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What maintenance issues are required for the operation of a solar micro-grid?


This is a question that I've been asked in the field so I wanted to share it with everyone on KnowledgePoint

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Assuming the photovoltaic (PV) micro-grid has been designed and built by an accredited supplier then maintenance needs should be minimal. The main issues in developing countries such as in semi-arid areas of Syria or Kenya relate to ensuring the performance of the PV is optimised.

General maintenance: Dust and fouling of the modules reduces the amount of sunlight that is able to reach the modules. This should be regularly removed.

Figure 1 and Figure 2 show examples.

Figure 3 shows even when washed residues may remain.

Dust in the air can be abrasive and, even when washed off, can cause scratches that affect the light properties of the modules.
Figure 4 shows shading so check the surroundings over time to ensure trees do not shade the modules.
Check for wildlife, insects and small animals can get into places they should not and can cause damage. Figure 5 shows a bird's nest behind an inverter.

General observations of the condition of the system should take place to check the wiring and connections are in good health.

The main factor with PV micro-grids is ensuring health of the batteries. The system design should ensure that the lead acid batteries are never discharged below 50%. This is to ensure they operate for as long as possible, up to 5 years. Over discharging will significantly shorten the life of the batteries and potentially cause the system to fail and fall out of use if they cannot be replaced.

The systems performance should be monitored, and data logged to see how it operates over time. This would include current, voltage and temperature parameters of the PV modules and batteries as well as the current and voltages of the end user loads. This will allow to see if any deterioration is taking place proactively repair the system.

Although expensive and requiring training a PV analyser, such as the Solarmetric PVA600, can test the current and voltage curves of PV modules and strings. This will troubleshoot issues as the performance of the PV microgrid can be tested against known PV model predictions.

So, to conclude, ensure the PV microgrid system has been correctly designed, preferably fully engaging with the energy needs of the recipients. The system is built by a reputable company. A maintenance programme is agreed and acted upon. Sustainability is costed into the financial lifecycle of the microgrid to ensure adequate funds for replacing components that are expected to fail such as batteries after 5yrs and an inverter after 10yrs.

Furthermore, end-users need to be educated on the limits of the system. Ideally, they should be co-designers. Whilst not a maintenance issue as such, there is a risk of overloading the micro-grid if extra loads are added that were not modelled. Hence the need to engage with the community regarding their energy needs. For example, in rural Nigeria an entrepreneurial shop keeper bought a fridge and overloaded a micro-grid causing the loss of power for the whole village for a week before the developer ... (more)

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