chapter 1 distribution systems and tariffs
TRANSCRIPT
UTILISATION OF UTILISATION OF ELECTRICAL ENERGYELECTRICAL ENERGY
CHAPTER 1CHAPTER 1DISTRIBUTION SYSTEMS AND TARIFFSDISTRIBUTION SYSTEMS AND TARIFFS
Name: Dr Goh Hui HwangName: Dr Goh Hui Hwang
BEE 4213BEE 4213
Outline
Introduction Electricity Generation Scenario in Malaysia HV Distribution Networks LV Distribution Networks Hardware for Distribution Systems Load Characteristics and Tariffs Rate
Learning Outcome
Explain the basic understanding of the electrical distribution systems
Overview of the Electricity Supply Industry in Malaysia
Explain the operational and design concepts of High Voltage (HV) and Low Voltage (LV) Distribution Networks.
Describe the basic of tariff rate in Malaysia
Introduction
We need energy in many areas of human endeavor such as: moving people and goods around - transporttransport producing and processing of food - agricultureagriculture manufacturing of useful materials and artifacts -
industryindustry Powering communication gadgets and equipment, and
going about other commercial activities - commercecommerce maintaining physical comfort and convenience in our
homes - householdshouseholds
Introduction - Transport
Transportation is the movement of people people and goodsand goods from one place to another.
Transportation depends on continuous supply of energyenergy.
Automobiles are powered by gasolinegasoline (petrol), aeroplanes by jet fuel (kerosene), and trucks, trains, and ships by diesel oil.
Conveyers, cranes, robots and pipelines use motors and pumps, which are powered by electricityelectricity.
Introduction - Agriculture
Agro-industries and processing of agricultural products require energy.
Mechanical implements powered by fuel or electricity are immensely more efficient and productive than humans and animals.
In developed countries, a major portion of electricity used in agriculture powers irrigation pumps.
The energy requirements in agriculture are mainly met using solar energy, fossil fuels (oil, coal and natural gas), fuel wood and electricity.
Introduction - Industry
Most of the energy used in industry is used by the machines and processes, which make the products of industry.
Industrial energy-consuming systems include boiler and other fired systems (furnace, kilns, incinerators, dryers), compressed air system, electric motors (for fans, blowers, pumps, conveyers, etc.) and lighting system.
Energy is also used to heat or cool the buildings and to provide hot water and other facilities for workers.
Introduction - Commerce
Highly sophisticated communication systems both for the supply of goods and services, and the maintenance of organisational cohesion requires a ready supply of suitable energy.
Information processing, storage and retrieval also use a lot of energy in commerce.
Electrical energy is the most common form of energy used and supplemented by chemical energy from batteries.
Introduction - Household
Energy is required in households for space heating or cooling, water heating, cooking, lighting, ironing, and power appliances like fridge, washing machines, sound systems, TV, hair dryers, shavers, clocks, blenders, toasters, vacuum cleaners, sewing machines, etc.
The energy may come from direct heating from the sun, electricity, burning of fossil fuels or fuel wood.
