Non-directional overcurrent 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 backup protection on items of plant such as transformers. On distribution system circuits overcurrent and earth fault protection are often the only protection installed.
The relay functionality allows highly flexible settings for current and time grading making it compatible with all types of overcurrent protection.
The relays are available in single and four pole variants housed in E4 cases with the IEC 61850 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 is provided.
Cold load settings
Four settings groups
Password protection - 2 levels
User programmable logic
Circuit breaker trip counter and timer
Fault, event and waveform records
Broken conductor (46BC)
Negative phase sequence overcurrent (46NPS)
Thermal overload (49)
Overcurrent (50, 51)
Earth fault (50G, 50N, 50SEF, 51G, 51N, 51SEF)
High impedance REF (64H)
CT supervision (60CTS)
Trip & close circuit supervision (74T/CCS)
Inrush detector (81HBL2)
Circuit breaker Fail (50BF)
Auto reclose (79)
Primary/secondary current phases and earth
Historical demand record
Positive phase sequence (PPS) current
Negative phase sequence (NPS) current