Overcurrent and Earth Fault protection
The 7SR11 series of relays provide overcurrent and earth fault protection. These relays are typically applied to provide the main protection on feeders and interconnectors and the back-up protection on items of plant such as transformers. On distribution system circuits overcurrent and earth fault protection is often the only protection installed.
The 7SR12 includes for directional control of the overcurrent and earth fault functionality and is typically installed where fault current can flow in either direction i.e. on interconnected systems.
The relay functionality allows highly flexible settings for current and time grading making it compatible with all types of overcurrent protections.
The relays are available in single and four pole variants housed in E4 cases with the IEC61850 protocol option housed in an E6 case. Integrated logic is provided to allow the optimal configuration of relay functionality with the relays analogue inputs and binary input/output circuits.
Protection, instrumentation and metering functionality is accessible via data comms channel(s). A front USB port for local PC connection or rear electrical RS485 port for remote connection are provided.
Broken Conductor (46BC)
Negative Phase Sequence Overcurrent (46NPS)
Thermal Overload (49)
Overcurrent (50, 51)
Earth Fault (50G, 50N, 50SEF, 51G, 51N, 51SEF)
Directional Control of Overcurrent & Earth Fault (67)
High Impedance REF (64H)
Under/Over Voltage (27/59)
Negative Phase Sequence Voltage (47)
Voltage Controlled Overcurrent (51V)
Neutral Voltage Displacement (59N)
CT Supervision (60CTS)
Trip & Close Circuit Supervision (74T/CCS)
VT Supervision (60VTS)
Inrush Detector (81HBL2)
Circuit Breaker Fail (50BF)
Auto Reclose (79)
Primary/Secondary Current Phases and Earth Direction
Primary/Secondary Line and Phase Voltages
Apparent Power and Power Factor
Real and Reactive Power
W Hr & VAr Hr Forward and Reverse
Historical Demand Record
Positive Phase Sequence (PPS) Voltage & Current
Negative Phase Sequence (NPS) Voltage & Current
Zero Phase Sequence (ZPS) Voltage
Cold Load Settings
Four Settings Groups
Password Protection - 2 levels
User Programmable Logic
Circuit Breaker Trip Counter and Timer
Fault, event and waveform records
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