Electricity Scenario in Malaysia
LEGENDHydro
Thermal
LEGENDHydro
Thermal
Note:GT - Open Cycle Gas TurbineCC - Combined CycleCSP - Conventional ThermalC/G/O - Triple Fuel Coal, Oil & GasDist - Distillate
SOUTH CHINA SEASTRAITS OF
MELAKA
NTeluk Ewa (68 MW)GT 2 x 34 MW Dist
PRAI (360 MW)CSP 3x120 MW Fuel Oil
GELUGOR CC 1 x 330 MW GasSERDANG (625 MW)GT 3x135 MW GasGT 2x110 MW Gas
CONNAUGHT BRIDGE (832 MW)
GT 4x 130 MW GasCC 1x 312 MW Gas
PORT DICKSON (360 MW)CSP 3x120 MW Gas/Oil
PASIR GUDANG (729MW)CSP 2x120 MW Oil/Gas
CC 1x269 MW GasGT² 2x110 MW Gas
PAKA (1,139 MW) CC 3x290 MW GasCC 1x269 MW Gas
KEV (2,420 MW)CSP 2x500 MW Coal/G/OCSP 2x300 MW Coal/G/OCSP 2x300 MW Gas/Oil
GT² 2x110 MW Gas
MANJUNG (2100 MW)3 x 700 MW Coal
THERMAL POWER PLANTS
Electricity Scenario in Malaysia
HYDRO POWER PLANTS
Note:GT - Open Cycle Gas TurbineCC - Combined CycleCSP - Conventional ThermalC/G/O - Triple Fuel Coal, Oil & GasDist - Distillate
SOUTH CHINA SEA
STRAITS OF MELAKA
N
LEGENDHydro
Thermal
LEGENDHydro
Thermal
Bersia3 x 24MWKenering3 x 40MW
Chenderoh3 x 10.7 MW1 x 8.4 MW
Cameron Highland261.9 MW
Sg.Piah2 x 7.3 MW2 x 27 MW
Pergau4 x 150MW
Kenyir4 x 100MWTemengor4 x 87 MW
Electricity Consumptions - 1
Electricity Consumptions - 2
Electricity Consumptions - 3
Electrical Energy Utilisation
GRID SYSTEM IN P. MALAYSIA
GRID SYSTEM IN SARAWAK
GRID SYSTEM IN SABAH
Electrical Supply Systems
High Voltage (HV) Overhead transmission lines (500 kV, 275 kV,
132 kV). Underground cables (66 kV, 33 kV, 22 kV, 11
kV, 6.6 kV). For large scale industry customers.
Low Voltage (LV) Voltage level below 1 kV. For residential, commercial, and small industry
applications.
Overview of Electricity Supply Systems
High Voltage Electrical Supply
A. Main Transmission Line Network System Connecting the electrical supply source from
electrical generation stations to the main distribution network system at certain large areas like states, districts and big towns.
The main transmission line networks are liked to each other to form the “National Grid System”.
The method used in the transmission line network is the 3ø, 3 lines (R-Y-B) system through main overhead line tower.
High Voltage Electrical Supply
B. Primary Distribution Network System It receives electrical supply from main
transmission line network system. It is located at few selected locations in a
state. The electrical power is delivered to the users
through several distribution levels as follows:
American Versus European
High Voltage Electrical Supply
First Level (1) – Main Entry Sub-station (MES) or Pencawang Masuk Utama (PMU).
It is a building with high voltage switches and received electrical supply from main transmission line network system.
Second Level (2) – Main Divider Sub-station (MDS) or Pencawang Pembahagi Utama (PPU).
It also furnished with high voltage switches. It operates to receive the electrical supply from
MES.
High Voltage Electrical Supply
Third Level (3) – Main Switch Station (MSS) or Stesyen Suis Utama (SSU).
It operates with high voltage switches in order to receive electrical supply from MDS.
Fourth Level (4) – Electrical Sub-station (ES) or Pencawang Elektrik (PE).
It receives electrical supply from MSS. 2 types : Single Chamber and Double Chambers.
High Voltage Electrical Supply
Under ground cables are used in the delivery system from level 1 – 4.
Types : 3C x 300 mm sq/ 3C240 mm sq/ 3C185 mm sq, XLPE (cross-linked Polyethylene), Aluminum.
Block diagram:
MTL MES MSSMDS
ES
ES
33 kV 33kV / 22kV 22kV/11kV
415V(LV)
415V(LV)
High Voltage Electrical Supply
C. Secondary Distribution Network System Begins whenever the High Voltage electrical
supply (11KV) received at ES is converted to Low Voltage electrical supply (415V).
Method used is the 4 lines (R-Y-B-N) through step-down transformer.
The number of ES is depends on the total load demands (VA) requested by the user.
