Cable damages in the wind farm lead to high costs. If they remain undetected, short circuits may occur, leading to turbine standstills. Usually, it takes several days until the wind farm is back in operation. \u201cThis depends on the type of the damage and on the availability of the service personnel. For a normal damage, operators\u00a0 can expect some five days of yield loss,\u201d Oliver Klausch, head of technical management at wpd windmanager GmbH & Co. KG explains. For an average wind turbine generator, down time yield losses amount to some 5,000 Euros a day. \u201cAt an average, we have five turbines to a wind farm, this means, we are speaking of 125,000 Euros of yield loss,\u201d so Klausch\u2019s calculation. If the wind farm is beyond the warranty period, costs for localization of the damage and repairs must be added. Money, that the wind farm operator could save by cable testing, says the head of technical management: \u201cAccording to experience, the reasons for a cable damage are always due to improper cable construction prior to commissioning of the wind farm \u2013 around 80 per cent based on faulty mounting of the fittings and the remaining 20 per cent based on incorrect installation in the ground\u201d. Since most operators check the cables at commissioning only by VLF and cable sheath measurements, the majority of damages remain undetected.<\/p>\n
Wind farm operators may protect themselves \u2013 for instance \u2013 by partial discharge measuring. This will uncover weak points, such as incorrectly installed fittings. The exchange will then be done during low-wind periods \u2013 even before down-times occur. Evaluations from the wind manager data bank show, that \u2013 on an average \u2013 every other wind farm will be affected by cable damage during its operating time. Especially prior to expiration of the warranty period, operators are advised to check their wind farm for cable damages, enabling them to claim compensation from the cable builder for possible faults. \u201cTime and cost involved for such a test are absolutely manageable,\u201d says Klausch, \u201cespecially in relation to a possible yield loss.\u201d<\/p>\n