Systems & Electronics
DIA4L – Interface protection relay for active consumers
(according to CEI 0-16 2019-04 Norm)
The protection relay DIA4L belongs to SIGMA-L digital protection line and it performs three phase overvoltage and undervoltage protection, over frequency and underfrequency protection, residual overvoltage protection; it could be used as interface protection for active Users connected to MV electric power system.
DIA4L protection relay is compliant with Italian document Norma CEI 0-16 (2019-04) in reference to “interface protections”. The user can choose one or more of the functions listed in the following table:
|Residual overvoltage protection||59N – 59Vo|
|Frequency thresholds with voltmetric control||81V|
|Positive sequence undervoltage protection (“)||27V1|
|Negative sequence overvoltage protection (‘)||59V2|
(*) These thresholds are used by frequency thresholds with voltmetric control (81V)
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 – DIA4L manages the following thresholds:
- 2 overvoltage thresholds
- 2 undervoltage thresholds
- 1 + 1 residual overvoltage threshold
- 2 overfrequency thresholds
- 2 underfrequency thresholds
- Frequency thresholds with voltmetric control
- 1 positive sequence undervoltage threshold
- 1 negative sequence overvoltage threshold
- remote trip
- breaker failure
All thresholds have definite-time delay.
Trip condition is shown and recorded with LEDs and with a message on the display.