STATIC

Home / STATIC

AZT

AZT Electronic self-powered overcurrent protection

The self-powered AZT 3/0 electronic overcurrent protection has a special construction, the main characteristics of which are as follows:

  • 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.

EI

Independent static overcurrent relay
EI  User’s guide

The EI electronic overcurrent protection has a special construction, the main characteristics of which are as follows:

  • The construction of the case is designed to be mounted on the rail of the terminal boxes.
  • The size of the casing is small: width: 45 mm, height: 120 mm, depth 111 mm (with the rail of the terminals, see Fig.1).
  • The overcurrent protection has a setting range between 0.05 A and 14.6 A.
  • The low current version of the device needs auxiliary DC power supply.
  • The medium and high current versions of the protection can be ordered as a selfpowered device.In the self-powered version the output of the relay is a contact for AC current.
  • In the version with external power supply the output is an NO relay contact. If additional relay contacts are needed, the casing can be extended, according to the ordering