SIPROTEC 7SA522
Distance Protection Relay for Transmission Lines
The SIPROTEC 7SA522 relay provides full-scheme distance protection and incorporates all functions usually required for the protection of a power line. The relay is designed to provide fast and selective fault clearance on transmission and subtransmission cables and overhead lines with or without series capacitor compensation. The power system star point can be solid or resistance grounded (earthed), resonant-earthed via Peterson coil or isolated. The SIPROTEC 7SA522 is suitable for single-pole and three-pole tripping applications with and without tele (pilot) protection schemes.
The SIPROTEC 7SA522 incorporates several protective functions usually required for transmission line protection.
- High-speed tripping time
- Suitable for cables and overhead lines with or without series capacitor compensation
- Self-setting power swing detection for power swing frequencies up to 7 Hz
- Digital relay-to-relay communication for two and three terminal topologies
- Adaptive auto-reclosure (ADT)
SIPROTEC 7SD52/53
Line Differential Protection (Multi Ends)
The 7SD52/53 relay provides full scheme differential protection and incorporates all functions usually required for the protection of power lines. It is designed for all power and distribution levels and protects
lines with two up to six line ends. The relay is designed to provide high-speed and phase-selective fault clearance. The relay uses fiber-optic cables or digital communication networks to exchange telegrams and
includes special features for the use in multiplexed communication networks. Also pilot wires connections can be used with an external converter. This contributes toward improved reliability and availability of the
electrical power system. The relay is suitable for single and three-phase tripping applications for two up to six line ends.
Also, transformers and compensation coils within the differential protection zone are protected as are serial and parallel-compensated lines and cables. The relays may be employed with any type of system grounding. The relay also provides a full-scheme and non-switched distance protection as an optional main 2 protection. Several teleprotection schemes ensure maximum selectivity and high-speed tripping time. The units measure the delay time in the communication networks and adaptively match their measurements accordingly. A special GPS-option allows the use of the relays in communication networks, where the delay time in the transmit and receive path may be quite different.
The 7SD52/53 has the following features:
- 2 full-scheme main protections in one unit (differential and distance protection)
- High-speed tripping 10 – 15 ms
- The serial protection interfaces (R2R interfaces) of the relays can flexibly be adapted to the requirements of all communication media available.
- If the communication method is changed, fl exible retrofitting of communication modules to the existing confi guration is possible.
- Tolerates loss of one data connection in a ring topology (routing in 120 ms). The differential protection scheme is fully available in a chain topology.
- Browser-based commissioning tool.
- Fault locator for one and two terminal measurement for high accuracy on long lines with high load and high fault resistance.
- Capacitive charge current compensation increases the sensitivity of the differential protection on cables and long lines.