Moment of Inertia? 1

[veritas]

Hi

I have an 11kV, 50Hz, 4.818MVA, 16-pole hydro generator. Shaft height = 1m, width = 1.95m. Any idea what the moment of inertia in J in kg.m2 is please? or what is a typical value for this type of machine. Have tried the manufacturer but it's like trying to pull chicken teeth!

Thanks in advance.

 

[dArsonval]

One of the more intriguing threads for me in a while here. For I have great respect for those who speak via higher mathematics.
Are you able to share any “hint” as to what you’re actually attempting to solve?

Your original post was worded, “…Any idea what the moment of inertia in J in kg.m2 is please? or what is a typical value for this type of machine.”

For proprietary reasons, it may be out of place to ask what you are going to do with the answer when you finally narrow it down.

Yet, I’ll throw the above sentence in the recycle bin and ask, what are you going to do with the answer?

John

 

[veritas]

You're welcome to ask. And I do agree regarding the maths bit. I'm doing the generator protection for the hydro-generator as introduced in my first post. The trickiest part is the loss of mains (LoM) protection which is critical to ensure that the machine is tripped off when the network supply is lost. What makes it even more dangerous is the fact that there is autoreclosing used on the network side. It is thus imperative that the LoM trips off the machine during the ARC deadtime (10s).

LoM = ROCOF and vector shift. Client cannot afford any transient studies and has requested I "see what I can do". I have found some guidance regarding this from ENA Engineering Recommendation G59, Aug 2014. In particular section 13.7.2 shows how the df/dt can be calculated manually.

Hence my request for the J value. If you are interested I'm willing to share my findings.

 

[Hoxton]

Is the hydro generator in the UK?

 

[veritas]

No, Australia.