Research On The Properties And The Applications Of The Triggered Vacuum Switch With Multi-rod Electrode System

The triggered vacuum switch with multi-rod(RTVS), characterized with high current capacity and short closing time, is developed on the basic technique of vacuum switch and three electrode spark gap. The influence of magnetic field on arc motion and arc shape was researched to analyze the arc erosion area in RTVS. For the demand of the power system, the electrode construction of RTVS is designed. The prototype of 12 kV and 45 kV RTVS was fabricated, and test on trigger characteristic, insulation level and current capacity is performed.Based on the different arc characteristics of RTVS under high and low current, two kinds of arc tunnel model was built. The transverse magnetic force and axial magnetic field are calculated. The calculation indicates that transverse magnetic has the influence on the arc motion to certain area, and axial magnetic field strength has different distribution on different gap which performing different effect on arc shape. Observation on arc in RTVS is performed to analyze the characteristics under high and low current.For the demand of 12 k V and 45 k V insulation level, the optimization on electrode construction of RTVS is carried out. To improve the electric field distribution in RTVS, the optimization is mainly on rod pairs, chamber size, gap space and shield size. The calculation results on electric field strength proves that chamber with proper size can decrease the maximum electric field strength effectively. The results also indicates that gap space increasing has opposite influence on the maximum electric field strength and the uniformity of the electric field. It is also concluded that adding shield of proper size can decrease the maximum electric field strength.Applied with a trigger source based on the pulse transformer, a high current test was carried out to analyze the trigger voltage and time delay of RTVS through the test. For the higher demand on trigger power of 40.5kv-RTVS, the trigger circuit was modified with two solution: adding current reflowing circuit and adding gap. With the experiments, the electrical parameter of trigger circuit and the reliable switching condition under the two solution was found.The prototype of 12 kV and 40.5kV RTVS was fabricated for the application of power system. A test platform is built on the combination of RTVS and fast current breaker. The test on rigger characteristic, insulation level and current capacity is performed. The test results shows that, 12kV-RTVS has the current capacity of 63 kA peak/10 ms duration/409 C charge transfer with lifetime of 20 times, 40.5kV-RTVS has the current capacity of 80 kA peak/15 ms duration/680 C charge transfer with lifetime of 20 times. The 12kV-RTVS maintains a high insulation level before and after the test. The 40.5kV-RTVS wasn't perform well on the lightening impulse experiment after the test.