Variable-weight and fuzzy integrated state evaluation method for relay protection with consideration of variable membership degree

Abstract

The invention discloses a variable-weight fuzzy comprehensive state evaluation method for relay protection considering variable membership degree. At present, the entropy method is only used to establish the constant weight coefficient, and the historical monitoring data is excessively relied on. At the same time, its linear model can only be evaluated simply, and the weight of the scoring items is fixed, so the accuracy of the evaluation needs to be improved. The present invention adopts the combined constant weight calculation method of the entropy value method and the fuzzy analytic hierarchy process, introduces the variable weight theory at the same time, constructs the penalty-incentive type variable weight function with different amplitudes, and establishes the combined variable weight phasor; combined with the fuzzy discrimination theory , constructed a variable membership function model based on variable coefficients and normal distribution, and considered the dynamic correction of the membership degree fuzzy discrimination matrix, proposed a dynamic correction method for the fuzzy matrix with more obvious effects, and finally selected the weighted average algorithm The sub-calculates the fuzzy evaluation result. The invention can accurately reflect the actual state of the relay protection equipment, and improves the accuracy of evaluating the state of the relay protection.

Description

technical field [0001] The invention relates to the field of relay protection, in particular to a variable weight fuzzy comprehensive state evaluation method of relay protection considering variable membership degree. Background technique [0002] With the continuous growth of the scale of the power grid, the traditional regular maintenance mode of relay protection based on the premise of equipment outage has gradually exposed some disadvantages: when the regular inspection period arrives, the scheduled maintenance time may be too long, and the scheduling cannot arrange for equipment power outages. This causes the maintenance to be postponed or even canceled; on the other hand, all equipment is inspected regardless of the actual state, and the maintenance is not very targeted. Blind maintenance may also bring safety risks. The condition-based maintenance, through the effective monitoring and scientific and objective evaluation of the equipment status, can timely and accurate...

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Problems solved by technology

[0006] Song Renjie and Chen Yuming published a fuzzy comprehensive evaluation method for relay protection status based on variable weight coefficients (Power System Protection and Control, 2016, 03:46-50), which simply uses the entropy method to establish constant weight coefficients , excessively rely on historical monitoring data, and cannot effectively use the existing experience of experts. At the same time, the variable weight equilibrium function introduced by it is a "one-class" variable weight function, and the applicable conditions ar

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