Voltage type direct-current power flow controller transformation ratio optimizing calculation method

Abstract

Provided is a voltage type direct-current power flow controller transformation ratio optimizing calculation method. The method comprises the steps that a mathematical expression of an improved weighting power flow entropy of a direct-current power grid is established and serves as a target function; equality constraint conditions are established; inequality constraint conditions are established; adirect-current power grid transformation ratio optimizing model composed of the target function, the equality constraint conditions and the inequality constraint conditions and containing DCPFC is solved through a fmincon function of an MATLAB to obtain the corresponding optimal transformation ratio when the improved weighting power flow entropy is minimum; and the like. An entropy theory is introduced into the direct-current power grid, the improved weighting power flow entropy, weighted in branch circuit load rate high-order term, of the direct-current power grid is proposed, the safe operation level of the direct-current power grid is reflected on the aspects of power flow distribution balance degree and load rate, and the branch circuit overload situation can be also reflected in a highlighted mode. The mathematical expression serves as the target function to conduct optimization control on direct-current power grid power flow, and thus the optimal transformation ratio of the DCPFC is obtained.

Description

technical field [0001] The invention belongs to the technical field of direct current power supply, and in particular relates to a transformation ratio optimization calculation method of a voltage type direct current power flow controller. Background technique [0002] As an important part of the future interconnected large grid, DC power grid should be paid more attention to its safe operation. Existing studies have shown that for a power grid with a certain topology, regardless of the occurrence of sudden faults (such as short circuits caused by meteorological factors), the main factors affecting the safe operation of the system are the average load rate of the system and the distribution of branch power flows. balance. [0003] The DC power flow controller (DCPFC) is the key equipment of the DC power grid. The voltage type DCPFC mainly includes two types: the parallel type DC / DC converter and the series type adjustable voltage source. If only the external characteristics...

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Problems solved by technology

[0004] The Chinese patent application with publication number CN106329511A proposes a method for adjusting DCPFC with the goal of power flow balance distribution, but this method only considers the balance degree of branch load rate and ignores its value, which may cause The load rate of some heavily loaded branches is further increased

The Chinese patent application with the publication number CN105162109B pointed out a method for calculating the DCPFC transformation ratio by introducing DCPFC to reduce the system network loss and aiming at minimizing the DC network loss, but the calculation results show that DCPFC is reducing the DC network loss relatively limited

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