Have you heard about surplus reactive power?
Publicado em 19 de October de 2020
We can say that active power is the power that can be converted in another kind of power and it’s represented in kilowatt hours (kWh). Reactive power, on the other hand, is the one that doesn’t generate work, that is, the energy that circulates between the various electric and magnetic fields of an altered current system. Reactive power is expressed in kilovolt-ampere-reactive-hour (kVarh). It plays an important role in producing magnetic flux which is necessary for the functioning of magnetic circuits.
Besides that, it is important to notice that the excess of reactive power can harm the electrical system. This occurs due the fact that the surplus causes an increase in power losses due to heating and voltage drop, in addition to increasing expenses with over dimensioning the conductors.
To define an acceptable reactive power limit, an indicator known as ‘power factor’ is used. This factor reflects the relationship between active and reactive power. Analyzing this concept in a basic way, it is clear that the greater the reactive power, the greater the power factor.
ANEEL (National Electric Energy Agency) Normative Resolution number 414 provides that group A consumers (industrial and commercial) are taxed if they have a power factor below 0.92. Residential consumers (type B) are also subject to a fine, although the power factor measurement is optional.
Charges related to excess reactive power appear on the energy bill. Charges are usually listed as ‘reactive consumption surplus’ or through the use of acronyms like EREX and FER. The most common causes for the low demand factor and, consequently, for the collection of the surplus are:
- Engines operating for a long time on small loads;
- Large number of low power engines;
- Engine oversizing;
- Transformers feeding small loads;
- Discharge lamps (mercury vapor, fluorescent, among others) without individual power factor correction.
SOURCES:
MANOELA, JOIRIS. Glossário da Energia. Disponível em: ENERGÊS
FLUXO. Como corrigir a energia reativa excedente? O que é energia reativa? Disponível em: Fluxo