Inverse time lag over excitation protection method of generator and transformer

An overexcitation, inverse time limit technology, applied in emergency protection circuit devices, electrical components, etc., can solve the problems of affecting the action time accuracy, inconvenient program implementation, large interpolation error, etc., to improve the action time accuracy, facilitate program implementation, reduce Effects of Interpolation Error

Active Publication Date: 2010-05-12
NR ELECTRIC CO LTD +1
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Problems solved by technology

The linear interpolation algorithm has a small amount of calculation and is easy to program, but its interpolation error is large, which affects the action time accuracy of the inverse time over-excitation protection of the generator set
[0003] "CN200310106434.1" proposed a transformer inverse time overexcitation protection method based on the least square method fitting, but its computational complexity is large, and it is not convenient for program implementation

Method used

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  • Inverse time lag over excitation protection method of generator and transformer
  • Inverse time lag over excitation protection method of generator and transformer
  • Inverse time lag over excitation protection method of generator and transformer

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Embodiment Construction

[0011] Below in conjunction with accompanying drawing, the present invention will be further described: install TV (for transformer, can get transformer high-voltage side TV or transformer low-voltage side TV, for generator, get the voltage amplitude calculation value of generator terminal TV) at protected object place U , the calculated value of frequency is f, then the calculation formula of overexcitation multiple n is:

[0012] n = U / U N f / f N Formula ①

[0013] In formula ①, U N is the TV rated voltage, f N is the rated frequency.

[0014] Compare the calculated value of the current overexcitation multiple n with the given set value of m (t i , n i ) (i=0, 1, ..., m-1) comparison, when it is judged that the over-excitation multiple value n is located in a certain two...

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Abstract

The invention discloses an inverse time lag over excitation protection method of a generator and a transformer. The method comprises the following steps: carrying out segment handling by making a given inverse time lag over excitation action characteristic curve, wherein the given inverse time lag over excitation action characteristic curve is obtained by a plurality of groups of input given values (generally 8 groups to 10 groups), calculating excitation multiple according to voltage and frequency, and adopting a segment Lagrange polynomial interpolation method to work out the corresponding action time of over excitation protection on the excitation multiple. Therefore, the inverse time lag over excitation protection method realizes high-precision inverse time lag over excitation protection.

Description

technical field [0001] The invention relates to an inverse time-limit overexcitation protection method for a generator and a transformer and a device using the method. Background technique [0002] Both the generator and the transformer have a certain over-excitation capability, and the higher the over-excitation multiple, the shorter the allowable time, that is, they have inverse time-limit characteristics, so inverse-time over-excitation protection is required. The inverse time overexcitation protection of generator sets is generally processed by segmenting the given inverse time overexcitation action characteristic curve. worth it, as attached figure 1 As shown, after the overexcitation multiple is calculated according to the voltage, the corresponding action time is obtained by using the piecewise linear interpolation method to realize the inverse time limit. The linear interpolation algorithm has a small amount of calculation and is easy to program, but its interpolat...

Claims

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Application Information

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IPC IPC(8): H02H7/06H02H7/04
Inventor 陈俊严伟沈全荣王光
Owner NR ELECTRIC CO LTD
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