% 0.52 601 100% 1.55
Total less Interruptions
94 99% 0.51 398 66% 1.17
Report month Dec'15
Oct'15 Dec'15