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the compensation becomes +1.5 IZ
7(b) this change would result in V
reduced rather than increased by the compensa-
tion. As the current increases V
reversed establishing restraining torque. Thus, the
current need not reverse in order to obtain a "short
reach" balance point. Instead the apparent imped-
ance need only move towards the origin in the - X
circle region to find the balance point. Therefore
the circle does not include the origin with a
reversed link position.
4. CHARACTERISTICS
The type KLF relay is available in one range.
4.1 Distance Unit
The distance unit can be set to have characteristic
circles that pass through origin, include it, or
exclude it, as shown in Figure 6.
The Z
and Z
values are determined by compen-
A
C
sator settings and modified by auto-transformer
settings, S, L, and R. The impedance settings in
ohms reach can be made for any value from 2.08
to 56 ohms for Z
, and from 0.79 ohm to 18 ohms
A
for Z
in steps of 3 percent.
C
The taps are marked as follows:
------------------------------------------------------------------------------------ -
,
,
,
2.4 3.16 4.35 5.93 8.3 11.5 15.8
T
------------------------------------------------------------------------------------ -
,
,
,
0.0 0.91 1.27 1.82 2.55 3.64 5.1
(
,
)
S
S
A
C
----------------------
, ,
1 2 3
(
,
M
A
-------------------------------------------------------------------------------- -
±
values between taps .03, .06, .06
4.2 Directional Unit
The KLF relay is designed for potential polarization
with an internal phase shifter, so that maximum
torque occurs when the operating current leads the
polarizing voltage by approximately 13 degrees.
The minimum pickup has been set by the spring
tension to be approximately 1 volt and 5 amperes
at maximum torque angle.
4.3 Undervoltage Unit
The undervoltage unit is designed to close its con-
tacts when the voltage is lower than the set value.
The undervoltage unit is energized with V
. In Figure
C
being
POL
will finally be
POL
T
A
,
,
,
C
,
,
,
)
M
C
1T
age. This voltage is equal to 1.5 V
contacts can be adjusted to close over the range of
65 to 85 percent of normal system voltage. The
dropout ratio of the unit is 98 percent or higher.
4.4 Trip Circuit
The main contacts will safely close 30 amperes at
250 volts dc and the seal-in contacts of the indicat-
ing contactor switch will safely carry this current
long enough to trip a circuit breaker.
4.5 Trip Circuit Constant
Indicating Contactor Switch (ICS)
0.2 ampere rating
1.0 ampere rating
2.0 ampere rating
4.6 Burden
T
& T
A
C
Settings
MAX.
MIN.
Phase AB
S
= S
VA
A
C
1
18.0
2
14.4
3
13.9
Rating
125
250
4.7 Thermal Ratings
Potential:
Current:
200 amperes for 1 second
5. SETTING CALCULATIONS
5.1 General Setting Recommendations
The KLF relay may be applied as a single-zone
device, or two relays may be used to provide
two-zone protection. The single-zone setting may
be fully offset (Zone 1) or may include the origin
-volt-
(Zone 2). The two-zone application would require a
41-748.21C
voltage. The
1N
8.5 ohm dc resistance
.37 ohms dc resistance
.1 ohm dc resistance
Current
5 amps, 60 Hz
Angle
VA
of LAG
18.6
77
3.8
51
POTENTIAL
120 VOLTS, 60 Hz
Angle
Phase BC
of LAG
Angle VA of LAG
°
2
2.6
°
31
5.9
°
39
6.6
dc Circuit
Watts + Rated
3.9
7.8
132 volts (L-L) continuous
8 amperes continuous
°
°
°
12
°
38
°
42
7
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