Coordination of Current Flow Controller with HVDC Circuit Breakers for Meshed HVDC Grid Systems

A Voltage Source Converter based High Voltage Direct Current (VSC-HVDC) are the most efficient and reliable method for electrical power transmission and implementation of HVDC grids over long distances. Generally, a meshed HVDC transmission grid has major problems such as protection against dc faults and to manage the power flows between the lines. As Current Flow Controllers (CFCs) will be required to balance line currents between nodes in meshed-HVDC grids. Hybrid circuit breaker with forced commutation can interrupt the fault current and thus protect grids of HVDC from dc faults but the fault clearing time for the available dc breakers are not fast enough and reliable to provide adequate protection for dc faults on multi-terminal networks. In order to overcome these problems CFCs is interline with hybrid dc circuit breaker. So, CFC will be interline with Pro-active Hybrid DC-Circuit Breaker (PHCB) by suffling the switches orientation within the Load Commutation Switch (LCS). The CFC design and its control performance will be verified by MATLAB Simulink. The two cases are studied which include, an integrated system consisting of CFC with Circuit Breakers (CBs) and the separate design that includes CFC and CB separately that are compared and thus power losses can be reduced.