Ampcontrol Pty Ltd
– ABN 28 000 915 542
IPD USER MANUAL
IPDB014 Version 14
– SEP/2020
Uncontrolled Copy - Refer to Ampcontrol Website for Latest Version
Page 45 of 96
A
P
P
R
OV
E
D
FOR
E
X
T
E
R
N
A
L
D
IS
TR
IB
U
T
ION
–
P
R
OP
E
R
T
Y
OF
A
M
P
C
ON
TR
OL
P
T
Y
LTD
–
N
O
T
T
O
B
E
R
E
P
R
OD
U
C
E
D
I
N
P
A
R
T
10
CURRENT RELATED FUNCTIONS
10.1 General Information
The IPD relay uses two current transformers to measure the three line currents. The measured currents
are used to implement the following protection functions:
Time Dependent Protection, including:
o
Over-Current Protection
o
Motor Overload Protection
Short Circuit Protection
Phase Current Balance
In addition to the above functions, IPD relays from Version 3 onwards have also had a Transient
Overreach Compensation function implemented to compensate for spurious tripping from overreach at
start-up. The IPD has a transient overreach performance figure of 35% (determined per IEC 60255-151,
section 6.5.2). See Section 10.5 for more information.
Figure 10.1: Current Transformer Circuit Terminations
10.1.1 Full Load Current Parameter
Full load settings cover a range from 7.5 Amps to 464 Amps. A current range and current multiplier are
utilised to select and store the full load current value in the non-volatile memory. This forms the basic
reference level for the over-current protection functions.
The current range is selectable in 4 Amp increments between 60 and 116 Amps. The current multiplier
is selectable at 1/8, 1/4, 1/2, 1, 2, 4 times (see Section 13, User Adjustable Settings).
NOTE
Example: Full Load Current Setting
To obtain a full load current of 152 Amps; select a current range of 76
Amps and a multiplier of 2.
A
B
C
Phase Conductors
Current TXF
1000/1
Current TXF
1000/1
IPD
Relay
Ic1
17
Ia1
15
Ic2
16
18
Ia2
S1
S2
P1
P2
S1
S2
P1
P2
