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MMC direct current transmission line fault identification method based on SOD transformation

A DC transmission line, fault identification technology, applied in the fault location, detection of faults by conductor type, etc., can solve problems such as damage to the transmission system, and achieve good application prospects, good quickness, and noise elimination.

Active Publication Date: 2019-10-22
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Once a fault occurs in a high-voltage operating environment, the transmission system is likely to be impacted by overvoltage and overcurrent transmission, destroying the entire transmission system

Method used

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  • MMC direct current transmission line fault identification method based on SOD transformation
  • MMC direct current transmission line fault identification method based on SOD transformation
  • MMC direct current transmission line fault identification method based on SOD transformation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] 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.

[0032] (1) Fault location: positive ground fault f 1 , 160km away from the measuring end; the fault start time is 0.4s; the sampling frequency is 10kHz.

[0033] (2) Acquire fault voltage and current data at the measurement point according to the first step in the manual.

[0034] (3) Acquire the fault voltage and curre...

Embodiment 2

[0037] 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.

[0038] (1) Fault location: bipolar short circuit fault f 2 , 160km away from the measuring end; the fault start time is 0.4s; the sampling frequency is 10kHz.

[0039] (2) Acquire fault voltage and current data at the measurement point according to the first step in the manual.

[0040] (3) Acquire the fault voltage and...

Embodiment 3

[0043] 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.

[0044] (1) Fault location: Three-phase short-circuit fault on the AC side of the rectifier station f3 ; The start time of the fault is 0.4s; the sampling frequency is 10kHz.

[0045] (2) Acquire fault voltage and current data at the measurement point according to the first step in the manual.

[0046] (3) Acquire the fau...

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Abstract

The invention relates to a MMC direct current transmission line fault identification method based on SOD transformation, belonging to the technical field of power system relay protection. The method comprises a step of reading fault voltage and fault current data acquired by a high-speed acquisition device of a measuring end, a step of performing cross-order differential SOD transformation on theobtained voltage and current data to obtain Su(n) and Si(n), a step of multiplying Su(n) by Si(n) to obtain Sp(n) and taking a minimum value Spmin from Sp(n) for fault judgment, a step of judging an out-of-zone fault when Spmin is larger than -20, a step of judging a positive pole ground fault when Spmin is larger than -450and is small than -20, and a step of judging a bipolar short-circuit faultwhen Spmin is smaller than -450. According to the method, the single-ended voltage and current data is used, then the voltage and current data is subjected to differential calculation and SOD transformation, a bipolar ground fault, the bipolar short-circuit fault and the out-of-zone fault are judged, the communication with an opposite end signal is needed, and the faults can be reliably and sensitively identified.

Description

technical field [0001] The invention relates to a method for identifying faults of MMC DC transmission lines based on SOD transformation, and belongs to the technical field of electric power system relay protection. Background technique [0002] MMC-HVDC is a new type of direct current transmission technology. The engineering experience at home and abroad is still shallow, and the research time for it is relatively short. Scholars at home and abroad have conducted relevant research on the topology and operating principles of the MMC-HVDC system, and have achieved fruitful results. However, the relevant research mainly focuses on the basic principles and control strategies of the MMC-HVDC system. There are not many studies on conservation methods. Only in a small number of fault characteristic analysis, the analysis content is mainly for the DC side line fault of the system. [0003] Once a fault occurs in a high-voltage operating environment, the transmission system is lik...

Claims

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Application Information

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IPC IPC(8): G01R31/08
CPCG01R31/085
Inventor 束洪春代月安娜张雪飞
Owner KUNMING UNIV OF SCI & TECH
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