Impedance analyzing method for sub-synchronous oscillation of thermal power unit

A technology of subsynchronous oscillation and thermal power units, which is applied in the fields of electrical digital data processing, special data processing applications, instruments, etc.

CN106599526AActive Publication Date: 2017-04-26NORTH CHINA ELECTRIC POWER UNIV (BAODING)
3 Cites 8 Cited by

Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2017-04-26

Smart Images

  • Figure 1
    Figure 1
  • Figure 2
    Figure 2
  • Figure 3
    Figure 3
Patent Text Reader

Abstract

The invention discloses an impedance analyzing method for sub-synchronous oscillation of a thermal power unit. The method comprises the following steps: partitioning a system to be researched into a power supply and a power grid, building state space models in sequence for the power supply and the power grid, and calculating admittance function matrixes of the power supply and the power grid; then, drawing Bode diagrams of the admittance function matrixes of the power supply and the power grid on the same graph; and lastly, picking up apparent resonance points on the bode diagrams, and calculating system series connection resonance frequency and an excited axis modal according to the apparent resonance points. Based on the basic principle of the impedance analyzing method, the power supply of the thermal power unit is modeled uniformly in a state space form, and the dynamic features of a mechanical control system of the unit are included in the state space of the power supply and modeled finally in the form of electric quantity. Compared with a conventional method, the method has the advantages that sufficient calculation accuracy can be obtained, and the dynamic features of continuous frequencies can be analyzed, so that beneficial conditions are created for the stable research of an electric-electronic power system.
Need to check novelty before this filing date? Find Prior Art

Description

technical field

[0001] The invention relates to a method for studying impedance by using subsynchronous oscillation of a thermal power unit, and belongs to the technical field of power generation. Background technique

[0002] Subsynchronous oscillation is one of the stability problems of the power system. In the 1970s, two accidents occurred in the United States in which the shaft system of the generating set was severely torsional and oscillated due to the exchange of subsynchronous energy, resulting in the unit being disconnected from the grid and the main shaft being damaged. Subsynchronous The problem of resonance has really attracted the attention of electrical engineering and academia, and thus set off a research boom of subsynchronous oscillation (SSO).

[0003] The linearization analysis methods of power system stability can be roughly divided into two categories: time-domain analysis methods based on State-Space Models (SSM), and frequency-domain analysis methods b...

Examples

Embodiment Construction

[0112] The present invention will be further described below in conjunction with accompanying drawing.

[0113] The invention mainly relates to a novel impedance analysis method and a new criterion proposed to adapt to the new method. Based on the basic principle of the impedance analysis method, this method uniformly models the model of the power supply part of the thermal power unit in the form of state space. Nanofunction matrix) form to be modeled. Therefore, compared with the traditional frequency sweep, the system impedance / admittance obtained by the new impedance analysis method will be more accurate. At the same time, based on the state space model, the calculation accuracy of the new impedance analysis method is the same as that of the eigenvalue analysis method, but it can analyze the dynamic characteristics of continuous frequencies, while the eigenvalue method can only obtain the dynamic characteristics of isolated points (at the eigenvalue frequency).

[0114] T...