Systems & Electronics
IAD3N – Digital directional earth fault or directional power relay
The protection relay IAD3N belongs to SIGMA-N digital protection line and it performs functions as directional power relay or directional earth fault relay.
Directional earth fault
|Directional power relay||67 – 32|
The protection relay IAD3N is used for the following applications:
- directional power relay
- directional earth fault protection in electrical systems with
- unearthed neutral
- neutral solidly earthed
- neutral earthed through a resistance
- neutral earthed through transformer
- neutral earthed through Petersen coil
All the functions of the relay are fully programmable by front panel keyboard or through a RS485 serial interface using a personal computer with set-up program; furthermore the relay can be programmed through a remote control and monitoring system.
Thresholds – the IAD3N relay manages up to 3 independent directional thresholds (S1, S2, S3); each threshold is defined by the following programmable information:
- current threshold Is>
- voltage threshold Us>
- characteristic angle and sector width
The thresholds can be programmed as definite time or dependent time (threshold S1 only) in compliance with BS142 and IEC 255-4 specifications (the time delay is function of the measured current and the Is> threshold).
Each definite time threshold delay can be combined with an additional timer controlled by the digital inputs.
The trip of the relay is shown by LEDs and by a message on the display.