A novel overvoltage protection approach using thyristor valve triggered by breakdown diode for overcurrent test equipment

Firstly the principle of overcurrent test equipment and the forming mechanism, harm and features of its fault overvoltage are analyzed. According to the defects of existing overvoltage protection modes, e.g., discharging gap and ZnO arrester, a novel type of overvoltage protection approach, i.e., thyristor valve triggered by breakdown diode (BOD), is proposed. The proposed approach possesses following advantages: suitable to frequent action; accurate and stable action voltage that is easy to adjust, fast response speed, low residual voltage and high blowout capacity. The principle of triggering thyristor valve by BOD, its design highlights and features are analyzed. Both simulation and testing results show that the proposed protection approach is effective and practicable.