Over-voltage protection


The over-voltage protection unit is directly connected to one or two anti-parallel thyristors; the voltages across these thyristors are monitored.

If the voltage exceeds a defined value (peak value), the thyristor is caused to fire to reduce the voltage. When the overvoltage firing is inactive, an external 24 VDC signal can control the thyristor, which enables simple thyristor control. Thus, this unit is very well suited for protecting excitation devices from overvoltage.


Supply voltage: 24 V DC

Thyristor force-firing when a defined peak value between 600 V and 1800 V (step-size: 100 V) is exceeded

Easy thyristor control via external signal when force-firing inactive

Display of important status information via LEDs




De-excitation of excitation circuit via thyristor control

Over-voltage protection for compound transformers