OLTC fooled by DG's
OLTC fooled by DG's
(OP)
One our single DESN station has x number of feeders and about 40MW load. There are 3 solar generations to be connected to 2 feeders and total maximum output from PV's are about 30MW. Some voltage problems may occur because the OLTC LDC might be fooled by the DG's since it may only see 10MW net load and lower the transformers tap, therefore, some heavily loaded feeder may have low voltage problems.
Any one has some ideas to solve the problem? Thank!
Any one has some ideas to solve the problem? Thank!






RE: OLTC fooled by DG's
RE: OLTC fooled by DG's
Bill
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"Why not the best?"
Jimmy Carter
RE: OLTC fooled by DG's
RE: OLTC fooled by DG's
With full load, and no solar contribution, The LDC on the straight feeders would call for 50% compensation. The LDC on the other feeders would call for 50% compensation. The result will be 100% compensation.
With full solar contribution and nil load on the solar feeders the LDC on the loaded feeders will cal for 50% compensation and the solar feeders will be high and the non solar feeders will be low.
You will, of course, have to juggle the percentages to satisfy site conditions.
With one bus feeding feeders with different loads, you will have to look for the best compromise.
To put it in perspective, cost wise, another option may be two buses, two LDCs, and two OLTC equipped transformers.
Bill
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"Why not the best?"
Jimmy Carter
RE: OLTC fooled by DG's
If this is the case, the solar won't cause any problems as it's a gradually changing load.
Perhaps you can confirm how the voltage is regulated on the TS?
Ian Dromey - www.dromeydesign.com
RE: OLTC fooled by DG's
RE: OLTC fooled by DG's
1) Separate the feeders so that the 'normal' feeders continue to use the LDC based tap changing and the generation feeders use a different regulation scheme.
This may work but I see potential problems (i.e. you wouldn't be able to balance transformer loading) and certainly reduced flexibility.
2) Stop using the LDC control and switch to a tap control that maintains voltage in a fixed band. This is the simplest option if you can get away without the voltage boost that the LDC gives you under heavy load conditions.
So I guess the questions I would have are:
- would you have voltage problems without using the LDC?
- what voltage is the station? - if you are using 27kV or above, I'd be suprised if you had voltage problems with only 40MW load on a complete DESN station.
Ian Dromey - www.dromeydesign.com
RE: OLTC fooled by DG's
Thanks guys for your valued comments!