Study On Interrupting Capability Of HVDC Circuit Breaker Based On Principle Of Current Division

With the rapid development of HVDC transmission in china, the high voltageDC circuit breaker, as a switch apparatus being interrupt the direct current flowing,has increasingly attracted attention across the field of investigation about breaker. Thehigh voltage DC circuit breaker used in existing HVDC transmission have been usedthe principle of the superposition of oscillatory current flowing of which theamplification become increase more and more. When the amplification of arc currentis higher value, oscillatory current flowing can not be sure of creating the current zero.So, the interrupting capability of this circuit breaker will be limited, even not realizeits aim, especially if it face to ultimate current.In view of existing situation, from the angle of arc characteristic, according tosimulation and analysis about typical high voltage DC circuit breaker, it is confirmedthat the results of not interrupting circuit is large current. Considering this situation, amethod of inserting a resistor that can divide and limit the current of DC circuit torealize the aim of reducing amplification of current to interrupt circuit is proposed inthe paper. In addition, in order to control the resistor of circuit, other circuit breaker iscorrespondingly installed in DC main circuit which parallel connected the resistor.The breaker could interrupt a small DC and work in with main breaker. Theinterrupting of the breaker is the process that DC current in main circuit is divided andreduced. According to above idea, Circuit topology of high voltage DC circuit breakerbased on division principle is built. The results of the simulation and its analysis coulddistinctly show that the DC circuit breaker has the more perfect interrupting capabilitythan the typical in the HVDC system.The simulation model of high voltage DC circuit breaker is a key in the paper. Inthe light of four application of breaker in HVDC transmission, taking MRTB forexample as a target of simulation, the simulation model is built, ignoring factors to thephysical structure of the circuit breaker. Firstly, Mayr arc model is considered as a contact and built in Matlab/Simulink. Secondly, the proper parameters of Mayr arcmodel and accessory circuit are given by the methods of establishing three orderdifferential equation. Finally, a whole simulation model is built in Matlab/Simulink,from the simulation, its results can be analyzed. After all parameters have beenselected, interrupting a current is a certain matter of bringing it to zero when main DCcircuit is opened by the simulation.