InteliGen
NT
, InteliSys
NT
, InteliMains
NT
– Troubleshooting Guide,
SW version IGS-NT-3.1.0, IM-NT-3.1.0, ©ComAp
– August 2018
18
IGS-NT Troubleshooting Guide.pdf
b) For IS-NT-BB or IG-xxC HW types, setpoint
Basic settings:
CT ratio sec / Im3ErFlCurCTs /
VgInpRangeSel / VmInpRangeSel
is set to a wrong secondary voltage/current range. Set it to
correct range (5A or 1A, 120V or 277V).
Power measurement does not work
Problem:
It may happen that controller measures correct generator/mains/bus voltages and currents
values, but active and reactive power values displayed by controller are not correct or even
zero. Power Factor (PF) value is incorrect too and there is a big difference in PF between
phases (e.g. phase L1 power factor is 0,9 and in phase L2 power factor is 0,2).
Solution:
Solution is to adjust CTs connection, it means changing polarity of CTs and/or swapping their
order.
Correct voltage and current measurement connection:
Imagine that a generator is loaded with a load bank which burns 100 kW in each phase. Load
bank Power Factor (PF) is 1. If power in each phase is 100 kW, total generator power (P
TOT
)
displayed by controller is 300 kW. Calculation is as follows:
U
L1
=U
L2
=U
L3
= 400 V
I
L1
=I
L2
=I
L3
= 250 A
PF
L1
=PF
L2
=PF
L3
= 1
P
L1
=P
L2
=P
L3
= U
L1
xI
L1
xPF
L1
=400x250x1= 100 kW
P
TOT
=P
L1
+P
L2
+P
L3
= 100+100+100=
300 kW
Example of incorrect connection with CTs swapped between phases L2 and L3:
