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MMC direct current power transmission line fault recognition method based on correlation

A DC transmission line and fault identification technology, applied in the direction of measuring electricity, measuring electrical variables, measuring devices, etc., can solve problems such as harsh conditions, long line distances, complex working environments, etc., and achieve the effect of sensitive identification

Active Publication Date: 2019-08-30
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The transmission line of the large-capacity MMC-HVDC system uses overhead lines. According to the traditional DC transmission system, the line distance is long, the working environment is complex, and the conditions are harsh, resulting in a high probability of failure, and the fault of the DC transmission line is one of the components with the highest failure rate of the DC transmission system. One, therefore, it is necessary to reliably identify faults in and out of the zone

Method used

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  • MMC direct current power transmission line fault recognition method based on correlation
  • MMC direct current power transmission line fault recognition method based on correlation
  • MMC direct current power transmission line fault recognition method based on correlation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Example 1: Establish as attached figure 1 The MMC HVDC transmission system shown is used as a simulation model. The winding on the valve side of the connecting transformer adopts a delta connection without a neutral point, and the AC side of the connecting transformer adopts a star connection, and its neutral point is directly grounded. The DC side is grounded through the clamping resistor, which has a large resistance value. Its main function is to clamp the two-pole voltage and provide a potential reference point for the DC system during normal operation. The DC voltage is ±320kV, the transmission line is 400km, and M is the measurement terminal.

[0027] (1) Fault location: positive ground fault f 1 , 200km away from the measuring end; the fault start time is 0.4s; the sampling frequency is 10kHz.

[0028] (2) Acquire fault voltage and current data at the measurement point according to the first step in the manual.

[0029] (3) According to the second step in the...

Embodiment 2

[0032] Example 2: Establish as attached figure 1 The MMC HVDC transmission system shown is used as a simulation model. The winding on the valve side of the connecting transformer adopts a delta connection without a neutral point, and the AC side of the connecting transformer adopts a star connection, and its neutral point is directly grounded. The DC side is grounded through the clamping resistor, which has a large resistance value. Its main function is to clamp the two-pole voltage and provide a potential reference point for the DC system during normal operation. The DC voltage is ±320kV, the transmission line is 400km, and M is the measurement terminal.

[0033] (1) Fault location: bipolar short circuit fault f 2 , 200km away from the measuring end; the fault start time is 0.4s; the sampling frequency is 10kHz.

[0034] (2) Acquire fault voltage and current data at the measurement point according to the first step in the manual.

[0035] (3) Take the fault voltage and cu...

Embodiment 3

[0038] Example 3: Establish as attached figure 1 The MMC HVDC transmission system shown is used as a simulation model. The winding on the valve side of the connecting transformer adopts a delta connection without a neutral point, and the AC side of the connecting transformer adopts a star connection, and its neutral point is directly grounded. The DC side is grounded through the clamping resistor, which has a large resistance value. Its main function is to clamp the two-pole voltage and provide a potential reference point for the DC system during normal operation. The DC voltage is ±320kV, the transmission line is 400km, and M is the measurement terminal.

[0039] (1) Fault location: three-phase short-circuit ground fault on the AC side of the inverter station f 3 ; The start time of the fault is 0.4s; the sampling frequency is 10kHz.

[0040] (2) Acquire fault voltage and current data at the measurement point according to the first step in the manual.

[0041] (3) Take th...

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Abstract

The invention relates to an MMC direct current power transmission line fault recognition method based on correlation, and belongs to the technical field of relay protection of a power system. The method comprises the steps of firstly reading a fault voltage and fault current data acquired by a high-speed collection device of a measurement terminal; then performing differential calculation on the acquired voltage data, and analyzing correlation between the original fault voltage and the fault current to acquire a correlation coefficient kui, performing correlation analysis on the original faultcurrent to acquire a correlation coefficient kuti; when the correlation coefficient between the original fault voltage and the current the absolute value of kui is less than 0.15, judging that the fault is a single pole ground fault; when kui is not more than -0.15, and the correlation coefficient between a voltage change rate and the original fault current kuti is more than 0, judging that the fault is a dual pole short circuit ground fault; when kui is not more than -0.15 and kuti is less than 0, judging that the fault is an alternating current side fault of an inverter station; and when kui is not less than 0.15, judging that the fault is an alternating current side fault of a rectification station.

Description

technical field [0001] The invention relates to a correlation-based MMC DC transmission line fault identification method, which belongs to the technical field of electric power system relay protection. Background technique [0002] As a highly controllable transmission system, MMC-HVDC relies heavily on control and protection. Once a fault occurs in a high-voltage operating environment, the transmission system is likely to be impacted by overvoltage and overcurrent transmission, which will destroy the entire transmission system. As an important power transmission device, MMC-HVDC requires long-term reliable operation. When a fault occurs, it is necessary not only to ensure that the system is not damaged, but also to quickly provide fault recovery support for the faulty system, so the protection strategy for the MMC-HVDC system is very important. In the MMC-HVDC system structure, except that the switching devices used in the converter are different from those used in traditi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/02
CPCG01R31/50
Inventor 束洪春代月安娜张雪飞梁雨婷
Owner KUNMING UNIV OF SCI & TECH
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