The recent “Voltage Matters” forum, attended by over 60 industry professionals, has sparked a critical conversation about the escalating issue of voltage complaints from customers. The forum, hosted by Fundamentals, revealed a stark reality: a 54% increase in voltage complaints, as reported by UK Power Networks in their 2023 study. This trend is not isolated to the UK; grid operators worldwide are grappling with similar challenges, which are poised to intensify. The root of the problem lies in the antiquated grid infrastructure, originally designed in the 1950s to manage a far simpler energy landscape. Today, this grid is tasked with accommodating thousands of distributed energy resources (DERs), low-carbon technologies (LCTs), and rapidly shifting customer demand patterns. The legacy transmission and distribution assets, degraded by age and poor maintenance, are struggling to keep up with these demands.
The forum highlighted that many customer complaints on low-voltage (LV) networks are symptomatic of deeper issues within the high-voltage (HV) sector. The grid’s outdated model, designed for one-directional power flows from centralised power stations, is ill-equipped to handle the dynamic nature of modern energy systems. The influx of intermittent renewable generation, domestic photovoltaic (PV) systems, electric vehicles (EVs), and heat pumps has created a grid environment characterised by large and rapidly changing peaks and troughs in both supply and demand. This dynamic environment is causing significant voltage surges, leading to equipment failures, energy wastage, and increased carbon emissions. In extreme cases, these surges can result in catastrophic failures of customer equipment and regulatory sanctions for operators.
The forum also shed light on the issue of “runaways,” where legacy transformers and tap changers, under increasing pressure, experience mechanical breakdowns and control system failures. This results in extremely high or low voltages on the network. While the demand for new units is growing, there is a global shortage with very long lead times. However, the situation is not hopeless. Legacy assets, if well-maintained, can be modernised to include new control panels, sensors, and communications add-ons, effectively converting them from “dumb” to “smart” units. This modernisation can integrate them with modern voltage control systems, future-proofing them for the low-carbon grid.
A key takeaway from the forum is the importance of control schemes—the interfaces between intelligent decision-making devices and the main assets that affect voltage regulation. Many of these schemes are broken or ineffective, leading to runaway voltages. Modern smart automatic voltage control (AVC) relays, equipped with runaway prevention functionality, can address these issues. These relays provide the intelligence and algorithms needed to manage highly dynamic load variations resulting from DER activity. Equipping the HV sector with smart AVCs, linked via well-designed control schemes to well-maintained tap changers, can ensure optimal voltage levels, increase asset service life, reduce energy wastage and emissions, and address voltage issues further down in the LV networks.
The forum also highlighted the need for a whole-system approach to apply smart voltage control solutions across the grid. Initiatives like Electricity North West’s CLASS (Customer Load Active System Services) voltage control initiative and Northern Powergrid’s Boston Spa Energy Efficiency Trial (BEET) demonstrate the potential of using smart meter data and advanced network management systems to optimise voltages. These initiatives show that addressing voltage control issues requires a comprehensive understanding of the system-wide causes, starting at the HV level and working down to LV.
The forum’s discussions underscore the urgent need for the electricity industry to adapt to the evolving energy landscape. The rise in customer voltage complaints is a clear indicator that the current grid infrastructure is under strain. The solutions to these problems already exist, but they require a systemic approach that involves modernising legacy assets, implementing smart voltage control solutions, and leveraging advanced network management systems. The industry must act decisively to ensure a reliable, efficient, and low-carbon energy future.
