Voltage Management

Voltage management is an umbrella term covering various distinct technologies, including voltage optimisation, voltage stabilisation, voltage regulation, voltage power optimisation, or voltage reduction.

If your site is being supplied with electricity at a higher voltage level than you need, you could be wasting energy and money, and be responsible for greater emissions than necessary. This is where voltage management can help.

Electrical equipment can sometimes consume more power at higher voltages. Voltage management reduces the voltage of the electricity supplied to equipment, minimising consumption while remaining within the operating conditions specified by the equipment manufacturer. Basic electrical laws mean the power required by certain loads is proportional to the square of the voltage. A supply voltage in excess of the nominal 400/230V may result in excessive energy consumption.

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How does it work?

The basic principal of all voltage management equipment is to reduce the voltage level from that of the incoming supply. To achieve this change in voltage level, an electrical transformer is required. The ratio of primary to secondary windings of these electrical transformers is set to provide the desired level of voltage reduction. Whilst there are a range of manufacturers and various specifications of voltage management equipment, it is this fundamental device which sits at the heart of the equipment.

Why might my supply voltage be higher than necessary?

Until 1995, the statutory supply specification in the UK was 415/240V ±6% (i.e. phase voltage (Vp) within the range 226-254V). The vast majority of the electrical distribution network has been in place for many years and was designed to deliver electricity within this range. There are many sites across the UK where the phase voltage is normally in excess of 240V. Historically the supply voltage in mainland Europe has been 380/220 volts with a typical tolerance of ±6%.

Steps to harmonise voltage levels were taken in 1995 when the statutory supply specification in the UK changed to 400/230V+10% -6%. This remains the current UK position today. To simplify the market for electrical equipment further, the European Union has introduced the Low Voltage Directive (LVD) 2006/95/EC to regulate the normal operating voltage of electrical equipment to be supplied in Europe.

Equipment that meets this standard bears the CE mark and is designed to operate with a nominal supply of 230V. Electricity Quality and Supply Regulations (EQS) will harmonise supply voltages across Europe at 400/230V±10%, i.e. Vp within the range 207–253V (current guidance from DECC suggests this will happen in the UK during 2011/12). This means any piece of equipment with the CE mark can be safely operated on the local electricity supply anywhere in Europe.

Therefore in the UK, where supply voltages have historically been higher, equipment made for European markets is often used at a higher voltage than it is optimised for. As a result the equipment may be consuming more energy than is necessary.