Static frequency converters with reduced parasitic effects

Parasitic effects caused by static frequency converters, like EMI, may endanger the reliable operation of drives or turbine shaft arrangements and diminish its lifetime. Converter drive applications for large plants up to 50 MVA can cause shaft voltages up to 500 V_PP if a non optimised converter design is chosen. This phenomenon is investigated. Design options for the converter and the plant arrangement are discussed. The influence of the most suitable solution and their influence upon electromagnetic interference (EMI) and the shaft voltages is shown and conformed by measurements in real power plants.