Voltage optimisation is a highly effective energy saving technique that has an excellent payback period. The technology has a significant impact on the amount of energy used because it brings the voltage supplied by the grid in line with what is actually required.
The statutory electricity supply range for Australia is 230V +10 per cent to -6 per cent, which means that electricity suppliers are required to provide a voltage level that is between 253V and 216V.
Therefore, the supplier will distribute electricity at 253V and over distances the voltage will decrease. On average, facilities receive it from the grid at 247V.
Companies in Australia’s manufacturing, food and beverage processing and mining industries would no doubt be aware that most electrical equipment used in Australia is designed to work most efficiently at 220V to 230V.
This means that any incoming power that is higher than this level is wasted energy and means organisations are paying for power that is not required and not used.
Voltage optimisation works best on inductive loads — motors and lighting for example, especially if these are not loaded at 100 per cent of their capacity for 100 per cent of the time.
Operating like a transformer, voltage optimisation effectively reduces the voltage to an optimum level whereby all the equipment operates correctly but consumes less power in the process.
These systems should also offer improvement in power quality by balancing phase voltages, cancelling damaging harmonics and transients from the electricity supply and reducing the reactive power, hence improving power factor.
Over-voltage means that energy consumption is not only higher, but as a result, the lifespan of equipment is shortened. Installing a voltage optimisation unit leads to reduced maintenance costs as less demand is placed on electrical equipment.
The technology presents an excellent opportunity for savings without compromising the supply to a building's electrical equipment.
Generally, voltage optimisers will deliver between 12-15 per cent savings. However, the most efficient solutions can save up to 26 per cent of total electricity consumption and related CO2 emissions without compromising the supply to electrical equipment.
Other benefits of installing a quality voltage optimisation system are:
* helps protect against damaging transients (power spikes) of up to 25,000V
* lowers the operating temperature of motors
* provides an improved power factor by up to 20 per cent
In addition, there are no moving parts and therefore zero maintenance on the voltage optimisation unit itself.
Voltage optimisation units are available in fixed, and also as an electronic-dynamic variation, which automatically adjusts voltage to the optimum level making it ideal for sites with high levels of fluctuating voltage, heavy night loading or critical operations that require additional security.
Sites that have their own HV distribution transformer such as supermarkets, data centres, hospitals, hotels and cold storage facilities are more likely to benefit from a system that ensures voltage is supplied to a site at a constant level regardless of the input instability.
This technology is recommended in these applications because when the grid voltage varies (often throughout the night as the load on the grid disappears), it is able to hold the site voltage at the optimum level and maintain a high level of savings.
The stabilised voltage output is a vital feature for sites with critical loads, secure data and important operations that require high levels of reliability and security. This system is also suitable for new build developments, sites with older transformers and those which have previously been faced with physical space restrictions, thus make voltage optimisation installations difficult to implement.
Engineers and operations managers who plan to investigate an electronic-dynamic unit should check to make sure it has an amorphous metal core and utilises electronic-dynamic intelligent technology. If it does, it’s likely it can provide a variable voltage output that will achieve high efficiency and save huge amounts of energy for a site. Standing losses can be reduced by around 75 per cent.
Older transformers have high levels of standing losses and the majority of modern transformers used on commercial sites use Cold Rolled Grain Oriented steel (CRGO) within their core, which still provide significant losses for buildings in comparison to amorphous steel.
Pegler’s reduces energy usage and cuts maintenance costs
Pegler Yorkshire, market leader in the field of manufacturing fittings, taps and valves, has two large extraction systems at its Doncaster facility that were heavy consumers of electricity and suffered motor failures from the high supply voltage within the company.
This company had a high voltage supply of up to 254V, which was suspected of being the cause of high electricity usage and a shortened life expectancy of two particular motors.
Investigations took place to see whether using voltage optimisation to achieve a 15V reduction in voltage would ensure the motors operated at their optimum parameter and reduced the amount of energy consumption and therefore their electricity bills.
The installation of voltage optimisation at Pegler’s achieved a voltage reduction by an average of 15V on the extractor motors. For one system, the average power consumption was reduced to 47.06kW (previously 53.22kW), the power factor increased to 0.88 from 0.83 while power demand fell from 64.1kVA to 53.9kVA.
For the other extraction system, the data showed a reduction in average power consumption from 56.36kW before installation to 46.72kW, an increase in the power factor from 0.66 to 0.70 and a reduction in power demand on the supply from 85.3kVA to 66.8kVA.
The resulting savings from the installation of voltage optimisation on one was 6.15kW or 11.56% and for the other the savings were 9.28kW or 16.6%. Each extraction system operates for 7,000 hours a year, which would result in annual savings in the region of 43,080kWh and 64,960kWh.
Combined, this reduced Pegler’s overall power consumption by 108,043kWh per annum and 46.4 tonnes of CO2.
To ensure optimum savings and performance, a comprehensive analysis of a site's power conditions should be completed before installation. As each building is different, with its own unique infrastructure and specific load requirements, a voltage optimisation strategy should be customised to each site.
It's very important to install a tailored voltage optimisation solution supplied by an experienced and reputable company.
This will not only provide maximum energy savings and carbon reductions, but will also ensure that equipment will operate as efficiently as possible at all times, that the lifetime of equipment will be maximised, and that maintenance costs will be significantly reduced.
Sam Czyczelis is General Manager of Powerstar Australia, a wholly-owned subsidiary of EMSc (UK) Ltd, which has been manufacturing the market leading and patented voltage optimisation solution Powerstar at its headquarters in Yorkshire for over a decade.