KCEG142 データシートの表示（PDF） - Unspecified
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KCEG142 Datasheet PDF : 22 Pages
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Features per model
Selective directionalisation phase elements
Selective directionalisation earth elements
Rectifier protection curve
Thermal protection
Broken conductor detection
Dedicated breaker fail protection
Undervoltage
Under frequency
IEC/IEEE/ANSI curves
Phased output contacts
Cold load pick up
CB maintenance
Remote CB control
Disturbance recorder
Event recorder - last 50 records
Fault recorder - last 5 full records
Load shedding by level
Single phase watts and vars
Thermal ammeter
Peak thermal demand
Table 1: Relay models available
Application
The KCGG and KCEG overcurrent
relays can be used in all applications
where overcurrent protection is
required, eg. radial and ring circuits,
and single and parallel feeders.
Furthermore, the integral starting
elements can be used to provide non-
cascade operation and busbar
protection, with additional directional
zone feeder protection available in
the KCEG.
Thermal and restricted earth fault
protection is also provided for lines
and transformers. When used with the
rectifier IDMT curve, this can provide
full protection of silicon rectifiers.
The low settings of KCGG/KCEG
relays are suitable for the protection
of high impedance earthed systems.
[For arc suppression earthed systems
(Petersen Coil) see publication R6537.]
Undervoltage and underfrequency
protection will operate for changes in
system conditions or can be used to
provide other protection and control
functions.
Functions
Phase fault protection
Figure 2 shows the characteristics of
the three phase overcurrent elements
(I>, I>> and I>>>), their respective
time delays (t>, t>> and t>>>) and the
undercurrent element (I<).
KCGG
122
KCGG
142
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The first phase element (I>/t>) in the
relay has a choice of nine inverse and
one definite time characteristic as
shown in Figure 12.
This element has a reset timer to assist
faster clearance of intermittent
recurrent faults. There are two other
elements [(I>>/t>>) and (I>>>/t>>>)]
for each phase function, which can be
selectively disabled if not required.
Thermal overload protection
The thermal overload element is a true
I2 characteristic, with adjustable
alarm and trip thresholds. The thermal
state is stored in non-volatile memory.
Earth fault protection
The earth fault elements are
designated (Io>/to>), (Io>>/to>>)
and (Io>>>/to>>>), and their
respective time delays are (to>, to>>,
to>>>).
Directional elements (KCEG)
Directional fault elements are
polarised by the quadrature phase-
phase voltage. The phase directional
elements are provided with
synchronous polarization which is
maintained after the voltage collapses
so that decisive operation is ensured.
For KCEG 142/242 relays, the
polarizing voltage (–-3Vo) is internally
derived from the three phase-neutral
voltages applied to the relay. In the
case of the KCEG 112/152, the
KCEG
112
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KCEG
142
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KCEG
152
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KCEG
242
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Ith
TC
I>
t>
I>>
I<
t>>
I>>> t>>>
Current
Multiple IDMT curves or definite time operation
for phase and earth fault low sets.
Two independent high set stages with definite
time operation for both phase and earth fault
elements.
Undercurrent element for breaker fail and the
auto-resetting of flags.
Figure 2: Overcurrent characteristic
polarizing voltage must be externally
derived from an open delta winding
on the line voltage transformers or via
a voltage transformer in the earth
path. The earth fault elements are
provided with the same range of time
and current settings.
Undercurrent elements and three
phase loss of load
Two undercurrent elements are
provided, one for phase faults (I<)
and one for earth fault (Io<).
The phase fault undercurrent element
can be used for loss of load detection.
3
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