A novel thyristor-based hybrid DC circuit breaker with short arcing capability

Abstract

Multi-terminal flexible high-voltage direct current (HVDC) transmission and DC grid technology are developing rapidly. The hybrid DC circuit breaker (HCB) has broad application prospects in the field of HVDC transmission and DC power grid. Nevertheless, existing HCBs have one or more following blemishes: arc suppression scheme of mechanical switch, high cost and unreliable adaptive reclosure. In this paper, a modified thyristor-based hybrid DC circuit breaker with short arcing capacity (SA-HCB) is introduced, which consists of the main branch, the fault handling branch and the pre-charging branch. Besides, the modified SA-HCB has the inherent capability of adaptive reclosing. The advantages of thyristors are fully used in the SA-HCB, such as low cost, low conduction voltage drop, and natural shutdown. The detailed structure diagram and mathematical model of the SA-HCB are introduced, and the operation processes of the fault current transfer are also analysed. Later, a design method for parameters of the proposed SA-HCB is provided. Then, a single-ended equivalent system is built in PSCAD/EMTDC to verify the accuracy of the theoretical analysis and parameter design. Subsequently, based on four-terminal simulation, the economy of the SA-HCB is verified by comparing with the topology proposed by ABB. Finally, the small-scale experiment of the proposed SA-HCB is introduced.