performance paramter and suggestion to optizing the performnce of grid connected solar pv plant

© 2013 UPES

Summer Internship Project Presentation

Performance parameters and recommendation for Optimizing performance of grid connected Solar PV Project

Ashish Verma M.Tech ES-II500022066

© 2013 UPESAug 2013Sept. 2013

Internship Company :Profile , Role & Responsibilities

Internship at Gensol Engineering Pvt Ltd ,from 22nd May -31st July An Engineering Division of Gensol Consultants Pvt Limited ,dedicated

division for EPC services to execute Solar rooftop and grid connected Solar Project

Gensol group –leading Solar Advisory and EPC consulting firm with portfolio more than 700MW+ in India.

Prepared detail project for grid connected solar PV Project Financial projection for project Under NSM Phase-II Techno-economic feasibility report for Grid connected Solar PV project Due diligence report for 20 MW SPV Project for NSL Learn basic project financing of Solar PV Project

© 2013 UPESAug 2013Sept. 2013

Presentation agenda Philosophy behind the performance evaluation & Optimization Methodology adopted for Project Various performance affecting variables Various factor affect in performance Performance ratio and concern losses PR v/s CUF Recommendation for optimum selection of component Due diligence for 20 MW Solar PV plant at Shivlakha ,Gujarat Existing various problem (as per site visit report) Recommendation for optimization (if it is possible ) Key findings Q&A

© 2013 UPESAug 2013Sept. 2013

Philosophy behind the performance evaluation & optimization Evaluation of technological aspect of Plant

Evaluation of variations of various climate(High temperature, radiation ) & environmental (dust), infrastructural condition

Performance knowledge will give better investment decision ,& confidence in adoption of technology in Solar PV ,Better regulatory framework

Optimization will increase the effectiveness of the plant operation i.e. Module output ,Inverter efficiency ,cable losses ,Energy yield .

Increasing the life expectancy of Component of Plant. Optimization increases the economics of the plant in terms of Energy

generation thus project revenue . Boost the component performance – turn your power into profits with in the Reduces the uncertainties of solar radiation resourcing

Design Optimization

Selection of Component •

© 2013 UPESAug 2013Sept. 2013

Methodology adopted for Project Literature review Overview of different performance parameter from various

sources(NREL,CERC ) Life expectancy of component various losses which affect the energy generation Meteo data source comparison

Recommendation during site simulation & Plant design Optimum angle consideration of various losses and their optimal limit Grid downtime Limit the various losses

Case study of 20MW Solar PV project at Sivlakha Gujarat

© 2013 UPESAug 2013Sept. 2013

Review based on data provided by Developer & Site visit Suggestion to developer for optimizing the performance Design side ( Selection of cable ,Inverter ,Transformers ,Module

placement ) Operation side(Cleaning of module , Connection of points ,monitoring

of string ) Test report based on Pre and post commissioning of plant Visualized defect – reason and suggestion to heal Savings by adopting optimum size of component Conclusion

© 2013 UPESAug 2013Sept. 2013

Various performance parameter Define overall system performance w.r.t o Solar radiation: which affect the energy generation ,dependent on

the location and orientation of module o Select the reliable meteodata source for site simulation o System Loss i.e. temp., soiling loss, DC/AC cable loss, module

degradation rate o Life expectancy of component :Module -25-30 years , Inverter 10-

15 years , Module mounting structure – 25 years o Performance ratio – which show the how much actual energy is

generating compare to the theoretical possible output ,high performance plant PR is around 80%

o CUF: ratio between the gross energy generation of power plant and the maximum gross energy generation possible in the period under operation

© 2013 UPESAug 2013Sept. 2013

Degradation of module quality : Power decline over the time ,essential for the project developer at the time of module technology selection ,Important in respective to the growth of PV industry

Generally module derating factor is 0.50 to .70% /year ,but now days power output assurance is provide by the module manufactures

opportunity for the researchers

© 2013 UPESAug 2013Sept. 2013

Performance ratio Gives the information about how plant is efficient – in term of energy

output and reliability Dependent on the irradiation ,optimum angle of the tilt ,design

parameter ,Quality of Modules, efficiency of Inverter Parameter is used for performance guarantee by O&M service

provider

PR= E(kWh)

GE (kWh/m²) * Aplant (m²)*efficiency of module * (1- Ptpv)

Ptpv= (Tc-NOCT )* power temperature coefficient of module /100

Factor affecting the PR: Temp of module , Solar radiation Measuring instrument Sensor box placement Recording period Efficiency of module and Inverter

© 2013 UPESAug 2013Sept. 2013

Energy generation and corresponding PR

Source: Results based on 1kWp plant from SolarGIS online tool ,cSi technology

Average annual PR: 75.80%

© 2013 UPESAug 2013Sept. 2013

System Losses with corresponding PR

cable losses can be reduce by opting the efficient cables

© 2013 UPESAug 2013Sept. 2013

PR v/s CUF

PR shows the how efficiency energy injected into the grid ,and CUF show that gross generation against the max possible generation during the period CUF does not take environmental factor like radiation and variation

of temperature Derating factor of module PR accounts grid availability into account but CUF not PR can be used as tool compare for solar PV plant at different

location

© 2013 UPESAug 2013Sept. 2013

Factor affecting the Performance Radiation at the site Losses associated with Solar Plant • cell operating out of STCs• Voltage drop in dc cable • Dirt and Dust Loss • partial shade • Grid downtime • angle of incidence

• Soiling losses • Module Mismatch losses • MPPT losses • Irradiance losses

© 2013 UPESAug 2013Sept. 2013

Inverter efficiency Operating temp. and temperature coefficient

© 2013 UPESAug 2013Sept. 2013

Energy generation loss from DC to AC

Source: Simulation through PV syst , 1MW plant at Bhilwara RJ

© 2013 UPESAug 2013Sept. 2013

Recommendation for optimizing the performance These are few general recommendation at time of designing optimum tilt angle

