On December 26, 2022, the first PCS-8353 arc less fast DC circuit breaker independently developed by NR was successfully put into operation on Zhengzhou Metro Line 3. The DC circuit breaker is based on the design concept of fast breaking without arc.
Compared with the air DC circuit breaker, the fault breaking time is shortened from tens of milliseconds to less than 2 milliseconds, and the number of near end-fault current breaking is increased to more than 200. After breaking, the equipment does not need maintenance, and the core performance parameters of the equipment are superior to those of the same level product.
DC traction power supply system
At present, the air mechanical circuit breaker widely used in the DC traction power supply system of urban rail transit will have a large number of arcs during the breaking process.
Each breaking will ablate the circuit breaker contact and arc extinguishing grid, resulting in low electrical life and high maintenance costs. In addition, due to the slow breaking speed, the actual cut-off current is close to the expected maximum short-circuit current of the system, which has a great impact on the system.
Hybrid DC circuit breaker topology
PCS-8353 arc less fast DC circuit breaker adopts an merged handcart system design, which is compact in size
In order to solve the above problems, NR creatively proposed a hybrid DC circuit breaker topology based on high arc voltage vacuum commutation, relying on the successful application of ± 500kV high-voltage DC circuit breaker and ± 10kV DC distribution network circuit breaker, which can realize no visible arc during the breaking process and maintenance free after equipment breaking, while greatly improving the breaking life to meet different application conditions of urban rail transit DC power supply system.
The PCS-8353 arc less fast DC circuit breaker adopts an integrated handcart structure design, which is compact in size. The external primary and secondary interfaces can be compatible with the air type DC circuit breaker to meet the rapid replacement application of new construction and reconstruction projects.
NR Rail Transit product solutions
NR has continuously cultivated the urban rail transit industry for more than ten years. More than ten kinds of products in three series of comprehensive control, smart power supply and green energy conservation have been successfully applied to nearly 200 subway lines in more than 40 cities in China, among which the market share of 35kV relay protection, SVG and master substation integrated automation system for rail transit is leading.
As an important member of NR Rail Transit product solutions, PCS-8353 arc free fast DC circuit breaker will provide a more safe and reliable protection means for urban rail transit DC power supply system.
