Siemens SIPROTEC 4 7UT6 Series Manual page 24

Introduction
1.3 Characteristics
•
With or without including the ambient or coolant temperature (by means of external resistance tempera-
ture detector via RTD-box)
•
Alternative evaluation of the hot-spot temperature according to IEC 60354 with calculation of the reserve
power and ageing rate (by means of external resistance temperature detector via RTD-box)
•
2 overload protection functions possible (only 7UT613/63x)
Overexcitation protection (only 7UT613 and 7UT633)
•
Processing of the voltage/frequency ration U/f, which represents the induction B of a shunt reactance
(transformer, shunt reactor)
•
Adjustable warning and tripping stage (with independent delay time)
•
Inverse standard characteristic or user-defined trip characteristic for calculation of the thermal stress,
selectable
Reverse power protection (only 7UT613 and 7UT633)
•
Real power calculation from positive sequence components
•
Short operating time or exact calculation of the active power via 16 cycles
•
Exact real power calculation for small power factor by compensating the error angle of the measuring
locations
•
Insensitive to power fluctuations
•
Short-time stage with external criteria, e.g. with closed emergency tripping
Forward power supervision (only 7UT613 and 7UT633)
•
Real power calculation from positive sequence components
•
Supervision of overvoltage (P>) or undervoltage (P<) of power with individually adjustable power limits
•
Short operating time or exact calculation of the active power via 16 cycles
•
Automatic blocking of stage P< for recognised measured voltage failure or wire break in CT secondary
circuit
Undervoltage protection (only 7UT613 and 7UT633)
•
Two-stage 3-phase undervoltage measurement
•
Evaluation of positive sequence component of the connected voltages, therefore independent of asym-
metries
•
Automatic blocking for measuring voltage failure
•
Adjustable dropout ratio
Overvoltage protection (only 7UT613 and 7UT633)
•
Two-stage 3-phase overvoltage measurement
•
Evaluation of the largest of the three phase-to-ground voltages or the largest of the three phase-to-phase
voltages (largest of the three phase-to-phase voltages (can be set)
•
Adjustable dropout ratio
Frequency protection (only 7UT613 and 7UT633)
•
Three underfrequency stages and one overfrequency stage
•
Frequency measurement via the positive sequence component of the voltages
24 SIPROTEC 4, 7UT6x, Manual
C53000-G1176-C230-5, Edition 09.2016