O&M of solar plants: Why wiring management plays a very important role in getting your plant running?
Successful O&M of a solar plant is dependent on how the electrical system is designed and wiring management is done. There are several joints in a solar plant ranging from PV modules to the inverters to the a SCB and finally the power evacuation system. Wiring management in a solar PV system can be classified into three broad categories which include open air wiring, direct buried wiring, and cable tray wiring.
Module to module wiring is done through the DC cables which are longest length in a quantity. In a typical 1 MW plant about 10 km of DC wires are used which are about 4 to 6 SQMM wires and we get most of the problem in these wires. Module to module and module to a string commander box wire runs in open air and are subjected to highest number of damages and it is easy to identify the problems and repair them.
The buried wires are generally ranging from the string combiner box to the inverter and the direct buried conductors are usually lower. Proper connection of the conductor happens on the both ends of the wires and rest of the wire is buried underground. In case the buried conductor, it is very difficult to locate the fault and the conductor must be dug up to fix the problem. It is very expensive to rectify the problem for buried cable.
wiring damage problem is minimal in the conductors which are running in Cable Tray is as it is easy to open the cable tray cover and do a proper maintenance of fewer wires running in the cable trays.
Wiring management plays a very important role for smooth operation and maintenance of a solar plant. It is important to use ultraviolet (UV) exposure free cable ties so that the wiring remains intact. Wiring gets damaged due to rubbing against modules or against the structure parts. This requires frequent inspection and testing and replacement of the damaged cables. Sometime the wires are laid down too tightly which eventually leads to fault and loose connections. The DC cables are frequently exposed to rats and squirrels and animal access to wiring leads to damages and cutting of the Insolation which is chewed by rats.
It is important to do a proper wiring management and taking of the wires so that proper access of cables can be identified and the fault detection is done as a part of comprehensive O&M programme of the solar plant.