Impedance network modeling and stability analysis method based on synchronized reference coordinate system

Abstract

The invention provides an impedance network modeling and stability analysis method based on a synchronized reference coordinate system, comprising the following steps of S1: collecting machine network parameters of the target system; S2: calculating the power flow according to the the machine network parameters to obtain the initial value of the state variable for constructing an impedance matrix model of each device in the system; S3:establishing the impedance matrix modeling of each device in the system according to the initial value of the state variable; S4: transforming the impedance matrix model of each device in the system into the coordinate system of the whole network system; S5: constructing the impedance matrix model of the whole system; S6: aggregating the impedance network model into the combined impedance matrix; S7: carrying out the oscillation stability analysis according to the combined impedance matrix. The invention can realize the impedance network modeling of the multi-converter large power grid, and has the advantages of wide application range, clear physical meaning, simplicity, and high efficiency.

Description

technical field [0001] The invention relates to the technical field of power system stability analysis, in particular to an impedance network modeling and stability analysis method based on a synchronous reference coordinate system. Background technique [0002] In recent years, power electronic converters have been widely used in modern power systems. Typical applications include adjustable-speed motor drive, high-voltage direct current transmission, wind power / photovoltaic and other new energy power generation systems. As a power electronic interface with good control performance, the converter enables a "flexible connection" between electrical equipment and the grid. However, the rapid increase in the penetration rate of power electronic converters has led to some new stability problems in new energy power generation bases, such as high-frequency harmonic oscillations in distributed generation and microgrid systems; Low-frequency power oscillations caused by power loads ...

AI Technical Summary

Problems solved by technology

The traditional impedance analysis method establishes the positive and negative sequence impedance model of the system in the abc coordinate system, but in the modeling process, the dynamic coupling of the AC-DC side, the structure or parameter asymmetry of the AC-D axis controller are ignored, and it is difficult to Solve the problem of asymmetric impedance of the dq axis of the actual converter

In terms of stability criteria, although the traditional Nyquist criterion and norm criterion can qualitatively judge the stability of the system, they cannot quantitatively analyze the frequency and damping of the oscillation, which is limited in practical applications

The existing impedance modeling method based on the dq rotating coordinate system is only suitable for the analysis of single-machine infinite system, and cannot be extended to the actual complex system containing tens of thousands of nodes and thousands of converters

Images