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Voltage oscillation frequency-based grounding electrode line overvoltage breakdown point positioning method

A technology of voltage oscillation and positioning method, which is applied in the direction of testing dielectric strength, etc., can solve the problems of no fault locating device, no fault locating device for DC grounding line, and inability to locate the breakdown point of grounding line.

Active Publication Date: 2017-08-08
STATE GRID SICHUAN ELECTRIC POWER CORP ELECTRIC POWER RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is that there is no special fault location device on the DC grounding line, and it is impossible to locate the breakdown point after the overvoltage breakdown of the grounding line. The voltage breakdown point location method solves the problem that there is no special fault location device on the DC grounding line, and it is impossible to locate the breakdown point after the grounding line has an overvoltage breakdown

Method used

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  • Voltage oscillation frequency-based grounding electrode line overvoltage breakdown point positioning method
  • Voltage oscillation frequency-based grounding electrode line overvoltage breakdown point positioning method
  • Voltage oscillation frequency-based grounding electrode line overvoltage breakdown point positioning method

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Embodiment 1

[0091] first according to Figure 1 to Figure 7 As shown, the derived transfer function formula and the voltage oscillation frequency fz and the total inductance L of the ground electrode line 3 The relationship between the curve L 3 -fz;

[0092] Among them, the derivation process of the transfer function formula in step 1 is as follows: figure 1 As shown, when a single-pole fault occurs in the UHVDC transmission project, before the converter is blocked, the fault current will pass through the rectifier-side converter CSr, pole line smoothing reactor La, DC line fault point f, and the sending end is grounded The pole address g, the ground pole lead wire, and the neutral pole line smoothing reactor Lb form a loop. Under the action of the converter control system and the centralized capacitors, inductors and other components in the circuit, the voltage and current in the circuit will produce a relatively complicated response process after a fault, and lead to the occurrence ...

Embodiment 2

[0165] The difference from Example 1 is; when in use: as Figure 8 , Figure 9 , Figure 11 As shown; the fault of Binjin DC pole 2 line causes the insulation breakdown fault of the ground electrode lead wire on the rectifier side, and the voltage waveform on the neutral pole bus is as follows Figure 11 . Use the prony algorithm to Figure 11 The voltage waveform of the oscillation frequency is estimated, and the oscillation frequency is 550Hz, which is determined by Figure 8 It is known that the corresponding line inductance is 0.0047H, and then according to Figure 9 The distance to the fault is about 2 kilometers. In the Binjin DC 4.16 incident, after line inspection, it was found that the actual breakdown point was 1.8 kilometers away from the converter station. There is a difference of 0.2 kilometers between the breakdown point positioning result obtained by using the oscillation frequency and the actual distance.

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Abstract

A voltage oscillation frequency-based grounding electrode line overvoltage breakdown point positioning method disclosed by the present invention orderly comprises the following steps of 1 selecting the fault grounding electrode lines, according to the prony signal analysis, obtaining an oscillation frequency fz of a fault voltage waveform after the overvoltage breakdown; 2 according to a transfer function of the head-end voltages of the grounding electrode lines, obtaining a relation curve between the voltage oscillation frequencies fz and the grounding electrode line inductances L; 3 according to the relation curve between the voltage oscillation frequencies fz and the grounding electrode line inductances L in the step 2, obtaining the grounding electrode line inductance L corresponding to the oscillation frequency fz; 4 traversing the grounding electrode line equivalent impedances corresponding to different fault distances, and obtaining a relation curve between the grounding electrode line inductances and the fault distances; 5 according to the relation curve between the grounding electrode line inductances and the fault distances in the step 4, obtaining the fault distance d corresponding to the grounding electrode line inductance L3, thereby realizing the overvoltage breakdown point positioning.

Description

technical field [0001] The invention relates to a method for locating an overvoltage breakdown point, in particular to a method for locating an overvoltage breakdown point of a ground electrode line based on a voltage oscillation frequency. Background technique [0002] At present, after a single-pole fault occurs in the UHV DC system, a large fault current will flow through the grounding pole line, and this transient process will lead to overvoltage in the grounding pole line. If there are weak insulation points along the grounding electrode line or the insulation configuration of the grounding electrode line is improper, it will easily lead to overvoltage breakdown of the grounding electrode line, causing DC current to directly enter the ground without the grounding electrode, causing subsequent control and protection actions. It may even cause DC blocking. In the actual UHV DC project, overvoltage breakdown of the grounding electrode line has occurred many times. After ...

Claims

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Application Information

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IPC IPC(8): G01R31/12
Inventor 李小鹏滕予非甄威张星海姜振超
Owner STATE GRID SICHUAN ELECTRIC POWER CORP ELECTRIC POWER RES INST
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