Quality of power or power quality – medium voltage power factor correction

By Keian Barnard, General Manager Ampcontrol – Power Division

‘Power quality’ technology and engineering that supports energy efficient practice is driving new developments in power factor correction. Instead of simply addressing reactive power demand through VAr tariffs on consumers, power quality technology is now at the heart of current debates surrounding energy efficiency and emissions trading for the future.

Reactive power, or kVAr tariffs imposed by supply authorities are designed to minimise reactive power demand which, in turn, reduces real line losses. For example, if a network has a power factor of 0.8, then 36 per cent of system line losses are due to reactive power flows. By increasing the system power factor to 0.9, the fraction of system line losses decreases to 19 per cent.

Significantly, this efficiency improvement reduces carbon emissions without any requirement for changes in consumer behaviour. Power factor correction also recovers system capacity in heavily loaded networks, thus deferring infrastructure capital costs associated with supplying increasing demand.

This motivation has driven development of products such as low maintenance, pre-fabricated medium voltage (MV) power factor correction units (PFCU) of a compact design.

General PFCU’s are pre-wired and commissioned with capacitor banks in multiple steps, as well as integrated protection and control instrumentation and safety interlocking for isolation and earthing by operators. Free standing outdoor units allows for ease of maintenance and operation and multiple units can be deployed for higher kVAR requirements.

PFCU’s require minimal on-site installation time and allow power utilities and high demand consumers to improve supply capacity, reduce line losses, improve voltage regulation and gain relief from reactive power tariffs.

Overall, lower energy consumption will reduce the greenhouse gas emissions which will provide long term benefits when the emerging carbon trading schemes are considered.

Ampcontrol’s Keian Barnard has 25 years’ experience in the electrical engineering industry and has been involved in medium voltage power factor correction and power quality systems for the past 22 years. Ampcontrol specialises in the application of automatic power factor boards, capacitors, harmonic blocking reactors and complex network management with centralised monitoring and control systems.