8
Time Overcurrent Protection (50HS and 50/51)
7UT51 v3
100 PRIM-2330C
8.3 High
-
Set Element
(50HS)
The high-set overcurrent element (50HS) has its own
pickup threshold level (Address 2103) and time delay
(Address 2104). They should be set so that the 50HS
element will not trip outside the zone of protection.
8.4 Overcurrent Element
(50 or 51)
The overcurrent element can have either a
definite-time (50) time delay or an inverse-time (51)
time delay with a choice of three types of ANSI
characteristic curves. The choice is made in
Address 2111.
2103 50HS PU
Pickup threshold level for the high
-
set overcurrent
element (50HS), which is specified as a multiple of the
rated nominal current (I
N
) of the monitored winding (or
side) of the protected object. A 50HS pickup will occur if
the fundamental component of a measured
phase
-
current reaches this threshold.
Range: 0.10
–
30.00 I
n
Default: 4.00 I
n
2104 50HS DELAY
Time delay between high
-
set overcurrent (50HS) pickup
and trip. At least one measured phase
-
current must
remain above the 50HS pickup threshold for this
duration for a trip to occur. This time delay is in addition
to the inherent operating time of the element. The value
∞ will prevent a 50HS trip.
Range: 0.00
–
32.00 s, or ∞
Default: 0.10 s
2111 PH CHARACT
Type of time overcurrent element: definite
-
time (50) or
inverse
-
time (51), including choice of inverse
-
time
characteristic.
Option Description
DEFINITE TIME Overcurrent element has a
definite
-
time delay (50).
MODERATELY
INV.
Overcurrent element has an
inverse
-
time delay (51) with
Moderately Inverse characteristic
curves (see Figure 8.1 on page 103).
VERY INVERSE Overcurrent element has an
inverse
-
time delay (51) with Very
Inverse characteristic curves
(see Figure 8.2 on page 104).
EXTREMELY
INVERSE
Overcurrent element has an
inverse
-
time delay (51) with Extremely
Inverse characteristic curves (see
Figure 8.3 on page 105).
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