Design And Research On The On-line Monitoring Of Mechanical Characteristics, Partial Discharge And Temperature Condition For Gas Insulated Switchgear

Power transmission and distribution equipment are important assets of power system asthey are in charge of power delivering and transmission. Their safe operation is thusextremely impotrant.，Strategies for preventing unexpected power losses, shortening theoutage time and reducing equipment’s maintenance time to the greatest extent so as tooptimally utilize the power and transmission equipment are important research areas in thepower industry. With the fast development of power system, the amount of equipment forpower transmission and distribution are significantly increased. Methodological andtheoretical researches on the condition monitoring techniques for power and distributionequipment are therefore becomes the focus of attention.Monitoring the operating condition of power equipment, which including powertransformers in substations, circuit breakers, arresters, high-voltage bushings, currenttransformers, voltage transformers and composite apparatus, etc)., is the basis of the conditionmonitoring technology. Based on the monitoring data analyses and predictions of equipment’scondition can then be made. The application of condition monitoring techniques is of greatsigniifcance to predict and remedy any possible power equipment failures in time.This thesis focused on the equipment of high-voltage GIS. The monitoring ofdielectiic，electrical and mechanical condition of high voltage GIS is firstly introduced. The paper thenelaborates specific condition monitoring techniques of high-voltage GIS based on modemsensors, including the condition monitoring of SF6，the partial discharging monitoring, the bustemperature rise monitoring and switchgear mechanical property monitoring techniques. Amodern sensor-based monitoring principle for high voltage GIS is ifnally proposed based ontheoretical analysis of modern condition monitoring technology and the practical equipmentmonitoring condition of power system. The thesis also compares two types of temperaturesensors for SF6condition monitoring in terms of their respective advantages anddisadvantages. Besides，the advantages of UHF partial discharge monitoring technology areexempliifed. The existing difficulties for bus temperature rise monitoring techniques areexplained. The theory of mechanical characteristics monitoring and deficiencies of imagemonitoring method are also presented.For elaboration on principles of high-voltage GIS monitoring and the application atpresent in greater detail，specific requirements on selection and design of four kinds ofmodem sensors are brought forward in combination with the author’s work practicality.Besides，a set of complete UHF sensors are designed based on the application. Relevant performance tests are carried out by using experiment and test platform to verify whether thesensors can meet the requirements of design and application. The rules of UHF signaltransmission characteristics of partial discharge are then concluded. The design schemes fortemperature monitoring and mechanical property monitoring are proposed, but performancetests on which are not yet carried out as110experiment has been conducted so far.Several design principles of condition monitoring of high-voltage GIS based on modernsensors is introduced in this thesis. And the practical design scheme and experimentalverification for comprehensive monitoring of high-voltage GIS is provided, which givereference and ideas to comprehensive fault diagnosis technology of GIS.