DC line fault detection method and device

A technology for DC line faults and DC lines, which is applied in the direction of measuring devices, fault locations, and measuring electricity, can solve the problems of low sensitivity of DC line faults, inability to accurately detect whether DC line faults occur, and extract fault characteristics, etc., to improve fault detection. The detection speed, simple and reliable implementation process, and the effect of improving sensitivity

Inactive Publication Date: 2018-05-15
CHINA ELECTRIC POWER RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] After a DC line fault occurs, the current of the DC line includes two parts, the load component and the fault component. When a slight fault such as high-impedance grounding occurs during the heavy load of the DC line, the load component is larger, the fault component is smaller, and the load component is greater than the fault component. component, covering up the fault characteristics, the detection method relying solely on the increase of DC current cannot extract the fault characteristics from the current after the fault, and cannot accurately detect whether the DC line fault has occurred, the sensitivity of DC line fault detection is low, and thus affects the protection of the DC line Overall action performance, DC line fault detection by DC voltage drop method Affected by DC voltage transformer disconnection

Method used

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  • DC line fault detection method and device

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Effect test

Embodiment 1

[0065] Embodiment 1 of the present invention provides a DC line fault detection method, the specific flow chart of the DC line fault detection method is as follows figure 1 As shown, the specific process is as follows:

[0066] S101: Determine the current fault component of the DC line according to the current of the DC line;

[0067] S102: Calculate the current fault component energy of the DC line according to the current fault component of the DC line determined in S101;

[0068] S103: Judging whether the current fault component energy of the DC line calculated in S102 satisfies the first DC line fault criterion, if the first DC line fault criterion is met, it indicates that the DC line is faulty, and the protection device operates; otherwise, it indicates that the DC line No fault occurs, the protection device does not operate.

[0069] In the above S101, the specific process of determining the current fault component of the DC line according to the current of the DC lin...

Embodiment 2

[0101] Embodiment 2 of the present invention provides a DC line fault detection method, the specific flow chart of the DC line fault detection method is as follows Figure 4 As shown, the specific process is as follows:

[0102] S201: Determine the current fault component of the DC line according to the current of the DC line;

[0103] S202: Calculate the current fault component energy of the DC line according to the current fault component of the DC line determined in S201;

[0104] S203: Judging whether the current fault component energy of the DC line calculated in S202 satisfies the second DC line fault criterion, if it meets the second DC line fault criterion, it indicates that the DC line has a fault and the protection device operates; otherwise, it indicates that the DC line has not occurred Fault, the protection device does not operate.

[0105] In the above S201, the specific process of determining the current fault component of the DC line according to the current ...

Embodiment 3

[0137] Embodiment 3 of the present invention takes Figure 5 The four-terminal flexible DC power grid shown is taken as an example to illustrate the specific process of the DC line fault detection method:

[0138] Figure 5 The four AC systems in Kangbao, Zhangbei, Fengning, and Beijing are respectively connected to the DC power grid, and the four AC systems are all connected to the corresponding converter stations. The converter stations are connected to each other through the DC busbar and the DC line. The line voltage level is ±500kV.

[0139] right Figure 5 The current fault component is simulated when a unipolar 300-ohm ground fault occurs at the midpoint of the Zhongkangbao-Fengning line. The specific simulation waveform diagram is as follows Figure 6 shown, from Figure 6 It can be seen that the current fault component remains stable after increasing from 0 to 0.8kA within 5ms after the fault.

[0140] right Figure 5 The current fault component energy is simula...

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Abstract

The invention provides a DC line fault detection method and device. Firstly the current fault component of a DC line is determined, then the current fault component energy of the DC line is calculated, and finally the fault of the DC line is judged according to the current fault component energy of the DC line so that finally fault detection of the DC line is realized. The current fault componentof the DC line is determined through different moments of current of the DC line so that the influence of the load component on the fault detection sensitivity can be eliminated, and fault detection of the DC line is performed only through the current fault component energy of the DC line without the influence of disconnection of the voltage transformer. Besides, continuous increasing change of the fault feature is realized so that the fault detection speed of the DC line can be enhanced and the sensitivity of fault detection can also be enhanced.

Description

technical field [0001] The invention relates to the technical field of relay protection, in particular to a DC line fault detection method and device. Background technique [0002] The flexible DC power grid has many advantages through DC networking of renewable energy power generation in a wide area: 1) Make full use of the complementarity of renewable energy power generation, realize large-scale centralized access to new energy power generation, and improve the utilization rate of new energy power generation; 2) The DC power grid does not have the inherent frequency stability problem of the AC system, which can realize the smooth access of new energy and reduce the reserve capacity of the system; 3) It can realize the independent control of active and reactive power, and reduce the demand for reactive power; 4) It can realize fast and flexible The distribution of the power flow can achieve wide-area power regulation and mutual aid; 5) Long-distance and large-capacity power...

Claims

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Application Information

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IPC IPC(8): G01R31/08
CPCG01R31/088
Inventor 王兴国王江天郭雅蓉杜丁香余越姜宏丽
Owner CHINA ELECTRIC POWER RES INST
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