General Characteristics - ABB KD-10 Instruction Leaflet

41-490J
5.8
------- - amperes
I =
T
For short reach relays (0.2-4.5 ohms) with an imped-
ance setting of 1.23 ohms the three-phase unit will di-
rectionally operate for faults which produce 0.5 volts
line-to-line and 2.7 ampere at the relay terminals.
Sensitivity with 0.75 volts line-to-line for any tap is
defined by Equation 8:
3.4
------- - amperes
I =
T
The KD-10 relay may be set without regard to possi-
ble overreach due to dc transients.
4.5 DISTANCE CHARACTERISTIC:
KD-11, 3-PHASE UNIT
The three-phase unit of the KD-11 relay has a char-
acteristic circle which includes the origin as shown in
Figure 13 (page 43).
A single turn current coil on the cylinder unit provides
for current-only torque and is small compared to the
many turns of the T Max. setting of the compensator
and has very little influence on the overall settings.
However, as the compensator setting is reduced, the
single turn current coil becomes larger by compari-
son and has more and more effect on the overall set-
tings.
For 1.3–36.7 ohms range the reach and maximum
torque angle will vary approximately as follows:
T Nominal T Actual
Overreach
10 10.1
7.02 7.13
5.0 5.12
3.51 3.64
2.50 2.64
2.00 2.14
1.50 1.656
For .75–21.2 ohms range the reach will vary approx-
imately as follows:
NOTE: When setting KD-11 Relays disregard
the change in T-Value, but
include the percentage error into test
current values.
6
[Equ. 7]
[Equ. 8]
% Equiv.
MTA
Reverse T
1.0 75 .13
1.5 76 .13
2.4 79 .12
3.7 82 .12
5.6 83 .11
7.2 85 .11
10.4 87 .11
Type KD-10 and KD-11 Compensator Distance Relay
T Nominal T Actual
5.8 5.92
4.06 4.18
2.90 3.036
2.03 2.17
1.45 1.615
1.16 1.33
.87 1.05
The .2–4.5 ohms range KD-11 relays have no over-
reach regardless of the tap being used. The maximum
torque angle will stay constant at 60°. The relay offset
is nominal 0.1 ohms and its obtained by a compensa-
tor T . Current-only torque is obtained through the
BR
energy provided by the T
4.6 SENSITIVITY: KD-11, 3-PHASE UNIT
The impedance curve for the KD-11 three-phase unit
is shown in Figure 12 (page 42).
The three-phase unit will operate to close the left hand
contact on current-only for the following conditions:
Range
(Ohms)
.75-21.2
--
1.3-3.6
For the .2–4.5 ohm range unit, the current sensitiv-
ity is defined as the product of the current and the T
setting which must be equal to or greater than 6, i.e,
≥
(I x T 6).
4.7

GENERAL CHARACTERISTICS

The phase-to-phase potential rating is 120 Vac
±10%.
Impedance settings in ohms reach can be made for
any value in the range of:
0.2 - 4.5 for short reach relays
0.75 - 21.2 for medium reach relays
1.27 - 36.6 for long reach relays.
The maximum torque angle for all phase-to-phase
units is set for 75 degrees at the factory, and may be
set for any value from 60 to 78 degrees. A change in
maximum torque angle will produce a slight change
in reach for any given setting of the relay. Referring
% Equiv.
MTA
Overreach Reverse T
2.2 79 .13
3.4 80 .13
7.6 82 .12
5.9 85 .12
8.3 89 .12
12 91 .11
17 98 .11
compensator.
BR
Minimum
Amps
T Set Required
5.8 3A
.87 7.5A
10.0 3A