Analysis of the effectiveness of methods for ensuring electromagnetic compatibility of electric drives with active rectifiers in real production conditions

A significant degradation of voltage quality of the in-plant network is possible during operation of electric drives based on a frequency converter with an active rectifier, due to the superposition of high-frequency harmonics of the electric drive current on the resonance region of the network frequency response. Due to the active introduction of such electric drives recently at metallurgical plants, various methods are implemented to ensure electromagnetic compatibility of the frequency converter and the power supply network. The purpose of this study is to analyze the efficiency of methods to ensure electromagnetic compatibility of electric drives and active rectifiers under industrial production. The effectiveness of various methods to improve the power quality in the power distribution system of the enterprise has been evaluated using the developed complex simulation model of the power supply system and electric drives of the hot strip mill. It considers the parameters of the main elements of the electrical complex, as well as the data of experimental studies obtained using the Fluke 435 and ELSPEC G4430 power quality analyzers. Two methods of ensuring electromagnetic compatibility of the frequency converters with active rectifiers are considered. The use of improved algorithms of the active rectifier PWM allows us to reduce the value of the total harmonics distortions at the point of common coupling THDU by 40,1 % to 8,08 %. The installation of a specialized passive filter 9000 kVAr allows us to achieve a significantly greater technical effect (THDU = 0,42 %). The obtained results show that for the enterprise under consideration the optimal option for ensuring the required power quality is the use of specialized passive filter. However, this option will require significant capital and operating costs. The adequacy of the simulation model has been previously confirmed by experimental data and previous studies.