Siemens Argus 7SR21 User Manual

Energy Management
7SR21 & 7SR22 Argus
Overcurrent Relay
Reyrolle
Protection
Devices

Siemens Argus 7SR21 Specifications

General

Brand	Siemens
Model	Argus 7SR21
Category	Other
Language	English

Summary

Section 1: Introduction

1.1 Current Transformer Circuits

Details the safety precautions regarding CT secondary circuits, emphasizing not to open circuit them to prevent injury or damage.

1.2 External Resistors

Warns about the potential danger of electric shock or burns from external resistors if touched.

1.3 Fibre Optic Communication

Provides guidance on viewing fibre optic communication ports and using optical power meters for signal level determination.

1.5 Disposal

Section 3: Protection Functions

3.1 Current Protection: Phase Overcurrent (67, 51, 50)

Explains phase overcurrent elements and measurement options (True RMS or fundamental frequency).

3.2 Current Protection: Voltage Controlled Overcurrent (51V) – 7SR22

3.3 Current Protection: Derived Earth Fault (67N, 51N, 50N)

3.5 Current Protection: Sensitive Earth Fault (67SEF, 51SEF, 50SEF)

3.13 Voltage Protection: Phase Under/Over Voltage (27/59) - 7SR22

Section 4: Control & Logic Functions

4.1 Auto-Reclose (79)

Covers the auto-reclose function, typical sequences, and methods for switching it in/out of service.

4.2 Quick Logic

Section 5: Supervision Functions

5.1 Circuit Breaker Failure (50BF)

Details the two time-delayed outputs for re-tripping or back-tripping and initiation of circuit breaker fail protection.

5.2 VT Supervision (60VTS) – 7SR22

5.4 CT Supervision (60CTS & 60CTS-I)

5.6 Trip / Close Circuit Supervision (74TCS & 74CCS)

Details the trip and close circuit supervision elements for monitoring circuit integrity.