Though reactive power is needed to run many
electrical devices, it can cause harmful effects to appliances and other
motorized loads, as well as electrical infrastructures. Since the current
flowing through the electrical system is higher than that necessary to do the
required work, excess power dissipates in the form of heat as the reactive
current flows through resistive components like wires, switches and
transformers (Hao & Papalexopoulos, 2007).
electrical devices, it can cause harmful effects to appliances and other
motorized loads, as well as electrical infrastructures. Since the current
flowing through the electrical system is higher than that necessary to do the
required work, excess power dissipates in the form of heat as the reactive
current flows through resistive components like wires, switches and
transformers (Hao & Papalexopoulos, 2007).
It is noteworthy that whenever energy is expended, someone
has to pay. It makes no difference whether the energy is expended in the form
of heat or useful work. We can determine how much reactive power an electrical
devices use by measuring their power factor, the ratio between real power and
true power. A power factor of 1 (i.e. 100%) ideally means that all electrical
power is applied towards real work. Homes typically have overall power factors
in the range of 70% to 85%, depending upon which appliances may be running (Miller,
2007).
has to pay. It makes no difference whether the energy is expended in the form
of heat or useful work. We can determine how much reactive power an electrical
devices use by measuring their power factor, the ratio between real power and
true power. A power factor of 1 (i.e. 100%) ideally means that all electrical
power is applied towards real work. Homes typically have overall power factors
in the range of 70% to 85%, depending upon which appliances may be running (Miller,
2007).
Newer homes with the latest in energy efficient
appliances can have an overall power factor in the nineties. The typical
residential power meter only reads real power, i.e. what you would have with a
power factor of 100%. While most electric companies do not charge residences
directly for reactive power, it is a common misconception to say that reactive
power correction has no economic benefit. To begin with, electric companies
correct for power factor around industrial complexes, or they will request the
offending customer to do so at his expense, or they will charge more for
reactive power. Clearly electric companies benefit from power factor
correction, since transmission lines carrying the additional (reactive) current
to heavily industrialized areas costs them money.
appliances can have an overall power factor in the nineties. The typical
residential power meter only reads real power, i.e. what you would have with a
power factor of 100%. While most electric companies do not charge residences
directly for reactive power, it is a common misconception to say that reactive
power correction has no economic benefit. To begin with, electric companies
correct for power factor around industrial complexes, or they will request the
offending customer to do so at his expense, or they will charge more for
reactive power. Clearly electric companies benefit from power factor
correction, since transmission lines carrying the additional (reactive) current
to heavily industrialized areas costs them money.
