Excitation system negative damping detection method based on oscillation energy injection

A technology of excitation system and oscillating energy, applied in the direction of measuring electricity, measuring devices, measuring electrical variables, etc., can solve problems such as low-frequency oscillations in power systems

Inactive Publication Date: 2014-10-15
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0013] Negative damping of excitation system is the main cause of low frequency oscillation in power system

Method used

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  • Excitation system negative damping detection method based on oscillation energy injection
  • Excitation system negative damping detection method based on oscillation energy injection
  • Excitation system negative damping detection method based on oscillation energy injection

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0122] K=0

[0123] The excitation amplification factor of 0 means that the excitation adjustment is not performed, and the excitation voltage does not fluctuate, Δu f (t)=0. In this case the excitation system neither injects nor absorbs oscillation energy; that is to say, it provides neither positive nor negative damping to the system. This is the damping ratio of the system ζ = 0.021.

[0124] K=10

[0125] The excitation magnification is K=10, see Figure 4(a)-Figure 4(b) , the excitation voltage and excitation current when K = 10, and the excitation voltage and excitation current waveforms from 0 to 7.5 seconds at the beginning of the simulation are given.

[0126] The data from 2.5 to 7.5 seconds were selected for analysis. In this time period, the approximate number of oscillations is m=9, and the sampling period Δt=0.01 seconds. According to equations (17) and (18), the oscillation frequency f of the main oscillation mode satisfies 0.6Hz≤f≤1.2Hz. Select the identi...

Embodiment 2

[0134] K=30

[0135] The excitation magnification is K=30, Figure 6(a)-Figure 6(b) The excitation voltage and excitation current waveforms from 0 to 7.5 seconds at the beginning of the simulation are given.

[0136] The data from 2.5 to 7.5 seconds were selected for analysis. In this time period, the approximate number of oscillations is m=9, and the sampling period Δt=0.01 seconds. According to equations (17) and (18), the oscillation frequency f of the main oscillation mode satisfies 0.6Hz≤f≤1.2Hz. Select the identification program order The identification program order P=8, Table 3 and Table 4 respectively give the TLS-Esprit analysis results of the excitation voltage and excitation current.

[0137] Table 3 Analysis results of excitation voltage TLS-Esprit when K=30

[0138]

[0139] Table 4 Analysis results of excitation current TLS-Esprit when K=30

[0140]

[0141] Select an oscillation mode whose oscillation frequency satisfies 0.6Hz≤f≤1.2Hz, reconstruct the...

Embodiment 3

[0144] K=50

[0145] The excitation magnification is K=50, Figure 8(a)-Figure 8(b) The excitation voltage and excitation current waveforms from 0 to 7.5 seconds at the beginning of the simulation are given.

[0146] The data from 2.5 to 7.5 seconds were selected for analysis. In this time period, the approximate number of oscillations is m=9, and the sampling period Δt=0.01 seconds. According to equations (17) and (18), the oscillation frequency f of the main oscillation mode satisfies 0.6Hz≤f≤1.2Hz. Select the identification program order The identification program order P=8, Table 5 and Table 6 respectively give the TLS-Esprit analysis results of the excitation voltage and excitation current.

[0147] Table 5 TLS-Esprit analysis results of excitation voltage when K=50

[0148]

[0149] Table 6 Analysis results of excitation current TLS-Esprit when K=50

[0150]

[0151] Select an oscillation mode whose oscillation frequency satisfies 0.6Hz≤f≤1.2Hz, reconstruct the...

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Abstract

The invention discloses an excitation system negative damping detection method based on oscillation energy injection and relates to the technical field of power system dynamic stability. The method includes calculating the excitation system oscillation energy injection through a formula of Wex=integral (t2, t1) delta mu f (t) delta i f (t) d t; only extracting the oscillation component of the concerned oscillation frequency through an identification algorithm for calculation; determining the negative and positive of the damping of the excitation system according to the positive and negative of the oscillation energy injection. The excitation system damping is detected through the directly measured generator excitation voltage mu f and excitation current i f for avoiding the reconstruction of generator internal variables, so that the calculation is simple; the generator internal parameters are not used for avoiding errors caused by inaccurate generator parameters, so that the calculation is accurate. The excitation voltage and the excitation current during oscillation can be extracted from a generator monitoring system database for being used for the analysis of excitation system damping characteristics; the method can also be programmed as a subroutine to be integrated into the generator monitoring system for application.

Description

technical field [0001] The invention relates to the technical field of power system dynamic stability, in particular to a method for detecting negative damping of an excitation system based on oscillation energy injection. Background technique [0002] In modern power systems, the use of fast excitation devices with high amplification factors is one of the main causes of low frequency oscillations. The excitation device may generate a negative damping torque on the generator rotor under special operating conditions, resulting in generator oscillation. [0003] On the other hand, the excitation system is also the key to suppress low-frequency oscillation. A Power System Stabilizer (PSS) is being installed in the excitation system to generate an additional excitation reference signal by feeding back the generator speed, machine terminal frequency or generator power through filtering, amplification, and phase compensation. For the excitation device, the excitation voltage is ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/00
Inventor 刘天琪杨毅强王峰
Owner SICHUAN UNIV
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