ABB KD-10 Instruction Leaflet page 30

41-490J
3.0 CALIBRATION AND
TROUBLESHOOTING HINTS
3.1 CALIBRATION OF THE RELAY FOR MAXI-
MUM TORQUE ANGLE
Experience has shown that calibration of the relay
for maximum torque angle is the procedure most
susceptible to error. Two potential sources of error
most common are:
a. Instrumentation errors: Be sure of the accuracy of
calibration of all instruments and phase-shifters
used. Instruments should be chosen and ranges
selected so that readings are taken with the in-
strument reading in the top third of the scale.
When a phase-shifter is used, attention should
be paid to voltage and current settings that
change as the angle is varied. To avoid inaccu-
racies due to this effect, check the voltage and
current settings when contact operation indi-
cates that maximum torque angle check point
has been reached.
b. Failure or miscalibration of components not con-
nected with angle adjustment: To distinguish be-
tween the two sources of error it is recommend-
ed a compensator nulling test be performed as
follows.
3.1.1 KD-4, 41, 5, 10, and 11 Relays:
Phase-to-Phase Unit (T
Compensators) Maximum Sensitivity Angle
a. Use "PH-PH-1-2 Phase" test connection for T
compensator, and "PH-PH-2-3" test connection for
T compensator. Refer to Figure 26 (page 55).
BC
b. Measure voltage across C
C for T .
2C BC
c. Set current equal to:
The current should be high enough to provide an
accurate phase angle meter reading, or any
convenient value if a phase-shifter is used for di-
rect angle reading.
d. Set the phase-shifter for the desired maximum
torque angle value. NOTE THE VOLTAGE.
e. Vary the phase angle in both directions of the set
value, to see that a low voltage (below one volt)
is obtained at the maximum torque angle set-
30
and T
AB BC
for T and across
2A AB
V
IF2F
----------------------------------------------- -
2X Relay Setting
Type KD-10 and KD-11 Compensator Distance Relay
ting. If within two degrees, it can be left undis-
turbed. If minimum voltage is obtained at some
other angle, readjust phase-shifting resistor or
potentiometer at the desired angle.
3.1.2 KD and KD-1 Relays:
Phase-to-Phase Unit (T
Compensators) Maximum Sensitivity Angle
Follow procedure above except:
a. For T compensator, use connection #2, omit
A
voltage connection to terminal 9, disconnect
L -lead, insert voltmeter to measure open circuit
A
voltage and use twice the current value obtained
for KD-10 tests. Follow procedure outline above
except adjust R
b. For T compensator, use procedure outline
B
above, except use #3 connection and adjust R
when required.
c. For T compensator, use connection #4, omit
C
voltage connection to terminal 7, disconnect
L -lead, and adjust R
C
part 1.
3.2 THREE-PHASE UNIT:
(T COMPENSATOR OF ALL KD TYPE RELAYS)
a. Use connection #1.
b. Measure voltage across C3A.
AB
c. Set the current equal to:
The current should be high enough to provide an
accurate phase meter reading, or any conve-
nient value if a phase-shifter is used for direct
angle reading.
d. Set the phase-shifter for the desired maximum
torque angle value.
e. Vary phase angle in both directions of the set
value, to see that a low voltage (below 1 volt) is
obtained at the maximum torque angle setting. If
minimum voltage is within 2 degrees, do not re-
adjust. If the minimum voltage is obtained at
some other angle readjust phase-shifting resis-
tor or potentiometer at the desired angle.
and T
AB BC
when required.
2A
when required as per
2C
V
1F2F
--------------------------------------------- -
1.5 Relay Setting
2B