A Configuration Method for Auxiliary Failure Protection of Transformer High Voltage Side in Converter Station

Abstract

The invention discloses a criterion for allocating high-voltage side auxiliary failure protection for a transformer used for a convertor station. (1), according to the rated capacity SN, the primary side nominal voltage UN and the rated short-circuit reactance Uk% parameters of the transformer used for the convertor station, the expression of short-circuit reactance of the transformer used for the convertor station is determined; (2), according to the situation that when the low-voltage side two-phase short-circuit fault of the transformer used for the convertor station happens, high-voltage side short-circuit current of the transformer is detected whether to meet the requirements for failure protection starting or not, whether a failure protection device needs to be allocated or not is judged, concretely, the determination is made according to results of the expression, when f(SN) >=0, auxiliary failure protection needs not to be allocated, and when f(SN) <0, the auxiliary failure protection needs to be allocated. Through the relationship between the high-voltage side short-circuit current IfAB output by a current transformer and the minimum value for starting the 500kV breaker failure protection, whether the auxiliary failure protection needs to be allocated or not is judged, and blind allocating of the high-voltage side auxiliary failure protection is avoided.

Description

technical field [0001] The invention relates to a configuration method for auxiliary failure protection on the high-voltage side of a transformer used in a converter station, which is mainly used as a configuration basis for the auxiliary failure protection on the high-voltage side of a 500kV transformer in a converter station. The utility model belongs to the technical field of electrical equipment of a power system converter station. Background technique [0002] The power supply system for DC converter stations plays a pivotal role in the reliable operation of the DC transmission system, and the reliability of the power supply for converter stations is not only related to the wiring form of transformers used in converter stations, but also to its control methods and Relay protection and other factors are related. There are usually three types of wiring methods for transformers used in converter stations. One is that the transformer for the converter station is connected ...

AI Technical Summary

Problems solved by technology

The disadvantage is that the transformer and circuit breaker must withstand short-circuit current for a long time until the failure protection can be activated, which may damage the equipment

[0005] Existing technology 2: According to the characteristics of small transformer capacity and large transformation ratio for 500kV stations, in order to avoid faults in the converter station transformer area and the hidden danger that the circuit breaker failure protection cannot be activated when the 500kV circuit breaker fails, increase The 500kV converter station transformer high-voltage side auxiliary failure protection is configured. This protection collects the current of the bushing current transformer CT4 on the high-voltage side of the transformer. When the circuit breaker fails, the auxiliary failure protection operates, but the protection cannot judge whether it is a side break. In order to reliably protect the equipment, the protection acts on the failure protection of the side circuit breaker and the circuit breaker at the same time, and all adjacent circuit breakers are jointly tripped.

However, the probability that the side circuit breaker and the circuit breaker fail at the same time is extremely small. If the failure occurs in the circuit breaker, this scheme will cause a bus power outage, and there is a hidden danger of expanding the scope of power outages.

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