Wide-area relay protection method for power grid considering the influence of unit output and load changes

Abstract

The invention discloses a method for protecting a power grid wide-area relay based on unit output power and load change influence. Firstly, a power grid existing wide area measurement system is used for synchronously measuring the voltages and currents of all transformer substations of a power grid to acquire power grid synchronous data. The incidence matrix between the currents of all circuits of the power grid is calculated through a wide area backup protection system, and the incidence matrix between the currents of all the circuits of the power grid and node injection currents is calculated. When a power grid topological structure is changed after a power grid dual-circuit fault and tripping occur, the admittance matrix of power grid branch circuits and the incidence matrix of power grid nodes do not need to be calculated again, the variation of the transient currents of other circuits of the power grid are calculated directly through power grid parameters before a dual-circuit fault, calculation time is short, and the protection movement speed is high and is higher than that of an existing circuit backup protection algorithm based on local quantity decisions.

Description

Technical field [0001] The invention relates to the technical field of power system relay protection, in particular to a power grid wide-area relay protection method considering the influence of unit output and load changes. Background technique [0002] The task of relay protection is to reflect the faults and abnormal operating conditions of the protected components, which can be divided into main protection and backup protection according to their functions. The main protection is only responsible for the task of quickly removing the fault of the protected component, and is basically not affected by the operation mode of the system. With the application of Fibre Channel, the main protection technology of high-voltage and ultra-high voltage systems based on double-ended electrical quantities has become increasingly mature. The backup protection is also responsible for the remote backup protection of adjacent electrical components. Due to the possibility of failure of the DC po...

AI Technical Summary

Problems solved by technology

[0003] 1) The coordination relationship of backup protection is complex and the action time is long

In severe cases, it may not meet the limit cut-off time required by the stability of the power system, and then become a hidden danger to the safety of the large power grid

[0004] 2) It is very difficult to configure and set the backup protection, and it cannot track the changes in the operation mode of the power system, and there may even be protection mismatch or insufficient sensitivity

[0005] 3) The backup protection cannot distinguish between the internal fault and the power flow transfer caused by the fault removal, which may lead to chain tripping of the backup protection under heavy load conditions

[0006] In a blackout accident, although the backup protection of the power system operates correctly according to the design principles, it objectively accelerates the system collapse.

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