SIEMENS SIPROTEC 4, 7UT613 DIFFERENTIAL PROTECTION RELAY FOR THREE WINDING

The SIPROTEC 7UT613differential protection relays are used for fast and selective fault clearingof short-circuits in transformers of all voltage levels and also in rotatingelectric machines like motors and generators, for short lines and busbars.The specificapplication can be chosen by parameterization. In this way, an optimaladaptation of the relay to the protected object can be achieved.In addition tothe differential function, a backup overcurrent protection for 1 winding/ starpoint is integrated into the relay. Optionally, a low or high-impedancerestricted earth fault protection, a negative-sequence protection, and abreaker failure protection can be used.7UT613 features 4 voltage inputs. Withthis option an overvoltage and under voltage protection are available as wellas frequency protection, reverse / forward power protection, fuse failuremonitor and overexcitation protection. With external temperature monitoringboxes (thermo-boxes) temperatures can be measured and monitored in the relay.Therefore, complete thermal monitoring of a transformer is possible, e.g.hot-spot calculation of the oil temperature.7UT613 features full coverage ofapplications without external relays by the option of multiple protectionfunctions e.g. overcurrent protection is available for each winding ormeasurement location of a transformer. Other functions are available twice:ground-fault differential protection, breaker failure protection, and overloadprotection. Furthermore, up to 12 user-defined (flexible) protection functionsmay be activated by the customer with the choice of measured voltages,currents, power and frequency as input variables.The relays provide easy-to-uselocal control and automation functions. The integrated programmable logic (CFC)allows the users to implement their own functions, e.g. for the automation ofswitchgear (interlocking). User-defined messages can be generated as well. Theflexible communication interfaces are open for modem communicationarchitectures with control system.

FUNCTION OVERVIEW1.    Differential protection for2- up to 3-winding transformers (3-/1-phase)2.    Differential protection formotors and generators3.    Differential protection forshort 2 up to 3 terminal lines4.    Differential protection forbusbars up to 9 feeders (phase-segregated or with summation CT) 

PROTECTION FUNCTIONS1.    Differential protectionwith phase-segregated measurement2.    Sensitive measuring forlow-fault currents3.    Fast tripping forhigh-fault currents4.    Restraint against inrush oftransformer5.    Phase-/earth overcurrentprotection6.    Overload protection with orwithout temperature measurement7.    Negative-sequenceprotection8.    Breaker failure protection9.    Low-or high-impedancerestricted earth fault (REF)10. Voltage protectionfunctions 

CONTROL FUNCTIONS1.    Commands for control ofc.b. and isolators2.    Control via keyboard,binary inputs, DIGSI 4 or SCADA system3.    User-defined logic with CFC 

MONITORING FUNCTIONS1.    Self-supervision of therelay2.    Trip circuit supervision3.    Oscillographic faultrecording4.    Permanent differential andrestraint current measurement, extensive scope of operational values 

COMMUNICATION INTERFACES1.    PC front port for settingwith DIGSI 42.    System interface IEC 61850Ethernet - IEC 60870-5-103 protocol  - PROFIBUS-FMS/-DP - MODBUS orDNP 3.03.    Service interface for DIGSI4 (modem)/ temperature monitoring (thermo-box)4.     Time synchronizationvia IRIG-B/DCF 77