Abstract
To protect power systems from severe short circuit faults, the zero-current switching (ZCS) technique is widely accepted due to its fast interruption speed. However, the traditional ZCS technique is more complicated in bidirectional switching, which limits its wide application, especially in AC power systems. Therefore, a novel auto-oriented bidirectional ZCS hybrid circuit breaker is proposed to simplify the overall topology of the circuit breaker. The design of the ZCS hybrid circuit breaker is based on the idea of diverting the pulse current toward the reverse direction of the fault current by the arcing voltage itself. The proposed scheme can interrupt bidirectional faults with just one ZCS circuit, without detecting fault current direction. Firstly in the paper, the topology and operating principles of the proposed bidirectional ZCS hybrid circuit breaker are introduced. Moreover, the key parameters are optimized to make the hybrid circuit breaker capable of bidirectional interruption automatically. Furthermore, dielectric recovery characteristics of the vacuum interrupter under special conditions are also measured to determine the design parameters. The proposed topology of the bidirectional ZCS hybrid circuit breaker is validated using a 450VAC/630A prototype. Short circuit breaking tests of the prototype are conducted without detecting fault current direction in advance. Experimental results show that the breaking time of the prototype is less than 1 ms in clearing either direction of fault current with a prospective value of 20 kA and $\text{d}i/\text{d}t$ of 8 A/ $\mu \text{s}$ . The feasibility of the proposed scheme is verified with these test results.
Highlights
The ever-increasing power capacity of modern power systems has increased the level of short-circuit currents significantly and is threatening the power systems’ stability and safety [1,2,3]
In the zero current switching (ZCS) technique, an additional pulse current is needed, which flows in the opposite direction to the mechanical circuit breaker after its opening, and brings the fault current in the Mechanical circuit breakers (MCBs) to zero without being restricted by the arcing voltage [13,14]
A novel bi-directional ultrafast hybrid circuit breaker (UFHCB) topology based on ZCS is proposed
Summary
The ever-increasing power capacity of modern power systems has increased the level of short-circuit currents significantly and is threatening the power systems’ stability and safety [1,2,3]. In the ZCS technique, an additional pulse current is needed, which flows in the opposite direction to the mechanical circuit breaker after its opening, and brings the fault current in the MCB to zero without being restricted by the arcing voltage [13,14]. The main contributions of this paper can be summarized as follows: 1) A novel bidirectional topology of the ZCS hybrid circuit breaker is introduced, in which the arcing voltage of the mechanical circuit breaker is utilized to orient the pulse current to the MCB in the reverse direction of the fault current. 2) The constraints on key parameters of the ZCS hybrid circuit breaker are deduced to have the optimal breaking performance The diode on another parallel branch is clamped at off state by the arcing voltage.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
