Thyristor overvoltage detection circuit used for TCR type high-voltage SVC device

Abstract

The invention is suitable for the technical field of SVC device safety detection, and provides a thyristor overvoltage detection circuit used for a TCR type high-voltage SVC device. AC voltage of the two ends of a thyristor is rectified into positive half-wave voltage by a rectification circuit. Positive half-wave generated through rectification is scaled to voltage range of the input end of an isolation amplifier by a high-voltage side differential proportion amplification circuit. Voltage signals detected by a high-voltage side circuit are transmitted to a low-voltage side circuit in an isolation mode by the isolation amplifier. Voltage outputted by the isolation amplifier is amplified and outputted to an overvoltage judgment and comparison circuit by a low-voltage side differential proportion amplification circuit. The detected voltage and an overvoltage threshold value Vref are compared via the judgment and comparison circuit. The thyristor is triggered to be conducted by controlling a thyristor trigger circuit according to the comparison result when the thyristor is overvoltage. The circuit is quite concise, element price is low, and problems that conventional high-voltage thyristor overvoltage detection circuits are high in cost, complicated in circuit and inflexible in overvoltage parameter setting can be solved.

Description

technical field [0001] The invention belongs to the technical field of SVC device safety detection, and in particular relates to a thyristor overvoltage detection circuit for a TCR type high-voltage SVC device. Background technique [0002] In recent years, with the continuous development of the industry, in order to improve the user's own power factor in high-voltage power consumption occasions, the application of TCR high-voltage reactive power compensation devices has become more and more extensive. important condition. The TCR high-voltage reactive power compensation device is composed of a control cabinet and a three-phase power valve group. Due to the relatively high operating voltage level, each phase valve group is composed of multiple high-voltage thyristors connected in series. If some thyristors are not turned on at the same time, it will inevitably cause overvoltage damage to the thyristors, thereby affecting the normal operation of the entire device. At presen...

AI Technical Summary

Problems solved by technology

The TCR high-voltage reactive power compensation device is composed of a control cabinet and a three-phase power valve group. Due to the relatively high operating voltage level, each phase valve group is composed of multiple high-voltage thyristors connected in series. If some thyristors are not turned on at the same time, it will inevitably cause overvoltage damage to the thyristor, which will affect the normal operation of the entire device

At present, high-voltage SVCs generally use BOD tubes for thyristor overvoltage detection, and then send overvoltage signals to the thyristor drive circuit to force the thyristors to trigger. Due to the high cost of this method, cumbersome circuits, and inflexible overvoltage parameter settings, it is not conducive to equipment maintenance. economy and miniaturization

Images