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A method for judging that low voltage of excitation of loss of excitation protection of the adjuster

A technology of loss-of-excitation protection and excitation voltage, which is applied in the direction of emergency protection circuit devices, electrical components, etc., can solve the problem that the low-voltage criterion of excitation cannot be applied to the loss-of-excitation protection of the condenser, and achieve the effect of preventing refusal

Active Publication Date: 2018-12-18
NARI TECH CO LTD
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Problems solved by technology

[0005] The invention provides a method for judging the excitation low voltage of the controller for loss of excitation protection, which solves the problem that the existing criterion of excitation low voltage cannot be applied to the protection of the controller for loss of excitation

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  • A method for judging that low voltage of excitation of loss of excitation protection of the adjuster

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Embodiment Construction

[0032] The present invention will be further described below in conjunction with the accompanying drawings. The following examples are only used to illustrate the technical solution of the present invention more clearly, but not to limit the protection scope of the present invention.

[0033] Such as figure 1 As shown, the method for judging the excitation low voltage of the condenser loss-of-excitation protection includes the following steps:

[0034] 1) The excitation voltage is sampled at equal intervals, and N points are sampled in the cycle time T. The cycle time is the minimum cycle of the AC voltage before the excitation voltage is rectified. N is an integer multiple of L, and L=3 or 6.

[0035] 2) Calculate the number of sampling points N of the loss-of-excitation protection action set .

[0036] The number of sampling points for loss of excitation protection is:

[0037] N set = t set *N / T

[0038] The loss of excitation protection of the condenser provides 5 s...

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Abstract

A method for judging low excitation voltage of excitation of loss-of-excitation protection of camera feature that square root mean square value criterion and pulse wave square root mean square value criterion are used as main criterion to accurately distinguish loss-of-excitation fault from deep phase advance operation of camera, and complete loss-of-excitation fault and partial loss-of-excitationfault can be identified. At that same time, the high value criterion of the average value is use as the auxiliary criterion to check the protection, the setting value does not need to be set according to the minimum excitation voltage when the dodging adjuster is in normal operation, The average low value criterion can be set according to the minimum excitation voltage in normal operation of thedodging adjuster, and can be used as the auxiliary criterion of the excitation low voltage criterion to prevent the excitation low voltage criterion from being rejected due to the inverter state or abnormal working condition.

Description

technical field [0001] The invention relates to a method for judging low voltage of excitation for demagnetization protection of a condenser, and belongs to the field of relay protection of power systems. Background technique [0002] Loss of excitation fault is a type of fault that may occur in synchronous motors with excitation circuits such as synchronous generators and condensers. After the loss of magnetism fault occurs, a series of changes will occur in the electrical quantity of the synchronous motor, and the synchronous motor will gradually transition to asynchronous operation. On the one hand, the synchronous motor will emit less reactive power or absorb more reactive power from the system, which may lead to insufficient reactive power in the system; on the other hand, after the synchronous motor transitions to asynchronous operation, a differential frequency current will be generated in the rotor winding, causing the rotor winding fever. [0003] In order to redu...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/06
Inventor 郑玉平郑作伟季学军揭萍郝后堂李延新潘书燕李志坚谭凌
Owner NARI TECH CO LTD
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