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Fault currents are a barrier to achieving net zero. What are they?

Fault currents present a threat to your site’s power infrastructure, your security of supply and you net zero ambitions. The changing way the UK collectively generates power, as well as how end users utilise it, also means that the risk of experiencing fault currents has increased. Here, we lay out what they are, what causes them, and how you can avoid them disrupting your operations. 

What Are Fault Currents? 

Put simply, a fault current is a current that exceeded normally intended levels. In the case of a fault, a fault current passes through a given transmission line. A fault current is typically several times larger than the current that usually flows during a non-fault condition. Exceeding the designed current carrying capacity risks damage to the cables themselves, or the electrical circuits and equipment they connect. It also impacts on safety, carrying a higher risk of electrical shock. As a result, devices including fuses, circuit breakers and relays are used to try and prevent fault currents from damaging equipment or infrastructure. 

The UK’s National Grid was designed for a central dispatch method, with power generated centrally at typically coal-fired power stations before travelling one way to end users. While how we generate power has completely transformed since then, our transmission and distribution has not seen the same changes and upgrades. With far more distributed generation such as localised wind and solar, aging infrastructure is now facing the need to manage hugely fluctuating power levels travelling in both directions. This includes network protection equipment, that can be placed under excessive strain or fail due to excess power flow. 

National Grid predicts a 166% increase in the amount of distributed generation by 2050. One impact of this increase in generation is likely to be a marked increase in fault currents. It will also increase the strain on infrastructure and protection, raising the risk of more significant power disruptions such as blackouts. 

Protecting Your Business 

This elevated risk means that increasing numbers of businesses, particularly those that are particularly vulnerable to power disruption, are turning to new on-site technology to protect themselves. Rather than trusting in a reliable grid supply that may no longer be the case, many are taking proactive steps to bolster their power resilience. 

There are a number of options available to minimise or eliminate the impact of fault currents. Voltage regulation technologies can provide a more consistent, high-quality voltage to your equipment and infrastructure, preventing fault currents and other disruptions such as voltage spikes from impacting on sensitive equipment. They also offer a substantial reduction in both energy costs and overall consumption. 

A battery energy storage system also has the potential to entirely insulate your site infrastructure from grid disruption. Constantly monitoring and optimising your energy performance and usage, battery storage can use stored power to ensure that the correct voltage is supplied to your equipment at all times. Battery storage can also be used as a buffer between your electrical equipment and the grid, meaning the installed equipment will not connect directly to the grid and, therefore, will not have an adverse effect on the network’s allowable fault level. This can provide your DNO with peace of mind and prevent any new projects, such as rapid EV charging, from being blocked for implementation.

To find out more about eliminating the risk of fault currents and other power disruption events, speak to one of our team here. 


09 September 2021


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