Static equivalence method for external network based on internal network routine Ward equivalent circuit

Abstract

The invention relates to a static equivalence method for an external network based on an internal network routine Ward equivalent circuit. The static equivalence method comprises the steps of first inputting a topological structure, parameters thereof and status information through programs by using a computer; then calculating to obtain a routine Ward equivalent network of the internal network and parameter values of the routine Ward equivalent network; thereafter establishing virtual measurement equation of equivalent circuit parameters of the external network based on the restraint relationship between the equivalent circuit parameters of the external network and the routine Ward equivalent circuit parameters of the internal network; and finally solving the virtual measurement equation by adopting a least square method to acquire parameter values of the equivalent network of the external network. The static equivalence method can be widely applied to interconnected networks to solve an equivalence problem of completely unknown adjacent subnets, provides an effective solution for carrying out equivalence on completely unknown adjacent subsystems in the interconnected networks, providing a profound theoretical basis for improving the precision of safe and stable correction for independent subsystems, and being conducive to safe and stable running of the interconnected networks.

Description

technical field [0001] The invention relates to a method for an electric power system to estimate a static equivalent model of an external network and its parameters based on internal network information, in particular to a static equivalent method for an external network based on a conventional Ward equivalent circuit of the internal network. Background technique [0002] With the continuous advancement of my country's power reform, China's power market will gradually take shape. In the electricity market environment, interconnected subsystems usually represent different interest groups, and the grid data held by them are increasingly considered as commercially valuable secrets, and various grid companies only share some basic information according to regulations. As a result, real-time data exchange cannot be performed between subsystems in the system, and there will be large deviations in the safety and stability check of independent subsystems, which will affect the safe...

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Problems solved by technology

The calculation conditions are harsh and difficult to apply in practice. At the same time, this method assumes that the injection power of the boundary nodes remains unchanged before and after the intranet line is disconnected. This assumption is difficult to establish and may lead to large model equivalent errors.

Some scholars in China have proposed a two-port external network static equivalent parameter estimation method based on the measured information of the internal network. This method is based on the power equation at the boundary node, establishes a virtual measurement equation of the equivalent parameter of the external network and solves it, but this method only Utilizes measurement information at boundary nodes

[0005] Therefore, the existing method of estimating the parameters of the equivalent model of the external network based on internal network information has the following main disadvantages: ① the required conditions are harsh and difficult to meet in the actual system; Use more intranet measurement information

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