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Frequency selection method and device for high-frequency injection signals based on line parameter errors

A high-frequency injection, signal frequency technology, applied in measurement devices, fault locations, instruments, etc., can solve the problem of low reliability, and achieve the effect of improving sensitivity and reliability, and reliable operation.

Active Publication Date: 2019-01-04
STATE GRID SICHUAN ELECTRIC POWER CORP ELECTRIC POWER RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0018] In order to overcome the limitations of the existing technology and the technical problems of low reliability, the present invention provides a high-frequency injection signal frequency selection method based on line parameter errors for UHV DC ground electrode line impedance monitoring, In this method, the element parameters and line length of the grounding line unit length are known, and the parameter error of the grounding electrode line unit length is considered at the same time. When any ground fault occurs, the monitoring system can operate reliably, which greatly improves the sensitivity and reliability of monitoring

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  • Frequency selection method and device for high-frequency injection signals based on line parameter errors
  • Frequency selection method and device for high-frequency injection signals based on line parameter errors
  • Frequency selection method and device for high-frequency injection signals based on line parameter errors

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Embodiment 1

[0051] use as figure 1 The ground electrode line impedance monitoring system (ELIS system) shown in the figure detects the faults of the UHV DC ground electrode line. Inject a high-frequency current signal into the ground electrode lead. At the same time, by measuring the same-frequency voltage amplitude at the signal injection point, the impedance change of the ground electrode lead is indirectly calculated. If the impedance detected by the impedance monitoring device enters the action area and lasts for a certain time delay, an abnormal signal of the ground electrode lead is sent to the DC transmission control and protection system to remind the operator to perform corresponding operations.

[0052] In order to cooperate with the implementation of the injection method, a parallel resonant filter is also connected in series at both ends of the ground electrode lead to prevent the injection of high-frequency signals. Among them, the filter on the ground electrode side will a...

Embodiment 2

[0074] In order to implement the method for selecting the frequency of the high-frequency injection signal described in the above-mentioned embodiment 1, this embodiment also proposes a device for selecting the frequency of the high-frequency injection signal based on line parameter errors, the device includes a parameter acquisition unit, a parameter calculation unit, a data Processing unit and optimization solving unit.

[0075] Among them, the parameter acquisition unit is used to obtain the ground electrode line length l, the ground electrode line unit length inductance L 1 and capacitance per unit length C 1 .

[0076] The parameter calculation unit is used to obtain the relative error ε of the inductance per unit length of the ground electrode line L , The relative error ε of the capacitance per unit length of the ground electrode line C And the relative error of line length e.

[0077] The data processing unit is used to determine an objective function for optimizin...

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Abstract

The invention discloses a frequency selection method and device for high-frequency injection signals based on line parameter errors, which is used for optimizing the frequency selection of high-frequency injection signals for impedance monitoring of an extra-high voltage DC grounding electrode line and solves the technical problems of limitations and low reliability existing in the prior art. Themethod takes parameter errors of the grounding electrode unit length line into consideration under the condition of knowing element parameters and line length of the unit length of the grounding line,and obtains an optimal value of the frequency of the high-frequency injection signals through optimized calculation, so that the monitoring system is ensured to operate reliably when various grounding faults occur in the grounding electrode line, and the monitoring sensitivity and reliability are greatly improved.

Description

technical field [0001] The invention relates to the field of fault monitoring of an UHV DC transmission system, in particular to a method and device for selecting a frequency of a high-frequency injection signal based on line parameter errors for monitoring the impedance of an UHV DC ground electrode line. Background technique [0002] The grounding electrode is an essential device in the UHV DC transmission system. It mainly plays the role of providing a path for the unbalanced current and clamping the neutral point voltage. With the rapid development of UHV DC projects, the selection of grounding poles is becoming increasingly difficult. In order to avoid the impact of DC bias on the converter station equipment, the grounding poles of some DC projects are more than 100km away from the converter station. Long-distance grounding The probability of pole lead wire failure can not be ignored, so the problem of fault monitoring of ground electrode lead wire has attracted more an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08
CPCG01R31/085G01R31/088
Inventor 滕予非李小鹏
Owner STATE GRID SICHUAN ELECTRIC POWER CORP ELECTRIC POWER RES INST