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-II
500022066

© 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. mm
System voltage is increased to 1000 V ,cable Size reduce to 2.5 sq.
mm with loss of 1%

© 2013 UPESAug 2013Sept. 2013
Case study
20 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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Performance paramter and suggestion to optizing the performnce of grid connected solar pv plant