Occurrence and Countermeasures for High-frequency Reignition Oscillation in Vacuum Switch for Shinkansen Changeover Section

Abstract

At substations of Shinkansen, two single-phase power sources whose phase difference is 90° face each other. Thérefore, in order to change from one source to the other in step with Shinkansen car running, a changeover section about 1km in length is set off with changeover switches provided. Thus, Shinkansen car can run through this point under power.
Recently, the air breathed breaker at the changeover switches used in Sanyo Shinkansen was replaced with a vacuum switch. When closing the vacuum switch, a high-frequency reignition oscillation occurs between the main transformer on the car and the vacuum switch. And there by it is likely that the voltage is magnified by resonance inside the transformer and insulation breaks down.
According to our computer simulations, it is possible to suppress the high-frequency oscillation and overvoltage by installing a CR oscillation suppressor at the changeover section. We conducted a field test at Himeji substation of Sanyo Shinkansen to confirm the effect of the countermeasure. The test result was satisfactory and now the countermeasure has been practically applied.