A Zero Crossing Hybrid Bidirectional DC Circuit Breaker for HVDC Transmission Systems

Abstract

With the increasing demand for renewable energy power generation systems, high-power DC transmission technology is drawing considerable attention. As a result, stability issues associated with high power DC transmission have been highlighted. One of these problems is the fault current that appears when a fault occurs in the transmission line. If the fault current flows in the transmission line, it has a serious adverse effect on the rectifier stage, inverter stage and transmission line load. This makes the transmission technology less reliable and can lead to secondary problems such as fire. Therefore, fault current must be managed safely. DC circuit breaker technology has been proposed to solve this problem. However, conventional technologies generally do not take into account the effects of fault current on the transmission line, and their efficiency is relatively low. The purpose of this study is to introduce an improved DC circuit breaker that uses a blocking inductor to minimize the effect of fault current on the transmission line. It also uses a ground inductor to efficiently manage the LC resonant current and dissipate residual current. DC circuit breakers minimize adverse effects on external elements and transmission lines because the use of elements placed on each is distinct. All of these processes are precisely verified by conducting simulation under 200 MVA (±100 kV) conditions based on the VSC-based HVDC transmission link. In addition, the mechanism was explained by analyzing the simulation results to increase the reliability of the circuit in this paper.

Design and Validation of efficient Z source breaker with voltage stress reduction for DC Microgrid

“…Suppose the fault conductance ramp from [0 t], the fault conductance can be expressed as (8) Where k is the rising fault rate Let us assume the internal source inductance is negligible and constant load current, the fault current by load capacitor is detemined as…”

“…However, switching and conduction losses are substantial [7]. Adapting advanced techniques with conventional DC circuit breaker can mitigate limitations, such as moderate fault-breaking capability, prolonged auto reclosing time, and sudden voltage spikes that affect the lifespan of the protective device [8].…”

4-Pole Hybrid HVDC Circuit Breaker for Pole-to-Pole (PTP) Fault Protection

“…In addition to the path through B pos and B neg , C pg is charged through D pos and D neg . For C PG , when charging is complete, DC current no longer flows and no additional power loss occurs [30]. In the case of PTP fault, as shown in Fig.…”

“…In general, this detection measures the current near the port of Converter Station 1(pos) and Converter Station 2(neg), and sends a signal when there is an abnormality of a predetermined value (1.3 times the stead-state current in this paper) accurately measured. During this process, as the T PG is turned on, a reverse charging process occurs, generating a higher resonant current [30], [31]. Turn B pos and B neg to completely break the main line when creating zero-crossing point on the positive and negative lines respectively [32], [33].…”

Protection of Future Electricity Systems

“…Both HVDC and LVDC systems are being developed, and the protection of such networks has a separate set of challenges in terms of ultra-fast fault detection and classification requirements, fault-ride through capabilities, and DC fault current breaking. Therefore, we are pleased to present four papers [3][4][5][6] that tackle various aspects of DC network protection.…”