Protection Logic Based on Intelligent Phase Change Switch Phase-to-Phase Short Circuit Fault

With the rapid development of distributed photovoltaic industry and new energy electric vehicles as well as flexible DC transmission, the phenomenon of three-phase imbalance in the distribution station area is becoming more and more serious. The phase change switch can solve the problem of three-phase unbalance by regulating the load balance and has been applied in the power grid. However, the current topology of phase change switches is generally defective in terms of phase-to-phase short circuits, which is a threat to the normal operation of the grid if the equipment fails. In this paper, we analyze the topology of the phase change switch, derive the defects of the topology, and propose a phase short circuit protection logic to address the defects. The protection logic interlocks the trigger signals of the phase change switch manipulator to effectively avoid phase short circuit faults. Finally, the effectiveness of the proposed protection logic is verified by MATLAB/Simulink simulation. The simulation results show that the phase-to-phase short-circuit protection logic avoids the risk of faults that may be caused by the phase change switch and makes its operation more stable and reliable.