Applying of surge arresters in power electronic network components

The increased use of renewable energy sources and connection of energy storage systems to energy distribution networks of the future on the basis of DC voltage demands new power electronic modules with a higher degree of efficiency, reliability and with materials saving. In this article, the overvoltage protection concept on the basis of metal oxide varistors (MOV) for such network components as pulse-width modulation (PWM) modules and DC-to-DC converters as well as a new patented, innovative power-electronic topology concept [1, 2], which allows the regenerative energy sources connect direct to the medium-voltage distribution system is introduced. The distorted voltages from converters and from other power electronic network components are characterized by high-frequency pulsating voltages which generate leakage currents because of MOV capacitance. This leakage current in its turn can overheat the MOV and accelerate its thermal ageing. The main focus of this work is to study the distorted voltages in already mentioned network concepts and its influence on installed MOV and vice versa. The concept of overvoltage protection for some network components is presented. Additionally, an effort to combine the overvoltage protection system with some other useful functions for converter, such as definition of reference potential of the internal ground, was fulfilled.