Line Differential Protection
General Information
- Description
The line differential protection is used to protect strictly selective areas at high speed. The simple measuring principle of current comparison requires a communication link between the partner devices.
While in former times, analog measured values used to be transmitted (current balance principle), modern devices use the advantages of digital communication. SIPROTEC4 line differential protection devices can protect system configurations with up to six ends.
Our Portfolio (3)
7SD61
Differential protection relay for two line ends with 4-line display, housing width 1/3", 7 LEDs
- Description
- Function overview
The 7SD610 relay is a differential protection relay suitable for all types of applications and incorporating all those functions required for differential protection of lines, cables and transformers. Transformers and compensation coils within the differential protection zone are protected by means of integrated functions, which were previously to be found only in transformer differential protection. It is also well-suited for complex applications such as series and parallel compensation of lines and cables.
It is designed to provide differential and directional back-up protection for all voltage levels and types of networks. The relay features high speed and phase-selective shortcircuit measurement. The unit is thus suitable for single-phase and three-phase fault clearance.
Digital data communication for differential current measurement is effected via fiberoptic cables, networks or pilot wires connections, so that the line ends can be quite far apart. The serial protection data interface (R2R interface) of the relay can flexibly be adapted to the requirements of all existing communication media. If the communication method is changed, flexible retrofitting of communication modules to the existing configuration is possible.
Apart from the main protection function, i.e. the differential protection, the 7SD610 has a full range of configurable emergency and / or back-up protection functions such as phase and earth overcurrent protection with directional elements if voltage transformers are connected. Overload, underand over-voltage/frequency and breakerfailure protection round off the functional scope of the 7SD610.
Protection functions
- Differential protection for universal use with power lines and cables on all voltage levels with phase-segregated measurement (87L)
- Two line ends capability
- Suitable for transformers in protected zone (87T)
- Restricted earth-fault protection (87N) if a transformer iswithin the protection zone
- Well-suited for serial compensated lines
- Two independent differential stages: one stage for sensitive measuring for highresistance faults and one stage for highcurrent faults and fast fault clearance
- Breaker-failure protection (50BF)
- Phase and earth overcurrent protection with directional element (50, 50N, 51, 51N, 67, 67N)
- Phase-selective intertripping (85)
- Overload protection (49)
- Over/undervoltage protection (59/27)
- Over/underfrequency protection (81O/U)
- Auto-reclosure single/three-pole (79)
Control functions
- Command inputs for control of CB and disconnectors (isolators)
Monitoring functions
- Self-supervision of the relay
- Trip circuit supervision (74TC)
- 8 oscillographic fault records
- CT-secondary current supervision
- Event logging / fault logging
- Switching statistics
Front design
- User-friendly local operation
- PC front port for convenient relay setting
- Function keys and 8 LEDs for local alarm
Communication interfaces
- 1 serial protection data (R2R) interface
- Front interface for PC connection
- System interface
- IEC 61850 Ethernet
- IEC 60870-5-103 protocol
- PROFIBUS-DP, DNP 3.0 and MODBUS - Service / modem interface (rear)
- Time synchronization via IRIG-B, DCF77 or system interface
Features
- Browser-based commissioning tool
- Direct connection to digital communcication networks
