Power flow calculation method for complex topology active distribution network containing direct current system

Abstract

The invention provides a power flow calculation method for a complex topology active distribution network containing a direct current system in allusion to a problem of poor convergence in the AC-DC system hybrid power flow calculation process of the existing distribution network. The method is characterized in that the active distribution network is divided into a direct current system and an alternating current system according to a voltage source converter; whether weak loop running exists in the system or not is determined according to opening-closing conditions at a loop closing point so as to perform corresponding power flow calculation; and a power flow calculation result of the active distribution network hybrid system is acquired finally by combining a power flow calculation result of the direct current system. Corresponding adjustment is performed on the power flow calculation sequence of the direct current system and the alternating current system and selection for power flow calculation parameters of the converter under different control strategies of the grid-connected converter, and power flow calculation for the whole hybrid system can be realized by performing only one time of alternative iteration convergence on the direct current system and the alternating current system.

Description

technical field [0001] The invention relates to the technical field related to the grid structure and operation mode of a distribution network, in particular to a method for calculating the power flow of a complex topology active distribution network including a DC system. Background technique [0002] With the continuous development and promotion of distributed power generation and advanced power electronics technology, the requirements for power quality and power supply reliability on the user side continue to increase, and the traditional AC distribution network will face distributed power access. , source-load coordination, and grid operation stability, economy, and power quality are huge challenges. On the one hand, the main distributed power sources are basically direct current (or use direct current technology), which must be incorporated into the AC distribution network through DC / AC converters; on the other hand, more and more industrial loads use frequency conversi...

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Problems solved by technology

[0006] The present invention aims at the current flow calculation process of the mixed connection of AC and DC systems in the existing distribution network. It is necessary to perform power flow calculations for each AC and DC system separately, which has a large amount of calculation and poor convergence. For the interconn

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