Spacing of Structure for avoiding shadow losses Periodic cleaning of Module to avoid soiling losses Minimize the Losses due to array mismatch – prefer DC side 5-

10% overload Module with lower temperature coefficient for power in High

temperature Zone after CB ananlysis Select Inverter with High euro efficiency ,large DC input

rangle ,Low cut in limit of voltage

© 2013 UPESAug 2013Sept. 2013

Select efficient cable – Select right conductor size with appropriate ampacity of cable ,Operating temperature of cable ,

Inverter location near to the array to minimize the voltage drop (VD limit -2-3%)

Lets take a example for cable calculation DC Cable Sizing String to Inverter16-07-2013.xlsx if system voltage is 600 V ,cable Size for 8 A current , Loss -2%, Cable

size 6 Sq. mmSystem voltage is increased to 1000 V ,cable Size reduce to 2.5 sq.

mm with loss of 1%

© 2013 UPESAug 2013Sept. 2013

Case study20 MW Solar PV project at Shivlakha Detaille analysis and recommendation for optimizing the plant performance

© 2013 UPESAug 2013Sept. 2013

Project summary

Project developer : NSL group project Business Model : REC +APPC

© 2013 UPESAug 2013Sept. 2013

Identified problem with in the Plant Size expansion 88 module were shifted from one place to another originally they were placed at dispute land

Only 55 Module adjusted to optimum tilt angle remain just placed according to lat. of location

Reduce the pitch to accommodate more module in less area . Module Shifting & effect on design loading of the plant Land constrain , Shifting of Module changes the Design of Plant

Affect the Design loading of Plant

Breaking of Module reduces the Module output

Options to mount the Module top of the Control

Room

© 2013 UPESAug 2013Sept. 2013

String cable length Few places the cable losses can be reduce by using the 10 Sq. mm cable in place of 6 Sq. mm cable

String cable length over the 10 km . Which is increasing the losses ,recommended to opt cable with High cross section area . Cavities with in the Plant Ground level cavities were found near the Mounting structure ,which reduces the strength of the Structure Identified problem in Monitoring Data Logging Monitoring data is not on string level ,so difficult to identify the location of under performing module or sting

© 2013 UPESAug 2013Sept. 2013

Design aspect of Plant PV Module 100 Wp A-Si module is used , suitable for the location of High

temperature (due to low temperature coefficient ) Tolerance limit range is ±4.99% which leads to be mismatch problem

DC side should be 5-10% overload

Module were found to be covered ith dust layer and broken

Module should be clean regularly & handling of thin film during transportation and construction should be care full

© 2013 UPESAug 2013Sept. 2013

vegetation seen below structure covering junction boxe of modue and raising upward creating shadow effect on module

The modules were placed at 20º tilt on structure which were at 23 degree . Due to area constrain pitch 7.4 meter is justified

tilt angle should be optimum

Collector width should be choose care fully .

© 2013 UPESAug 2013Sept. 2013

Inverter The inverter for this plant will give an o/p of 665 kW ,the Max

designed DC loading is 716 kWp which is under maximum DC rating of 802 kWp

The operating temperature of Inverter is -10 to 40 degree .But Ambient temperature of the site in summer reached up to 50 degree .Thus performance of the inverter affected

Inverter selection should be according to the ambient temperature specially place like RJ and gujarat

Cable Module interconnection cable is 2.5 sq. mm cable ,voltage drop were

in permissible level (<1%), Correct selection of cable 6 Sq. mm cable which is using for connecting String to SJB is not

appropriate , loss were around 6% with in 2 km range

© 2013 UPESAug 2013Sept. 2013

Total DC loss is arround 6.55 % .

Suggestion DC loss should be 2-3% , efficient cable should be used

Transformer Output of the 2 inverter is fed with the Transformer of 1.5

MVA ,0.320/11 kV transformer

Transformer should be 10-15 % overload to avoid failure due to overloading for some time Two Auxiliary transformer with 250 kVA each were using for supplying

power to 90 kW load which is highly oversized .

© 2013 UPESAug 2013Sept. 2013

Detailed evaluation of various Loss of 20 MW plant Losses during the Site simulation

Loss data provided by the O&M contractor

© 2013 UPESAug 2013Sept. 2013

Observation from Graph Temperature derating losses increase due to increase in in

temperature on actual site compare to the temp. recorded by the meteodata source

Shading losses reduces due to proper selection of pitch and site condition

Module mismatch increases due to module break down , actual power deviation and shifting of module from one location to another

cable losses increases because of improper selection of cable from string to SJB and length was long . On max length DC 6 sq. mm cable loss is 5.8 % . These losses can be minimized by using 10 Sq. mm cable which save the 59 cr. With replacement cost of 2.75 Cr. After Cost benefit analysis .

© 2013 UPESAug 2013Sept. 2013

Difficult to predict the losses inside the Inverter due to complex Power electronics circuit and devices

Losses occur in 11/66kV transformer can investigate by using SCADA which give us better idea of losses where they occurring

© 2013 UPESAug 2013Sept. 2013

Key findings Selection of Optimal value of Tilt angle at time of simulation ,Limit the

shading losses by proper pitch control . Proper selection of cable with optimum diameter with proper ampacity Module technology selection as per site specific condition after cost

benefit analysis periodic cleaning ensure the power restore of the Module Transformer selection should be optimum ,so that losses can be

reduce Grid downtime should consider Give better confidence to upcoming project developer in India Better PR save you from penalties

performance paramter and suggestion to optizing the performnce of grid connected solar pv plant

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