Quantum mechanics

Direct current

Overvoltage

Voltage

Engineering

Short circuit

Materials science

Power (physics)

Resistive touchscreen

Computer science

Fault (geology)

Seismology

Limiter

Geology

Current (fluid)

Current limiting

Mechanical engineering

Physics

Prospective short circuit current

Fault current limiter

Electric power system

Superconductivity

Condensed matter physics

Circuit breaker

Short circuit ratio

Limiting

Converters

LED circuit

Electrical engineering

Superconductor Science and Technology

Resistive-type superconducting fault current limiters (R-SFCLs) can limit short-circuit fault current and help DC circuit breakers (DCCBs) to isolate short-circuit faults in medium voltage and high voltage DC (HVDC) systems. SFCLs are always used with circuit breakers to break short-circuit current in power systems. The interruption characteristics of the DCCBs influence the current-limiting characteristics of the SFCLs. However, there has been a lack of investigation into the current-limiting and interruption characteristics when R-SFCLs are combined with mechanical-type DCCBs (M-DCCBs) based on the self-excited oscillation interruption principle in medium voltage and HVDC systems. The objective of this paper is to obtain the short-circuit fault current-limiting characteristics of a designed R-SFCL combined with an M-DCCB in DC grids. This paper describes the design of a 10 kV DC R-SFCL which was tested in combination with an M-DCCB in a DC circuit in order to obtain the quenched resistance and the required current interruption characteristics. Besides, a modular multilevel converter-based multi-terminal direct current (MMC-MTDC) grid was used to investigate the current-limiting and interrupting characteristics of the R-SFCL and the M-DCCB in a realistic HVDC grid. The experimental results show that in the 10 kV DC circuit the R-SFCL combined with the M-DCCB limited a 10 kA DC to the peak value of 1416 A and then interrupted this limited current successfully. And unlike other methods of DC interruption, this did not create overvoltage after interruption. The highest voltage on the R-SFCL is the system voltage during interruption. This means that the R-SFCL can effectively delay the voltage drop in MMC-MTDC grids, and provide enough time for the M-DCCB to interrupt the limited current. Thus, a combination of R-SFCLs and M-DCCBs might be an effective and reliable method to interrupt short-circuit fault currents in medium voltage and HVDC grids.

Short-circuit fault current-limiting characteristics of a resistive-type superconducting fault current limiter in DC grids