A Modulus Correlation Based MMC DC Transmission Line Pilot Protection Method

A technology for DC transmission line and longitudinal protection, which is applied in emergency protection circuit devices, electrical components, power transmission AC networks, etc. The effect of good speed and small amount of transmitted data

Active Publication Date: 2021-10-22
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Moreover, the existing protection methods for DC transmission lines also have many deficiencies. For example, high-resistance ground faults cannot be effectively identified, and effective identification of high-resistance ground faults has always been a difficult problem in the field of power system relay protection.

Method used

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  • A Modulus Correlation Based MMC DC Transmission Line Pilot Protection Method
  • A Modulus Correlation Based MMC DC Transmission Line Pilot Protection Method
  • A Modulus Correlation Based MMC DC Transmission Line Pilot Protection Method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Example 1: Establish as attached figure 2 The pseudo-bipolar 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 360km, and the transmission active power is 1200MW. A metal short-circuit fault occurs at a distance of 260km from the rectification side of the positive line.

[0031] Specific steps such as figure 1 Shown:

[0032] Step1: After the failure of the MMC DC transmission system, according to the positive and negative pole voltage and current measured ...

Embodiment 2

[0036] Example 2: Establish as attached figure 2 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 360km, and the transmission active power is 1200MW. It is assumed that a two-pole short-circuit fault occurs at a distance of 300km from the rectification side of the line, and the transition resistance is 200Ω.

[0037] Step1: After the failure of the MMC DC transmission system, according to the voltage and current measured at the measuring point where the double-...

Embodiment 3

[0040] Example 3: Establish as attached figure 2 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 360km, and the transmission active power is 1200MW. It is assumed that a single-phase short-circuit fault of the AC system occurs on the rectification side.

[0041] Step1: After the failure of the MMC DC transmission system, according to the voltage and current measured at the measuring point where the double-terminal protection is installed (in order to meet the ...

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PUM

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Abstract

The invention relates to a modulus correlation-based MMC DC transmission line longitudinal protection method, which belongs to the technical field of electric power system relay protection. When the MMC DC transmission line fails, first collect the positive and negative pole voltages and currents at both ends of the line, and obtain the line-mode voltage and current according to the phase-mode transformation, so as to calculate the correlation coefficient of the line-mode voltage and current at both ends of the line, and then use the correlation coefficient to carry out Identification of internal and external faults, if the judgment result is that one end is positive and the other end is negative, it is an external fault, and if both ends are negative, it is an internal fault. The invention has a strong ability to withstand the transition resistance, the data window is only 3ms, the quick action is good, and the application prospect is strong.

Description

technical field [0001] The invention relates to a modulus correlation-based MMC DC transmission line longitudinal protection method, which belongs to the technical field of electric power system relay protection. Background technique [0002] MMC-based flexible DC transmission technology has many advantages compared with traditional DC, such as no reactive power compensation problem, no commutation failure problem, and many advantages such as being able to supply power to passive systems, and has become a research hotspot today. At present, there are few researches on MMC HVDC line protection. Since the topology structure of the MMC basic unit and the working principle of the sub-modules are very different from those of the traditional DC transmission line, the protection method of the DC transmission line can refer to the protection method of the traditional DC transmission line, but not all of them are applicable to the protection of the traditional DC transmission line. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26G01R31/08H02J3/36
CPCG01R31/085H02H7/268H02J3/36Y02E60/60Y04S10/52
Inventor 束洪春朱亮安娜范俊薄志谦
Owner KUNMING UNIV OF SCI & TECH
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