Method of detecting cascading failure in AC-DC hybrid system

Abstract

The invention discloses a method of detecting cascading failure in an AC-DC hybrid system. The method comprises steps: the AC-DC hybrid system is initialized; failure is set; load flow calculation is carried out; whether the load flow converges is judged, if yes, voltage of each DC commutation bus in the AC-DC hybrid system is checked, a DC commutation bus whose voltage is smaller than a preset value is locked, and the next step is carried out; if not, a part of loads are added or reduced, and load flow calculation is carried out again; whether a line is broken is judged, if yes, failure is set again; if not, loss load is calculated, the cascading event probability is obtained, and classification and confirmation on cascading failure in the AC-DC hybrid system are carried out. The method of the invention has the advantages that cascading failure can be effectively detected, and the amount of calculation is small.

Description

technical field [0001] The invention relates to a cascading failure of a power system, in particular to a method for detecting the cascading failure of an AC / DC hybrid system. Background technique [0002] In the AC-DC hybrid power system, there are interactions between AC and DC, DC and AC, and DC and DC. The AC / DC hybrid power grid will produce many new electrical characteristics during faults, which will have an adverse effect on the action behavior of the relay protection of the AC system. For example, the small transmission capacity of the DC line will affect the transmission capacity of the AC channel running in parallel; when multiple branch lines are fed into a receiving power grid at the same time, simultaneous commutation failures or even blockages are prone to occur; the voltage amplitude of the commutation bus drops and the If the zero-crossing point of the commutation line voltage moves forward, it can cause commutation failure in the DC transmission system, an...

AI Technical Summary

Problems solved by technology

AC / DC hybrid power grids will produce many new electrical characteristics during faults, which will adversely affect the action behavior of AC system relay protection

For example, the small transmission capacity of the DC line will affect the transmission capacity of the AC channel running in parallel; when multiple branch lines are fed into a receiving power grid at the same time, simultaneous commutation failures or even blockages are prone to occur; the voltage amplitude of the commutation bus drops and the If the zero-crossing point of the commutation line voltage moves forward, it can cause commutation failure in the DC transmission system, and in severe cases, it will lead to blocking

Therefore, the AC-DC hybrid power system is prone to cascading failures, which poses a great challenge to the safe operation of the power grid.

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