User`s guide

V3-T9-210 Volume 3—Power Distribution and Control Assemblies CA08100004E—November 2013 www.eaton.com
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9.4
Metering Devices, Protective Relays, Software and Connectivity
Protective Relays
Product Selection
DT-3000
Options and Accessories
Additional Products by Eaton’s Cutler-Hammer Series
Dual-Source Power
Supply Option
The Digitrip 3000 with Dual-
Source Power Supply (DSPS)
is available in two versions,
DT-3010 and DT-3020. They
include an integral power
supply module that:
●
Powers the relay from
nominal 120 Vac, 50/60 Hz
(DT-3010 model) or 240
Vac, 50/60 Hz (DT-3020
model) auxiliary power,
which is normally
connected and available.
●
Operates solely from the
main current transformers
(CTs) during a fault if
the normally connected
auxiliary ac voltage is
not available, like an
electromechanical relay
or an electronic “self-
powered” relay.
Functional Description
The integral Dual-Source
Power Supply (DSPS)
contains one AC voltage
transformer and three AC
current transformers. The AC
voltage transformer is used to
supply nominal ac control
power to the unit. The current
transformers are used to
power the unit from the line
current. Normally, the unit
will operate from the AC
auxiliary voltage.
Because this voltage is
usually obtained from the
system containing the circuit
that the relay is protecting, a
fault on the protected line
could cause the AC voltage
to drop below an acceptable
operating level. Below
approximately 70 volts for
DT-3010 or 140 volts for
DT-3020, the DSPS switches
over to current powering.
All three current transformer
secondaries are connected in
series to supply this power.
The DSPS will supply enough
power to operate the Digitrip
3000 overcurrent relay in the
tripped state with currents
greater than 1.8 per unit rated
secondary current, or 9A, in a
single-phase. The DSPS will
operate with three-phase
currents in a tripped state
with currents greater than
1.2 per unit or 6A rated
secondary current.
Note: There will be no effect
to the DT-3000 relay trip time
accuracy when the Dual-Source
Power Supply switches from
normal ac voltage to fault-
current power.
Burden Data
In normal operating
conditions, the burden is
<0.08 ohms with three-phase
1A CT current, or 0.2 per unit,
and drops to less than 0.04
ohms at high current levels.
Present CT burden data in
ohms and volt-
amperes, see
Page V3-T9-212 .
In these cases, the burden
shown is the total CT terminal
value, which is the DSPS plus
the relay measuring circuits,
for the indicated operating
condition.
The trip curve on Page V3-
T9-212, right, shows burden
impedance magnitude in
ohms. The two lower curves
are the values with AC power
applied; the upper two are
with CT powering only. For
each of these pairs, one
curve shows the burden
for a single-phase current
(representing a single-phase-
to-ground fault) and the other
for three balanced phases
with normally arrayed
120-degree phase angle
increments. There is no
phase sequence sensitivity.
Page V3-T9-212, trip curve,
upper left, shows the burden
in volt-amperes for the same
four cases.
Digitrip 3000 Optional
Drawout Case
The Digitrip 3000 overcurrent
protective relay is available
in a new drawout case for
quick release, removal and
replacement of the unit
without disruption of the
wiring. The CT circuits are
self-shortening to prevent
damaging voltages from
existing across-the-current
transformer windings. All
voltage inputs, discrete
inputs and contact inputs
are disconnected while
maintaining security against
false tripping.
The terminal blocks feature
a two-stage disconnect
operation. Removal of the
DT-3000 Inner Chassis will
disconnect the trip circuits
and short the CT secondaries
before the unit control power
is disconnected. Upon
insertion of the Inner
Chassis, the control power
connections are made before
the trip circuits are activated.
This feature provides
added security against
false tripping.
Description
Catalog
Number
DT-3000 protective relay DT3000
DT-3000 protective relay Chicago version DT3100
DT-3030 protective relay (24–48 Vdc CE Mark version) DT3030
DT-3000 drawout case protective relay DT3001
DT-3000 Chicago version drawout case protective relay DT3101
DT-3030 drawout case protective relay (24–48 Vdc CE Mark version) DT3031
DT-3000 protective relay with 120 Vac dual-source power supply DT3010
DT-3000 protective relay with 240 Vac dual-source power supply DT3020
DT-3000