ABB Distribution Protection Unit 1500R
1-3
Protective Functions
9/99
website:www.abb.com/papd
There are two selectable re-
set modes available for the
51N element. The instanta-
neous mode is used to co-
ordinate with other instanta-
neous reset devices such
as solid state or micropro-
cessor based relays. In the
instantaneous mode the 51N
will reset when the current
drops below the pickup set-
ting for one half cycle. The
delayed mode simulates
the action of an electrome-
chanical induction disk relay.
In this mode the 51N reset
follows a slow reset charac-
teristic that depends upon
the duration of the overcur-
rent condition and the
amount of load current flow-
ing after the event. The de-
layed reset equations are
described later in this sec-
tion. When the DPU1500R
“Multiple Device Trip Mode”
(see “Multiple Device Trip Mode” in Section 2) is enabled the 51N reset characteristic defaults to the instantaneous
mode and cannot be set to delayed. The reset mode applies to all time overcurrent elements in the DPU1500R.
Phase Instantaneous Overcurrent Element 50P-1 (3I>>1) - Level 1, Low set
The 50P-1 function operates when the level of any phase current exceeds the pickup level. It should be enabled where
phase instantaneous tripping is desired. It is typically set equal to or higher than the phase time overcurrent pickup.
The pickup level of 50P-1 is set as a multiple of the 51P pickup. The timing of the 50P-1 element varies depending
upon which curve is selected (see Table 1-3). The curves can be found later in this section. The 50P-1 pickup, curve
type, and time dial are all set in the Primary, Alternate 1, and Alternate 2 settings groups. For the 50P-1 element to
operate the “Trip” contact, it must be selected in the “Master Trip Output” mapping (see “Programmable Master Trip
Contact” later in this section). The 50P-1 element is set by factory default to operate the “Trip” contact.
Table 1-2. 51N (IN>) Characteristics
The 51N element tripping
can be enabled or disabled
in each step of the reclose
sequence. See “Reclosing”
later in this section for more
details. The 51N element
can be supervised (“torque
controlled”) by mapping the
“GRD” logical input to a
physical input for external
supervision or Logical Out-
put for internal supervision.
See “Programmable I/O” in
Section 6 for programming
instructions.
** See model number for applicability
*** Optional
See Table 5-1 for the 51N factory default settings
.
User Prog. Curve #3 *** 0 to 10 0.1
User Prog. Curve #2 *** 1 to 10 0.1
51P Parameter
Range/Curve
Time Dial
Increment
Pickup for 5 ampere model
1 to 12 amperes
0.1 ampere
Pickup for 1 ampere model
0.2 to 2.4 amperes
0.02 ampere
Time Overcurrent Curves **
ANSI
Inverse
1 to 10
0.1
Very Inverse
1 to 10
0.1
Extremely Inverse
1 to 10
0.1
Long Time Inverse
1 to 10
0.1
Long Time Very Inverse
1 to 10
0.1
Long Time Ext. Inverse
1 to 10
0.1
Short Time Inverse
1 to 10
0.1
Definite Time
0 to 10
0.1
Recloser Curve
1 to 10
0.1
IEC
Inverse 0.05 to 1.0
0.05
Very Inverse 0.05 to 1.0 0.05
Extremely Inverse 0.05 to 1.0 0.05
Long Time Inverse 0.05 to 1.0 0.05
User Prog. Curve #1 ***
1 to 10 0.1