ERL 8700/BUS, User Manual

Page: 83 / 166

6 Testing the B-PRO Functions
D01908R02.12 B-PRO User Manual 8700 6-3
Testing the Inverse
Time Overcurrent
Function
Test function 51 by injecting current into the relay. The setting pickup of func-
tion 51 is done on a secondary current basis.
The equation for the IEEE overheating curves is displayed in the B-PRO
Of-
fliner Settings program and can be used to determine how long it takes to op-
erate the overcurrent function for a given input current. The overcurrent curve
function is equation-driven and uses fixed constants to generate the operation
curves. See “50/51/67 Phase Overcurrent” on page 4-14 for details on the
equations and constants.
Test the 51 reset time by using the following example and equations. Use your
test software to setup an appropriate test sequence and measure time t1, tx and
t2 to determine the relay’s performance with your setting parameters.
Equation 1
If then
Where t
1
equals the time to operate for the applied current and t
m
equals the
value of solving Equation 1 .
Testing the Loss of
Potential Function
There are no user settings for device 60. If one or two of the AC voltages go
below 0.5 per unit or below 33.2 volt-seconds an ac Loss Of Potential alarm
will take place after a definite 10 second delay. This can be tested by dropping
all combinations of one and two voltages and waiting 10 seconds
T I
( )
TMS
TR
I
Pickup
------------------
 
 
2
1 –
-----------------------------------
=
t1 tx t2
Torque
Current
t
x
t
I
( )
> ( )
t
2
t
1
=
t
2
t
x
t
m
-----
t
1
⋅
=
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