Security Assessment Of Switchgear Operating State In Distribution Network

High Voltage Switchgear of distribution network plays an important role in control and protection of power lines. It is one of the important equipment in power systems. Early regular maintenance has not satisfied the requirements of maintenance. Use condition-based maintenance approach can not only improve the operational reliability of the switchgear, but also to generate greater economic benefits. Without affecting the normal operation of the switchgear, how to obtain the operating state data of the switchgear, and using these data to evaluate the operational status of the switchgear, which is the necessary prerequisite for the condition-based maintenance approach the switchgear.This paper described the research background of Condition Monitoring and evaluation algorithm. Analyzed and discussed the research status and issues to be addressed of switchgear status assessment, pointed out its development direction. Analyzed the switchgear structure, Special studied the structure of the high-voltage circuit breakers. Analyzed and discussed common faults and the causes of the switchgear. Selected the indicators which effects the switchgear operating state. Studied the methods of the detection and feature extraction of these indicators. Designed a switchgear condition assessment model which based on normal cloud model and the D-S evidence theory. Finally, used Examples to validate the accuracy of the evaluate model.Indicators parameter extraction and evaluation model building is the key to the state assessment of high voltage switchgear. According to the characteristics of different indicators, this paper developed appropriate normalization algorithm for each indicator data. Based on full consideration the fuzziness and randomness during the assessment, Established switchgear operating state assessment model which comprises two assessments. Designed an optimal weight calculation method, Using normal cloud model calculated the degree of membership of every indicators. Using fuzzy comprehensive evaluation algorithm evaluated subsystems. In order to avoid the impact of the subjective weights, the second layer of assessment used the D-S evidence fusion algorithm to calculate.Using KYN28A-12 type switchgear test data to verify the accuracy of the results of the assessment. By example verification, the evaluation results is more accurate. The evaluation model of normal cloud model and the D-S evidence theory has great benefit to expand switchgear status monitoring.