Description

Siemens 7SK80

Siemens  7SK80 SIPROTEC Compact is a multi-functional motor protection relay is designed for protection of asynchronous motors of all sizes. The relays have all the required functions to be applied as a backup relay to a transformer differential relay.

The Siemens  7SK80 SIPROTEC Compact features “flexible protection functions”. Up to 20 additional protection functions can be created by the user.

Therefore protection of change for frequency or reverse power protection can be realized, for example.

The relay provides circuit-breaker control, further switching devices and automation functions. The integrated programmable logic (CFC) allows the user to add own functions, e.g. for the automation of switchgear (interlocking). The user is also allowed to generate user-defined messages.

Hardware of Siemens 7SK80

• 4 current transformers
• 0 / 3 voltage transformers
• 3 / 7 binary inputs (thresholds configurable using software)
• 5 / 8 binary outputs (2 changeover)
• 0 / 5 RTD inputs
• 1 life contact
• Pluggable current and voltage terminals.

Functions

• Definite and inverse time-overcurrent protection (phase/ground) (50, 50N, 51, 51N)
• Directional time-overcurrent protection, ground (67N)
• Directional overcurrent protection, ground (definite/inverse)(67Ns, 50Ns))
• Displacement voltage, zero-sequence voltage (59N)
• Trip-circuit supervision (74TC)
• Undercurrent monitoring (37)
• Temperature monitoring (38)
• Thermal overload protection (49)
• Load jam protection (51M)
• Locked rotor protection (14)
• Intermittent ground fault protection
• Directional intermittent ground fault protection (67Ns)
• Overcurrent protection, voltage controlled (51V)
• Restart inhibit (66/86)
• Undervoltage/overvoltage protection (27/59)
• Forward-power, reverse-power protection (32)
• Power factor (55)
• Overfrequency/underfrequency protection(81O/U)
• Circuit-breaker failure protection (50BF)
• Phase-balance current protection (negative-sequence protection) (46)
• Unbalance-voltage protection and/or phase-sequence monitoring (47)
• Start-time supervision (48)
• Lockout (86)
• Rate-of-frequency-change protection (81R)
• Rate-of-voltage-change protection (27R/59R)

Applications

Motor protection

The SIPROTEC 7SK80 device is specifically designed to protect induction-type asynchronous motors..

Transformer protection

The SIPROTEC 7SK80 device provides all the functions for backup protection for transformer differential protection. The inrush suppression effectively prevents unwanted trips that can be caused by inrush currents.

Perfectly suited for protection in distribution systems and industry, with minimal space requirement. SIPROTEC Compact devices provide a comprehensive range of functions in a surprisingly compact and space-saving housing. Whether as main or as backup protection, a single SIPROTEC Compact device provides protection functionality for every conceivable fault. And it can do even more it supports the control, automation, and monitoring functions in the substation.