IB02602004E
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Instructional Literature
Effective: May 2008
Page
153
Instructions for the FP-6000 Protective Relay
(3 x I
n
). Movement of the pickup portion of the curve in a
horizontal direction and the time portion of the curve in a vertical
direction is similar to phase inverse time overcurrent, short delay
and instantaneous functions as previously described. Therefore,
the ground fault curve movement is not graphically illustrated.
When programming ground fault protection, keep in mind that if
“Disable” is selected, the ground fault protection is disabled.
Direction Control
Overcurrent protection elements, time inverse or instantaneous
or time delay, etc, can trip in a specified fault current direction.
When the trip direction is set to Both, the direction control takes
no effect. When it is set to Forward, a trip is only permitted in the
Forward direction where fault current lies within ± 90° around the
maximum torque angle line. When it is set to Reverse, a trip is
only permitted in Reverse direction where fault current lies
within ± 90° around the opposite of the maximum torque angle
line. See Figures 15, 17 & 18 for detailed information.
8.3.4 Negative Sequence Current Protection (46)
The FP-6000 provides monitoring and protection based on the
percent of current unbalance or negative sequence. The
presence of negative sequence current identifies either a phase
unbalance in the voltage magnitude or reverse phase rotation
condition. The positive and negative sequence currents are
calculated from the three phase currents. The % unbalance is the
ratio of negative sequence current to positive sequence current
(%Unbalance = I
2
/I
1
). A current unbalance pickup occurs when
I
2
/I
1
exceeds the IUB % Unbalance setting, and I
1
or I
2
magnitude
exceeds the IUB Threshold setting. The Current Unbalance trip is
set when the pickup condition exists for the delay time specified.
The current unbalance pickup and trip is reset when the positive
sequence current drops below the IUB Threshold setting or I
2
/I
1
drops below the IUB % Unbalance setting minus 1%. The
settings associated with voltage unbalance or negative sequence
voltage protection are listed in Table 40.
Figure 50. 50P (Instantaneous) Setting Adjustment.
Table 40. Negative Sequence Current Protection
Settings.
8.4 Curve Overlapping Issues
Several calculations are performed simultaneously for the
determination of trip and alarm conditions. Each of these trip and
alarm criteria are considered independently of each other.
Whichever condition occurs first will cause the fault with no
additional coordination between the processes.
8.5 Zone Interlocking Behavior and Application
To minimize damage to the system, faults should be cleared as
quickly as possible. Zone interlocking provides this capability
better than a system with only selective coordination. Zone
interlocking functions must be programmed (see Section 5.4.2.9)
before they can be used. By default the function is disabled. The
zone interlocking protection scheme provides a way for a
protective device to determine if a device, in a downstream zone,
picks up a fault and is taking action. With this information, the
protective device can immediately trip if no other device is taking
action or use its programmed time delay if another device is
taking action.
8.5.1 Compatible Zone Interlock Devices
The Eaton FP-6000 and DT-3000 protective relays support the
zone interlocking function and are compatible with each other.
Refer to the DT-3000 instruction book (I.B. 17555) for details on
the DT-3000 implementation of the zone interlocking function.
8.5.2 Connection Rules
Zone interlocking information is passed on a two-wire Twisted
pair communication pair, see Section 6.11, for complete wiring
details. All devices in the same zone wire their zone-out
terminals (J3-1 and J3-2) in parallel see Figure 51. Zone
Interlocking Example with FP-6000 and DT-3000. This daisy
chained wire pair is then connected to the upstream zone
protection device zone-in terminal (J3-4 and J3-2). Up to 10
devices can have their zone-out terminals wired in parallel. Only
one device, in the upstream zone should have these wires
connected to its zone-in terminals.
Any downstream device can drive the daisy chained wire pair
active, signaling that the device is going to take action. In this
case the upstream device will not trip immediately but will use
the programmed time delay.
PARAMETER
RANGE
STEP
46-1 IUB
Threshold
0.10 to 20 pu,
Disabled
0.01 pu
46-1 IUB %
Unbalance
2% to 40%
1%
46-1 IUB
Delay
0 to 9999 Cycles
1 Cycle
46-2 IUB
Threshold
0.10 to 20 pu,
Disabled
0.01 pu
46-2 IUB %
Unbalance
2% to 40%
1%
46-2 IUB
Delay
0 to 9999 Cycles
1 Cycle
