Capacitor Placement in Distribution System
Capacitor Placement in Distribution System
(OP)
I have been working for capacitor placemnet in our 12.47 kV distribution system for power factor correction. 3 substations that are feeding from a 115 kV radial transmission line have really power factor. Each substation have kVAR demand around 5000 kVAR. To correct substation power factor to 96/97, i at least need 2000 kVAR Capacitor bank in each substation during peak. I was wondering wheather i should go for different distribuiton line capaciotrs banks or single capbank at substation.
Most of the distribution feeders are underground. And laod factor is 50-60%.
I would appreciate your suggestions.
Lali
Most of the distribution feeders are underground. And laod factor is 50-60%.
I would appreciate your suggestions.
Lali






RE: Capacitor Placement in Distribution System
http://www.nepsi.com/pros_cons.htm
Some things to consider:
You mention that most of the feeders are underground, does that mean you will need padmounted capacitors rather than pole mounted banks?
Is voltage drop on long feeders a consideration? Sometimes capacitors are placed approximately 2/3rds of the way down a feeder to create a more uniform voltage profile. In general, line losses will be reduced the closer to the loads the capacitors are. Capacitors also increase the system capacity upstream of the location.
Will the capacitors be switched? Daily, weekday/weekend, seasonally or never? Is switching 1 large substation bank ok, or will you need multiple smaller sections. Capacitors on the feeders can cause high voltage problems during light load periods, and correcting to leading pf can aggravate harmonic issues.
RE: Capacitor Placement in Distribution System
The 2/3 rule of thumb mentioned by bacon4life should be adequate for the fixed capacitors if the load is relatively uniformly distributed along the line. The loss reduction is not very sensitive to location.
RE: Capacitor Placement in Distribution System
Therefore, the low power factor must be due to customers with low power factors.
Doesn't your utility 'punish' industrial customers via billing penalties for bad power factors (such as charging for kVA rather than kW, etc)?
Sometimes, the best place to correct for loads with bad power factors is right at the loads themselves.
RE: Capacitor Placement in Distribution System
Correcting power factors at load level, in my case, requires lage numbers of Underground capacitor bank with controllers which is expensive than correcting in substation.
I was just wondering wheather any body has gone through this kind of situation, and which one they believe is better option.
Thank you all for your time.
LaliGuras
RE: Capacitor Placement in Distribution System