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EHV (extra-high voltage) DC grounding electrode line fault monitoring method based on injection signal

A technology of UHV direct current and signal injection, which is applied in the direction of measuring devices, instruments, measuring electronics, etc., can solve the problems of large influence of ground electrode line parameter changes, low reliability of impedance monitoring strategy, etc., and achieve accurate response to standing wave ratio Effect

Inactive Publication Date: 2018-03-20
STATE GRID SICHUAN ELECTRIC POWER CORP ELECTRIC POWER RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is that the current ground electrode line fault monitoring method based on impedance monitoring is greatly affected by the change of ground electrode line parameters, resulting in low reliability of the impedance monitoring strategy in practical applications. The purpose is to provide UHV based on injection signals DC grounding electrode line fault monitoring method to solve the above problems

Method used

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  • EHV (extra-high voltage) DC grounding electrode line fault monitoring method based on injection signal
  • EHV (extra-high voltage) DC grounding electrode line fault monitoring method based on injection signal
  • EHV (extra-high voltage) DC grounding electrode line fault monitoring method based on injection signal

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Embodiment

[0043] The method for monitoring faults of UHV DC grounding pole lines based on injected signals of the present invention includes the following steps: S1: injecting high-frequency sinusoidal current signals into the head end of the grounding pole lines of UHVDC power transmission system through a signal injection device, and recording the current signals Measure the amplitude and phase of the same frequency voltage at the signal injection point at the same time, and calculate the phase difference between the voltage and current; S2: Calculate the wave impedance of the ground electrode line according to the line parameters in step S1; S3: According to the step Calculate the voltage amplitude, current amplitude, line wave impedance, and phase difference between voltage and current calculated in S1 and S2, and calculate the voltage standing wave ratio of the ground electrode line; S4: According to the voltage standing wave ratio of the ground electrode line in step S3 Identify fa...

Embodiment 2

[0046] This embodiment refines the specific implementation method of each step in the above-mentioned embodiment 1. In the step S1, the frequency of the injected high-frequency current signal is 13.95kHz, and the amplitude and phase sign are I s and The amplitude and phase angle of the same-frequency voltage measured at the signal injection point are U s and The phase difference between voltage and current is written as

[0047] In the step S2, calculate the ground electrode line wave impedance Z c The specific calculation formula is:

[0048] In the formula, r, l, g, and c are the resistance, inductance, conductance, and capacitance of the unit length of the ground electrode line, respectively, and ω is the angular frequency.

[0049] In the step S3, according to the measured voltage amplitude, current amplitude, line wave impedance, and phase difference between voltage and current, the voltage standing wave ratio of the ground electrode line is calculated, and the s...

Embodiment 3

[0072] Such as Figure 1~5 As shown, in combination with the above embodiment, this embodiment discloses a specific application example of the above method. Specifically, a DC transmission system model is taken as an example to provide a simulation example.

[0073] The method of the present invention builds a ±800kV UHV DC power transmission system simulation model, and the model parameters refer to the actual engineering parameters in Southwest-East China. Among them, the rated transmission capacity of the DC transmission system is 8000MW; the length of the transmission line is 1652km. figure 1 shown. The ground electrode line in the simulation system adopts the Bergeron model, and the line length is 100km.

[0074] When the ground electrode line is in normal operation, it is easy to get

[0075] VSWR=1.18set

[0076] It can be seen that, considering factors such as the resistance of the ground electrode line itself and the resistance at the end of the line that cannot ...

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Abstract

The invention discloses an EHV (extra-high voltage) DC grounding electrode line fault monitoring method based on an injection signal, and the method comprises the following steps: S1, injecting a high-frequency sine current signal to the head end of a grounding electrode line of an EHV DC power distribution system through a signal injection device, recording the amplitude and phase of the currentsignal, measuring the amplitude and phase of a co-frequency voltage of a signal injection point at the same time, and calculating the phase difference between the voltage and the current; S2, calculating the wave impedance of the grounding electrode line according to the line parameters at step S1; S3, calculating the voltage standing wave ratio of the grounding electrode line according to the voltage amplitude, current amplitude, line wave impedance and the phase difference between the voltage and current, which are measured at steps S1 and S2; S4, carrying out the recognition of a fault according to the voltage standing wave ratio of the grounding electrode line at step S3.

Description

technical field [0001] The invention relates to the field of fault identification of grounding electrode lines of UHVDC power transmission systems, in particular to a monitoring method for faults of grounding electrode lines of UHVDC power transmission systems based on high-frequency voltage standing wave ratio. Background technique [0002] The UHV DC transmission technology has the advantages of large transmission capacity, long transmission distance, and strong control performance. It plays a pivotal role in the long-distance transmission of electric energy and the interconnection of regional power grids. The grounding electrode is an important part of the UHV DC transmission system. , It mainly plays the role of providing the earth return path and establishing the system voltage reference point. With the continuous construction and operation of UHV DC transmission projects, the distance between the ground electrode and the converter station has exceeded 100km, which has ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/02
CPCG01R31/50
Inventor 滕予非李小鹏姜振超龙呈段翔兮
Owner STATE GRID SICHUAN ELECTRIC POWER CORP ELECTRIC POWER RES INST