First author:	Lukamp, H.
Organization:	Fraunhofer Institut für Solare Energiesysteme by order of IEA PVPS Task 7 and funded by the German Ministry BMWi under contract 032 9786.
Reference:	IEA T7-08: 2002
Date of issue:	March 2002
Type:	Report IEA  PVPS Task 7
Details:	31 p.: figures, graphs, photographs, tables; with references and separate appendices
Download:	Open or download this report as PDF document (826 KB) Open or download separate appendices to the report as PDF document (651 KB)
Available from:	Task 7 members
Abstract:	In the frame of IEA PVPS Task 7 PV in the Built Environment a survey was conducted to collect information on faults, failures and poor performance from PV plants. Data were collected from Australian, Austrian, British, Canadian, Dutch, German, Japanese, Spanish, Swedish, Swiss and US systems. The focus lies on residential systems with a nominal power of 1–5 kWp, but large systems up to the 3,3 MWp "Serre" plant were included as well. Looking at failures statistics over time from residential PV programs shows the typical "learning curve" of decreasing failure rates. The inverter still proves to be the weakest component. Standard PV modules have reached a high quality standard today. They have matured over the last 20 years and show failure rates down to 0,01% per year. However, there are some brands which exhibit less STC power than stated by the manufacturer. Inverters too, have matured remarkably. Experience from most recent projects shows troublefree operation for 10 years. Nevertheless, when a high buy-back rate has been contracted, then care should be given for a good service of the inverter manufacturer, for example a 24 h replacement warranty. Critical are novel electronic components, e.g. inverters, special grid interfaces or ac/dc RCDs. These need some field experience before they work reliably. Main reasons for low yield of some systems within the German "1000-Roofs-Programme" systems were inverter failures, over-rated power of modules, partial shading of the array, soiling, and faulty connections on the dc side. Failure analysis leads to recommendations for good design and installation practice and improved junction boxes. Modern Class II components offer the system designer the liberty to dismiss string diodes and string fuses. This results in simpler and more reliable systems. As a minimum level of maintenance it is recommended: To inspect arrays once per year To clean arrays regularly, if soiling is noticed. To perform a monthly check of electrical production

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