July 8, 2016


Regulation of electrical voltage

Effienergy Faites des economies

How does the regulation of voltage by Effi-Save® operate?

The theory of energy savings through voltage management is based on simple electrical formulae, which see a connection between the consumption of electrical power and voltage for constant resistance.

The power required (kW) can be expressed according to the voltage:

This means that for a simple linear resistive charge, the power consumed is proportional to the square of the electrical supply voltage. Consequently, the higher the power supply is, the stronger the energy consumption is. The equipment which displays these characteristics, may be described as “dependent on voltage”.

effienergy économie d'energie

Electrical supply companies bill the energy supplied measured in kilowatt/hours (kWh). These reflect the consumed capacity (kW) and operating hours:

Energy = Power x Time

If your site is supplied by electricity at a voltage greater than your needs, it is possible that you may be wasting energy and money, and are responsible for greater emissions than necessary.

Management of voltage reduces the voltage of electricity that supplies equipment, thus reducing consumption while respecting the operating conditions specified by the manufacturer of the equipment.

Basic electric laws indicate that the power required for certain loads is proportional to the square of voltage. A power voltage greater than the nominal voltage of 400/230 V could lead to excessive energy consumption.

Why could power voltage be higher than necessary?

Historically, the electrical voltage in continental Europe is 380/220 volts, with a tolerance type of ±6%. Harmonisation levels concerning voltage were taken in 1995.

In order to further simplify the electrical equipment market, the European Union introduced the low voltage directive (LVD) 2006/95/EC with a view to regulating the normal voltage of electrical equipment supplied in Europe. Equipment that respects this standard bear the mark CE, and are designed to operate under a nominal voltage of 230 V (±10%).

Electricity Quality and Supply Regulations or EQS) harmonise electricity voltages in Europe to 400/230 V ±10%, that is to say a simple voltage in the 207–253 V range. This means that any device bearing the EC mark can operate in full safety on the local electricity supply network anywhere in Europe. (Standard IEC 60038)

Electricity production, transport and distribution are based on a tri-phase alternative current (AC). For low electricity voltages, phases are connected in “star” formation and supplied with the use of four wires: Each of the three phases and the “neutral” point between them. The nominal electricity voltage is currently 400/230 V, which means that the voltage between the phases is 400 V (often referred to as a composite voltage), whereas the voltage between each of the phases and the neutral point is 230 V (often called simple voltage). To take into account the geographic distribution of electrical distribution networks, as well as day to day changes to electrical demand, operators on the electrical distribution network are authorised to provide simple voltages in the range 230 V +10%/-10%, that is to say between 207 V and 253 V. (Standard IEC 60038)