Employing predictive maintenance to reduce temperature derating issues in PV systems

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

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 solar photovoltaic inverters:

- Avoiding direct sunlight from solar inverters and electrical boards.

- Clean electrical boards and solar inverter filters regularly to remove dust and dirt.

- Ensure adequate air circulation around electrical boards and solar inverters.

SMA Sunnyboy inverter

SMA three phase inverter filte

SMA Sunnyboy dusty filter

Fig 1. 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 to dissipate the heat generated during operation. In most systems, cooling mechanisms are protected by filters designed to prevent dust and dirt from damaging internal components. For inverters with fan-based active cooling, filters also protect the fan from damage. For inverters with passive cooling, filters prevent dust from adhering to radiators, which could reduce cooling efficiency. When cooling efficiency declines, inverters risk overloading, particularly at high temperatures.

Fig 2. Power Performance Index (PPI) is decreasing from ideal 1.0 to below 0.9 upon severe solar inverter derating.

At high temperatures, many solar inverters experience overloading. In mild cases, this leads to efficiency losses (derating). In severe instances, clogged filters or improper assembly can cause components to melt, resulting in irreversible damage and even fire hazards. Keeping inverter filters clean is critical to preventing overheating during peak production and maintaining optimal output.

Most monitoring platforms lack effective mechanisms to warn of solar inverter overloads. Where indicators exist, they are often qualitative and insufficient for precise decision-making. A quantitative performance assessment is essential to gauge the severity of solar inverter derating and take appropriate operational measures. SysMap’s performance analytics solution addresses this by identifying quantifying derating issues and providing active warnings for chronic overheating. This allows for optimized maintenance schedules, prevents unnoticed performance drops, and reduces the risk of inverter failure.

Curious about how Sensorless technology measures Solar PV inverter performance for predictive maintenance? Fill-in the demo request form or contact us to get more details.