Real-Time Simulation Modeling Study of the HVDC Circuit Breaker Based on Nodal Dynamic Equation

Voltage-sourced converter based high voltage direct current system is expected to play a vital role in the future power transmission system. As one of the key equipment to ensure safe and reliable operation of the VSC-HVDC systems, HVDC circuit breakers play a critical role in establishing DC grids, improving grid operation flexibility and enhancing power supply reliability. In order to save the computational resources and accurately simulate the characteristics of each part of the circuit breaker during the fault isolation process, with the help of nodal dynamic equation and the transmission line decouple modeling method, this paper proposes a simplified equivalent modeling method for the DC circuit breaker and establishes a hybrid DC circuit breaker model in Field Programmable Gate Array (FPGA) to realize real-time simulation. By using the method proposed in this paper to conduct DC breaker real-time simulation, there is no need to implement any kind of delay compensation algorithm, which simplifies the DC breaker modeling studies and makes this method become easy to implement. Detailed comparisons have been made between this FPGA model and the detaild DC circuit breaker model in PSCAD. Results show a good match between these two models, which verify the proposed DC breaker model and the solving method, which is based on the nodal dynamic equation.