Reducing Wildfire Risk at the Source: Trench Group’s ARCC® System

Overhead lines stretch for kilometers across forests, farmland, and rural communities. Often supported by tall wooden poles, these lines carry electricity at voltages of up to 36 kV over long distances, supplying homes, cities, businesses, and factories with power. As reliance on this infrastructure grows, so does the importance of operating it safely. Under dry conditions, however, a single fault on an overhead line can trigger a fire. A branch touches the line. An arc may form and ignite the dry vegetation below. Trench Group’s ARCC® Wildfire Mitigation System addresses this risk at its point of origin – the fault location.

Read this article in German

An Overlooked Risk
Wildfires are usually associated with heat, drought, and vegetation. Yet one contributor is often overlooked: the power grid. Devastating fires in Australia and the United States have shown that overhead lines can start fires. The Black Saturday fires in Victoria in 2009 burned more than 450,000 hectares, killed 173 people, and destroyed more than 2,000 homes. In California’s 2018 Camp Fire, a fault on a power line was identified as the ignition source. These events led to new protection requirements: in Victoria, protection systems against power-line-induced fires were mandated in high-risk areas, while utilities in California use similar systems voluntarily as part of regulator-approved wildfire mitigation plans.

Climate change is contributing to higher temperatures and prolonged droughts, leaving vegetation increasingly dry. In these conditions, fires can take hold more easily and spread more rapidly. At the same time, global electricity demand is expected to reach around 33,600 TWh per year by 2030, while more than 2,500 GW of projects worldwide are waiting to be connected to the grid. Data centers, semiconductor facilities, industrial electrification, and renewable energy are driving this development. As utilities expand their networks – including overhead lines – they must operate safely in dry and fire-prone environments. For utilities and grid operators in exposed regions, reducing this risk is therefore both an environmental concern and an energy-infrastructure challenge.

How Overhead-Line Faults Can Become Fire Risks
Overhead line faults can result from storm-driven vegetation contact, tree encroachment, extreme weather events, or material fatigue.

During an earth fault, electrical current takes an unintended path through vegetation, another conductive object, or the ground. If an arc forms, the resulting heat and sparks can set dry vegetation alight. In a landscape already affected by drought, a single technical fault can be enough to start a wildfire.

This is where Trench’s ARCC® (Advanced Residual Current Compensation) system comes in: ARCC® is a REFCL system – a Rapid Earth Fault Current Limiter – designed to reduce residual earth-fault current and fault energy in overhead medium-voltage networks. Many medium-voltage networks already use an arc-suppression coil, commonly known as a Petersen coil. It compensates for the capacitive component of the earth-fault current and helps reduce the effects of an earth fault. ARCC® builds on this established principle by combining the coil with advanced power electronics, control technology, and rapid fault detection.

Fast Response at the Fault Location
ARCC® detects earth faults in real time and reduces residual earth-fault current, fault energy, and voltage at the point of occurrence, lowering the risk of an arc that could ignite dry vegetation. While compensation is underway, the EFD500 identifies the affected feeder, enabling targeted intervention. BoostPRO® speeds up compensation, reducing current and voltage more rapidly at the fault location. Where operating conditions permit, the power supply can be maintained without immediate disconnection. ARCC® is available for compensated (resonant-earthed) medium-voltage networks up to 36 kV and supports both 50 Hz and 60 Hz applications.

ARCC® addresses one specific way in which the power network can contribute to fires. It does not replace broader wildfire mitigation measures, but it can complement and be integrated into wider programs. Operational experience demonstrates that it works: ARCC® systems are installed at six sites in Australia. Over the past three years, none of these sites has reported an earth-fault-related ignition.

Trench Austria has worked with Petersen coils since 1954 and develops and manufactures them at its site in Leonding, near Linz, as a core component of the ARCC® system. The first ARCC® systems were delivered to Victoria, Australia, in 2020, followed by a project for one of the major utilities in California. But Trench Austria’s technology is becoming relevant far beyond Australia and the United States. Wherever overhead lines operate in increasingly dry landscapes, utilities must reduce the risk of network faults becoming ignition sources.

Europe’s Growing Relevance
Europe has warmed at roughly twice the global average rate since the 1980s, making it the fastest-warming continent. In 2025, both the area burned by wildfires and fire emissions reached record levels. So far in 2026, severe wildfires have burned more than 650,000 hectares across the European Union. European utilities and network operators are increasingly having to consider how technical faults can contribute to wildfire risk. Recent incidents in Germany and Austria have once again demonstrated that damaged overhead lines can cause fires in nearby vegetation. In southern Spain, investigators considered a fallen power line a possible cause of a major wildfire.

At present, no ARCC® system is installed in Europe. This raises an important question: Are existing protection approaches still sufficient? Or does wildfire mitigation require a broader approach? The challenge concerns not only the protection of forests and landscapes, but also the operation of distribution grids that are safer, more resilient, and better adapted to a changing climate.

TRUE TECH

In this series, we explore the technologies, engineering expertise and innovations shaping the future of high-voltage power transmission, from breakthrough solutions and advanced testing to grid security, system performance and new ways of applying Trench Group’s technical know-how.