Design Of SF₆ Circuit Breaker Internal Temperature Real-time Monitoring System

Among the tests with SF₆ circuit breaker,the temperature rise test is a compulsory test of the national standard.Compared with other types of high voltage switchgear,the temperature rise test of SF₆ circuit breaker is more complex,which requires more time and cost because the internal structure of the air box is closed,complex and small in space,for which it is difficult for the thermocouple to be buried at a predetermined position.And the thermocouple needs to transmit the electrical signal through the transmission line,when testing the temperature inside the circuit breaker,the test object cannot be inflated,so the test cannot conform to the actual working condition of the equipment,and also will cause inaccuracies for the final result of the measurement.In addition,when the thermocouple is used as a wired measurement method,too many transmission lines will occupy too large a test site,resulting in confusion in the test site.In order to solve these shortcomings in the temperature rise test of SF₆ circuit breaker,based on the internal temperature of SF₆ circuit breaker,a new passive wireless monitoring system is proposed in this paper.In this paper,the relevant standards of temperature rise test of SF₆ circuit breaker were studied,and the methods of temperature rise test at home and abroad,and the difficulties in the test were analyzed.Aiming at these problems,a new passive wireless temperature measurement system based on surface acoustic wave sensor was proposed,of which the principle,structure,device and composition of the system were designed,and the corresponding software system was developed.Finally,in order to verify this new test method,this paper compared it with the existing thermocouple method.Through the quality control method,the same SF₆ circuit breaker was tested by using two different methods respectively,and the final test results of the two methods were compared to judge whether the accuracy of the surface acoustic wave method can meet the requirement of the current standards of the temperature rise test,so as to study the advantages of the new test method for internal temperature measurement of SF₆ circuit breaker,and also to verify the feasibility of replacing the existing method of the temperature rise test.