Setting The Relay - ABB KD-10 Instruction Leaflet

41-490J
NOTE: If for some reasons an exact correction is
required to match up the line impedance
at an angle α, and the relay has been
Z
L
recalibrated from nominal maximum
torque to a new maximum torque angle
β≠α
, then the relay setting Z should be
equal to:
Z Line
Z = --------------------------------------- -
β
sin cos
–————–—| Example 4 |———–———
θ
Relay with original m = 75° has been recalibrated
to = 60° and to be applied to 5 ohm-line with line an-
gle a = 50°.
The relay setting Z relay should be according to
Equation (13):
5 sin 75°
Z relay =
------------------------------------------------------------ -
• (
sin 60 cos 60° 50°
Or, referring to Table II (page 14), the relay actual
setting should be:
S = 1
T = 5.8
M = +.03

7.0 SETTING THE RELAY

!
Since the tap block screw for all "T" taps carries
operating current, be sure that the screws are
turned tight.
In order to avoid opening current transformer
circuits when changing taps under load, the re-
lay must be first removed from the case. Chassis
operating shorting switches on the case will
short the secondary of the current transformer.
The taps should then be changed with the relay
outside of the case and then reinserted into the
case.
The KD-10 and KD-11 relays require settings for
each of the three compensators (T, T
each of the auto-transformers primaries (S, S
S ) and secondaries (M, M
C
10
θ
sin
m
[Equ. 13]
( β α )
–
5.65 ohms
=
)
–
CAUTION
, and T
AB BC
, and
A
, and M ). All of these
A C
Type KD-10 and KD-11 Compensator Distance Relay
settings are made with the relay de-energized using
taps on the tap plate located between the operating
units. Figure 3 (page 36) shows the tap plate.
7.1 COMPENSATOR (T, T
Each set of compensator taps terminate in inserts
which are grouped on a socket and form approxi-
mately three quarters of a circle around a center in-
sert which is the common connection for all of the
taps. Electrical connections between common insert
and tap inserts are made with a link that is held in
place with two connector screws, one in the common
and one in the tap. There are two T
made since phase B current is passed through two
compensators. A compensator tap setting is made
by loosening the connector screw in the center. Re-
move the connector screw in the tap end of the link,
swing the link around until it is in position over insert
for the desired tap setting, replace the connector
screw to bind the link to this insert, and retighten the
connector screw in the center. Since the link and
connector screws carry operating current, be sure
that the screws are turned to bind snugly. Be careful
not to overtighten these screws.
7.2 AUTO-TRANSFORMER PRIMARY
(S, S , AND S
A
Primary tap connections are made through a single
lead for each transformer. The lead comes out of the
tap plate through a small hole located just below or
above the taps and is held in place on the tap by a
connector screw (see Figure 3, page 36).
An "S" setting is made by removing the connector
screw, placing the connector in position over the in-
sert of the desired setting replacing and tightening
the connector screw. The connector should never
make electrical contact with more than one tap at a
time.
7.3 AUTO-TRANSFORMER SECONDARY
(M, M , AND M
A
Secondary tap connections are made through two
leads identified as L and R for each transformer.
These leads come out of the tap plate each through
a small hole, one on each side of the vertical row of
"M" tap inserts. The lead connectors are held in
place on the proper tap by connector screws.
Values for which an "M" setting can be made are
),
from -.18 to +.18 in steps of .03. The value of a set-
ting is the sum of the numbers that are crossed when
going from the R lead position to the L lead position.
AND T )
AB BC
settings to be
B
)
C
)
C