Grid system protection method based on local information of transformer substation

Abstract

The invention relates to a grid system protection method based on local information in a transformer substation and belongs to the technical field of relay protection of power system. The method comprises the following steps: according to continuously collected and calculated voltage and current amplitude and sequence component of each line in the transformer substation, whether a fault occurs in the back-up protection areas of all lines is judged, if the fault occurs, a tripping command is sent out to trip off the line; if fault characteristic disappears in setting time and the line is overloaded, the maximum overload bearing time of the line is calculated as a protective fixed time value, and the current overload capacity of the line is calculated. Through summarizing, the total overload value of an incoming line and an outgoing line is obtained to determine whether the transformer substation needs deloading, and according to the needed deloading capacity and the reducible load of the transformer substation, the deloading capacity is determined and a deloading command is sent out. By adopting a method of combining local identification, local processing and system coordination, the protection method realizes the coordination between relay protection and emergency control, can reduce dependency on communication network and real-time property of communication, and can improve the safe operation level of electricity.

Description

technical field [0001] The invention belongs to the field of electric power system relay protection technology and electric power system emergency control. Background technique [0002] The role of relay protection is not limited to removing faulty components and limiting the scope of accidents (this is the primary task), but also to ensure the safe and stable operation of the power grid system. However, the design of traditional relay protection focuses more on the former. It only constructs protection from the perspective of the protected equipment, without considering the impact of its action behavior on the power grid system. At the same time, it lacks effective coordination with safety automatic devices. In some In some cases, it will deteriorate the condition of the power grid system, and even cause chain trips and blackouts. [0003] When a tie line in the power grid is cut off, the power flow on it will be transferred to other tie lines in normal operation in the sy...

AI Technical Summary

Problems solved by technology

However, this method only uses the magnitude of the load current of one line as the judgment basis, and cannot distinguish between ordinary overload and power flow transfer overload, and cannot reasonably determine the load shedding point and load shedding amount

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