Critical Damping in Travel Curves of Piezoelectrically Actuated Fast Mechanical Switches for Hybrid Circuit Breakers

The direct current circuit breakers are considered a promising option to protect the transmission line against commonly appearing line-to-ground fault. However, the challenges of losses in the nonoperational stage, escalation of response against fault current, and large fault current handling capability remain the debatable issues for direct current circuit breakers. This paper introduces a novel topology of the hybrid circuit breaker with fault-current-limiting characteristics, which contains three branches: the main branch, fault-current-limiting branch, and energy absorption branch. The main branch includes a mechanical switch, breaker impedance, and bidirectional power electronics switches. In the fault-current-limiting branch, a fault-current-limiting circuit is introduced which contains n numbers of bidirectional switches and current-limiting inductors, which are connected in series to make the design modular in nature. During the normal working stage, the current flows through the main branch of the breaker. Once a fault in the system is confirmed, the fault current is transferred to the fault-current-limiting branch. At this stage, the intensity of the fault current is reduced significantly using the fault-current-limiting circuit, and finally, the residual current is shifted to the energy absorption branch. The working principle, design considerations, and parametric analysis concerning the design of hybrid circuit breakers are incorporated in this paper. The performance of the proposed breaker is evaluated using a three-terminal voltage-source converter-based high-voltage direct current transmission network; for this purpose, a PSCAD/EMTDC simulation tool is used. The performance of the proposed breaker is also compared with other topologies. The comparative analysis shows that the proposed breaker is a good alternative considering high fault current interruption requirements, response time against fault current, and power losses.

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Low-Voltage Circuit Breakers Based on WBG Solid-State Devices

Journal of Circuits System and Computers ◽

10.1142/s0218126618500202 ◽

2017 ◽

Vol 27 (02) ◽

pp. 1850020 ◽

Cited By ~ 1

Author(s):

Jelena Milojković ◽

Vančo Litovski ◽

Simon Le Blond

Keyword(s):

Solid State ◽

Low Voltage ◽

Systematic Evaluation ◽

Circuit Breakers ◽

Electrical Arc ◽

Solid State Circuit ◽

Silicon Devices ◽

Solid State Devices ◽

Power Switches ◽

Hybrid Circuit

Conventional circuit breakers suffer from two main deficiencies: they are slow to operate and develop an electrical arc. These may be overcome by using solid-state switches which in turn introduce other problems, most significantly power dissipated while in the on-state. Nevertheless, a number of solid-state devices are candidates for implementation as low-voltage circuit breakers and there are several options based on the semiconductor material that may function as high-power switches. This paper presents a unique, extensive and systematic evaluation of these options. Voltage-controlled devices are selected due to the simplicity of the controlling circuit and their resilience to [Formula: see text]/[Formula: see text]-induced switching. Properties of fully solid-state circuit breakers are established and systematic comparisons are made among switches built of silicon and other wide bandgap (WBG) devices such as SiC MOS and GaN HEMT transistors. Using SPICE simulation it is shown that solid-state circuit breakers (SSCBs) based on WBG devices exhibit superior characteristics compared with silicon devices, with faster switching and higher voltage and current ratings. Hybrid circuit breakers, combining both conventional and solid-state switches, are discussed too and a new design circuit is simulated and compared to both conventional and fully solid-state designs.

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