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Instructional Literature
Page
96
Effective: May 2008
Instructions for the FP-6000 Protective Relay
For more information visit: www.eaton.com
IB02602004E
5.4.2.4 Unbalance Settings
47-1 Voltage Unbal
This is the 47 device Voltage Unbalance setting, which consists of
the Threshold, %(V2/V1), and Delay settings. The voltage
unbalance function is based on the Main VT system 3-phase
voltages. The positive and negative sequence voltages are
calculated from the 3-phase voltages.
The Threshold setting defines a minimum operating voltage
magnitude of either V1 or V2 for the 47 function to operate, which
ensures that the relay has a solid basis for initiating a voltage
unbalance trip. This is a supervisory function and not a trip level.
The %(V2/V1) setting is the unbalance trip pickup setting. It is
defined by the ratio of negative sequence voltage to positive
sequence voltage (% Unbalance=V2/V1), or %(V2/V1) for ABC
rotation and %(V1/V2) for ACB rotation. The FP-6000 will
automatically select the correct ratio based on the Phase
Sequence setting in the System Configuration group described
above.
The time delay is a definite time delay adjustable from 0 to 9999
cycles in 1 cycle steps.
This function requires positive or negative sequence voltage
magnitude above the threshold setting and the percentage
voltage unbalance above the %(V2/V1) setting before allowing a
voltage unbalance trip. Therefore, both the threshold and percent
settings must be met for the specified Delay time setting before
the relay initiates a trip for voltage unbalance.
The voltage unbalance pickup and trip functions are reset when
the positive and negative sequence voltages V1 and V2 drop
below the Threshold setting or (V2/V1) drops below the %(V2/V1)
setting minus 1%.
46-1 Current Unbal
This is the 46 device Current Unbalance setting, which works
similar to the 47 device Voltage Unbalance setting. The positive
and negative sequence currents are calculated from the 3-phase
currents.
The Threshold setting defines a minimum operating current
magnitude of either I1 or I2 for the 46 function to operate, which
insures that the relay has a solid basis for initiating a current
unbalance trip. This is a supervisory function and not a trip level.
The %(I2/I1) setting is the unbalance trip pickup setting. It is
defined by the ratio of negative sequence current to positive
sequence current (% Unbalance=I2/I1), or %(I2/I1) for ABC
rotation and %(I1/I2) for ACB rotation. The FP-6000 will
automatically select the correct ratio based on the Phase
Sequence setting in the System Configuration group described
above.
The time delay is a definite time delay adjustable from 0 to
9999 cycles in 1 cycle steps.
This function requires positive or negative sequence current
magnitude above the threshold setting and the percentage
current unbalance above the %(I2/I1) setting before allowing a
current unbalance trip. Therefore, both the threshold and percent
settings must be met for the specified Delay time setting before
the relay initiates a trip for current unbalance.
The current unbalance pickup and trip functions are reset when
the positive and negative sequence current I1 and I2 drop below
the Threshold setting or (I2/I1) drops below the %(I2/I1) setting
minus 1%.
5.4.2.5 Voltage Protection Settings
27M-1 Undervoltage
This is the 27 device Undervoltage setting for the Main 3-phase
VT. This function consists of a Phase, Threshold V and Delay
setting. The Phase setting allows the user to select which phase
(any one, any two or all) the undervoltage function operates. The
Threshold V setting is the magnitude (10 to 150 V in 1 volt steps)
at which the undervoltage function operates. The Delay setting
(0 to 9999 cycles in 1 cycle steps) is the time period an
undervoltage must occur before the FP-6000 initiates a trip. This
function will operate if any of the 3-phase voltages drop below
the set point. This setting is based on line-to-line voltages for
Delta configurations and line-to-neutral voltages for a Wye
configuration.
The undervoltage pickup and trip functions are reset when the
voltage raises above 102% of the undervoltage set threshold.
59M-1 Overvoltage
This is the 59 device Overvoltage setting for the Main VT. This
function consists of a Phase, Threshold V and Delay setting. The
Phase setting allows the user to select which phase (any one, any
two or all) the overvoltage function operates. The Threshold V
setting is the magnitude (10 to 150 V in 1 volt steps) at which the
overvoltage function operates. The Delay setting (0 to 9999 cycles
in 1 cycle steps) is the time period an overvoltage must occur
before the FP-6000 initiates a trip. This function will operate if any
of the 3-phase voltages rise above the set point. This setting is
based on line-to-line voltages for Delta configurations and line-
to-neutral voltages for Wye connections.
The overvoltage pickup and trip functions are reset when the
voltage drops below 98% of the overvoltage set threshold.
Loss Potential
This is the Loss of Potential setting, it consists of LOP (loss of
potential) Block and Alarm Delay settings. The LOP Block setting,
when enabled, will block the voltage restraint function of the
51P2 time overcurrent and the under-power protection functions,
and the LOPB flag bit, which is one of the programmable logic
input options. The Alarm Delay (0 to 999 cycles in cycle steps) is
the time period a LOP must occur before the FP-6000 initiates an
alarm.
59N-1 Overvoltage
This is the 59 device for the Neutral Overvoltage settings. This
function consists of a Source and Criterion setting. The Source
setting dictates if the function is operated based on internally
calculated zero sequence voltage or the measured neutral
voltage through auxiliary voltage input. The criterion setting tells
if the threshold is based on the fundamental (Phasor) or rms.
59N-1 Overvoltage Trip
This is the 59 device for the Neutral Overvoltage trip settings.
This function consists of a Threshold and Delay setting. The
Threshold sets the magnitude (5 to 250 V in 1 volt increments) at
which the neutral overvoltage function operates. The delay
setting (0 to 9999 cycles in 1 cycle steps) is the time period a
neutral overvoltage must occur before the FP-6000 initiates a trip.