Voltage sag state estimation method based on finite information

Abstract

The invention discloses a voltage sag state estimation method based on finite information, and the method comprises the steps: collecting voltage sag monitoring data and power grid structure parameters of any node in a power grid, enabling a grounding point to be taken as a virtual node, and forming an impedance matrix; In combination with the impedance matrix, according to boundary conditions offault sequence components under different fault types, sequence voltages of other nodes are represented by sequence voltages of monitoring points, and a sag phase voltage equation of the other nodes is obtained through phase sequence transformation; Analyzing each sequence impedance relationship in the residual voltage equation, and simplifying the fault residual voltage equation by utilizing a conversion relationship of fault phase sequence voltages under different fault types; And based on the voltage sag monitoring information of any point, deriving a residual voltage equation general formula under each fault type so as to obtain voltage sag state distribution of the whole network. According to the method, the voltage sag state distribution of the whole network is analyzed according tothe actual monitoring information, the calculation is simple, the conservative property of a traditional voltage sag state estimation method is improved, and the method better conforms to the engineering practice.

Description

technical field [0001] The invention belongs to the technical field of power quality monitoring and analysis, and in particular relates to a voltage sag state estimation method based on limited information. Background technique [0002] With the development of industrial technology, various types of power quality sensitive power electronic equipment, such as adjustable speed drive equipment, programmable logic controllers and personal computers, have been widely used in industry, making a large number of users reliable power supply to the power system Performance and power quality put forward higher requirements. Due to the high frequency of occurrence and the large economic losses caused, voltage sag has become one of the most concerned issues in power quality, and it is the main interference to the normal and safe work of modern industrial loads. Therefore, it is of great practical significance to predict and evaluate the characteristics of voltage sag in distribution net...

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Problems solved by technology

[0004] The research on voltage sag in my country started relatively late, and the monitoring cycle of voltage sag in complex power grids is relatively short. The lack of long-term and reliable voltage sag monitoring data has seriously affected the in-depth research on voltage sag.

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