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A Fault Identification Method of mmc DC Transmission Line Based on SOD Transformation

A DC transmission line, fault identification technology, applied in the direction of fault location, fault detection according to conductor type, etc., can solve problems such as damage to the transmission system

Active Publication Date: 2021-07-06
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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  • A Fault Identification Method of mmc DC Transmission Line Based on SOD Transformation
  • A Fault Identification Method of mmc DC Transmission Line Based on SOD Transformation
  • A Fault Identification Method of mmc DC Transmission Line 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 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. First read the fault voltage and fault current data obtained by the high-speed acquisition device at the measurement end; secondly, perform cross sequence differential SOD transformation on the obtained voltage and current data respectively to obtain Su(n) and Si(n); finally, Su( Multiply n) and Si(n) to get Sp(n), take the minimum value Spmin of Sp(n) for fault judgment; when Spmin>-20, it is judged as an out-of-area fault; when -450<Spmin<-20 , it is judged as a positive ground fault; when Spmin<-450, it is judged as a bipolar short circuit fault. The invention adopts single-end voltage and current data, and then sequentially performs differential calculation and SOD transformation on the voltage and current data, and then identifies unipolar ground faults, bipolar short-circuit faults and out-of-area faults, and can be reliable and sensitive without communicating with the opposite end signal identify faults.

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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Patent Type & Authority Patents(China)
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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