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Power Factor Correction

In layman’s terms, Power Factor is the percentage of the burden on the supply which is actually doing real, useful work.

Power Factor Correction is the application of properly designed, manufactured and installed equipment which will compensate for the ‘useless’ yet essential part of the demand on the supply, leaving only ‘useful’ power to be drawn from the mains.

The nearer Power Factor is to unity, the less reactive power is drawn from the supply, the lower the demand, and the greater the overall efficiency.
Technical Benefits
By improving and maintaining the Power Factor at an optimum level:

Power Quality is improved.
The ‘voltage drop’ evident on an increasing load is greatly reduced by maintaining an optimum level of Power Factor. The improvement in this aspect of Power Quality has numerous benefits, not least that any load connected to the network will be presented with a clean and consistent supply voltage. Reliability and performance are improved when compared to less well-regulated supplies.

The Demand on the supply is reduced.
A significant reduction in the demand for any given loading can release additional supply capacity. This can then be used to connect additional loads to the existing distribution network. Otherwise, supply reinforcement is the only option, often costing many tens of thousands of pounds.
Network Reliability is increased.
The reduction in demand as a result of improvement in Power Factor affects all components of the upstream distribution network. The resulting reduction in losses means that transformers, cables and switchgear all operate at lower temperatures. This reduction in stress on the distribution system increases both the reliability and useful life of these components, resulting in a more reliable and longer lasting network.

Harmonic Distortion is reduced.
When a properly-specified ‘Detuned’ Power Factor Correction system is installed on a network subject to significant levels of Harmonic Distortion, the levels of distortion are reduced. The amount of reduction varies according to the particular characteristics of each system. This reduction in distortion increases the reliability and lifetime of any item of equipment, and is a significant improvement in Power Quality.

Specification Compliance is Achieved.
The 18th edition wiring regulation (BS7671) are scheduled to come into force at the end of 2018. They will include a new section (part 8) focused on energy efficiency. This will include Power Factor Correction, Harmonic Reduction and Distribution Equipment losses.
Commercial Benefits
Financial penalties imposed by the supply companies can be avoided by maintaining a Power Factor better than 0.95 lagging under all load conditions. Power Capacitors Ltd will typically select a target Power Factor of between 0.96 and 0.98 lagging, depending on the specific requirements of each installation.

By maintaining an improved Power Factor:

Excess Reactive Power Charges are avoided.
Half-Hourly metered consumers are charged for ‘excess reactive power’, which is defined as occurring when the power factor is lower than 0.95 lagging. These charges can vary from tens to thousands of pounds per month, depending on the loading. The installation and proper maintenance of a well-designed PFC system can remove these charges completely.
Availability Charges are reduced.
When the metered demand exceeds the Authorised Supply Capacity, Penalty Charges for excess demand are applied. By improving the Power Factor, the demand is reduced, and these penalty charges are reduced or removed entirely.

The Overall Demand on the supply is reduced.
A chargeable item on all half-hourly metered supplies is ‘Authorised Capacity’. By improving the power factor, less supply is required to do the same amount of work. This may permit a reduction in the authorised supply capacity required, with an associated reduction in charges from the supply company.

System Losses are reduced.
Losses in distribution networks increase exponentially with the load. Doubling the load quadruples the losses. By reducing the demand on the supply network, the losses in all network components are reduced. Depending on the installation, this reduction may be between 0.5% and 3% of the total kWh consumption. These additional, hidden savings can amount to many thousands of pounds over the course of a year.
Environmental Benefits
The increasing focus on environmental issues is supported by maintaining an optimum level of Power Factor:

Carbon Dioxide emissions are reduced.
The reduction in demand, losses, and loading which is achieved by properly improving the Power Factor is accompanied by a reduction in Carbon Dioxide emissions. The exact reduction will vary according to each particular installation, but studies have shown that reductions in the region of 150kg of CO₂ per kVAr of PFC equipment are readily achievable.
Building Regulations compliance (Conservation of Fuel and Power).
Part ‘L’ of the Building Regulations details reductions in the effective carbon dioxide emissions of a building which can be applied, if a properly designed and implemented Power Factor Correction scheme is installed and monitored. The optimum Power Factor Correction system can attract a reduction of 5% in the total CO₂ emissions for the building.

A Capable Partner

When specifying an item of electrical equipment such as a Power Factor Correction system, it is essential that you have confidence in the company you choose as your partner and supplier
A leader in PFC solutions
Power Capacitors Ltd has been a leader in the specification, design and manufacture of Power Factor Correction systems for over 45 years, consistently demonstrating a commitment to delivering the right solution for every application.

The increasingly diverse and arduous demands made of modern Industrial Electrical equipment are now met by the three ranges of automatic Power Factor Correction systems manufactured by Power Capacitors Ltd.
PowerCab Blueline
Designed with performance and unparalleled reliability in mind, the BlueLine range offers the most robust solution for the most demanding applications, with the emphasis on Performance and Extended Lifetime.
Harmonic Distortion? No Problem!
The Blueline range of Power Factor Correction cubicles is available in both standard and detuned designs, ensuring that the optimum solution is available whatever the requirements of a particular application.

Our team of highly trained and experienced engineers will properly identify the rating and design of Power Factor Correction equipment required in every case.

PowerCab BlueLine Cubicles

Specification Summary
  • Ratings from 50kVAr to 400kVAr as standard
  • Both standard ( plain ) and detuned designs
  • The top of the range line
  • Performance oriented
  • Minimum 480V continuously rated capacitors throughout
  • Choice of incomer ( terminals, isolator or fuse switch )
  • Copper-wound detuning reactors with 2.2x linearity in detuned types
  • CX+ controllers as standard
  • Bespoke controller set-up
  • Specification design driven
  • Small capacitor steps possible
  • Many variations and customisation possible
  • Cable entry to any requirement (on request)
  • Specification matches or exceeds any competition
  • Intended for performance sensitive applications
  • Automatic temperature control (where fitted)
  • Overtemperature protection (where fitted)
  • 2 year parts Warranty


Power Factor Correction
Powercab Blueline Cubicles

Get in Touch

Our Power Quality, Power Factor Correction, Power Electronic Capacitors and Site Services teams are always available. The team includes Matt Robbins, Joe Jordan, Teale Withers and Phil Bond.

Complete our form to send an email.


Power Capacitors Limited
30 Redfern Road
B11 2BH
0121 708 4511


Contact us to arrange your Power Factor survey, usually performed free of charge on the UK mainland.
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