Siemens siprotec SJ62 User Manual page 31

1 Introduction
Ground Fault Pro-
tection 50N, 51N
Directional Time
Overcurrent Pro-
tection 67, 67N
Dynamic Cold Load
Pick-up Function
50C, 50NC, 51C,
51NC, 67C, 67NC
Single-Phase Over-
current Protection
Voltage Protection
27, 59
Negative Sequence
Protection 46
29
• Two definite time overcurrent protective elements and one inverse time overcurrent
protective element for high-resistance ground faults in grounded systems;
• Different curves of common standards are available for 51 and 51N, or a user-
defined characteristic;
• Second harmonic inrush restraint;
• Instantaneous tripping by any overcurrent element upon switch onto fault is possi-
ble.
• Three directional time overcurrent elements for both phase protection and ground
protection operate in parallel to the non-directional time overcurrent elements. Their
pickup values and time delays can be set independently from the non-directional
time overcurrent elements.
• Fault direction with cross-polarized voltages and voltage memory. Dynamically un-
limited direction sensitivity;
• Fault direction is calculated phase-selectively and separately for phase faults,
ground faults and summation current faults.
• Dynamic changeover of time overcurrent protection settings, e.g. when cold load
conditions are anticipated;
• Detection of cold load condition via circuit breaker position or current threshold;
• Activation via automatic reclosure (AR) possible;
• Start also possible via binary input.
• Evaluation of the measured current via the sensitive or insensitive ground current
transformer;
• Suitable as differential protection that includes the neutral point current on a trans-
former side, a generator side or a motor side or for a grounded reactor set;
• As tank leakage protection against illegal leakage currents between transformer
casing and ground.
• Two undervoltage elements 27-1 and 27-2 measuring positive sequence voltage or
the smallest of the applying voltages;
• Choice of current supervision for 27-1 and 27-2;
• Two overvoltage elements 59-1 and 59-2 for separate detection of overvoltages for
the largest voltage applied; in addition, detection of the negative sequence compo-
nent;
• For a single-phase connection, the connected single-phase phase-to-ground or
phase-to-phase voltage is evaluated;
• settable dropout ratio for all elements of the undervoltage and overvoltage protec-
tion.
• Evaluation of 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.
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015