Cascading failure analytical method of alternating current and direct current multiple-series electric system

Abstract

The invention discloses a cascading failure analytical method of an alternating current and direct current multiple-series electric system. The method comprises the steps of setting up the alternating current and direct current multiple-series electric system; initializing the alternating current and direct current multiple-series electric system; setting an initial failure; balancing overall load and overall discharging electricity of the alternating current and direct current multiple-series electric system; carrying out load flow calculation of the alternating current and direct current multiple-series electric system; judging whether a load flow is in convergence or not, returning and calculating the load flow according to a result, or checking out direct current commutation bus voltage in the alternating current and direct current multiple-series electric system, shutting direct current commutation buses smaller than a set value, simulating an alternating current cascading failure, and forming a fault tree expression; and judging whether a line is cut off, returning and calculating the load flow according to the result, or calculating loss load, and figuring out a cascading accident probability. According to the method, cascading failure analysis can be effectively carried out, the calculated quantity is small, and a practical application analysis effect is not affected.

Description

technical field [0001] The invention relates to power system cascading failures, in particular to an analysis method for cascading failures of an AC / DC hybrid power system. Background technique [0002] In the AC / DC hybrid power system, the interaction between the AC and DC systems: 1) AC to DC: Symmetrical faults, asymmetrical faults or insufficient reactive power caused by commutation bus voltage amplitude drop and commutation line voltage before zero crossing point Any shift may cause commutation failure in the DC transmission system, and serious cases may lead to blockage. 2) DC to AC: The transmission capacity of the DC line will affect the transmission capacity of the parallel running AC channel. In the case of a DC fault, power flow transfer will occur, and the active power transmitted by the AC line will increase, and the reactive power loss will increase. 3) DC to DC: When multiple branch lines are fed into a receiving grid at the same time, if the electrical dista...

AI Technical Summary

Problems solved by technology

[0002] In the AC / DC hybrid power system, the interaction between the AC and DC systems: 1) AC to DC: Symmetrical faults, asymmetrical faults or insufficient reactive power caused by commutation bus voltage amplitude drop and commutation line voltage before zero crossing point shift, it may cause commutation failure in the DC transmission system, and serious cases will lead to blocking

2) DC to AC: The transmission capacity of the DC line will affect the transmission capacity of the AC channel running in parallel. In the case of a DC fault, the power flow transfer will occur, and the active power transmitted by the AC line will increase, and the reactive power loss will increase.

However, these methods all have defects such as large amount of calculation or the influence of the actual application analysis effect due to over-simplification.

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