41-133S
13
Directional Overcurrent Ground Relays
Types IRP, IRC and IRD
ENERGY REQUIREMENTS – 60 HERTZ
DIRECTIONAL UNIT OPERATING CIRCUIT BURDEN
VOLT AMPERES
Relay
Type
Range
AMPS
Continuous
Rating
(Amperes)
One Second
Rating
†
(Amperes)
Power
Factor
Angle
φ
At
Minimum
Tap Value
Current
At 3 Times
Minimum
Tap Value
Current
At 10 Times
Minimum
Tap Value
Current
At 20 Times
Minimum
Tap Value
Current
0.5-2.5
2-6
4-12
0.5-2.5
2-6
4-12
0.5-2.5
2-6
4-12
--
--
12
10
10
12
10
10
12
230
230
280
230
230
280
230
230
280
44.0
42.5
31.8
34.5
34.5
25.0
45.0
45.0
32.4
0.033
0.58
0.64
0.03
0.44
0.48
0.07
1.04
1.16
0.30
5.28
6.12
0.23
4.08
4.62
0.59
9.9
10.8
3.3
58.0
70.0
2.8
48.0
53.6
6.6
106.0
121.2
14.2
240.0
272.0
11.5
182.0
216.0
26.0
420.0
472.0
IRC
IRP
IRD
Degrees current lags voltages at tap value current.
Thermal capacities for short times other than one second may be calculated on the basis of time
being inversely proportional to the square of the current.
φ
†
ENERGY REQUIREMENTS – 60 HERTZ
DIRECTIONAL UNIT POLARIZING CIRCUIT BURDEN
RELAY TYPE
RATING
VOLT AMPERES
∆
POWER FACTOR ANGLE
φ
IRC
IRP
IRD Current Unit
IRD Current Unit
230 Amperes
†
208 Volts
††
230 Amperes
†
208 Volts
††
1.45
11.2
1.45
11.2
8°
Lag
28
°
Lag
8°
Lag
28
°
Lag
Degrees current leads or lags voltage at 120 volts on voltage polarized units and 5 amperes on current polarized units.
Burden of voltage polarized units taken at 120 volts. Burden of current polarized units taken at 5 amperes.
30 second rating. The 10 second rating is 345 volts. The continuous rating is 120 volts.
φ
∆
††
One second rating.
†
