SIEMENS SIPROTEC 4 SIPROTEC 7UT63 DIFFERENTIAL PROTECTION RELAY

The SIPROTEC 7UT63 and 7UT635 differential protection relays areused for fast and selective fault clearing of short-circuits in transformers ofall voltage levels and also in rotating electric machines like motors andgenerators, for short lines and busbars. The protection relay can beparameterized for use with three-phase and single-phase transformers. Thespecific c application can be chosen by parameterization. In this way, anoptimal adaptation of the relay to the protected object can be achieved.In additionto the differential function, a backup overcurrent protection for 1winding/star point is integrated into the relay. Optionally, a low orhigh-impedance restricted ground-fault protection, a negative-sequenceprotection, and a breaker failure protection can be used.

7UT633 features 4 voltage inputs. With this option anovervoltage and under voltage protection is available as well as frequencyprotection, reverse / forward power protection, fuse failure monitor andoverexcitation protection. With external temperature monitoring boxes(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.7UT63x 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 differentialprotection, breaker failure protection, and overload protection. Furthermore,up to 12 user-define (flexible) protection functions may be activated by thecustomer with the choice of measured voltages, currents, power and frequency asinput variables. The relays provide easy-to-use local control and automationfunctions.The integrated programmable logic (CFC) allows the user implementstheir own functions, e.g. for the automation of switchgear (interlocking).User-defi ned messages can be generated as well. The fl exible communicationinterfaces are open for modem communication architectures with control system.

Transformers are most critical and costly asset in substations.It requires best of the protection for its long life and reliable operation.SIEMENS Transformer Protection Relays takes best care of your transformers byproviding best of the technology by virtue of their years long experience intransformer and protection technology.

Various products offered by Siemens for Transformer Protectionare 7SR242, 7UT61/62/63/65.

These relays can be used to cater all possibilities forprotecting your transformers. Also these relays can be used to protect Motors,Generators, short lines and Busbar.

1. Differential protection for 2- up to 3-winding transformers up to 5 ends (3-/1-phase)
2. Differential protection for motors and generators
3. Differential protection for short 2 up to 5 terminal lines
4. Differential protection for busbars up to 12 feeders (phase-segregated or with summation CT)

Protection functions

1. Differential protection with phase-segregated measurement
2. Sensitive measuring for low-fault currents
3. Fast tripping for high-fault currents
4. Restraint against inrush of transformer
5. Phase /ground overcurrent protection
6. Overload protection with or without temperature measurement
7. Negative-sequence protection
8. Breaker failure protection
9. Low/high-impedance restricted ground fault (REF)
10. Voltage protection functions

Control functions

1. Commands for control of circuit-breakers and isolators
2. 7UT63x: Graphic display shows position of switching elements, local/remote switching by key-operated switch
3. Control via keyboard, binary inputs, DIGSI 4 or SCADA system
4. User-defined logic with CFC

Monitoring functions

1. Self-supervision of the relay
2. Trip circuit supervision
3. Oscillographic fault recording
4. Permanent differential and restraint current measurement, extensive scope of operational values

Communication interfaces

1.     2.     3.     4.     Timesynchronization via IRIG-B/DCF 77