The power grids of industrial plants have changed dramatically over the past two decades. In the past, the primary concern was still reactive power compensation to ensure that the voltage would remain stable and transmission losses would be reduced. But since the 2000s, an increasing number of frequency-controlled drives are being used in machines. These machines are very energy-efficient, but the power electronics have negative impacts on the grid. The more these types of drives are used, the more harmonics occur.