A Calculation Method for the Lower Limit of Inductance Suppressing Large Current in DC Traction

Abstract

The present invention relates to a calculation method for a magnitude lower limit of direct current traction large-current suppressing inductance. In a current trolleybus traction power supply system, when a metal short-circuit occurs near a joint of a direct current out-feed cable and a contact line, a direct current inlet wire circuit breaker is prone to an override trip. After inductance is added at a joint of a direct current inlet wire and a direct current bus, a rapid increase of a short-circuit current can be effectively suppressed, so as to avoid the direct current inlet wire circuit breaker from having the override trip. If a magnitude of the added inductance is excessively large, protection can be detected when a far zone of the contact line has a short-circuit, which causes protection rejection. According to the calculation method for the magnitude lower limit of the direct current large-current suppressing inductance, which is provided by the present invention, by analyzing a trip process of a direct current feeder circuit breaker and an opening time of an inlet wire circuit breaker, a time condition on which the inlet wire circuit breaker does not have the override trip is determined, and a value lower limit of direct current additional inductance is calculated, without the need for performing a special engineering experiment or complex power plant simulation calculation, so that the problem that the direct current inlet wire circuit breaker has the override trip can be effectively solved, the problem that feeder protection is difficult to be detected when a distant end of the contact line has the short-circuit is avoided, and design difficulty of a direct current traction power supply system is greatly simplified.

Description

technical field [0001] The invention relates to a calculation method for the value range of inductance, in particular to a calculation method for the lower limit of the value of inductance suppressed by direct current traction large current. Background technique [0002] In the trolleybus traction power supply system, the traction power supply station can provide DC power to the trolleybus. From the perspective of the power supply structure of the traction power supply station, high-voltage AC power is converted into low-voltage AC power through a transformer, and then converted into DC power through a rectifier. The transformer and rectifier are collectively called a rectifier group. Generally, the traction power supply station is equipped with 2 to 4 sets of rectifier groups, which are respectively connected to the DC busbar through the DC incoming line. The DC busbar can feed out multiple DC feeders, and the DC feeders are led out through cables and then connected to the...

AI Technical Summary

Problems solved by technology

[0022] In order to effectively solve the leapfrog tripping of the DC incoming line circuit breaker, the increase of high DC current can be suppressed by adding inductance between the DC incoming line and the DC bus; if the added inductance value is too large, it will cause a short circuit at the far end of the contact line Difficult-to-detect problems in feeder protection

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