10
INTRODUCTION
51LR(48)/14 Locked rotor
51V Voltage restraint overcurrent
55 Minimum power factor
59 Overvoltage
59N Residual overvoltage
59V2 Negative sequence overvoltage
64F Rotor Earth Fault
64REF Low impedance restricted earth fault
66 Maximum number of startings (Restart inhibition)
67N Ground directional overcurrent
67N(Comp) Ground directional overcurrent with calculated
residual current
81O/81U Overfrequency and underfrequency
87G-87M/87T Double slope biased differential for generator/motor/transformer
BF Circuit breaker failure
74CT-74VT CT-VT supervision
78 Out of Step Protection
79 Automatic Recloser
74TCS Trip circuit supervision
52 o CB (Circuit Breaker) Circuit Breaker
52a Auxiliary contact in the breaker that is in the same position as the
breaker. It can be assigned to a binary input to locate the CB position
(Breaker failure and/or CB diagnostic functions).
52b Auxiliary contact in the breaker that is in the opposite position as the
breaker (52b open = CB closed)
DFR Digital Fault Recorder (Oscillography)
SER Sequential Event Recorder
SFR Sequential Fault Recorder
ANSI American National Standard Institute
IEEE Institute of Electrical and Electronics Engineers
IEC International Electrotechnical Commission
CENELEC Comité Européen de Normalisation Electrotechnique
K1...Kx Output relays
Pulse Output relay with pulse operation
tTR Output relay minimum pulse width
Latched Output relay with latched operation (manual reset) Output relay with
latched operation (automatic reset)
No-latched Output relay with no-latched operation (automatic reset)
VT Voltage Transformer
CT Current Transformer
ThySensor Combo device
P1 IEC nomenclature for primary polarity mark of CTs (as an alternative to
a ANSI dot)
P2 IEC nomenclature for primary polarity mark of CTs (as an alternative to
a ANSI no-dot)
S1 IEC nomenclature for secondary polarity mark of CTs (as an alternative
to a ANSI dot)
S2 IEC nomenclature for secondary polarity mark of CTs (as an alternative
to a ANSI no-dot)
Self test Diagnostic
Start Leave an initial condition or reset condition (Pickup)
Trip Operation (with operate time)
Operating time Duration of time interval between the instant when the characteri-
stic quantity in reset condition is changed, under specified condi-
tions, and the instant when the relay operates
Dropout ratio The ratio of a reset value to an operate value in well-specified con-
ditions. The dropout ratio may be lower or greater than 1 according
as an over or under element is considered
Reset time Duration of the time interval between the instant when the characte-
ristic quantity in operate condition is changed, under specified con-
ditions, and the instant when the relay operates.
The stated reset time is related to a step variation of characteristic
quantity in operate condition to the reset condition.
Overshoot time The critical impulse time for a relay which is in its reset condition, is
the longest duration a specified change in the input energizing quan-
tities (characteristic quantity), which will cause the relay to change
to operate condition, can be applied without the relay switches. The
overshoot time is the difference from the operate time and the cri-
tical impulse time. The declared values for the overshoot time are
applicable with the lower setting value of the operation time.
XMR-D EQUIPMENT MANUAL
Ed. 2.9 - 02/2021
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