A Guide to Voltage Optimisation

We live in an era in which it has never been more important to temper our energy use. But while switching to energy-efficient equipment and using it as efficiently as possible - by, for example, switching off appliances when not in use - is important, there are also other steps that you can take, and one that many people seem unaware of is voltage optimisation. 

What is Voltage Optimisation?

Voltage optimisation is the term used to describe the systematic, controlled reduction of voltages received by an energy consumer, aiming to reduce energy use, power demand, and reactive power demand. While some voltage 'optimisation' devices have a fixed voltage adjustment, others electronically regulate the voltage automatically. 

How Does Voltage Optimisation Work?

Most UK businesses receive an overvoltage from their grid connection, substantially higher than the level most equipment is designed to work optimally at, causing substantial inefficiencies.

Voltage optimisation is a transformer-based technology that comes in many forms and works by controlling or optimising the incoming grid voltage to return energy savings. The principle is based on supplying an optimised voltage level more suitable for the actual electrical device, allowing it to perform its task more efficiently and in line with the limits of European harmonised voltage. The basic design is a low-loss series-connected transformer, optimising a whole site or individual loads to target the most optimisable loads.

Pros and Cons of Voltage Optimisation

As with all technologies of this nature, there are potential costs and benefits that you should take into account when deciding whether to proceed with voltage optimisation or not: 

Pros 

• Lower monthly bills and lower carbon emissions from streamlined energy consumption.

• A relatively quick return on investment - payback can be as little as two years.

• Voltage optimisation is an extremely mature technology. It has been implemented for over 100 years.

• It’s flexible and can be installed at the distribution level or the low-voltage incomer.

Cons

• The initial setup costs can be very high. Research should be conducted to determine whether it is worthwhile in the long term.

• You may find your power supply disrupted during set-up or maintenance related to voltage optimisation.

How Does Voltage Optimisation Save Energy?

Generally, power from the National Grid is supplied at a higher voltage than is required. Although the official normal supply voltage in the UK is 230V, the actual voltage supplied by the National Grid fluctuates around 242V. Most appliances are rated at 220V. Therefore, appliances are being supplied with more electricity than necessary to operate, resulting in energy and financial waste, as well as increased wear and tear.

How Does Voltage Optimisation Save Money?

Installing a voltage optimiser can reduce the voltage your business receives. Voltage optimisers are installed in series with your electricity supply between the distribution transformer and the main low-voltage distribution board. When electricity passes through your voltage optimiser, the supply voltage is reduced to the required level. Any excess voltage being supplied will simply be returned to the grid and not used on-site. Your electrical equipment will benefit from an optimised power supply by simply rejecting and returning the surplus to the grid. 

Applications of Voltage Optimisation

Voltage optimisation can be applied across various uses, from residential to industrial properties. 

Residential Use

These optimisers are designed for domestic environments. They are smaller and less obtrusive, allowing them to be fitted in limited spaces, such as your utility room.  

Commercial Use

These optimisers are built bigger and with more sophisticated controls. Commercial operations typically have greater demands than a normal household. As such, you can expect commercial voltage optimisers to have advanced controls, such as phase balancing and power factor correction, to meet the demanding needs of a business. 

Industrial Use

The bigger and more complex your business, the more complex your demands may be. Dynamic voltage optimisers are best used in specialised settings that require a sophisticated device capable of meeting the dynamic, rapidly changing demands of those environments. They’re often integrated with smart technology to enable remote monitoring and control over electrical equipment performance. 

Power Problems Solved By Voltage Optimisation

Voltage optimisation can solve several common power-supply problems in businesses. 

Harmonics

These are the waveforms of currents and voltages at multiples of any fundamental frequency of the national grid supply. They occur due to non-linear loads, including variable-speed drives and discharge lighting. When the level of harmonics becomes too high, it can damage some sensitive electrical equipment. Similarly, they can reduce the efficiency of HV (high-voltage) transformers. Voltage optimiser units come with a voltage stabiliser, which helps reduce these high levels and prevent potential damage. 

Transients

These are brief, very large, and potentially destructive surges in voltage. They can come from lightning, switching off a large electrical load or switching between power sources. Although they last for a fraction of a second, they can be very destructive to any electrical equipment. They can easily cause data loss, shorten equipment lifespans, and degrade electronic components. A voltage optimiser comes with transient protectors that help protect against these surges.

