HV Motor starting

1. "Best" is a subjective statement. I think soft starters are best. Others may not agree. You say "except soft start" in your question which implies a bias so I can infer that you do not agree with me, so I can say no more.
2. Synchronous motors are good when you need slow speeds, and/or you want to run it continuously for the purpose of improving the overall power factor of a plant. If you need high speed and/or PF is not a concern, don't use synchronous, they add complexity. They are also physically larger and the STILL need to be started just the same as an asynchronous motor, so again a soft starter or auto-transformer starter.
3. At 11kV (which by the way is Medium Voltage, not High Voltage), an RVAT (Korndorfer) starter will probably cost 2/3 the price of a solid state starter up to about 15MW. Above that a soft starter will probably be less and definitely smaller.
   

Appreciated. Thanks a lot.

Looking forward to getting more views from others.

Thanks

There is a method called FCMA (Flux Controlled Magnetic Amplifier) Soft Starters. There is a Pune (India) based manufacturer (I think, his name is Innovative Technomics) for these types of soft starters. Try googling "FCMA" or Innovative Technomics.

But be aware that there is only ONE source for technical help / design assistance etc. and if you are outside of India, that may be a problem.

You are right, Pune based manufacturer is there and I will try to provide the mail Id etc to-morrow.

But it is not known whether they make startes for this capacity discussed in this thread.

sdr710

First of all at this rating it is necessary to know what is the load .If it is a high inertia drive like a fan or low inertia drive like a pump, speed etc before a satisfactory answer can be suggested.Also 23 MW starting means you should have a strong system.what is the main transformer capacity and also the capacity of the transformer supplying this motor.Further new series of motors with low starting current of3.5to 4 times rated current as achieved with a soft starters are available.For this type of rating one has to carefully chose the motor. Synchronous motors are useful where very low speeds are involved and where PF can be maintained at a higher value by controlling the excitation.