Distinguishing method of PT ferromagnetic resonance

Abstract

The invention provides a distinguishing method of PT ferromagnetic resonance, which comprises the following steps of: 1, converting a distribution network system containing PT into a simple single-phase serial-parallel connection circuit structure; 2, establishing a mathematical model of nonlinear inductances of a capacitor, a resistor and the PT in the equivalent circuit of the step 1; establishing a time-varying vector based state equation of the nonlinear inductances of the capacitor, the resistor and the PT in the equivalent circuit; 4, converting the state equation in the step 3 into a vector relation between the nonlinear inductances of the capacitor, the resistor and the PT and a magnetic flow; 5, solving the relation among the PT, the total voltage at two ends of the capacitor and the magnetic flow according to the time-varying vector based state equation, and converting vector relation into relation between effective values; 6, defining an energy function and calculating stability margin and disturbance quantity of the distribution network system; and 7, distinguishing the PT ferromagnetic resonance. The PT ferromagnetic resonance is distinguished by comparing the stability margin with the disturbance quantity, which has guidance for operators.

Description

technical field [0001] The invention provides a method for discriminating ferromagnetic resonance of PTs, which belongs to the field of safety analysis of power systems, and is especially applied to the technology of safety analysis of ferromagnetic resonance of PTs in distribution network systems and transmission network systems. Background technique [0002] The occurrence of ferromagnetic resonance in PT has always been a major problem for power system operators, and it has also brought huge economic losses to the majority of power supply units and large power-consuming enterprises. The occurrence of PT ferromagnetic resonance is due to the existence of many capacitive and inductive components in the power system, such as transformers, transformers, generators, arc suppression coils, reactors, line wire inductance, etc. can be used as inductive components; the ground capacitance of the line wire And phase-to-phase capacitance, compensation capacitance, stray capacitance o...

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Problems solved by technology

[0003] At present, extensive and in-depth research on ferromagnetic resonance has been carried out at home and abroad, and some criteria and corresponding analysis methods have been given, such as Peterson's theorem, graphical method, analytical method, digital simulation analysis method, wavelet identification method, nonlinear dynamics Analytical methods, etc., in which Peterson's theorem gives the conclusion of the ratio range of the zero-sequence capacitive reactance of the line and the inductive reactance under the rated line voltage to judge the type of ferromagnetic resonance through a large number of experiments. Its disadvantage is that it only shows the type of ferromagnetic resonance. Explain the conditions of ferromagnetic resonance; the graphic method is intuitive, simple and easy to understand, and analyzes the power frequency ferromagnetic resonance through qualitative graphics, and roughly gives the conditions for ferromagnetic resonance to occur. The disadvantage is that it is only a qualitative analysis without a quantitative one. Analysis; the analytical method analyzes the power frequency by filtering out other frequencies through complex mathematical transformations, and obtains the critical condition when a system occurs with power frequency ferromagnetic resonance. Its shortcoming is that it is only a qualitative analysis rather than a quantitative analysis. ;Digital simulation analysis method, wavelet identification method and nonlinear dynamic analysis method carry out digital simulation by using simulation software and programming, and analyze the type of power frequency resonance. The disadvantage is that there is no analysis of the conditions for resonance occurrence

[0004] So far, there is no method at home and abroad that can quantitatively analyze and compare the stability of power systems in various situations?

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