Pilot protection method based on discrete Frechet distance of current sampling values on two sides of line

A technology of current sampling and longitudinal protection, which is applied in the direction of only measuring current, measuring current/voltage, and emergency protection circuit devices, etc., which can solve the problems of limited compensation effect, increased TV faults and voltage signal transmission errors, and inability to compensate transient capacitive currents and other problems, to achieve the effect of long distance and large distributed capacitance

Active Publication Date: 2019-08-09
CHINA THREE GORGES UNIV
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Problems solved by technology

The shunt reactor compensation method and the phasor compensation algorithm can only compensate the steady-state capacitive current, but cannot compensate the transient capacitive current, and the compensation effect is limited
The time-domain compensation algorithm and the above-mentioned new principle protection need to transmit double-terminal voltage data, which increases the risk of TV failure and voltage signal transmission error

Method used

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  • Pilot protection method based on discrete Frechet distance of current sampling values on two sides of line
  • Pilot protection method based on discrete Frechet distance of current sampling values on two sides of line
  • Pilot protection method based on discrete Frechet distance of current sampling values on two sides of line

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Embodiment Construction

[0038] The longitudinal protection method based on the discrete Fréchet distance of current sampling values ​​on both sides of the line includes the following steps:

[0039] Step 1: At the sampling frequency of 4kHZ, extract the sampling value on the side of the line with the bus flowing to the line as the positive direction to obtain I 1 , on the other side of the line, take the line flow to the bus as the positive direction to extract the sampling value to get I 2 . Sampling at 80 points per cycle, the current signal sequence of a data window is I 1 ={I 1 (1), I 1 (2),...I 1 (i),...I 1 (80)}, I 2 ={I 2 (1), I 2 (2),...I 2 (i),...I 2 (80)}, i=1,2,...80;

[0040] Step 2: In the sequence of 80 sampling points in one cycle, find out the current I respectively 1 The maximum value of I 1.max and minimum I 1.min , and I 2 The maximum value of I 2.max and minimum I 2.min , for each sampling point I(i) in the data window, the formula After normalization, the sampl...

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PUM

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Abstract

The invention discloses a pilot protection method based on discrete Frechet distance of current sampling values on two sides of a line. The method comprises the steps of: in a certain sampling rate, collecting currents at two sides of line protection, and forming current signal sequences I1 and I2; performing normalization processing of the I1 and the I2 to obtain two values as shown in the description and allow the ranges of the two values within the range of [0, 1], employing a Frechet distance algorithm to calculate Frechet distances as shown in the description of current waveform samplingvalues at two sides, and forming an F distance value sequence by promotion point by point according to the time; comparing the calculated and obtained F distance value sequence with a set threshold value Fset, if the F distance value sequence is lower than the threshold value Fset, determining that the line is normally operated or has external faults to perform shutting protection, or else, determining that the line has internal faults to perform action protection. The method can perform accurate determination for various typical faults such as CT saturation and the like, can perform reliableaction and shutting when the waveform is influenced by white noise, and has a high anti-interference capability.

Description

technical field [0001] The invention relates to the field of line longitudinal protection, in particular to a longitudinal protection method based on the discrete Fréchet distance of current sampling values ​​on both sides of the line. Background technique [0002] The longitudinal protection of the transmission line uses the electrical quantities on both sides of the line to compare and work together at the same time, so as to achieve the purpose of quickly and reliably removing any faults on the entire line. At present, the commonly used longitudinal protection mainly includes directional longitudinal protection, distance longitudinal protection and longitudinal current differential protection. Among them: the principle of directional longitudinal protection is simple and easy to realize, and it is not affected by factors such as system oscillation, load change and non-full-phase operation. The distance longitudinal protection can cut off the fault instantaneously when th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/26G01R19/00G01R31/08
CPCG01R19/0092G01R31/086H02H7/26
Inventor 翁汉琍陈皓万毅黄景光李振兴王胜
Owner CHINA THREE GORGES UNIV
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