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A traveling-wave protection method for double-circuit HVDC transmission lines on the same tower

A high-voltage direct current and transmission line technology, applied in emergency protection circuit devices, electrical components, etc., can solve problems such as low reliability, increased fault types, and complex protection setting process.

Active Publication Date: 2018-04-13
SOUTH CHINA UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Traveling wave protection of double-circuit HVDC transmission lines on the same tower also has the problem of poor tolerance to transition resistance
In addition, the double-circuit HVDC transmission line on the same tower has two circuits, and the arrangement of the lines is asymmetrical. Different polar line faults have different coupling amounts on other polar lines. Therefore, the traveling wave characteristics obtained by different line faults are different, and the types of faults are relatively increased. , if the protection criterion of the single-circuit DC transmission line is still used, and the protection is carried out by the change rate and amplitude of the voltage traveling wave or the modulus traveling wave, the protection setting process is more complicated and the reliability is not high

Method used

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  • A traveling-wave protection method for double-circuit HVDC transmission lines on the same tower
  • A traveling-wave protection method for double-circuit HVDC transmission lines on the same tower
  • A traveling-wave protection method for double-circuit HVDC transmission lines on the same tower

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Embodiment

[0115] Such as figure 1 As shown, a fault line selection method for double-circuit HVDC transmission lines on the same tower based on single-circuit local information includes the following steps:

[0116] For upper polar lines:

[0117] (1) Calculate the absolute value of the pole line voltage change rate |du / dt(t)| in real time,

[0118]

[0119] u(t) is the real-time voltage sampling value, T is the time scale for calculating the voltage change rate, selected as T=t d . The absolute value of the voltage change rate is the starting criterion for the pole line protection. If the absolute value of the pole line voltage change rate reaches the set value, the protection will start and the subsequent steps will start. The start time is recorded as t a .

[0120] (2) Take the average value of voltage and current of 20 sampling points in a certain period of time before the starting criterion meets the setting value as a reference quantity, and subtract the reference quantit...

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Abstract

The invention discloses a traveling wave protection method for a double-circuit high-voltage direct current transmission line on the same tower, which comprises the following steps: adopting different criteria for upper and lower polar lines and setting them separately, and adopting voltage change rate and current direction exclusion area for the upper polar line For external faults, use ground mode wave change rate for the lower polar line to eliminate out-of-area faults, use voltage integral ratio for the upper polar line to distinguish faults of the local polar line from other polar line faults, and use voltage integral ratio and modulus integral ratio for the lower polar line Realize the distinction between the pole fault and other pole line faults. This protection scheme has the advantages of high sensitivity, small amount of calculation, only local information, no communication between different circuits, short judgment time, little influence by transition resistance, and can quickly determine the fault pole line of the double DC transmission line on the same tower And it is not easy to misjudge the situation and other advantages.

Description

technical field [0001] The invention relates to a relay protection technology for high-voltage direct current transmission lines in power systems, in particular to a traveling-wave protection method for double-circuit high-voltage direct current transmission lines on the same tower. A traveling-wave protection scheme for double-circuit HVDC transmission lines on the same tower with different protection criteria satisfying the setting value and realizing reliable protection operation. Background technique [0002] With the continuous development of the grid scale, HVDC transmission systems are more and more widely used in practical projects, and at the same time, double-circuit HVDC transmission systems on the same tower have emerged. Compared with single-circuit line transmission, the DC transmission system adopts the method of erecting double-circuit lines on the same tower, which is more conducive to saving the transmission corridor and improving the power transmission cap...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26
Inventor 马燕君李海锋郭履星梁远升王钢
Owner SOUTH CHINA UNIV OF TECH
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