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A method and system for preventing misoperation of zero-sequence directional protection of vertical connection of multi-circuit lines on the same tower

A zero-sequence direction, multi-return technology on the same tower, applied in the direction of emergency protection circuit devices, emergency protection devices with automatic disconnection, electrical components, etc. Protection against misuse, etc.

Active Publication Date: 2022-07-01
CHINA ELECTRIC POWER RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In multi-circuit lines with the same tower and same pressure, after a non-full-phase operation or disconnection fault occurs in the first circuit, the busbars on both sides of the transmission line will have zero-sequence voltages with opposite phases. voltage compensation, it will cause malfunction of the healthy line
At the same time, the load transfer caused by non-full-phase operation or disconnection fault is likely to cause overload of other lines, and there is also the possibility of malfunction
For the mixed-voltage line on the same tower, due to the mutual inductance between the loops, the other loop will have a zero-sequence electrical quantity distribution that is exactly the same as the broken line, resulting in misoperation
At present, there is no complete solution to the problem of misoperation of longitudinal zero-sequence direction protection caused by non-full-phase operation or disconnection fault, and it does not meet the technical standards

Method used

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  • A method and system for preventing misoperation of zero-sequence directional protection of vertical connection of multi-circuit lines on the same tower
  • A method and system for preventing misoperation of zero-sequence directional protection of vertical connection of multi-circuit lines on the same tower
  • A method and system for preventing misoperation of zero-sequence directional protection of vertical connection of multi-circuit lines on the same tower

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Embodiment 1

[0070] figure 1 It is a flow chart of the method for preventing misoperation of zero-sequence directional protection in the vertical connection of multi-circuit lines on the same tower according to the preferred embodiment of the present invention. like figure 1 As shown, the method 100 for preventing the misoperation of the zero-sequence directional protection of the vertical connection of the multi-circuit lines on the same tower according to this preferred embodiment starts from step 101 .

[0071] In step 101, set the station domain information to be received for the zero-sequence directional protection device of each circuit in the multi-circuit line on the same tower, and input the pre-measured positive-sequence impedance, zero-sequence impedance and zero-sequence of each circuit. Mutual inductance, wherein the station domain information includes three-phase phase current measurement value, three-phase phase voltage measurement value, circuit breaker switch status and m...

Embodiment 2

[0127] In this preferred embodiment, a real-time digital simulator RTDS (Real Time Digital Simulator) is used to establish a simulation model of the same tower and same voltage double-circuit line. The length of each circuit is 100km, and the system voltage level is 500kV. The impedance parameters are shown in Table 1:

[0128] Table 1 System parameters of the multi-circuit simulation model on the same tower

[0129]

[0130] image 3 It is a schematic diagram of the zero-sequence voltage distribution when a disconnection fault occurs on the same-tower and same-voltage double-circuit line according to another preferred embodiment of the present invention. like image 3 As shown, the double-circuit line of the same tower and the same voltage in this preferred embodiment includes a C1 return line and a C2 return line, and the two sides of the return line are the M-side system and the N-side system respectively. Now let the C1 loop line be separated from the M-side system ...

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Abstract

The present invention provides a method and system for preventing misoperation of zero-sequence directional protection of multi-circuit lines on the same tower. The method and system are based on the station domain information, determine whether the faulty return line exists by whether the first criterion is established, and judge whether there is a return line other than the faulty line in the multi-circuit line of the faulted voltage level according to the second criterion. Zero-sequence voltage zero-crossing point, and reverse compensation when there is zero-sequence voltage zero-crossing point; in the mixed-voltage multi-circuit line on the same tower, it is determined whether there is zero-sequence voltage zero-crossing point in the return line with no fault voltage level according to the third criterion , and when there is a zero-sequence voltage zero-crossing point, the longitudinal zero-sequence protection is blocked. The method and system completely solve the problem of misoperation of the zero-sequence directional protection of the pilot-connected zero-sequence directional protection of the same-tower and same-voltage or mixed-voltage multi-circuit lines caused by non-all-phase operation or disconnection fault, and can ensure the accuracy of the zero-sequence directional protection of the pilot-connected line. Therefore, it can improve the anti-misoperation ability of the power system and the safe and stable operation level of the power grid.

Description

technical field [0001] The present invention relates to the field of power protection, and more particularly, to a method and a system for preventing misoperation of zero-sequence directional protection of multi-circuit lines on the same tower. Background technique [0002] The multi-circuit line on the same tower has the characteristics of few towers, small area of ​​transmission corridor, strong power transmission capacity, and large required path width, which can avoid redundant engineering that must be implemented when crossing mountains, forests and cities. The return transmission line has significant economic advantages and can also meet the requirements of large-capacity transmission. In the multi-circuit line on the same tower, the application of longitudinal zero-sequence directional protection is quite extensive, and the technology is mature. In the prior art, the zero-sequence directional protection of the pilot connection should not be affected by the magnitude ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26H02H3/05
CPCH02H3/05H02H7/26H02H7/267
Inventor 戴飞扬王兴国杨国生周泽昕
Owner CHINA ELECTRIC POWER RES INST