Load Management & Load Factor

Power factor is the name given to the ratio of the real or usable power measured in kilowatts (kW) to the total power kilovolt-amperes (kVA). kVAr is the unit of measurement of reactive power. It is the portion of total power that does no work but must be supplied to most types of magnetic equipment, such as motors, transformers and ballasts. kVArh is reactive energy. The meter used for measuring the reactive kVArh consumed by a customer is referred to as a var-hour meter. It is an integrating instrument that measures lagging reactive energy in var-hours.

The maximum system power factor occurs when the reactive kVArh supplied is zero, so that the kilowatts (kW) are equal to the kilovolt-amperes (kVA) and the power factor is therefore 100 per cent or unity. Purely resistive loads, such as heaters, ranges, toasters and incandescent lighting have a power factor of 100 per cent.

Any electrical load such as motors, or transformers-type lighting having an iron core will contribute to a lagging power factor.

Lagging power factor can be corrected by installing energy management control equipment such as:

Time Controllers- Time controls are the simplest of available automatic control devices. They operate on the principle of turning energy systems on and off according to a predetermined schedule.

Programmable Thermostats- Programmable thermostats are intelligent thermostats that have the ability to alter their temperature settings according to a preset time schedule.

Stand Alone Controllers- The most commonly used energy management control device. They control a variety of equipment in a building based on a combination of time schedules and external inputs.

Multifunction Computer Based Systems- The multifunction computer based system is commonly called the building automation system. It includes the energy management and control system, the fire protection system, security system, elevator system and lighting control system. The five systems are controlled by a dedicated computer or analog controller and they are interfaced with the building security computer which is monitored at all times.

Programmable Logic Controllers-They are a form of stand alone controller.