Siemens 7SC80 Manual page 28

Introduction
1.3 Characteristics
•
Direction determination with cross-polarized voltages and voltage memory and dynamically unlimited
direction sensitivity
•
Fault direction is calculated phase-selectively and separately for phase faults, ground faults and summa-
tion current faults.
Dynamic Cold Load Pick-up Function 50C, 50NC, 51C, 51NC, 67C, 67NC
•
Dynamic changeover of time overcurrent protection settings, e.g. when cold load conditions are recog-
nized
•
Detection of cold load condition via circuit breaker position or current threshold
•
Activation via automatic reclosure (AR) is possible
•
Activation also possible via binary input.
Single-Phase Overcurrent Protection
•
Evaluation of the measured current via the sensitive ground current transformer
•
Suitable as differential protection that includes the neutral point current on transformer side, generator
side, or motor side or for a grounded reactor set
•
As tank leakage protection against abnormal leakage currents between transformer tanks and ground
Voltage Protection
•
Two element undervoltage detection via the positive-sequence system of the voltages, phase-to-phase or
phase-to-ground voltages
•
Phase-specific undervoltage detection
•
Choice of current supervision for 27-1 and 27-2
•
Separate two element overvoltage detection of the largest applied voltages or detection of the positive-
sequence component of the voltages
•
Phase-specific overvoltage detection
•
Settable dropout ratio for all elements of the undervoltage and overvoltage protection
•
Residual-voltage protection
Negative-Sequence System Overvoltage Protection
•
Detection of the negative-sequence component of the voltages
Voltage Protection for Vx
•
Two element undervoltage and overvoltage protection for 1-phase voltage connection to Vx
•
Settable dropout ratio for all elements of the single-phase undervoltage and overvoltage protection Vx.
Negative Sequence Protection 46
•
Evaluation of the negative sequence component of the currents
•
Two definite-time elements 46-1 and 46-2 and one inverse-time element 46-TOC; curves of common
standards are available for 46-TOC.
Frequency Protection
•
Monitoring of falling below (f<) and/or exceeding (f>) with 4 frequency limits and time delays that are
independently adjustable
•
Insensitive to harmonics and abrupt phase angle changes
•
Adjustable undervoltage threshold.
28 SIPROTEC Compact, 7SC80, Manual
E50417-G1140-C486-A8, Edition 07.2017