Kongzhi Yu Xinxi Jishu (Jan 2021)
A Scheme of DC-side Short-circuit Protection for Bi-directional Converterin Urban Rail Traction Power Supply System
Abstract
Using bi-directional converters for traction power supply in urban rail transit, traditional PWM rectifiers cannot meet the requirement of DC feeder protection for 27 kA short-circuit current with 120 ms continuous time. For this reason, this paper proposes a DC-side short-circuit protection method to adapt to the traditional subway DC feeder protection. The scheme realizes effective isolation of the fault point in the case of a catenary short-circuit without affecting the power supply of the bi-directional converter. A bi-directional converter topology based on thyristor bypass is constructed, and then short-circuit bypass parameters, short-circuit current distribution parameters and short-circuit current rapid transfer control schemes are designed. At the same time, a traction power supply system simulation model based on bi-directional converters is constructed. The test results show that the system can withstand 27 kA short-circuit current and last for 146 ms. When the DC-side circuit is short, the system quickly transfers the short-circuit current to the thyristor bridge to bypass within 53 μs, which protects the safety of IGBT devices and ensures the reliability disconnection of the DC feeder circuit breaker.
