A Surgeless Solid-State DC Circuit Breaker for Voltage-Source-Converter-Based HVDC Systems

Abstract

This paper proposes a dc circuit breaker for voltage source converter (VSC) based high-voltage dc transmission (HVDC) systems. Technical challenges for applying dc circuit breakers are to increase blocking voltage and to suppress surge voltage at the current clearing. The proposed dc circuit breaker is a solid-state breaker which consists of a number of semiconductor devices in series. It maintains equal voltage balancing among the devices to apply it to high-voltage applications. Moreover, the surge voltage across the circuit breaker is reduced by employing a freewheeling diode. Considering a system rated at 300 MW in power and 250 kV in dc voltage, the conduction loss of the proposed circuit breaker is estimated to be 0.045% of the rated power. The value is smaller than the power loss of the VSCs. A downscaled HVDC system rated at 10 kW in power and 360 V in dc voltage was built and tested. A series of experimental results demonstrates the dc fault clearing and rapid restoration of power transmission. Index Terms-DC circuit breaker, fault protection, high-voltage dc transmission (HVDC), voltage-source converter (VSC).

Fault Handling Methods and Comparison for Different DC Breaker Topologies and MMC Topologies of the HVDC System

“…The first way uses different circuit breakers in the HVDC line in order to cut off the fault current. There are three types of circuit typologies: all-solid HVDC breakers [3], resonant HVDC breakers [4], and hybrid HVDC breakers [5].…”

Protection of the MMCs of HVDC Transmission Systems against DC Short-Circuit Faults

“…Meanwhile, DC circuit breakers can provide fast responses for blocking fault current. However, this technology is short in terms of practical field experience and expensive [7], [8]. It is presently under development for high power applications.…”

Hybrid Energy Storage Implementation in DC and AC Power System for Efficiency, Power Quality and Reliability Improvements

“…Alternatively, the surge arrester can be directly connected in parallel with the semiconductor device [205]- [207]. However, this will result in a higher rating and volume of the surge arrestor [208].…”

“…In this case, a similar resistor should be connected in parallel to switching devices to maintain voltage balance in steady states. Also, in order to balance the voltage of the semiconductor device during turn-off transients, a snubber circuit can be utilized, as shown in Figure 8.6, to realize zero voltage switching [206], [208]. The main advantage of the SSCBs is that they are very fast and are able to operate in microseconds.…”

“…Thus, for the safety issues and in order to interrupt the leakage current after the SSCB operation, implementation of galvanic isolators is essential [177], [206], [208]. Galvanic isolators, also known as disconnecting switches, realize physical isolation through a mechanical method.…”