{"id":70887,"date":"2021-12-03T07:49:38","date_gmt":"2021-12-03T07:49:38","guid":{"rendered":"https:\/\/www.dewetron.com\/news\/harmonics-in-wind-power-plants-part-2\/"},"modified":"2026-09-20T02:24:09","modified_gmt":"2026-09-20T02:24:09","slug":"harmonics-in-wind-power-plants-part-2","status":"publish","type":"post","link":"https:\/\/www.dewetron.com\/us\/news\/harmonics-in-wind-power-plants-part-2\/","title":{"rendered":"Harmonics in wind power plants – part 2"},"content":{"rendered":"
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Already in the “Harmonics in Wind Power Plants – Part 1\u2019\u2019 <\/em>blogpost, we recognized that harmonics are a major problem in power generation. They lead to premature aging of components, power losses and endanger the stability of the power grid. For all these reasons, one would like to avoid harmonics as much as possible. However, this is not an easy task and the very first thing we need to do is to find out how harmonics do emerge in the first place.<\/p>\n\n <\/div>\n <\/div>\n <\/div>\n <\/div>\n<\/div>\n\n\n

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The origin of harmonics in wind turbines<\/h2>\n
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The reasons which lead to the development of harmonics are manifold. However, non-linear effects, i.e. effects that distort the ideal sinusoidal signal, almost always play a role.<\/p>\n

Many power electronic components are non-linear. They use only certain parts of the sinusoidal signal, distorting it and creating higher modes. Such components may be capacitors, coils or frequency converters. Especially frequency converters are the reason that only certain harmonics are present in the signal. For example, a 6-pulse frequency converter leads to strong harmonics of order 6n+1 and 6n-1 where n is a positive integer (orders 5, 7, 11, 13, 17, 19…). On the other hand, a 12-pulse frequency converter leads to strongly present harmonics of order 12n+1 and 12n-1 (11, 13, 23, 25…).<\/p>\n

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Harmonic analysis with OXYGEN software<\/em><\/p>\n

Another source of higher modes are transformers. To keep the efficiency of transformers as high as possible, they usually operate at the saturation point. Since this is where they have the lowest power losses. However, this brings with it the risk that the transformer can also go into the oversaturated range. In this state, it produces harmonics with odd order (3, 5, 7, 9…).<\/p>\n\n <\/div>\n <\/div>\n <\/div>\n <\/div>\n<\/div>\n\n\n

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How to avoid harmonics<\/h2>\n
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Now we can discuss what to do to avoid higher modes. In practice, there are two methods, which one usually combines:<\/p>\n