Voltage Optimisation

How is it possible to optimise voltage on a site-specific basis?

The statutory supply range for electricity in Australia is 216V to 253V (i.e. 230V -6% to +10%). Due to the fact that transmission losses occur through the electricity grid, the majority of premises receive voltage at the high end of this range. This is to ensure that the premises located at the extremities of the grid receive voltage above the minimum allowable level.

However most electrical equipment used in Australia is designed to function optimally at 220-230V and will even operate effectively down to 200V. When motors and equipment operate at voltage levels higher than what they are designed for (i.e. greater than 220V) there is a degradation of the equipment and energy is lost through heat, vibration etc. (the iron losses are proportional to the square of the voltage increase). This over-voltage leads to significantly higher electricity consumption due to the energy that is wasted.

From the extensive data logging that we have performed across Australia, we estimate that approximately 90% of sites in this country are operating at an over-voltage level (with an overall average of approximately 240V) and could therefore significantly benefit from installing The Ark Energy Saving Unit to optimise their voltage.

The Ark’s unique technology optimises voltage, enabling motors and equipment on-site to operate within their optimal (and design specified) voltage range of between 220-230 Volts, while also delivering energy savings to the end user. With >99.8% internal efficiency, The Ark is able to reduce voltage without increasing current and hence achieves a net reduction in power usage for the same net output of motors and equipment.

Why do electricity suppliers provide high voltage levels?

It is most common for network operators to set voltages towards the higher end of a statutory band for a number of reasons:

Voltage drop – setting a course tapping on substations ensures that supply quality is maintained across all customers on the grid i.e. the approximate 10% of premises that are already receiving voltage levels at the lower end of the statutory band would have their power supply seriously compromised by broad scale voltage reduction by the electricity suppliers.
Transmission losses – high voltage transmission produces lower losses on the network’s grid – thus saving the network operator money and improves the working life of their network assets.
Reducing the voltage would result in an immediate loss of income for the network operator and retailer, as consumers would be paying less for their supply.
It would take a colossal level of investment for the electricity suppliers to alter the electrical infrastructure to lower voltage universally while still ensuring adequate supply to all end-users.

Accordingly, supply authorities are not in a practical position to be able to step down voltages universally. Site-specific voltage optimisation is the best method to refine electricity supply and The Ark technology is able to do this in a manner that achieves significant electricity savings and power quality improvements for the end user.

What voltage optimisation levels can The Ark be set at?

The voltage optimisation of The Ark can be set at tappings of 6%, 8% or 10%.

In Australia, the statutory minimum voltage is 216V, hence the voltage optimisation cannot be set to reduce the voltage below this level.

Assuming a typical voltage of approximately 240V, an 8% tapping will reduce the voltage to approximately 221V. If the incoming voltage is higher than this, it is often possible to optimise the voltage by 10%, providing larger energy savings.

The voltage at a site will generally fluctuate substantially over a 24-hour period. By measuring the voltage at 3-minute intervals over a 7-day period, we are able to get a very thorough understanding of the electricity supply quality delivered to a site, enabling us to set the appropriate voltage tapping level with regard to the statutory band.

Is the output voltage in direct proportion to the supply voltage?

The output voltage level is directly proportional to the supply voltage. From the results of our power quality analysis we are able to determine the appropriate voltage optimisation for a site – either 6,8,or 10%.

The graph below illustrates a voltage profile in the typical range for Australian premises. At this voltage level, The Ark is set to an 8% tapping, bringing the output voltage into the optimum range for the efficient operation of equipment and machinery. The green line at 220V represents a safety zone that we use when determining the appropriate optimisation level for a site, ensuring the voltage clearly exceeds the minimum statutory level (represented by the bottom of the chart) after it has been optimised.

Voltage Chart

Could I tap down my transformer to generate energy savings?

The purpose of the supply authority transformer tap-downs is to provide voltage within the Australian statutory range, rather than provide energy savings for the end-user.

When a traditional step-down transformer with high internal losses is used to tap down Voltage (V), the system losses are maintained and the Current (I) increases with the decrease in Voltage and hence there is only a small net reduction in energy used. Hence, the savings achieved by tapping down the voltage on a conventional transformer will only be very minor compared to those achieved from an Ark installation.

The Ark’s ability to optimise voltage with greater than 99.8% internal efficiency (in combination with its other energy saving principles – improving power factor, 3-phase voltage balancing and reducing harmonic distortions), without drawing more current, is what makes the technology unique and enables it to provide electricity and carbon emission savings.

In addition to the energy savings generated by The Ark, its installation benefits a site’s overall power quality and helps protect its electrical infrastructure. Hence, the savings and benefits from an Ark installation far exceed those offered by a traditional transformer tap.

What are the differences between The Ark and traditional autotransformers?

There are fundamental differences between the two devices.

The Ark Energy Saving Unit	Traditional Autotransformers
Designed to save energy and to improve the quality of power supplied to a site	Designed to control voltage
Operates with exceptional efficiency (i.e. greater than 99.8%)	High internal losses (energy dissipated via heat and vibration) results in efficiency of around 85-90% varying according to loading conditions.
No moving parts or electronics enables maintenance free operations, with an expected lifespan of 30+ years.	Inefficiencies and wear from moving parts increases maintenance requirements and results in short life spans.
In addition to optimising supply voltage, also improves power factor, 3-phase voltage balance and reduces harmful harmonics.	Negatively affected by Harmonic distortions.
Does not produce noise	Produces noise
Pin ≅ Pout	Pin ≠ Pout
Compact size	Large size

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The Ark Energy Saving Unit - Up to 20% electricity & carbon emission savings across your entire site with one maintenance free product.

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