Traction transformer over current protection method

Abstract

The invention discloses a traction transformer over current protection method. The method comprises steps: 1) a state of a main circuit breaker connected with a power supply of a target traction transformer is detected and controlled in real time, and when the main circuit breaker is detected to be in a closing state, the second step is carried out; 2) primary current signals of the target traction transformer are acquired, pre-judgment is carried out on the over current state of the target traction transformer according to the value of the acquired primary current signals, and if an over current state is pre-judged, the third step is carried out; and 3) according to similarities of the primary current signals in a former half current period and a latter half current period, the type of the over current state is judged, an over current protection action is not triggered if a magnetizing inrush current generation state is judged, and if a fault over current state is judged, the main circuit breaker is broken, and over current protection is executed. Over current protection misoperation caused by magnetizing inrush current can be avoided, and the method has the advantages of simple realization method, low needed cost, and high over current protection accuracy.

Description

technical field [0001] The invention relates to the technical field of AC locomotive power supply protection, in particular to an overcurrent protection method for a traction transformer. Background technique [0002] In locomotives powered by AC, traction transformers are needed to convert high voltage into low voltage available for the traction system. In order to prevent damage to the transformer caused by abnormal conditions such as internal faults or short circuits of the transformer, the traction system usually designs corresponding protection functions. Traction transformer overcurrent protection It is one of the most basic functions. [0003] At present, the overcurrent protection of the traction transformer usually sets a setting value through the system. When the primary current of the traction transformer is greater than the set value, the overcurrent protection fault is triggered to disconnect the high-speed circuit breaker for protection. like figure 1 As show...

AI Technical Summary

Problems solved by technology

Therefore, if the traction transformer adopts the above-mentioned over-current protection method, it is easy to accidentally trigger the over-current protection action by the excitation inrush current, which will cause the failure of the locomotive to be put into operation when the switch is closed. Normal use has a greater impact

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