On-site Diagnostics

On-site Diagnostics focuses majorly on assessing a plant's current health quality and understanding the necessary steps which need to be taken to optimise the plant’s performance. 

The aspects addressed during the study are: 

• Estimate the reasons for underperformance in your plant

• Identify the causes of degradation and nature of defects in the modules

• Evaluate the health of your BoS (both civil and electrical)

• Suggest possible and most feasible solutions to improve generation from your solar power plant

The major tests included in the diagnostics study are:

• Drone and hand-held thermography of modules and other BoS components

• Module and string IV curve measurement (for 1000V and 1500V system)

• EL Image analysis

• PR analysis

• Visual inspection

• Inverter measurements 

  • Inverter efficiency measurement

  • Inverter efficiency analysis (via data log)

  • Power quality analysis (Information of TDH and Harmonics)

  • Energy loss analysis

  • Components and phase sequence

  • Dips and swells of voltage and currents

• Other inverter tests 

  • Earth Resistance test

  • PV array isolation resistance test

  • Soft start test

  • Automatic start stop test

  • LCD Display checking

  • Communication functioning inspection

  • Power factor test

  • Conversion Efficiency test

  • Nominal input and output test

  • Contactor contact point abnormal warning test

  • SPD test

  • Grid connection current harmonics test

  • Anti-islanding test

• Transformers tests

  • Insulation resistance and polarity index

  • Capacitance and tan delta test

  • Dissolved Gas analysis (DGA) Test Methane, Ethane, Ethylene, Acetylene, Carbon-dioxide, Carbon monoxide, Hydrogen, Total Gas content, and BDV test

• Insulation test, Earth resistance test and Structure coating

• Soiling analysis

• Basic review of O&M practices

Case Studies

01.

Root cause analysis for an EPC

Plant details: 10.8 MW in UP (2 years old)

The EPC was not able to meet generation guarantee leading to huge penalty

PV-D was appointed as a technical consultant to identify the root cause and suggest amendments to avoid penalties. 

Observations

• Modules underperforming by 14%

• 25-30% modules were found to have solder contact failures

• 15-18% modules found to have cracks mostly due to improper module handling

• Pyranometer not calibrated properly which led to reporting of approx 10% higher PR

• Modules exposed to PID due to improper earth pit maintenance

Performance improvement measures

• Increasing the DC side loading of the plant to increase generation

• Filing for warranty claim for modules with solar contact failures

• Improving maintenance practices for earth pits and cleaning cycle.

02.

Performance improvement through re-binning and PID reversal

Plant details: 8 MW in Gujarat (6 years old)

Underperformance indicated by the client

PV-D was appointed to conduct the diagnostics study and identify the reasons behind it and list out necessary amendments to optimize the performance

Observations

• Modules underperforming by 8.3%

• Soiling losses found around 2.6%

• 20% modules suffered from PID

• Poor ventilation in the shaft reduced inverter efficiency by 2%

• Other damages include corrosion and inter-table shadow losses

• Overall 4% loss in revenue due to excess degradation

Performance improvement measures

• 1.1% plant performance improved by reducing mis-match losses in the modules

• Up to 80% power recovery in PID impacted modules by installing PID reversal box

• 2% improvement in inverter efficiency through proper maintenance

• Structural changes in the plant to remove tilt and shadow losses

03.

Modules frame buckling

Plant details: 20 MWp plant in Rajasthan (7 years old)

Observations

• EPC did not provide scope for expansion to the modules

• As a result, the frame of the modules started bulging because of excessive heat in the region

Performance improvement measures

A preventive plan was shared with the client with root cause analysis

Remote Diagnostics

PV-D has integrated all the on-site parameters in its desktop to analyse and produce accurate and reliable results. This diagnostics is possible remotely which increases its utility.