Type of ES : Single Chamber (200 A) and Double Chambers (600 A).
High Voltage Electrical Supply
Number of chamber indicating the number of transformers needed.
Type of transformer : Oil Immersed Type, cheap but low efficiency (for
small users). Cast Resin - Dry, more expensive but higher
efficiency (larger customers). Nominal Volt-Ampere (VA) capacity of the
transformer : 250 kVA, 500 kVA, 1000 kVA.
High Voltage Electrical Supply
What are inside the ES?
(i) Switch gear
(ii) Transformer
(iii) Low Voltage Distribution Board The 415V supply will then connected to the
kWh metering system (user side) through LV underground cables.
High Voltage Electrical Supply
Layout of an ES (Single Chamber):
LV BoardLV Board
Switchgear Room
Transformer Room
Outgoing Points
High Voltage Electrical Supply
D. Types of Electrical Supply Users: HV – Higher institutions, shopping
complexes, large factories (owned the MDS, MSS, ES).
LV – Domestic users, shop lots, public buildings.
Low Voltage Electrical Supply
Types: 3ø, 4 wires + E – 415V 1ø, 2 wires + E – 240V
Types of LV electrical installation: Small Industry Buildings. Small Commercial Building (shop, office, restaurant). Small Residential Building (Condo, Terrace,
Apartment). Small Public Building (wet market, bus station,….) Public Utilities (Street lights, traffic lights,…..)
Low Voltage Electrical Supply
Main components in a LV electrical supply distribution system (building): kWh meter TNB Main Switch Board (MSB) Sub Switch Board (SSB) Distribution Board (DB)
Low Voltage Electrical Supply
Example of residential connection:
ES M Users
TNB User
Low Voltage Electrical Supply
Example of industry connection:
ESMSS
FACTORY
MSB
HT Switch Room
HT Meter Room
HT Switch Room
User’s Transformer Room
Main Switch Board
SSB
Main Switchboard (MSB)
Sub Switchboard (SSB)
Low Voltage Electrical Supply
Example: Double-storey House Lighting Power
DB2
Lighting Power
DB1
M
1st Floor
Ground Floor
Incoming TNB
kWH meter TNB
Low Voltage Electrical Supply
Example: Terrace house installation
Terrace House
TH 1 TH 2 TH 3 TH 4
Service Cable
kWHMeter
Road
MM M M
Tap- off Unit
Economic Aspects
Utility company must plans for the electricity demand in advance as requested by its consumers.
Common terms used: Connected load Maximum demand Demand factor Average demand Load factor Diversity factor
Economic Aspects
Connected Load – sum of the rated maximum values of all loads used by consumer. It may be expressed in watts, kW, A, hp, kVA etc.
Maximum Demand – highest or peak demand for a specified time (might be in hour, day, month, or year).
Demand Factor (DF)
load Connected
demand Actual DF
Economic Aspects
Average Demand – Sum of the total demand (in kWh) divided by the demand period (hr).
Load Factor (LF) - The ratio of the average load over the peak load. LF ≤ 1.
(hr) period Demand demand Maximum
(kWh) load Average LF
or
demand Maximum
kW)(in demand Average LF
Economic Aspects
Diversity Factor (DF) - The ratio of the sum of the individual peak demands in a distribution system to the peak demand of the whole distribution system. DF ≥ 1.
Example 1 – Economic Aspects
A load rises from zero to 10 kW instantaneously and stays constant for 1 minute, then rises to 20 kW and remains constant for 1 minute, continues at this rate of rise until it reaches a maximum value of 50 kW for 1 minute, then instantly falls to zero for 1 minute, after which it again rises in 10 kW steps at 1 minute intervals to a maximum of 50 kW and returns to zero for 1 minute. If the load continues to vary in these steps: What is the average demand over the first 15 minutes? Over the second 15 minutes? Over the 30 minutes demand interval?
