The SIPROTEC 7SD80 is a numerical line differential protection relay, which in addition to its main function, the selective protection of overhead lines and cables, also covers control and monitoring tasks.

Line protection

SIPROTEC 7SD80 devices are suitable as selective line protection for application in high-voltage and medium-voltage systems of all types of neutral designs (solid, low-resistance or high-resistance earthed, isolated or compensated). Apart from the main protection function, the line differential protection, SIPROTEC 7SD80 offers a lot of additional protection functions. These can be used in parallel as a backup protection function, or as an emergency function if the main protection function fails, and they complement the range of functions of 7SD80 for application in transmission lines.

Control

The integrated control function permits control of disconnect devices, grounding switches or circuit-breakers through the integrated operator panel, binary inputs, DIGSI 4 or the control or automation system (e.g. SICAM).

Programmable logic

The integrated logic characteristics (CFC) allow the user to add own functions for automation of switchgear (e.g. interlocking) or switching sequence. The user can also generate user-defi ned messages. This functionality can form the base to create extremely flexible transfer schemes.

Operational measured values

Extensive measured values (e.g. I, V), metered values (e.g. Wp, Wq) and limit values (e.g. for voltage, frequency) provide improved system management as well as simplification by the commissioning As for the operational measured values, a special focus was placed on the measured values critical for differential protection. So, the attenuation values and the signal-to-noise ratio of the communication connection, for example, are acquired and indicated in addition to the measurement of the quality of the telegram exchange per time unit. Particular attention was paid to making the commissioning of the differential protection easier and safer. In this context, the amplitude and angle of the currents and of the voltages, if applicable, are displayed additionally with reference to the local measuring variable. In this way, a possible incorrect connection (polarity reversal) of the current transformers can be detected and eliminated early enough.

Operational indication

Monitoring of operation is ensured and documented by storage of event logs, trip logs, fault records and statistics.