Solar Plant Performance Assessment: Three Key Factors which you should never overlook while project commissioning

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Proper planning plays a very important role in implementing a defect free solar PV installation. O&M aspects are often ignored while planning the solar power project which lead to the reduced plant performance of your solar plant than the expected performance. While we are in the planning phase, great care is taken in equipment selection and system design aspects, however the issues related to O&M are generally overlooked which cause lot of problems during the day to day operation of your solar plant and intern lead to reduced electricity generation. The major reason of the ignorance towards O&M issues right at the planning stage is the lack of data available related to the site O&M issues and its impact on the plant losses. there is a need to create benchmarking of the O&M related interventions and its impact on the energy yield. While there is no specified methods and guidelines related to the consideration of O&M issues during, we would like to highlight three critical factors which lead to the plant under performance during operation stage of the plant.

Loose cable connections
Loose cable connections are a common problem in solar plant as a part of installation lapse. A loose cable connection can also cause fire and safety hazard in the plant. The loose cable connection problem is more prominent in the combiner boxes connecting about 16-24 strings together with several wires. The best method to avoid the loose connections in the cables is to specify the torque applicable while tightening the cables in the combiner boxes. This work needs to be carried out through use of an automatic torque wrench while in the installation. The loose cable connections in the combiner boxes and the inverters needs to be checked on regular basis xo that the sparking and heat losses due to loose cable connections can be avoided in the plant.

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Unsealed Cable Conduits

The cable conduits are also a major maintenance prone area. If your cable conduits are unsealed, it can lead to the rats and other insects entering in to the conduits and can cause damage to the cables. Many times the combiner boxes are not sealed properly and prone to the water seepage, leading to the ground faults which will lead to the non operation of several strings. The unsealed enclosures can also lead to the dust and moisture deposition in the boxes and causing corrosion and erosion to your cables and connector lugs.

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Underperforming strings

There are several instances when the strings connected to a inverter are underperforming. The major causes of string underperformance are the blown fuses in the module junction box, loose connections, etc. Underperformance of the string can also be due to the module mismatch, hotspots in the PV modules connected to the string. Some time shadow losses also cause underperformance of the string. The underperforming strings can be easily detected through the data monitoring at the string level and the O&M staff can visit the respective string to detect the faults.

The above examples are from our regular evaluation of solar plant performance exercises and intention is to demonstrate the need to carry out proactive O&M strategy rather than merely the module cleaning of the plant to maximise the yield. It is important to conduct a regular third party plant performance assessment exercise which will enforce your O&M staff to adopt some of the proactive measures to identify the problematic areas. Some of these issues can be avoided if the suitable measures are taken during the design process itself.

String performance monitoring

 

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