782 / 2019-04-28 21:47:56

Research on Characteristics of Pole-to-Pole Fault in DC/DC Transformer with Fault Blocking Capability

DC/DC transformer,fault characteristic,fault blocking,pole-to-pole fault

DC/DC transformer with fault blocking capability can isolate fault without DC circuit breaker, which is an important research and development direction of DC system. Studying its fault characteristics is of great significance to ensure the safe operation of the power system. The working principle of hybrid modular multilevel DC/DC transformer with fault current blocking capability is analyzed, and the equivalent circuit models of DC/DC transformer before and after its blocking operation are studied. When the system has pole-to-pole fault on one side of the DC/DC transformer, the transient characteristics of electric quantities on both ports of DC/DC transformer before and after its blocking operation are studied. The analytical expressions of transient voltage and short circuit current of the fault port are studied and compared with the fault characteristics without blocking operation. Finally, PSCAD/EMTDC is used to build the simulation model and verify the analysis results.