Example 1 – Economic Aspects
Solution:
10
20
30
40
50
kW
15 minutes
Time (minute)
Example 1 – Economic Aspects
Solution (Cont.):
Total demand
= (10 kW x 3 + 20 kW x 3 + 30 kW x 3 + 40 kW
x 2 + 50 kW x 2)
= 360 kW
Average demand = 360 kW/15 minutes
= 24 kW.
Example 1 – Economic Aspects
Solution (Cont.):
(ii) Total demand for the second 15 minutes
= 390 kW
Average demand = 390 kW/15 minutes = 26 kW
(iii) Total demand over 30 minutes
= 360 kW + 390 kW = 750 kW
Average demand = 750 kW/30 minutes = 25 kW
Example 2 – Economic Aspects
A factory consumes 425,200 kVAh in a year
with the yearly average power factor, 0.86. If
the half-an-hour demand was 120 kW, find,
(i) The average load demand
(ii)Annual load factor
If the factory decided to increase the electricity
usage to 450,000 kWh and the load factor to
65%, what will be the maximum demand?
Example 2 – Economic Aspects
Solution:
(i) Average load demand
= (425,200 x 0.86) kWh/ (365 x 24) hr
= 41.74 kW.
(ii) Load factor = 41.74 kW/ 120 kW = 35%.
(iii) Maximum demand
= 450,000 kWh/ (8,760 x 0.65) = 79.03 kW.
Example 3 – Economic Aspects
A group of Parit Raja consumers has an annual
individual maximum demand of 132 kVA
supplied from a single phase distribution
transformer. If the average diversity factor
between the group of consumers is 2.8,
determine the nearest standard size of the
distribution transformer that serving the
consumers.
Example 3 – Economic Aspects
Solution:
The size of the transformer is determined
according to the maximum demand of the whole
group.
Group Maximum demand,
= Annual individual maximum demand/ DF
= 132 kVA/ 2.8
= 47.14 kVA.
Nearest standard size = 50 kVA.
Tariffs
The rate of charging for electrical energy supplied by the utility company to its consumer.
Tariff charge is depends on various factors: Type of consumer (industrial, commercial, or
domestic) Type of service (lighting, heating, etc) Total fixed running annual charges of the utility
company Facility for calculating the bill
Tariffs
Definition of electricity tariff:
3 types of tariffs:i. Residential
ii. Commercial
iii. Industrial
[kWh]consumer the tosuppliedenergy Total
[RM] running) (fixed charges actual Total Tariff
[kWh]consumer the tosuppliedenergy Total
[RM] running) (fixed charges actual Total Tariff
TNB Tariffs
Refer to “ TNB Tariffs Book” (updated 2006). Power Factor Tariff:
Below 0.85 and up to 0.75 lagging, 1.5% of the bill for that month for each one-hundredth (0.01).
Below 0.75 lagging, A supplementary charge of 3% of the bill for that month for each one-hundredth (0.01).
Example 4 – Power Factor Tariff
A medium voltage industrial consumer having
the following data for its monthly electricity bill: Total electricity consumption in kWh
- 160,000 units The reactive power consumption in kVArh
- 120,000 units The monthly load factor - 68% For each kilowatt of maximum demand per month
= RM 19.50/ kW For all kWh = 22.2 cents/kWh
Example 4 – Power Factor Tariff
i. Determine the monthly maximum demand for this consumer. [take 30 days/month]
ii. What is the total monthly bill charge for this consumer?
Example 4 – Power Factor Tariff
Solution:
(i) Monthly max. demand
= 160,000 kWh/(30 x 24) = 222.22 kW.
(ii) Monthly bill without PF consideration,
= 222.22 kW x RM 19.50 + 160,000 kWh x
RM 0.222 = RM 39,853.29
PF = cos (tan-1 120,000/160,000) = 0.8
Poor PF charge = 1.5% x (0.85 - 0.8) x 100
x RM39,853.29 = RM 2,989.00
Total monthly bill charge = RM 42,842.29