Method for detecting saturation of current transformer (CT) on the basis of third-order central moment

A technology of a current transformer and a detection method, which is applied in the field of power system relay protection, can solve problems such as high accuracy and speed, and achieve the effects of ensuring calculation speed, detection speed and simple algorithm.

Active Publication Date: 2015-11-18
ELECTRIC POWER SCHEDULING CONTROL CENT OF GUIZHOU POWER GRID CO LTD +2
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Problems solved by technology

All of them can realize the saturation detection of current transformers, but there are advantages and disadvantages, and few can meet the two requirements of high precision and fast speed at the same time.

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  • Method for detecting saturation of current transformer (CT) on the basis of third-order central moment
  • Method for detecting saturation of current transformer (CT) on the basis of third-order central moment
  • Method for detecting saturation of current transformer (CT) on the basis of third-order central moment

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Embodiment Construction

[0028] The technical solution of the present invention will be further introduced in detail below in conjunction with the accompanying drawings and specific embodiments.

[0029] The present invention proposes a method for detecting CT saturation using an algorithm of the third-order central moment, which can effectively and quickly detect whether CT saturation occurs and the degree of saturation. The whole process is as Figure 6 shown in the flow chart.

[0030] Depend on figure 1 Equivalent model of current transformer, i 1 Indicates the primary current flowing through the system, i 2 is the current transformer secondary side current, i m is the excitation current. Establish figure 2 The power system simulation model shown is a double-sided power supply system, the phases on both sides are inconsistent, and a fault is set in the middle of the line to saturate the current transformer. The method of the invention is used to sample the ideal secondary current and the a...

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Abstract

Provided is a method for detecting the saturation of a current transformer (CT) on the basis of a third-order central moment. The method comprises: sampling current at the secondary side of the CT; acquiring a current waveform from a position near the peak value of a waveform by using a data window in order to obtain a waveform symmetric about the peak value and with less sampling points; computing a dispersion coefficient by using the third-order central moment after the acquired waveform is subjected to waveform mirror image transformation; and outputting a detected result. In the method, a dispersion coefficient after a standard sinusoidal current waveform is subjected to mirror image transformation. By means of analysis and computation, the dispersion coefficient can be considered as a fixed value so as to be used as a comparison basis. The method mainly solves problems of low detection rate and low detection precision when the CT saturation occurs, may fast and accurately detect the generation of the CT saturation just by using sampled data in half cycle so as to improve relay protection reliability to a certain extent and have certain practical significance in the aspect of guaranteeing the accurate and reliable operation of the CT.

Description

technical field [0001] The invention belongs to the technical field of electric power system relay protection, and in particular relates to a detection method for realizing the saturation of an electromagnetic current transformer by using a third-order central moment algorithm. Background technique [0002] With the construction of ultra-high voltage and smart grids in my country, the reliability requirements of power systems are getting higher and higher. The increase of grid voltage level is accompanied by the increase of grid short-circuit current level, which poses greater challenges to the performance of electrical equipment. . Current Transformer CT (Current Transformer) is one of the important electrical equipment in the power system. It is also an important component for various secondary equipment to monitor and perceive the real operating conditions of the primary system. It is widely used in power system monitoring, protection, distance measurement and wave recordi...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/00G01R35/02G01R29/04
Inventor 白加林高昌培王宇恩牛静赵武智戴宇郑涛黄婷马玉龙赵建新
Owner ELECTRIC POWER SCHEDULING CONTROL CENT OF GUIZHOU POWER GRID CO LTD
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