Abstract: ABSTRACT：  Current-breaking test is the core part of the operation tests for DC circuit breaker, whose effectiveness is directly related to the verification of the electrical performance of DC circuit breakers. This paper studies the current-breaking test method of hybrid HVDC circuit breaker for MMC-HVDC system, aiming to present the current-breaking test method and  test parameters for engineering feasibility. Firstly, based on the analysis of the principle and working condition of hybrid  HVDC circuit breaker, we reveal the its stress characteristics； then, on the basis of stress extraction, we present the LC source test circuit and parameters； finally, we verify the accuracy of the simulation circuit and test method through the short-circuit current-breaking test for a 200 kV circuit breaker, whose results can provide reference for the current-breaking test design of hybrid HVDC circuit breaker.

Key words:  MMC-HVDC, LC circuit, hybrid HVDC circuit breaker, operation test, breaking test, stress analysis