Method of self-adaptive 100hz protection criterion for AC/DC transmission system

A technology of power transmission system and AC system, which is applied in measuring current/voltage, phase angle between voltage and current, measuring electricity, etc. It can solve problems such as converter valve equipment cannot be removed quickly, AC system asymmetry, DC blocking, etc.

Inactive Publication Date: 2016-01-20
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It can be seen that the existing DC 100Hz protection cannot take into account the different requirements of the two faults at all, which will cause the failure of the converter valve equipment to be quickly removed and the asymmetrical fault of the AC system to cause unnecessary DC blocking

Method used

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  • Method of self-adaptive 100hz protection criterion for AC/DC transmission system
  • Method of self-adaptive 100hz protection criterion for AC/DC transmission system
  • Method of self-adaptive 100hz protection criterion for AC/DC transmission system

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Effect test

Embodiment 1

[0088] like figure 1 As shown, the method for adapting the 100Hz protection criterion of the AC / DC power transmission system in this embodiment includes the following steps:

[0089] 1) Calculate the corresponding K of the AC-DC transmission system according to the parameters of the AC-DC transmission system set , the K set Threshold value for the criterion to distinguish valve faults from AC system asymmetry faults;

[0090] 2) Obtain the valve-side three-phase current of each 6-pulse converter in the converter station and the current sampling value of the DC side through the current transformer, and obtain K after data processing, and the K is the current of the 6-pulse converter in the converter station The ratio of the maximum value of the amplitude of the power frequency negative sequence component of the switching function to the minimum value of the amplitude;

[0091] 3) Combine K with K set The size of the comparison, if K>K set , it is judged as a valve failure;...

Embodiment 2

[0162] like Figure 7 In a 12-pulse high-voltage AC-DC power transmission system shown, taking the failure of the valve on the rectification side of the Y-bridge converter as an example, the method for adapting the 100 Hz protection criterion of the AC-DC power transmission system in this embodiment includes the following steps:

[0163] 1) Calculate the K corresponding to the 12-pulse high-voltage AC-DC transmission system set ;

[0164] 1.1) According to the parameters of the AC-DC transmission system, calculate the maximum value of K when the AC system is asymmetrically faulted

[0165] According to the parameters of the rectifier side, the particle swarm optimization algorithm is used to obtain For the inverter side, use the same method to get K I m a x a c f = 1.95 , then the...

Embodiment 3

[0189] Same as Embodiment 2, taking a 12-pulse high-voltage AC-DC power transmission system and taking the failure of the valve on the rectifier side of the Y-bridge converter as an example, the method for adapting the 100 Hz protection criterion of the AC-DC power transmission system in this embodiment includes the following steps :

[0190] 1) Calculate the K corresponding to the 12-pulse high-voltage AC-DC transmission system set ;

[0191] This step is with embodiment 2, K set =12.81;

[0192] 2) Calculate K during actual operation, the sampling frequency is 2kHz, that is, 40 points are sampled per cycle;

[0193] This step is with embodiment 2, obtains:

[0194]

[0195]

[0196] Use formula (17) to calculate K under the actual fault condition:

[0197] K = m a x ( | S · ...

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Abstract

The invention discloses a self-adaptive 100 Hz protecting criterion method for an AC / DC power transmission system, which comprises the following steps: 1), analyzing parameters of the AC / DC power transmission system, and computing Kset corresponding to the AC / DC power transmission system; 2), obtaining valve side three-phase current and a DC side electric current sampling value of various six-pulsation current converter of a converter station through a current transformer, and obtaining K after data processing; 3), comparing the K and the Kset; judging a valve fault occurs if the K is larger than the Kset, and judging an AC system asymmetric fault occurs if the K is smaller than the Kset. According to the invention, based on the difference of current breaker function power frequency negative sequence component amplitude ratio of the current converter in the two kinds of fault situations, the AC system asymmetric fault and the converter valve fault can be identified through the self-adaptive protecting criterion, so as to adopt different action schemes according to the different requirements for DC 100 Hz protection of the two kinds of faults, realize the mutual protection coordination of the AC / DC power transmission system, and further protect the safety of the equipment and power grid when a fault occurs.

Description

technical field [0001] The invention relates to a method for a 100Hz protection criterion, in particular to a method for adapting an AC / DC power transmission system to a 100Hz protection criterion, and belongs to the field of power system protection. Background technique [0002] In the current DC project, the 100Hz protection is also responsible for the backup protection function of the asymmetric fault of the AC system and the fault of the converter valve (false opening fault and false non-opening fault). When the main protection refuses to operate, it acts as an alarm and locks. However, the current DC 100Hz protection uses the size of the DC 100Hz component as the protection action criterion in the event of a fault. It cannot distinguish between a converter valve fault and an AC system asymmetry fault, and its action logic, setting and delay are exactly the same. In fact, the two kinds of faults have different influences on the main equipment such as the converter valve,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/00G01R19/165G01R25/00
Inventor 王钢刘俊磊李海锋舒兵成
Owner SOUTH CHINA UNIV OF TECH
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