InteliGen
NT
, InteliSys
NT
, InteliMains
NT
– Troubleshooting Guide,
SW version IGS-NT-3.1.0, IM-NT-3.1.0, ©ComAp – August 2018 14
IGS-NT Troubleshooting Guide.pdf
Synchronizing, Load control
Gen-set voltage is increasing/decreasing over/under the limits during
synchronization
Problem:
When gen-set is synchronizing to the Bus/Mains its voltage goes out of limits and GCB is
opened due to over/undervoltage protection.
Solution:
a) Check setpoints GenNomV or GenNomVph-ph if they are adjusted to proper value.
b) If the voltage is adjusted properly check if the same value is in MainsNomV/BusNomV or
MainsNomVph-ph/BusNomVph-ph. These values need to be adjusted to the same value
even if nominal voltages of gen-set and Bus/Mains are different!
c) See the example below for proper adjustment of system with different nominal voltages on
Mains/Bus and gen-set.
Example:
Both setpoints GenNomV or GenNomVph-ph and MainsNomV/BusNomV or MainsNomVph-
ph/BusNomVph-ph must be adjusted to the same values according to the value of actual
generator nominal voltage. E.g. gen-set nominal is 231 V but Bus/Mains nominal is 240 V.
- In this case both setpoints need to be adjusted to 231 V and setpoints of corresponding
protections for Bus/Mains need to be set assymetrically.
- For 240 V on Bus/Mains it is typical to open MCB when voltage reaches 254 V or 225 V.
- Since the setpoint for Mains/Bus nominal voltage is adjusted to 231 V corresponding
protection setpoints need to be adjusted to Mains >V/Bus >V = 106% and Mains <V/Bus
<V = 97 % (hence the desired values are reached).
GCB is opened before the Load ramp time is over
Problem:
After reverse synchronization and during generator unloading is GCB opened before the Load
ramp time is over.
Solution:
a) AMF settings: BreakerOverlap time is shorter than the Sync/Load ctrl: Load ramp time
setting. Set Breaker overlap to the same or longer time than Load ramp setpoint.
b) GCB is opened during generator unloading as soon as generator power level given by
setpoint Sync/Load ctrl: GCB open level is reached. Decrease the GCB open level setting to
avoid premature GCB opening.
c) Load in island was much lower than gen-set nominal power. The real time of load ramp is
Load ramp x Pinitial_island / Nomin power; controller switches off GCB immediately (with 1s
delay) as soon as generator power gets below the GCB open level.
Sync fail alarm is issued
Solution:
a) Setpoint Sync/Load ctrl: Sync timeout is set to too short time -> set it to a longer time to allow
controller to match all synchronizing conditions.
b) Speed governor or AVR control is not setup correctly. See chapters Speed Governor Interface
List and AVR Interface List in IGS-NT Installation Guide for information about proper
connection of a speed governor and AVR. See Sync/load control adjustment and Volt/PF
control adjustment chapters in an IGS-NT Reference Guide for information how to setup
controller speed and voltage regulation loops correctly.
MGCB is not closed even all conditions are fulfilled
Solution:
a) IM-NT Bus protect: Bus >V Hst, Bus <V Hst, Bus >f, Bus <f do not have the same settings as
IG/IS-NT generator control unit (use the same settings for generator and mains control unit).
b) IM-NT and other gen-sets are not in the same logical group. See setpoints Pwr Management:
Control group (Controller cannot see each other via CAN bus).
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