AZT Electronic self-powered overcurrent protection
- The device is self-powered; it does not need auxiliary power supply for the operation. The power source is the current transformer set.
- The device has power storage capacity; no auxiliary power is needed to operate the circuit breaker. The power is stored in internal capacitances, charged from the current transformers during the fault.
- The overcurrent protection has special inverse definite minimum type characteristics.
- The characteristics can be shifted parallel along the time axis.
- As an option the protection can be extended with special logic for discontinuity in one of the phase conductors.
The features above have main advantages in applications as a back-up protection. In case of failure of the auxiliary DC power supply of the substation this device provides back-up protection. It can be applied for selective protection in mashed networks too, due to the special IDMT characteristics.