Advantages of module level power electronics in O&M for commercial systems

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As the UK PV industry matures and with the dramatic cuts to the feed-in tariff, it has become significantly more important to make sure all systems are performing as expected.

This has initiated a lot of discussion regarding operation and maintenance (O&M) and PV asset management as part of the system’s long-term financial planning. Standardised and digitalised O&M, along with effective PV asset management, can help improve a system’s financials.

However, these terms are often used interchangeably in the PV industry even though they have very different roles.

PV asset management refers to the financial and administrative activities that are completed in order to translate energy production into revenue. This is work that is typically done in an office. While O&M is the physical, labour-intensive, technical work in the field that is conducted in order to ensure a system’s uptime.

Part of what is contributing to the blurring of the lines of these separate activities is the advent of module-level power electronics (MLPE). With remote monitoring and troubleshooting, MLPE is helping to transition some of the O&M activities into PV asset management.

There are two different types of O&M activities that have been improved as a direct result of the enhanced digitised monitoring provided by MLPE – preventative and corrective maintenance. Preventative maintenance is intended to maintain the PV system at its highest working condition and limit system downtime. Corrective maintenance is conducted after an issue has been discovered and includes the actual repair process. MLPE impacts each of these differently and actually helps shift some corrective maintenance tasks into preventative maintenance, and can even eliminate some preventative and corrective maintenance activities altogether.

A significant aspect of preventative maintenance is the annual site visit during which a thorough evaluation of all PV system components is conducted. This measure is meant to check system health of commercial PV installations. With traditional inverter systems, each module needs to be inspected to ensure proper functioning. This is both a costly and a time-consuming procedure, not to mention the safety concerns that arise from working at heights, potentially poor weather conditions, and with high voltages. During these preventative maintenance activities, latent problems causing decreased energy production are often uncovered.

However, with monitoring offered by MLPE, this corrective maintenance can now be performed without needing a specific site visit to identify the problem. Module-level monitoring provides pinpointed alerts, fault detection, and remote troubleshooting that reduces trips to and time spent at PV sites. This is because module-level monitoring enables O&M service providers to perform many of the preventative maintenance activities from the comfort of an office. For example, if a module has a failed diode, then an automatic alert will notify the O&M provider to underperformance. The module can be easily identified, pinpointed to its specific location, and a screenshot can be provided by the O&M provider to the module manufacturer for a warranty claim. This means that during the annual site visit for preventative maintenance, the O&M provider is actually replacing the module instead of doing so during the follow up visit. Both preventative and corrective maintenance can now occur simultaneously.

The highly-detailed resolution that module-level monitoring offers is especially important for commercial systems as it significantly decreases the resources needed to maintain such large projects. Combining module-level monitoring with other performance monitoring tools, such as fleet management, inter-site and multi-site comparisons, pre-scheduled performance and status reports of multiple sites, and executive reporting, is key for O&M providers to be able to offer standardised services, performance guarantees and high performance ratio for system lifetime.

The transition of O&M activities from a labour and time-intensive task to being one that requires a few simple clicks is happening at the same time that new challenges are arising in the maturing PV market.

Aging systems require more maintenance, and with installations being geographically spread out, O&M teams are faced with an even greater burden in reaching these installations in a time-effective manner. This is where solutions with module-level monitoring, real-time detection, automatic alerts, and remote troubleshooting can be leveraged as strategic PV asset management tools in order to provide post installation services. These solutions enable O&M providers to become more effective by front loading many of their activities in the office. This not only helps improve the response time, but frequently saves costs for the O&M provider. In fact, these types of digitised strategic tools can actually enable 15-25% savings on annual O&M costs.   

While the new demands on O&M providers could potentially be overly demanding, module-level power electronics help these providers rise to the challenge. In fact, O&M providers can use module-level monitoring and remote troubleshooting in order to standardise and streamline their businesses and create new revenue streams through tailored O&M services.