questions in power

[Emadshaaban1987]

hello
1-Does the very fast load change (600kw per 0.5 sec ) affect the generator 11000kva ?
2-whar are the impacts of VFC loads on the generator ?
3-WHat are the possible reasons bad current sign-wave in which the viotlage waveform is good and no THD ?

 

[waross]

600 kW on a 11 KVA generator?
Voltage collapse and possibly stalling the prime mover or at least slowing it.
Did you mean 11 MVA?
It depends on your governor response and the ability of your prime mover to pick up the load.
It depends whether you are islanded or grid connected.
11 MVA, that would be about 8.8 MW.
600 KVA is less than 7% of rated full load.
Unless you are on an aero-derivative turbine with a very slow throttle response it should have no problem accepting that load.
If that load is causing problems your protection settings are probably set too tight.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Emadshaaban1987]

thank you waross
yes the it is 11000KVA generator .
i would like to highlight that the load change frequently by 600kw each 0.5 sec .

 

[itsmoked]

So you have an approximately an 11kW generator (about a 20HP engine) that you're changing the load on 1,200kW/second... How is that even possible?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

I took that as a 600 kW load cycling every 0.5 sec, Keith.
You tell us, Emadshaaban1987.
What is happening?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Mbrooke]

Perhaps 11kv? Or is the OP talking about inrush/locked rotor capabilities on an 11,000 watt generator?

 

[itsmoked]

I bet you hit it Mbrooke. 11kV. Which still doesn't help.

Time will tell.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[itsmoked]

Emadshaaban1987; You are incorrect! You do NOT have an 11kVA generator!!

Please get it straight! You are receiving incorrect information from everyone because everyone is guessing about what you have as a generator.

[!]Please provide us with a picture

of the generator's information plate so we can get you meaningful answers.[/!]

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Emadshaaban1987]

hi all
Mr itsmoked
it is s set of three 11000KVA 6.6kv alomost 8KW ,here you will fine a screenshot of the ECS workstation .
because we have a high power heaters 2000kw that are driven by VFC the load swings by 600kw per 0.5 sec .
the turbines get a power fluctuation whit out any load new load engaged

 

[Emadshaaban1987]

Before shutdown unbalance occurred in power load suddenly increase in Turbine A from 3,478MW up to 5,116MW, and after decrease back to 3.478MW then increased again to 4.876MW see below photos with trends(the power load is the red line on trend):

After one second the power suddenly decreases in Turbine B from 3,272MW up to 2,316MW, to compensate load sharing see below photos with trends:

 

[itsmoked]

11KVA = 11,000VA that's approximately one residential house..........................

k means x1,000

M means x1,000,000

Keith Cress
kcress -

http://www.flaminsystems.com

 

[itsmoked]

Thanks Emadshaaban1987 for clarifying elsewhere.

Okay folks we have an 11MVA generator that's 6.6kV output voltage.

Carry on.



Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

VFC? Is that Variable Frequency Control?
Try dialing in about 10% Proportional band on the PID controller of the VFC.
It may be easier to correct the root cause than to worry about the effects.

Bill
--------------------
"Why not the best?"
Jimmy Carter