System and method for judging negative damping oscillation and forced oscillation based on second order difference method

A negative damped oscillation, quadratic difference technology, applied in measuring devices, instruments, and electric power measurement by applying digital technology, etc., can solve problems such as threats to power grid security and stability, long oscillation duration, and low oscillation frequency.

Active Publication Date: 2012-08-29
CHINA ELECTRIC POWER RES INST +1
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Problems solved by technology

Low-frequency oscillation has low frequency, wide oscillation range, and long oscillation duration, which poses a huge threat to the security and stability of the power grid

Method used

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  • System and method for judging negative damping oscillation and forced oscillation based on second order difference method
  • System and method for judging negative damping oscillation and forced oscillation based on second order difference method
  • System and method for judging negative damping oscillation and forced oscillation based on second order difference method

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Embodiment

[0100] Below in conjunction with accompanying drawing, the patent of the present invention is described in further detail, but the present invention is not limited to the example given.

[0101] The software implementation method for distinguishing negative damped oscillation and forced oscillation based on the quadratic difference method consists of the following two parts:

[0102] 1. Obtain the measured frequency and power oscillation curves through PMU or WAMS data, and directly use the measured signals (or process the low-frequency oscillation curve based on the PRONY method or HHT method) to obtain the curve signal of the dominant oscillation mode. The relevant content of this article is no longer within the scope of the present invention, and will not be discussed in detail.

[0103] 2. The method used by the software to identify negatively damped oscillations and forced oscillations consists of the following two parts:

[0104] (1) Obtain the primary differential valu...

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Abstract

The invention provides a system and method for judging negative damping oscillation and forced oscillation based on a second order difference method. The method for judging the negative damping oscillation and the forced oscillation based on the second order difference method mainly comprises the following steps of: triggering start calculation according to an active power signal curve for hinge nodes, the frequency of transformer substation bus voltage or connecting lines, generator outlets and active power signals of the generator outlets through break-variable of current; finding out peaks of the signal curve by a sampling comparison method; calculating a first order difference value and a second order difference value of peak power in the first several or more than a dozen of cycles at the beginning of increasing oscillation, and comparing the symbols of the first order difference value and the second order difference value; if the first order difference value and the second order difference value are same in symbol, judging to be the negative damping oscillation; and if the first order difference value and the second order difference value are different in symbol, judging to be the forced oscillation. A corresponding alarm signal is given by a monitoring host according to the property of the oscillation so as to dispatch operating personnel to rapidly take the measure of restraining low-frequency oscillation, or a command of the measure of restraining the low-frequency oscillation is directly given, thereby, the safe and reliable runnability of a power grid is enhanced.

Description

technical field [0001] The invention belongs to the field of power systems, and in particular relates to a system and method for judging negative damping oscillation and forced oscillation based on a quadratic difference method. Background technique [0002] With the deepening of the marketization process of the power industry, the power system is increasingly operating at its limit, and the low-frequency oscillation problem is a common technical problem faced by domestic and foreign power grids. Low-frequency oscillation has low frequency, wide oscillation range, and long oscillation duration, which poses a huge threat to the security and stability of the power grid. There are two main reasons for low-frequency oscillation. One is negative damping low-frequency oscillation. Negative damping oscillation is a process of gradual increase in amplitude. If there is no human intervention, the amplitude of oscillation will continue to increase. Instability; the other is low-frequ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R21/133G01R31/00
Inventor 刘增煌贾文双李莹李文锋陶向宇王官宏何凤军朱方
Owner CHINA ELECTRIC POWER RES INST
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