Solar Power Plant Operation and Maintenance

For ensuring smooth and efficient power generation by the solar power plant, Operation & Maintenance (O&M) plays an important role. Effective Operation & Maintenance (O&M) helps the solar power plant for maximizing energy throughout its operational life. Cleaning, adjustments, lubrication, repairs, replacements, and the extension of equipment life should be checked regularly. A general inspection of the installation-site needs to be conducted by O&M personnel at least twice a year.

Following matters need to be checked during this inspection:

• Its should be confirmed that there is an adequate roof drainage system, roof drains are not clogged and no signs of water pooling near the array.
• Ensure that roof penetrations (if any) are watertight.
• Ground corrosion near the footings of a ground mount system should be checked.
• Corrosion on the outside of enclosures and the racking system should be checked.
• Ensure that only the authorized personnel can access the electrical enclosures.
• Cleanliness throughout the site should be checked and confirmed that there is no debris in the inverter pad area or elsewhere.
• Signs of animal infestation under the array should be checked.
• Wires which are loosely connected in the array should be checked.

 

Some specific checks should be done as part of the preventive maintenance.

• PV Modules: Cleaning and preventive maintenance are key factors for getting maximum efficiency from PV modules.
• Cleaning Interval: Cleaning is carried out on a fortnightly basis in normal conditions, where there isn’t too much dust or dirt.
• Quality of Water: The cleaning of the modules is done keeping in mind the TDS (total dissolved solids) levels, water specifications and certain wiping details. The chlorine and calcium level of the water as well as the electrical conductivity is kept in mind while carrying out the cleaning. Water quality is tested after every six months to confirm that set standards are maintained.
• Quality of Cleaning Equipment: For cleaning PV modules, Brushes without fiber brushes should be used. A low-quality brush, like one with metal bristles, could negatively impact the glass surface of the modules. Detergent should be used to clean the surface where hard substances like bird droppings have gotten stuck on the PV module. Ensure that detergent has very high-water content and is not highly concentrated.

Taking care after washing:

It is important to confirm that modules are wiped off properly and no stain is left. It will help to avoid affecting the generation capacity. Ultra Poly Vinyl Chloride (UPVC) conduit pipes should be arranged for ensuring water supply. The current produced is noted along with weather conditions including temperature, irradiance etc. after the system returns to steady-state temperature. This maintenance work is recorded in the log book, and the production of the clean system to the previous production values is compared.

• Inverter: The ventilation of inverter is provided via a filter which needs to be cleaned regularly. Therefore, usage of high-quality filters is advantageous. The voltage of the string inverter should be checked and recorded it in the periodic log book as part of preventive activities. It will help to check the fluctuations of voltage if any.
  
• MC4 Cabling Connector: No gap between the male and female connector pipes should be confirmed appropriately. Any gap, irrespective of the size, could cause a fire and damage the modules. Separately, off-takers can install a “check” meter of equal or higher accuracy with reference to the main meter to cross-check the production level on a monthly basis. All readings have to be, more or less equal, with a 2-3% correction allowance.
• Transformer: Parameters such as the operating temperature, OTI (oil temperature), WTI (winding temperature), and oil level are monitored daily for transformers at the site with installed capacity in megawatts. If there is any internal disturbance in the transformer, it reflects in these parameters which are monitored at least three times in a day (at 11 AM, 02 PM and 04 PM as solar power is generated at its peak during these slots). The transformer has to be cleaned thoroughly once in six months.
• Protection from external materials: The plant should be sealed properly for ensuring that the plant is working smoothly without any shutdown. Else, rats and other rodents can enter, and get electrocuted which can cause a short circuit, and affect the entire plant. High-pressure water can damage the modules.
• Monitoring Remotely: In order to detect breakdowns and optimize the operation, a solar power plant constantly needs to be monitored. Retrieving all the data either from the inverter or from communicating equipment (probes, meters etc.), it can be performed both remotely and on site.

Regularly monitoring the solar PV panels is the foundation of the O&M of a solar power plant which includes supervision, inspection, sending signals and messages, end-to-end solar power plant maintenance execution (from modules to substations) and receiving signals from the environment about irradiation technology.