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A high-voltage direct current transmission line protection method that can identify high-resistance ground faults

A high-resistance ground fault, high-voltage DC technology, applied in emergency protection circuit devices, electrical components, etc., can solve the problems of DC line protection not being able to act in time to cut off, low sensitivity of longitudinal differential protection, and small longitudinal differential setting value, etc. Satisfy the requirements of rapidity, improve the sensitivity, and the effect of short action time

Active Publication Date: 2015-09-02
EXAMING & EXPERIMENTAL CENT OF ULTRAHIGH VOLTAGE POWER TRANSMISSION COMPANY CHINA SOUTHEN POWER GRID
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0023] Due to the influence of constant current control, the longitudinal difference protection of DC line has a small fixed value, and at the same time, it is affected by the transmission delay of line communication, and its delay is relatively large
In addition, due to the influence of unbalanced current and capacitive current in the fault transient process, the sensitivity of longitudinal differential protection is not high. At present, longitudinal differential protection can only be used as a slow backup protection
[0024] To sum up, there are weak links in the existing HVDC transmission line protection traveling wave protection and longitudinal differential protection configuration, and the DC line protection cannot act in time to remove the fault when the high-resistance grounding fault occurs

Method used

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  • A high-voltage direct current transmission line protection method that can identify high-resistance ground faults
  • A high-voltage direct current transmission line protection method that can identify high-resistance ground faults
  • A high-voltage direct current transmission line protection method that can identify high-resistance ground faults

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Embodiment Construction

[0047] The content of the present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

[0048] 1. The principle of DC line protection using the firing angle of the converter

[0049] After the DC line fails, the control system immediately intervenes to take effect, the converter phase shifts, and the firing angle is adjusted. During the initial transient process, the DC voltage on the rectifier side drops and the DC current rises; the DC voltage and DC current on the inverter side both drop. If a high-impedance ground fault occurs, the firing angle of the steady-state control system that escapes the initial transient process will be greater than a certain value, and this firing angle is greater than the firing angle during normal operation.

[0050] The protection principle of the DC line using the trigger angle of the converter proposed by the present invention is as follows: the longitudinal differentia...

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Abstract

The invention discloses a high-voltage direct-current transmission line protecting method capable of identifying high resistance grounding faults. The method comprises the following steps that (1) direct-current line currents of a rectification station side and an inversion station side are monitored in real time, and when || I d L | - | I d Los || is larger than I set, a high-voltage direct-current transmission line protection motion is started; (2) a transverter firing angle measured value is added in fieldbus communication with pole control and direct current protection, and when alpha is larger than kc alpha0, a fault removal motion is started. The method can not be influenced by transition resistance, the high resistance grounding faults can be identified only through comparison between a transverter firing angle actual value and an initial steady state minimum firing angle, the defect that an existing direct current line protection high resistance grounding fault failure to operate is overcome, and sensibility of protection motions is improved.

Description

technical field [0001] The invention relates to the technical field of high-voltage direct current transmission, in particular to a high-voltage direct current transmission line protection method capable of identifying high-resistance grounding faults. Background technique [0002] High-voltage direct current (HVDC) transmission plays an increasingly important role in long-distance, high-power transmission and asynchronous networking due to its advantages of large transmission power, low line cost, and good control performance. At present, the number of HVDC transmission projects in China ranks first in the world. The HVDC transmission line is generally used as the connection line of the regional network, which not only affects the stability of the system, but also affects the stable operation of the grid connected to it. Due to the long DC lines and high failure probability, it is of great significance to improve the operation level of relay protection of HVDC transmission...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26
Inventor 翟永昌张怿宁李永丽杨光源
Owner EXAMING & EXPERIMENTAL CENT OF ULTRAHIGH VOLTAGE POWER TRANSMISSION COMPANY CHINA SOUTHEN POWER GRID
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