Multi-end flexible DC power grid fault positioning method and system

A DC power grid and fault location technology, which is applied in the direction of fault location and fault detection according to conductor type, can solve the problems of no multi-terminal flexible DC power grid fault location method, etc., and achieve high practical value, accurate identification, and simple principle.

CN108107319AInactive Publication Date: 2018-06-01SHANDONG UNIV +2
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2018-06-01
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a multi-end flexible DC power grid fault positioning method and system. The method comprises steps: positive and negative current traveling wave signals at two ends of a DC transmission line are acquired in real time; wavelet transform modulus maxima of the positive and negative current traveling waves of the DC line after fault is calculated; validity test is carried out on the wavelet transform modulus maxima data; fault electrode recognition based on a current traveling wave wavelet transform modulus maxima difference is carried out; fault line recognition based on atwo-end current traveling wave wavelet transform modulus maxima symbol difference is carried out; and an accurate fault position is solved. The simulation analysis shows that in various fault conditions, a fault electrode and a fault line can be correctly recognized, the fault position can be accurately calculated, the sensitivity is high, the reliability is high, and besides, a positioning device in a local end only needs to transmit symbol and sampling time information of the wavelet transform modulus maxima to the opposite end, and requirements on communication are not high.
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Description

technical field

[0001] The present invention relates to the technical field of DC power grid fault location, in particular to a method and system for fault location of a multi-terminal flexible DC power grid. Background technique

[0002] With the rapid development of power electronics technology, flexible DC transmission technology has developed rapidly in the past ten years. Compared with traditional high-voltage DC transmission, flexible DC transmission has the advantages of independent control of active power and reactive power, no need to change voltage polarity for power flow reversal, and power supply for passive systems.

[0003] At present, there are many flexible DC projects that have been completed and put into operation in China, such as the Nan'ao project, the Shanghai Nanhui demonstration project, the Zhoushan project, and the Xiamen project. These projects include point-to-point and multi-terminal flexible DC transmission projects, and do not form a DC grid. ...

Examples

Embodiment Construction

[0068] The present invention will be further described below in conjunction with accompanying drawing.

[0069] The invention discloses a multi-terminal flexible DC power grid fault location method, such as Figure 6 shown, including the following steps:

[0070] (1) The positive and negative current traveling wave signals are collected in real time on both sides of each DC line, and filtered;

[0071] (2) Extract the positive and negative current traveling wave data of the DC line, and after wavelet transform, calculate the wavelet transform modulus maximum value;

[0072] (3) Establish wavelet transform modulus maxima data validity inspection criterion, record the size, sign, and arrival time of the first wavelet transform modulus maxima satisfying the criterion, for subsequent steps;

[0073] (4) Establish fault pole identification criteria, and carry out fault pole identification based on the difference in modulus maximum value of current traveling wave wavelet transform...