Operation And Maintenance

Solar PV

Solar PV systems have no moving parts and just sit there generating electricity as long as light is falling on the solar modules.

How do you know if they are working as efficiently as they were intended to? If the output from a solar PV installation is degraded for any one of a number of reasons you are unlikely to know unless you have a substantial incident like an inverter failure. It is difficult to quantify the reduction in output due to dirty modules. Bird droppings, dust and algae build up will all impact on the output of a system and its profitability.

On large systems where there can be six or eight strings to one inverter a faulty string can go in-noticed for a long time. There are numerous reasons why a single string might go down on a site which may have as many as 150 strings in a 1MW array. In our experience we think we have seen most of them with possibly the most bizarre being a family of field mice setting up home in a DC cable duct and then eating through the 6mm cable insulation just prior to their unfortunate and untimely incineration at 900V.

On most of our sites we are responsible for 24/7 monitoring of the site down to individual string level. If a fault develops we are automatically informed usually within 1 hour of it arising. From our office or anywhere we happen to be at the time we can then log into the site and drill down to the specific inverter or string and identify the problem. Very often the first thing our client knows is when we advise that we have been to site to correct an issue.

Off Grid Systems

The battery pack and the standby generator are usually the components which represent the largest element of the investment in an off grid system requiring specific and scheduled checking and maintenance.

Good quality modern deep cycle FLA batteries are supplied with a 10 year warranty. Their ultimate life will depend on the number of cycles (discharge > recharge) and the depth to which the battery has been discharged in each cycle. Discharging the battery to 80% will reduce its life by around 30% relative to one which is only discharged to 50% on each cycle.It is important to check the battery electrolyte levels on a monthly basis and top up each cell to its correct level with de-ionised water if required. At least twice a year the individual cells should be checked for both voltage and specific gravity and the results recorded in the battery maintenance log book. If at any time in the future you need to make a claim under warranty then the log book is an essential record without which your claim may be rejected.

Checking the battery charging parameters set in the inverter/charge controller on an annual basis to ensure that they are still correct for the battery being used and the site loads will ensure that the system is operating correctly and delivering the performance expected.

Generators require servicing based either on the hours that they have run or at most, annually. The service schedule will vary with the make of generator but will include changing the engine oil and filter, fuel and air filters and checking for any leaks or adjustments required. Ensuring that the generator starter battery is in good condition and fully charged will ensure that the "genny" will always start when required.