Impact on Current-Interrupting Characteristic by Parameter Settings of Superconducting Hybrid DC Circuit Breaker

Sang-Jae Choi,Sung-Hun Lim

doi:10.3390/en14092469

Abstract

DC faults cause severe disruption in not only the DC system but also the AC system because the fault current is very large and rapidly increases. The DC circuit breaker used to separate the DC faults from the power system is still being researched, but it is very expensive due to the use of multiple power semiconductors to interrupt a large fault current in a short time. However, if the quench characteristic of a superconductor is used, the amplitude of fault current can be reduced. Therefore, it is possible to effectively interrupt a large fault current even if a relatively cheap mechanically passive DC circuit breaker is used. In the current study, a superconducting hybrid DC circuit breaker is proposed, and the limiting characteristics of each element are analyzed. By using two superconducting elements, the quench occurs sequentially twice according to the magnitude of the fault current, and the current-limiting reactor and resistance are used. If a current-limiting reactor is used in the DC system, the fault current rises slowly at the beginning of the fault, and the use of resistance can reduce the magnitude of the fault current. The inductance of the current-limiting reactor and resistance parameter settings of the hybrid DC circuit breaker was analyzed by the step-changing case method, and the interrupting characteristic of the DC circuit breaker was improved.

Highlights

IntroductionThe MTDC (multiterminal DC) system, called the electrical power system of the future, is expected to improve power quality and system stability
The MTDC system, called the electrical power system of the future, is expected to improve power quality and system stability
If CLR1 is set to resistance and CLR2 is set to inductance, the current flowing through the SW is greatly reduced, but on the contrary, the interrupting time is lengthened because the current flowing through the mechanical switch is large

Summary

Introduction

The MTDC (multiterminal DC) system, called the electrical power system of the future, is expected to improve power quality and system stability. The proposed DCCB uses the superconducting characteristics of HTSC1 to quickly limit the current in case of fault and reduce the power burden of the MS (mechanical switch). At this time, HTSC1 distributes power to dissipate energy, and the auxiliary circuit is configured in parallel with the main circuit to reduce the power capacity of HTSC1.In the auxiliary circuit, two CLRs (current limiting reactor/resistor), a second superconducting element, and a power switch are connected. For connecting CLR1 in this way is to increase the limiting effect of the fault current, and the reason for connecting CLR2 is to reduce the power burden by RSC2

Resistance Modeling of HTSC

Resistance Modeling of Arc

Discussion

Conclusions