initialized out of limit(s)

answered May 8 '14

Nihal Mohan
61 ●1 ●2 ●7

updated May 8 '14

I would agree with above answer that "parameters of dynamic models shall be modified as 'last resort' ". Fine tuning your input powerflow case always helps. One of the other things to look for is MBASE in powerflow for the machine. If the Pgen is say quite different from the MBASE ( for e.g. a 400 MW machine is dispatched at 70 MW, but MBase =410 MVA), it might cause the machine to initialize out of limits. It is because the Vr max or Vmin values are set expecting machines to operate within some limit. Changing MBase helps to bring that machine within the limits. ( In this example, I would try to change MBase ~80)

answered May 6 '14

jconto
2756 ●10 ●30 ●41

Parameters of dynamic models shall be modified as 'last resort' unless you are tuning or performing a model validation of the exciter. See if variables in the base case can be adjusted first near the unit under question, like the unit(s) voltage setting value, adjust voltage settings of SCV, STATCOM dynamic devices, bringing on or taking off capacitor(s), voltage control of transformer taps and switching shunts, etc.

answered May 6 '14

Mahesh
113 ●2 ●2 ●11

Either increase the bounds VRmax and VRmin or reduce bounds of VR1 and VR2. You can try decreasing KA as well. Basically one of you internal variable VR is going out of limits during initialization. You can change time constants also. Get a change which affects you exciter least.