Frequently Asked Questions
Power Factor Correction Questions
- What Is Power Factor?
- What Is Power Factor Correction?
- What Are the Benefits of Power Factor Correction?
- Which Industries Are Most Likely to Benefit from Power Factor Correction?
- Are Fines Being Imposed on Electrical Power Consumers Who Have a Poor Power Factor?
- What Is the Typical Payback Period for an Investment in Power Factor Correction?
- Is Power Factor Correction New Technology?
- Does Power Factor Correction Reduce My Carbon Footprint?
In the simplest terms, power factor is the measure of how effectively your electrical equipment converts electric current (supplied by your power utility) into useful power output.
In technical terms, it is the ratio of Active Power (also known as Working Power and measured in watts or kilowatts (W or kW)) to the Apparent Power (measured in volt amperes or kilovolt amperes (kVA)) of an electrical installation.
The Active Power consumed by an electrical device is used to perform a useful power output such as heat, light, mechanical energy, etc.
Inductive devices (such as electric motors, transformers, welding units, lighting ballasts, and static converters) also consume Reactive Power (measured in volt ampere reactive or kilovolt ampere reactive (var or kvar)) in order to generate a magnetic field. This magnetic field does not perform any “useful” work, but is required in order for the device to work. The reactive current drawn by an electrical device lags 90 degrees behind the active current drawn by it.
The Apparent Power drawn by an electrical installation is the vectorial sum of the Active and the Reactive Power drawn by the installation.
Power factor correction is the process of improving a low power factor present on a power system by installing power factor correction capacitors and in so doing, increase the ratio of active power to apparent power.
When the apparent power is greater than active power, then the utility provider must supply the excess reactive power AND the working power.
Power capacitors act as reactive power generators and they reduce the total amount of current a system draws from the grid.
Power factor matters because it can cost your company money and increase your company’s carbon footprint.
When your power system has a low power factor, your power system is demanding significantly more power than it is actually using. This results in additional charges on your electricity bill and increases the amount of energy demanded on the power grid.
The main benefits of power factor correction are:
- Lower electricity bills
- Increased system capacity (free up capacity on your supply transformer)
- Reduced voltage drop on the supply transformer and supply cables
- Reduced transmission losses
- Reduced carbon footprint
While all industries can benefit from power factor correction, industries where motors are operated at less than full load (cyclical processes) have the most to gain. This includes:
- Saw mills
- Plastic: extrusion and recycling
- Industries using machine tools, stamping machines, welders, compressors
- Mining industries
- Bottling plants
- Refrigeration plants
- Grocery stores
Many power utilities in the USA and Canada charge users a penalty when their power system’s power factor drops below a certain level, usually below 0.90 (or, 90%). This power factor surcharge covers the electric utility’s cost of supplying your power system with additional reactive power.
Power Survey can assess your utility bill to determine if you are being charged a penalty for low power factor. Contact us now.
The payback period for an investment in a well-designed power factor correction system is usually between 3 and 18 months.
Power Survey’s capacitor banks and power factor correction equipment have a life expectancy of more than 10 years, offering significant return on investment over time.
We have been designing and servicing power quality solutions since 1948.
Power factor correction reduces the total current drawn from an electrical distribution network (which affects systems such as the power stations, distribution grid, and supply transformers). In so doing, the heat or transmission losses incurred on these systems are reduced, which reduces your carbon footprint.
Harmonic currents and voltages are integer multiples of the system’s fundamental frequency. For example, with a fundamental frequency of 60Hz, the 3rd harmonic frequency is 180Hz (3 x 60Hz).
The fundamental frequency’s sinusoidal waveform, which is always predominant, becomes distorted by the addition of harmonic sinusoidal waveforms.
The measure of distortion is given as Percent Total Harmonic Distortion of the Fundamental Waveform (%THDv [voltage] & %THDI [current]).
Non-linear loads are the source of harmonic currents. That is, the load’s current waveform is non-sinusoidal. As a result, the distorted current waveform is rich in sinusoidal harmonic current waveforms.
Non-linear loads include electronic devices such as rectifiers, current controllers, AC and DC drives, cyclo-converters, and devices with switch-mode power supplies such as computers, monitors, telephone systems, printers, scanners, and electronic lighting ballasts.
The electrical distribution system’s harmonic impedance cause the load-generated harmonic currents to produce harmonic voltages (EH = IH x ZH). Transformers, and feeder and branch circuit impedance will cause maximum voltage distortion at the non-linear loads.