motor starting calculation diverged

[nasim khalilnejhad]

I run a motor starting with 1600kw motor on 6kv switchgear. ETAP has this error "Motor starting calculation diverged due to ill-conditioned system/component parameters or a large value of simulation time step. Run calculation again with a reduced simulation time step".
I reduced simulation time step but it doesn't work.
Can anyone help me to solve this problem?

 

[Kiribanda]

My advice is to contact ETAP HELP. They are very prompt in giving you an answer.

 

[beyond86]

Do you use motor acceleration or transient stability case?
Check again motor paraments like CKT model, characteristic model, load model, inertia.

 

[nasim khalilnejhad]

I use motor acceleration

 

[Gr8blu]

nasim Sounds like you have either an inertia issue (on the motor itself or in the connected load) or one of your other nominal parameters for the electrical system is out by an order of magnitude. To give you an idea of the "typical" acceleration time: 1600 kW operating at nominal 1500 rpm will accelerate to speed in under 4 seconds when unloaded. For one operating at nominal 300 rpm, accel time will likely fall in the 8-10 seconds range for an unloaded start. If the connected train inertia is high, accel time will be correspondingly lengthened in both cases. And if the machine cannot develop sufficient torque through the entire speed range, it will eventually stall.

Converting energy to motion for more than half a century

 

[nasim khalilnejhad]

Thanks alot