7PG2113/4/5/6 Commissioning & Maintenance
©2012 Siemens Protection Devices Limited
Chapter 6 Page 25 of 77
Voltage inputs may not be required for this function if the Phase Overcurrent functions are not directional but it
may be advantageous to apply balanced 3 phase nominal rated voltage to the VT inputs during testing to avoid
inadvertent operation of other functions. Particular care should be taken when testing overcurrent functions that
the thermal rating of the current inputs is not exceeded.
2.3.1 Definite Time Overcurrent (50)
If DTL setting is small, gradually increase current until element operates.
If DTL is large apply 0.9x setting, check for no operation, apply 1.1x setting, check operation
Apply 2x setting current if possible and record operating time
Phase Dir.
Is
(Amps)
DTL
(sec)
P.U. Current
Amps
Tol Operate
Time
2 x Is
Tol
I
L1
(I
A
)
I
L2
(I
B
)
I
L3
(I
C
)
Check correct indication, trip output, alarm contacts, waveform record.
Table 2.3-1
50 Results
2.3.2 Inverse Time Overcurrent (51)
It will be advantageous to map the function being tested to temporarily drive the relevant Pickup output in the
Pickup Config
sub-menu in the
Output Config
menu as this will allow the Pick-up led to operate for the function.
Gradually increase current until Pickup LED operates.
Apply 2x setting current and record operating time,
Apply 5x setting current and record operating time.
Compare to calculated values for operating times.
Gradually reduce current until the element drops off and record the level.
Operate Current
Operate Time
Ph. Dir Char.
Curve
Is
(A)
TM
P.U.
(Amps)
D.O.
(Amps)
Tol
2 x Is
(sec)
5 x Is
(sec)
Tol
I
L1
(I
A
)
I
L2
(I
B
)
P.U.
D.O.
&
TIMIN
G
TESTS
I
L3
(I
C
)
Table 2.3-2
51 Results
Calculated Timing values in seconds for TM =1.0
Curve
2 xIs
5 xIs
IEC-NI
10.03 4.28
IEC-VI
13.50 3.38
IEC-EI
26.67 3.33
IEC-LTI
120.00 30.00
ANSI-MI
3.80 1.69
ANSI-VI
7.03 1.31
ANSI-EI
9.52 1.30
Table 2.3-3
Standard Timing Curve values
Note that the operate time may be subject to the
Minimum op time
setting for the element and/or may have a
Follower DTL
applied.