Binary Output Operation; Bo Trip/Reset On Battery Power And Usb Power; Bo Trip/Reset On Ct Power; Impulse Output - Siemens 7SR45 Argus User Manual

3.13 Binary Output Operation

The relay reset can be performed from the Relay Identifier Screen > TEST/RESET► key.
If the fault current persists and if the user presses TEST/RESET► key, the pop-up message appears as
"Fault persists"
Based on the availability of power source, the flag can be reset by using any one of the following conditions:
3.13.1

BO Trip/Reset on Battery Power and USB Power

In this mode, the relay uses the power from battery to operate/reset the binary output and takes approximately 4 s
to perform the action.
The relay does not perform any actions. If consecutive commands are provided within 4 s and displays a pop-up
message on HMI as "Insufficient Energy".
3.13.2

BO Trip/Reset on CT Power

In this mode, the relay uses the power from CT to operate/reset the binary output instantaneously.
If the relay is operating on CT power and if the current threshold set by the user is less than the current setting
value of any protection functions, the binary outputs reset instantly.

3.14 Impulse output

The impulse output is used to interface directly with the low energy circuit breaker tripping coil directly. The
impulse output provides 24 V, 0.1 Ws pulses of 50 ms ON and 500 ms OFF. The OFF duration can vary based on
the magnitude of the fault current.
The impulse output operates when any protection function trips. The trip energy for the trip coil is stored by a
capacitor built into the protection relay. The capacitors are charged by the current input. The pulses are repeated
till the threshold exceeded. The impulse output does not require any mapping with protection functions.
In the presence of CT power, impulse output can be operated by mapping to a binary input. The impulse output
operates and TRIP LED glows when the assigned binary input is triggered. Impulse output is provided till the
current is available. The impulse output can be reset by performing reset flags.

3.15 Modes of Operation

7SR45 self powered overcurrent and earth fault relay operates in the following priority and modes:
· CT Power
· USB Power
· Battery Power
7SR45 self powered overcurrent and earth fault relay is powered primarily from CT power even though all the
power sources such as USB, battery power are available. When CT power is not available (<0.2xIn) and if both
the USB and battery power are available, the relay uses the power from USB.
If both the USB and CT power are not available, the relay uses power from the battery.

3.15.1 CT Power

All the protection and measurement algorithms are active only when the 7SR45 self powered overcurrent and
earth fault relay is powered by CT. The binary outputs and impulse output can be operated with CT power only.
3.15.1.1 Sensitivity
Sensitivity of the relay is the minimum phase current required for the relay to energize, detect a fault and trip as
per the configuration.
The sensitivity of 7SR45 Self Powered Overcurrent and Earth Fault Relay is 0.20xIn (minimum phase current)
in single phase or 0.13xIn (minimum phase current) in three phases.
NOTE:
If the minimum phase current is less than 0.1xIn in a three phase network and if the battery is in low or drained
condition, there may be a time lag in the RTC performance.
© 2017 Siemens Protection Devices Limited
7SR45 Description of Operation
Chapter 1 Page 29 of 34