Voltage Optimisation
Voltage Power Optimisation
WM Energy has partnered with the UK’s leading Voltage Optimisation equipment supplier to bring organisations further savings of up to 22% on top of energy efficiency savings that we have already identified. We can establish the scope for implementation of Voltage Optimisation as part of our energy efficiency opportunity survey.
What is Voltage Optimisation?
In the UK, the statutory supply band for electricity is 230V +10% to -6% (i.e. 216V to 253V), following European harmonisation in 1995. However, the average voltage supplied from the national grid is 242V, whereas the average European voltage is 220V. From 2008, to further align the UK system with the rest of Europe, the statutory minimum voltage will reduce further to 207V.
Most electrical equipment used in the UK is manufactured to European standards, designed for 220V and will operate effectively down to 200V. By forcing appliances to operate at a higher voltage in the UK leads to significantly higher energy consumption, increased heat losses and a reduced life span.
“A 230V linear appliance used on a 240V supply will take 4.3% more current and will consume almost 9% more energy.” (Electricians Guide 16th Edition BS7671).
It is estimated that 90% of sites in the UK are operating at too high a voltage and could therefore benefit from installing Voltage Optimisation Equipment.
Green technology
Voltage Optimisation makes an electrical supply more robust, and your site better protected. Transients – which are very brief surges in voltage from the grid – are eliminated provided they are less than 25,000V.
Voltage Optimisers are able to filter harmonics on the mains incomer. Harmonic distortion is on the increase, leading to apparently random failures of electronic equipment.
As the site is protected from mains-borne harmonics, disruptions to the operation of sensitive electronic equipment are minimised. By preventing harmonics from entering the secondary side of the HV supply transformer, a voltage optimisation unit is able to improve the transformer’s efficiency and increase its effective capacity.
In addition, a voltage optimisation unit helps to reduce the level of triplen harmonics on a site, by balancing the three phase voltages, which leads to reduced neutral currents and temperatures.
“the life of incandescent light bulbs is almost doubled by optimising their supply voltage”
Most equipment benefits from the lower ‘pressure’ when voltages are optimised. Other examples include Variable Speed Drives – which are particularly sensitive to over-voltage – and the capacitor banks in Power Factor Correction systems.
A lightly-loaded induction motor operating at an optimum 380V instead of a ‘raw’ 415V experiences less heating and vibration, reducing wear on bearings and prolonging its operational life. The operation of three-phase equipment, particularly induction motors , is much more efficient if the phase voltages are closely balanced.
For large industrial sites that are heavily dependent upon such loads, balancing phase voltages at an optimum level with voltage optimisation equiptment can yield energy savings of over 20% in motors, which also benefit from improved reliability and lifetime.
Optimising supply voltages reduces the reactance of electrical equipment, as it prevents over-excitation of magnetic components. The effect of this is to reduce the level of wasteful reactive power in the electrical system. By reducing reactive voltage optimisation improves power factor by 3-10%.
The maximum demand of a site is expressed in kVA (incorporating both real and reactive power). So reducing reactive power reduces the maximum demand of a site, which will lead to reduced kVA demand charges, Agreed Service Capacity (ASC), and increase spare capacity for further growth. (8% optimisation = 6%-10% reduction in MD normally)
Optimising voltage brings your supply voltage to the “higher efficiency” operating range of your equipment.
Without this, the ‘raw’ supply voltage to your site is likely to be at the top end of the range of voltages your electrical equipment can tolerate. As well as reducing energy consumption, this reduces the strain on your equipment, extending its lifespan. Power qualityis improved, and the lifetime of your equipment is extended, reducing maintenance costs. The exact saving is difficult to quantify, hoiwever it is estimated that benefits are in the order of a 10%+ reduction of your maintenance and capital replacement costs.
For further information or to receive an onsite demonstration call 0207 378 5800 or contact us by email.
