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Employing predictive maintenance to reduce temperature derating issues in PV systems

In this short essay we will expand on the topic of solar inverter overload and derating, including advanced options for detecting those chronic issues on time. We shall also review the preventive measures such as cleaning inverter filters and the importance of such procedures for the proper operation of a solar photovoltaic system.

Here are some tips for proper conduct during days of extreme heat in order to prevent damage and flare-ups in electricity production and consumption systems and in particular photovoltaic systems:

- Avoiding direct sunlight from solar inverters and electrical boards;

- Cleaning electrical boards from dust and dirt, cleaning filters in solar inverters whenever necessary;

- ensure air circulation for electrical boards and solar inverters;

Filters that require cleaning and a filter that was not assembled properly in commercial SMA solar inverter systems (March 2018).

All solar inverters have a cooling system, which helps to dissipate the heat generated in the inverter during load. In most solar inverters, the cooling systems are protected by filters, which are designed to prevent dust and dirt from entering the internal parts of the inverter and thus causing damage. Within inverters with fan-based active cooling - the filters also protect the fan from damage. Within inverters with passive cooling - the filters prevent the dust from sticking to the radiators thus reducing their efficiency. Reducing the efficiency of a cooling system can lead to an overload at high temperatures.

Hence, at high temperatures we will see many cases of overloading in solar inverters, which in the mild cases will cause an overload, and in the more problematic cases the melting of components with irreversible damage and even a fire hazard. In a mild overload situation, there will be a reduction in inverter efficiency (derating), and this will happen a lot when the ventilation openings are blocked. In cases of incorrect assembly and complete clogging of the filters, this could cause the melting of inverter components. The output of the inverters can be optimized by keeping the filters clean and thus prevent any serious damage, which may be caused by overheating during peak production times.

Most of the monitoring portals on the market do not have an effective warning mechanism to indicate an overload in solar inverters and the indication is typically qualitative if exists. Hence, a quantitative performance assessment is required to measure the severity of the issue in each case in order to make an operational decision. The SysMap performance analytics solution enables quantification of the derating problem and an active warning for cases when inverter overheating is excessive chronically (rather than a single event) - thus optimizing maintenance schedule, preventing an elusive drop in output over time and reducing the risk to an inverter.

Interested to know more on Sensorless technology to measure PV performance and the options to integrate it into your service application? Fill-in the demo request form or contact us to get more details.

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