Traction transformer over current protection method

A traction transformer and overcurrent protection technology, applied in emergency protection circuit devices, electrical components, etc., can solve the problems of normal operation of locomotives, heavy-duty locomotive breakage, and failure of locomotive input, so as to avoid triggering protection actions and avoid false positives. Protection action to achieve the effect of overcurrent protection

CN104993455AInactive Publication Date: 2015-10-21ZHUZHOU CSR TIMES ELECTRIC CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2015-10-21
Estimated Expiration
Not applicable · inactive patent

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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.
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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...

Examples

Embodiment Construction

[0038] The present invention will be further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0039] like figure 2 As shown, the traction transformer overcurrent protection method of this embodiment, the steps include:

[0040] 1) Real-time detection and control of the state of the main circuit breaker connected to the power supply of the target traction transformer, and when it is detected that the main circuit breaker is in the closing state, proceed to step 2);

[0041] 2) Collecting the primary current signal of the target traction transformer, and pre-judging the overcurrent state of the target traction transformer according to the value of the collected primary current signal, if the pre-judgment is an overcurrent state, proceed to step 3);

[0042] 3) According to the similarity between the first half cycle and the second half cycle of the prima...