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May 13, 2014  | Glenna Wiseman  | 4 Comments

Solar fault reduction

Guest contributor Glenna Wiseman discusses best solar operations and maintenance practices for resolving PV power plant faults

The prompt resolution of photovoltaic plant faults and incidents is one of the most critical functions of a solar operations and maintenance (O&M) program. Incidents can have an immediate impact, and depending on their frequency, they can be a stubborn obstacle to achieving the operational optimization of PV assets. Incident handling is thus a key factor in efforts to maximize power plant performance and hence revenue.

Solar PV plant fault resolution time depends primarily on three factors:

–Time until a fault is detected.
–Intervention time and responsiveness of field technicians.
–Actual resolution/remedy time on site.

There are three “best practice” cornerstones of solar PV plant optimization that can directly reduce incident-handling issues: proper monitoring and other IT infrastructure; knowledge building and dissemination across the organization; and training of personnel, mainly field technicians.

For an effective solar O&M program, the importance of a robust IT infrastructure incorporating a suitable monitoring system cannot be overemphasized. Monitoring acts as the eyes of the contractor on the PV plant, without which the system plant operator is fundamentally blind and in the dark. In relation to incident handling, a well-designed monitoring solution should be capable of:

–Instantly recognizing and logging malfunctions and creating the respective notifications.
–Recognizing medium- and long-term deviations in the data.
–Capturing more operational parameters than just the typical inverter and meter energy, irradiation, and       temperature data.

Recognizing malfunctions quickly is sometimes easier said than done. During plant operation, especially during high irradiation hours, massive data is generated. The key to a sophisticated alerting system lies in the capture and evaluation of all this data with specialized algorithms so that false positives and negatives are minimized. After all, what good is an alert system if it generates hundreds of false alerts? This kind of malfunction can distract control room personnel from authentic issues and thus prolong the actual detection time of real faults.

Supervisory control and data acquisition (SCADA) systems can generate alerts based on the data measured online, yet they cannot evaluate medium- or long-term trends. This analytical capability becomes especially important when there is no immediate acute fault, but rather when a fault manifests as a trend of gradual performance degradation not identifiable with the comparison of parameters over a short period of time (e.g., 15 minutes). Soiling on the panels provides a simplified example of the drawbacks of a time-limited SCADA system that does not reveal any immediately evident fault. A proper monitoring system would provide a comparison of performance over a period of days or weeks and expose the loss of performance.

Another important parameter of a well-designed monitoring solution is the collection of the event-log entries of the devices used in the PV plant as well as a series of other measurements not related to the inverters. While most monitoring software in the market captures only the inverter energy, meter energy, temperatures, irradiation, and other basic data, a sophisticated platform analyzes dozens of additional parameters that can provide plant personnel with valuable information.

Whatever their location, PV plants all over the world operate on the same principles and use similar designs and equipment. Consequently, similarities in fault occurrences and origins can be tracked across geographically distributed plants. Building a knowledge base of the resolution of various faults and distributing this knowledge across the organization assists technical personnel. Workers do not have to reinvent the wheel on each occasion, but can refer to a database of solutions to problems encountered in the past. This dramatically shortens the time needed to actually resolve issues since research time is minimized.

Even with a perfect monitoring system and an extensive knowledge database, the job is still done by humans. Training is a critical part of providing high-quality services. The better technicians are trained, the quicker they can understand instructions, provide reliable information, and act decisively on site.

Training should not be a one-off task. There is clearly a need and a benefit of closely monitoring the performance and competency of technical crews and reviewing them on a regular basis. The ultimate goal should be to understand the shortcomings of a team and organize specialized training sessions to address such deficiencies.

Companies with experience in other O&M sectors (e.g., telecommunications or facility management) are entering the solar PV O&M market.  Although at first glance this migration may seem to be a logical step, one should consider what level of efficiency that a technical crew not trained specifically on PV technology can have when asked to resolve complex issues on solar power plants. Without ongoing, solar-specific training, such experienced personnel may not perform up to expectations.

Responsiveness and the quick resolution of faults are critical to maximizing the performance and output of PV power plants. Of course, the ultimate goal is to avoid failures altogether. This may be theoretically possible if failure prognosis methods are used. Such techniques are widely deployed in other mission-critical industries and are now being introduced in the solar PV sector.

(This article is excerpted and adapted from “Increasing Solar PV Plant Profitability by Minimizing Fault Resolution Times – Part 1,” originally published on the Alectris corporate blog.)

Glenna Wiseman, the founding partner of communications firm Identity3, has been an executive marketing professional in the solar industry since 2007. Her expertise includes work with companies along the solar supply chain. Glenna and her partner, Raina Russo of #SolarChat, are the cofounders of Women4Solar. She can be reached at GWiseman@Identity3.com.

PHOTO OF SOLAR POWER PLANTS IN GEORGIA COURTESY OF ORIGIS ENERGY AND ALECTRIS


 
Sources: Alectris, Glenna WIseman

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