Single-ended protection method of flexible DC power grid based on similarity of traveling wave energy spectrum matrix
A flexible direct current, similarity technology, applied in the field of high-voltage power transmission and transformation, can solve problems such as identification of internal and external faults, and achieve the effect of identifying internal and external faults
Active Publication Date: 2022-03-01
CHONGQING UNIV +1
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[0008] In view of at least one defect in the prior art, the purpose of the present invention is to provide a single-ended protection method for flexible DC power grid based on the similarity of traveling wave energy spectrum matrix, which can effectively solve the problem of identifying faults inside and outside the area when the flexible DC power grid line fails. technical issues
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[0084] The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.
[0085] Such as Figure 1-Figure 2 As shown, a single-ended protection method for flexible DC power grid based on the similarity of traveling wave energy spectrum matrix, the steps include:
[0086] Step 1. For the ±500kV four-terminal flexible DC power grid model, set the length of one of the DC transmission lines to 200km, set a positive grounding short-circuit fault with a transition resistance of 150Ω at the first end of the line at 0km, and collect the faults at the protective measurement device at the first end of the line The positive voltage, negative voltage, positive current, and negative current at each sampling time in the sampling time window with a width of 2 ms are respectively subtracted from the positive voltage, negative voltage, positive current, and negative current during normal operation to obtain the positive vol...
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The invention discloses a method for single-end protection of a flexible DC power grid based on the similarity of traveling wave energy spectrum matrix, which comprises the following steps: setting a fault every set distance from the head end of the line, and establishing three types of faults of the line Fault sample matrix library; calculate the voltage gradient at the head end of the line by using the reverse traveling wave sequence of the line mode voltage at the protection measuring device at the head end of the line; establish the start criterion of the line protection; collect protection Measure the data at the device and calculate the fault spectrum matrix E f ;Calculate the ground model voltage; calculate the sum of the ground model voltage; establish the fault pole identification criterion; calculate the fault energy spectrum matrix E f The kth fault sample matrix E in the fault sample matrix library corresponding to the fault type k The similarity between them; take the maximum value as the line fault degree. The invention can effectively solve the technical problem of identifying faults inside and outside the zone when a fault occurs in a flexible DC grid line.
Description
technical field [0001] The invention relates to the technical field of high-voltage power transmission and transformation, in particular to a single-end protection method for a flexible DC power grid based on similarity of traveling wave energy spectrum matrix. Background technique [0002] The flexible DC grid solves the problems of commutation failure and high harmonic content in traditional DC transmission, and becomes the key to building global energy interconnection in the future. However, when a fault occurs on the DC side of the flexible DC grid, the fault current has the characteristics of fast rising speed, large amplitude, and non-linearity, which endangers the entire grid within a few milliseconds, and the existing flexible DC grid protection cannot withstand high resistance at the same time , Influenced by noise interference, there are problems of refusal to operate due to high-resistance faults at the far end within the zone, and misoperation due to faults with ...
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IPC IPC(8): G01R31/08H02H7/26
CPCG01R31/085G01R31/088H02H7/268
Inventor 王洪彬周念成权文杰童晓阳王强钢
Owner CHONGQING UNIV