A New Method of Distribution Network Fault Line Selection Based on the Similarity Degree of Correlation Coefficient Vectors
A distribution network fault and correlation coefficient technology, applied in the direction of measuring electricity, fault location, measuring electrical variables, etc., can solve problems such as the scope of application is not wide, achieve the goal of improving the scope of application, avoiding the protection threshold, and reducing the interference of human factors Effect
Active Publication Date: 2020-09-25
GUANGDONG POWER GRID CO LTD +1
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Problems solved by technology
For example, use the wavelet packet correlation coefficient method, prony correlation coefficient method, S-transform amplitude-phase method, etc. to select fault lines. However, such methods still need to manually set the protection value, which is greatly affected by human factors and has great limitations. , not widely applicable
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Embodiment 1
[0032] The embodiment takes a 10kV distribution network resonant grounding system with 5 outgoing lines as an example for a brief description, such as figure 2 shown. figure 2 Among them, the line parameters of the system model are shown in Table 1, and the line length details and load conditions are shown in Table 2.
[0033] Table 1 System model circuit parameters
[0034]
[0035] Table 2 Details of line length and load
[0036]
[0037] The arc suppression coil in the system adopts overcompensation, and the compensation degree is 8%, so the inductance value L of the arc suppression coil is set as 0.923H. Now a group of single-phase ground fault experiments are carried out in the system model. The fault condition is that a single-phase ground fault with a closing angle of 45° and a fault resistance of 5Ω occurs at 50% of line 1. The present invention adopts 5-layer decomposition of wavelet packet, and can decompose 32 frequency bands. Firstly, the zero-sequence ...
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The invention relates to the detection field of distribution network fault line selection, and more specifically relates to a new method for distribution network fault line selection based on similarity degree of correlated coefficient vectors. The new method comprises the following steps of S1, extracting a zero sequence voltage U0 at a bus; S2, extracting a zero sequence current of each line when a single-phase grounding fault occurs, that is, the zero sequence voltage U0 is less than 0.15 times of a rated system voltage Um; S3, extracting a characteristic frequency band current of each lineby using a wavelet packet analysis method; S4, calculating a correlated coefficient of characteristic frequency band currents of all lines; and S5, calculating a fault degree value and a soundness degree value of each line, if the fault degree value of the line is greater than the soundness degree value, indicating that the line is a failed line, or, indicating that the line is a sound line. Themethod sets no protective threshold, reduces man-made interference, and increases failure criterion protection margin, thereby being used in larger scope.
Description
technical field [0001] The invention relates to the field of detection of distribution network fault line selection, and more specifically relates to a new method for distribution network fault line selection based on the similarity degree of correlation coefficient vectors. Background technique [0002] In the resonant grounding system of 10kV distribution network, the fault characteristics in the system are weak due to the function of the arc suppressing coil, so the effect of the traditional line selection method in the resonant grounding system is not ideal. For this reason, many experts and scholars have conducted research on it. For example, use the wavelet packet correlation coefficient method, prony correlation coefficient method, S-transform amplitude-phase method, etc. to select fault lines. However, such methods still need to manually set the protection value, which is greatly affected by human factors and has great limitations. , the scope of application is not ...
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IPC IPC(8): G01R31/08G01R31/52
CPCG01R31/086G01R31/088G01R31/50
Inventor 方涛伍建炜高兴李华辉周悦龚岛颜金佑黄练栋刘海光麦炳灿
Owner GUANGDONG POWER GRID CO LTD