Hybrid DC circuit breakers

based on current transfer principle

are uneconomical for the high construction cost when they are applied in multi-line high-voltage DC grids

and that DC switchyard shares "main breaker" is an effective way to solve the above problem. Different topologies of DC switchyard have different characteristics. Summarizing

analyzing

and comparing characteristics of different topologies of DC switchyard will help deepen the understanding of DC switchyard and provide a guidance for selection of engineering applications. In this paper

the proposed DC switchyard is divided into three types

based on three different kinds of current transfer modes of DC switchyard: selective transfer

single transfer

and all transfer

The topologies and working principles of different types of DC switchyard are introduced

and the basic requirements for the DC switchyard in the future high-voltage DC networks are summarized. Reclosing function

failure protection for ultra fast disconnector

complexity of action and economy of different kinds of DC switchyard are also compared and analyzed. It is concluded that transfer-type DC switchyard is the most promising DC switchyard in high-voltage DC power grids. Finally

the relative research recommendations of DC switchyard are given.