Flexible DC power grid single-end protection method based on traveling wave energy spectrum matrix similarity
A flexible DC and similarity technology, applied in the field of high-voltage power transmission and transformation, which can solve problems such as fault identification inside and outside the area
Active Publication Date: 2021-09-10
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] like 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 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 voltage faul...
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The invention discloses a flexible DC power grid single-end protection method based on traveling wave energy spectrum matrix similarity. The method comprises the following steps: setting a fault at a set distance from the head end of a line, and building a fault sample matrix library of three fault types of the line; calculating a line head end voltage gradient by using a line mode voltage reverse traveling wave sequence at a line head end protection measurement device; establishing a line protection starting criterion; for a first sampling time window after the protection starting moment, collecting data at a protection measurement device, and calculating a fault energy spectrum matrix Ef; calculating floor model voltage; calculating a floor model voltage sum; establishing a fault pole identification criterion; calculating the similarity between the fault energy spectrum matrix Ef and the kth fault sample matrix Ek in the fault sample matrix library of the corresponding fault type; and taking the maximum value as the line fault degree. According to the method, the technical problem of identifying internal and external faults when the flexible DC power grid line has a fault can be effectively solved.
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