Power Factor Controller

Dear Sir,
Please give me in details,
I am working in textailes industries , In our plant electric supply Power Factor is very low at power substation.( it is 0.72) what types of benifits we can get if we increase upto 0.87 to using power factor controlled capacitor panel

my power supplier demands above .90..if i am above that number i am not penalized..It cost the plant around 50k and they got there money back in 2 years...our PF realy sucked!!

D

It depends

There are two potential benefits. The first is that you may increase the capacity of your in-plant power distribution system. The second is a reduction in electric power charges.

The first benefit is only worthwhile if your facility is nearing the capacity of your internal power distribution. If you have some sections of the plant that have lower voltage, lights dimming when motors start, or don't have enough capacity for planned load additions then you can benefit from better power factor and lower currents. To get this benefit you need to add capacitors at individual loads or groups of loads.

The second benefit is only going to apply if you are being charged a penalty on your electric bill for low power factor. Not all utilities bill all customers for power factor. It is only worthwhile or them to do so on larger customers because of the cost of the metering equipment and the fact that improving small loads will have a neligible effect on their distribution costs. Check your electric bill first. If this is your objective then a bank of capacitors at the service entrance may be a reasonable approach.

What do they bill on?

Tom Jenkins said:

The second benefit is only going to apply if you are being charged a penalty on your electric bill for low power factor. Not all utilities bill all customers for power factor. It is only worthwhile or them to do so on larger customers because of the cost of the metering equipment and the fact that improving small loads will have a neligible effect on their distribution costs. Check your electric bill first. If this is your objective then a bank of capacitors at the service entrance may be a reasonable approach.

Click to expand...

I thought all power companies billed by Real Power consumption. Apparently I am mistaken in this? If this were a true statement, correcting PF would have an immediate savings, regardless if the power company charged an additional penalty. I guess I am wondering why any power company would "not" bill on real power?

Another way to improve the power factor is to use synchonous motors.

russrmartin said:

I thought all power companies billed by Real Power consumption. Apparently I am mistaken in this? If this were a true statement, correcting PF would have an immediate savings, regardless if the power company charged an additional penalty. I guess I am wondering why any power company would "not" bill on real power?

Click to expand...

Most utilities have a number of billing rate structures. The larger the user, the more complex the bill. That's because the metering equipment is expensive, and the return in revenue has to justify the expense.

Examples are:

Residential and small commercial - only kWh and a fixed charge

Medium commercial - time of day kWh with different rates for on peak and off peak

Larger commercial - time of day kWh with different rates for on peak and off peak plus peak demand charge (largest kW in a 15 minute period each month)

Very large commercial or industrial - time of day kWh with different rates for on peak and off peak plus peak demand charge plus power factor penalty (usually less than 85% causes increase in demand charge)

Most utilities have service representatives that will povide you with an analysis of your bill and the components of it. Before you spend money on any energy conservation measure it is a good idea to have this analysis so you know your measure is going to be effective.

Originally posted by russmartin:

I thought all power companies billed by Real Power consumption.

Click to expand...

I'm pulling this from memory, but I believe this is largely true of the 'standard' metering equipment that most of us see. For example, the old spinning disk meters will record only real power. The issue as far as the utility is concerned is they incur losses based on the reactive power component also. They couldn't recover these losses in revenue since they weren't measured.

So with the standard metering equipment adding PF correction wouldn't be noticed on the electric bill but it would make the power company happy. It would ultimately cost the power conmpany less to deliver the real power required by its customers. Not only is this a direct economic benefit to the power company it is also a long term benefit as it puts off the requirement for additional generating capacity.

As Tom said more sophisticated metering equipment now allows the power company to really see what is going on and they can more accurately bill if it becomes an issue.

Keith

Keith

In a nutshell if you have a three phase service of signifcant size the power company will most likely use CT's and PT's to measure your power useage both real and apparent power. You will be charged for kVA, peak demand (usally 15 minute average of maximum power usage), and pay a power factor penalty if you dont keep your power factor in the range of your contract with the power company. Smaller industrial sites typically use power factor correction capacitors. I worked for companies that specify power factor correction capacitors with any motor larger than 50hp. If you have large hp applications medium voltage synchronous motors you can improve the power factor. Finally, if you have in house power generation along with external power you can correct the power factor with your in house generator(s).