Method for acquiring asymmetrical short-circuit current DC components of complex power system

Abstract

The invention relates to a method for acquiring asymmetrical short-circuit current DC components of a complex power system, and the method comprises the following steps of 1) respectively constructingcomposite sequence networks including a positive sequence network, a negative sequence network and a zero sequence network for calculating asymmetrical short-circuit current periodic components of the complex power system according to a fault point and a fault port, and increasing the reactance in an original branch of each sequence network to k times to form a positive sequence k network, a negative sequence k network and a zero sequence k network; 2) respectively acquiring an input impedance Z2sigma.N of the negative sequence network, an input impedance Z0sigma.N of the zero sequence network, an input impedance Z2sigma.k of the negative sequence k network and an input impedance Z0sigma.k of the zero sequence k network at the fault port; 3) calculating additional impedances under different types of short circuits, introducing the additional impedances into the complex power system, and simplifying the composite sequence networks to obtain a network simplified model; and 4) respectively calculating corresponding initial values of the DC components and decay time constants thereof for each type of asymmetric short circuit. Compared with the prior art, the method provided by the invention has the advantages of being suitable for a complex network, simple and accurate calculation, and the like.

Description

technical field [0001] The invention relates to the field of power systems, in particular to a method for acquiring a DC component of an asymmetrical short-circuit current in a complex power system. Background technique [0002] With the development of the power system and people's pursuit of energy saving and consumption reduction, my country's power system is constantly developing to a higher voltage level and a larger scale. In order to reduce the loss, the reactance-resistance ratio of the main primary components such as generators, transformers, and transmission lines is getting larger and larger, resulting in slower and slower attenuation of the DC component in the short-circuit current of the system. The series reactance and high impedance used to limit the short-circuit current Transformers exacerbate the problem. [0003] Some regional power grids in my country (the economically developed Beijing-Tianjin-Tangshan, Yangtze River Delta, Pearl River Delta regions, and...

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Problems solved by technology

However, there is still a lack of simple and easy methods for calculating the DC compon

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