This article describes the development of current sensors used in DCU-type high-speed circuit breakers. DCU-type circuit breakers use the principle of turning off a constant short-circuit current by means of countercurrent. The article presents a new current sensor design called PIKh, which uses Hall sensors to measure current and determine its direction. PIKh sensors allow parallel operation of high-speed circuit breakers during the “parking” operation. The article includes the algorithm and principle of operation of the PIKh sensor. The proposed solution was verified on an electric traction vehicle.

This article describes various designs of high-speed DC circuit breakers used in the world and current detection methods using modern current sensor solutions. The crite-rion for selecting circuit breakers for testing was their certification for use in the European Union – the LOC&PAS TSI certificate of conformity (Commission Implementing Regula-tion (EU) 2023/1694). The possibility of parallel operation of circuit breakers from different manufacturers and different methods of switching off the short-circuit current were ana-lyzed. Tests were carried out at a 3 kV traction substation in real operating conditions of circuit breakers, which allowed us to answer the question regarding the possibility of using two different types of circuit breakers on one traction vehicle.

The use of advanced switching technologies, including hybrid and fully semiconductor-based circuit breakers, enables a significant reduction in the prospective short-circuit current. This enhances the level of circuit protection by minimizing thermal and electrodynamic stresses. One of the available solutions is a hybrid DC circuit breaker employing the forced commutation method, in which a counter-current generator is incorporated into the auxiliary branch. Increasing requirements not only for short-circuit protection reliability but also for operational flexibility impose the need to configure DC breakers for parallel operation. This paper presents an analysis of the performance of forced-commutation circuit breakers connected in parallel with another identical device, as well as with a conventional fast magnetic blow-out breaker. To prevent unintended and undesired tripping, the influence of counter-current generator parameters on the overcurrent protection response was investigated. In the analyzed configuration, the applied hybrid DC breaker limits the expected short-circuit current from approximately 45 kA to 5 kA within about 2 ms.