Overvoltage

This refers to inputting a higher voltage than a piece of electrical equipment requires and is designed to operate at. The UK national power grid outputs an average of 242V, but can reach 252V in some areas. Most electrical equipment is designed to operate only on about 220V. This excessive and unnecessary voltage can shorten the lifespan of electrical equipment, increase power consumption, and not improve performance.

Power Dips

This refers to a reduction in voltage over a short duration; though in some cases the effects may be minimal, they might take a longer period to become apparent. Power dips can cause machinery to stop and contactors and relays to drop out. 

Phase Voltage Imbalance

Commercial sites and industries are provided with 3-phase electricity. If there is any imbalance between the phases, overheating may occur, resulting in energy waste. A voltage regulator can help balance the voltage among these phases, thereby saving energy and improving the energy efficiency of your equipment, while also enhancing its longevity. 

Evaluating the Effectiveness of Voltage Optimisation - Does it Work?

To determine the impact that voltage optimisation could have on a site's energy consumption, a detailed survey should be carried out to understand the dynamics of the load, identify what proportion of the electrical equipment is voltage-dependent, and assess what proportion of total energy consumption that represents.

The survey should also include detailed load monitoring for a suitable period of time to ensure all load types and processes are recorded and evaluated, including voltage levels, phase balance, demand levels, and voltage drop throughout the site.

If most of a site's electrical consumption consists of voltage-dependent loads, savings are likely to be substantial. Savings from voltage-independent loads are likely to be poor, although benefits still exist: operating equipment close to its fundamental design voltage may maintain life expectancy in line with the manufacturer's expectations.

System features should also be considered based on return on investment, load dynamics, site conditions regarding voltage fluctuations, and the level of functionality required.

What to Consider When Buying a Voltage Optimiser

So, if voltage optimisers can be very different to each other, what factors should be taken into account when choosing which one to buy yourself? 

Efficiency

The voltage optimiser unit to be installed must have an impeccable efficiency rating of about 97% to 98%. This should remain constant across different load conditions and even work with the lowest input voltage. Whether the voltage optimiser has a 50% or 100% input, it must operate at full performance. 

In addition, it should not contain any wearable or consumable parts to ensure no maintenance or repair is undertaken thereafter. The lifetime of an effective optimiser should be around 25 years. It should go without saying that the more efficient your optimiser is, the better the returns will be for your business. 

Uninterruptible Functions

Your system should be able to keep manufacturing operations running even during a breakdown or overload. For this reason, an automatic system that can bypass these issues is preferred. Some come with a voltage stabiliser to counter power surges. After the load or problem is solved, the system comes back on and continues functioning normally. 

Fast Voltage Management

Your system should be able to manage this optimisation independently and quickly. The transformers used for each phase, the switching elements, and the power control devices should all be independent to maintain the system's full performance. The system should have high-speed stabilisation to prevent machine failures, which could affect production rates.

Cost Considerations

Cost considerations for voltage optimisation broadly fall into two categories: initial setup costs and long-term savings. Ensure that you consider both when calculating your expenses and savings. Reducing the voltage to the lower end of the statutory voltage range will save money and energy, resulting in a significant reduction in your electricity costs. The average business energy consumer should recover the initial costs within a few years.

Can Voltage Optimisation Harm My Electrical Appliances?

If anything, the opposite! One significant advantage of installing voltage optimisation is that it helps prevent damage to electrical equipment caused by power surges or power outages. This means that your electrical equipment will last much longer and ensure the optimum lifespan.

Voltage Optimisation vs Power Factor Correction

The choice between a power factor correction (PFC) and a voltage optimisation system depends on the specific needs of your electrical system. In general, PFC is better suited to applications with a high proportion of inductive loads, such as motors and transformers.

Voltage optimisation is more suitable for applications with a high proportion of resistive loads, such as lighting and heating. In some cases, it may be beneficial to use both systems. This combined approach can deliver the most comprehensive energy savings and power-quality improvements.

Voltage optimisation can be complex and important in driving down your business costs. At SwitchPal, we can help! Contact us today, and we can discuss all your options to make your energy bills more affordable while boosting your green credentials. By making the switch today, you could save significantly.