Power Factor Correction
Benefits Of Power Factor Correction
What Is Power Factor Correction?
Power Factor (Cos φ) is the ratio of True Power (kW) to Apparent Power (kVA) and is used as an indication of how efficiently an industrial or commercial site is operating. The closer the Power Factor is to unity (1), the more efficiently a site is said to be operating. Generally, anything higher than 0.95 is said to be a healthy Power Factor and will usually be sufficient to avoid penalty charges on the electricity bill. However, there are times where it’s essential to operate as close to unity as practically possible in order to keep the current levels to a minimum to avoid tripping breakers on overload.
The presence of Reactive Power (kVAr) on the system leads to a lower Power Factor. Equipment that requires a magnetic field in order to operate (traditional motors, chillers, induction heaters, fluorescent tubes etc) will all draw current that is said to “lag” behind the Voltage; thus producing a “lagging” Power Factor – also known as an inductive Power Factor. The more inductive Reactive Power there will be on the system, the higher the Apparent Power will be and in turn the higher the total current drawn from the network will be.
Reactive Power (kVAr) is the element that Power Factor Correction works to eliminate. The capacitors within draw current that is said to “lead” the Voltage, naturally producing a “leading” Power Factor – also known as a capacitive Power Factor. By having capacitors automatically switched into circuit in equal measure to the nominally inductive site load, the two effectively cancel each other out.
The end result is that the overall Reactive Power levels are decreased and the Power Factor is improved accordingly.
How To Correct The Power Factor
“Surely it’s just a case of checking the kVAr levels on the main meter and finding a suitably rated box of capacitors to install?”
That may well have been the way to approach things in the 70’s & 80’s when the only thing network companies cared about was the average lagging power factor over the course of a month. Now, it’s not just lagging, but also a leading power factor that they penalise on. And it’s not over the course of a month either, it’s every half hour period! So not only do we need to be considering automatically switched capacitors to avoid a leading power factor, but we also need to be aware of what the power factor is at at all times to fully eliminate penalty charges – no more monthly average calculations.
“Ok, so it’s a little more complicated now, but can’t we just have a box of capacitors with different ratings to cater for load variations?”
Getting closer, but NO!
That may well have been the way to approach things in the 90’s & 00’s when motors were just motors and when lighting largely consisted of fluorescent tubes. Now, it’s not as simple as just correcting the power factor (that’d be too easy); you’ve also got to consider Power Quality & Harmonics. With the dramatic increase in non-linear loads over the past decade or so, harmonic levels have never been higher. And whether we like it or not, PFC capacitors if not correctly specified, can magnify harmonics and cause underlying power quality issues to be worse.
The Solution: We Can Help
PFC Engineering has been solving power factor correction and power quality issues since 1976. We have the expertise to identify what your PFC requirements are and whether we need to make allowances for high levels of harmonics – in most cases this is done free-of-charge. Whether your sole aim is to make financial savings or if you need to reduce load, here’s how we can help:
- Make initial contact with us in whichever way suits you best – we can discuss any problems you’re having, what you’d like to achieve and at this point we can go over any questions you might have.
- Send us copies of electricity bills and your half-hourly consumption data for us to carry out an appraisal; both of which are freely available from your electricity supplier. Note: If you’re struggling with this in any way, we can request them on your behalf with signed permission.
- We’ll crunch the numbers and let you know how healthy your power factor is at present and what can be done to improve it.
- We’ll discuss likely savings with you and then look to arrange a site survey so that we can carry out those all important harmonic checks and look at the logistics of installing new or replacement equipment.
- We collate all of the information; costs, savings, recommendations and details of any installation work and put them into a formal quotation for you to consider with no obligation.
All of this preliminary work would be free of charge.
The only time we’ll ever consider charging at this stage is if there is no prior information available and we have no other work scheduled in your area. If this is the case, we’ll provide a cost-covering quotation for a full site survey and provide a detailed report showing load conditions, power factor, a harmonic spot-check and any recommendations based on our findings. Any order to come from these recommendations would see the cost of the initial survey fully reimbursed.
Contact us on 01799 530728 or complete the contact form below and a member of our team will be in touch.
Already Have PFC?
Visit our dedicated maintenance page to find out about our service and repair offerings for existing power factor correction equipment. A full survey is also included as part of every maintenance visit to ensure that your PFC unit is still suitable for the job and that harmonic levels are still at an optimal level.