Static safety risk assessment method for AC-DC hybrid micro-grid in island operation

Abstract

The invention discloses a static safety risk assessment method for an AC-DC hybrid micro-grid in island operation. The method comprises the following steps of: simulating the N-1 open-circuit fault ofthe AC-DC hybrid micro-grid in island operation with a given topology; performing a disconnection analysis to obtain an island system with the fault disconnected and the unrecoverable power loss loadin a fault area; establishing a probability distribution model of the random failure of an interlinking converter and a distributed generation device, the random output of an intermittent distributedgeneration device, and the load random fluctuation, performing Monte Carlo sampling to obtain a random input variable sample value; performing regional load-shedding operation on the island system toobtain the power loss load in a non-fault area, and performing conventional power flow calculation by using an accelerated LM algorithm with non-monotone linear search (ALMNL); and obtaining the probability distribution of each static safety risk indicator. The method of the invention can assess the static safety risk level of the AC-DC hybrid micro-grid in island operation, is an effective method for researching the static safety reliability of the AC-DC hybrid micro-grid in island operation, and provides technical support for the planning and operation of the AC-DC hybrid micro-grid.

Description

technical field [0001] The invention relates to the field of power system analysis, in particular to a static security risk assessment method for an AC / DC hybrid microgrid operating in an isolated island. Background technique [0002] The AC-DC hybrid microgrid structure includes the AC subsystem (AC busbar), the DC subsystem (DC busbar) and the interlinking converter (ILC) connecting the AC and DC subsystems. The AC-DC hybrid microgrid combines the AC microgrid The advantages of the two structures of power grid and DC microgrid can directly supply power to AC loads and DC loads, reducing unnecessary power conversion. It is the most promising microgrid structure in the future and has become a hot spot for academic research and engineering demonstration. The AC / DC hybrid microgrid has two operation modes: grid-connected operation and island operation. The island operation AC-DC hybrid microgrid using the droop coordination control strategy lacks the support and regulation of...

AI Technical Summary

Problems solved by technology

In the island operation AC-DC hybrid microgrid under the droop coordinated control strategy, each subsystem has no balance node and contains DG devices with droop control, which makes the Jacobian matrix of the power flow equation easy to be singular, and the conventional power flow algorithm of the traditional distribution network is no longer applicable ; and in its static safety risk assessment, it is necessary to carry out power flow calculations for the three types of island systems formed after decoupling

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