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Imagine a bustling city sidewalk suddenly erupting in flames as an underground network transformer fails. Or picture entire city blocks plunged into darkness when aging infrastructure gives out without warning. Critical emergency services, businesses and residents stand to lose services for an indeterminate period, demonstrating the potential consequences of compromised network transformer failures that can paralyze critical infrastructure and impact hundreds, if not thousands, of people.
This is not a theoretical discussion, as we all can see from news reports covering transformer fires that occur on a regular basis.
How could this happen? If you were to ask an operations manager what the condition of your network transformer fleet is right now, they wouldn’t be able to tell you.
André Marais, Executive Vice President of Sales & Marketing at H2scan, explains the background of trying to maintain network transformers in a busy city environment.
“Utility companies managing urban networks struggle to find answers for the worst-case scenarios that keep power executives and managers awake at night,” he said. “The traditional approach of periodic manual sampling is operationally and logistically challenging, and expensive, straining maintenance budgets that are already stretched thin.”
“Working in close proximity to network transformers where the condition is unknown also adds an element of personnel risk,” he added.
This conventional method of condition monitoring requires technicians entering the vault, drawing a manual liquid (oil) sample and returning that sample to labs for Dissolved Gas Analysis. Sidewalk vaults can be hostile environments, are often cramped spaces filled with debris and water that must be flushed out to allow access. As the number of vaults increases and as they become increasingly difficult to access, the frequency of sampling decreases from 1 to 2 to 4 years, and in some cases, oil samples are not drawn at all. Transformer watchlists are normally constructed to prioritize transformer maintenance or replacement, but they are almost always incomplete, and some of those transformers will eventually fail, increasing the unplanned outage minutes and potentially putting the public and utility personnel at risk.
Utilities have been looking for a viable solution for decades. They needed a monitoring solution that is reliable and will operate in the harshest of environments, does not add to the maintenance burden, integrates into their existing infrastructure, and above all, is cost-effective.
The picture of the challenges is harsh enough, but leaves out another lingering challenge – how can utilities place a device in a hostile location with limited access to power and communication support to provide continuous information, and not require regular on-site calibration and maintenance?
A Breakthrough Solution for Underground Transformer Monitoring
H2scan’s newly announced HY-VAULT™ system represents a dramatic breakthrough for utilities to monitor and maintain their network transformers because it offers, for the first time, a cost-effective, safer, and easily implemented means of collecting valuable and actionable data on the health of their transformers.
“H2scan is the first company to solve an old problem with reliable technology in an extremely cost-effective way,” explains Marais. “It’s not like people haven’t tried before. But a cost-effective solution has always evaded us, and we now have it. Our new HY-VAULT is the combination of two superior pieces of equipment into an integrated solution – the GRIDSCAN® 5000 series of hydrogen sensors with the new AVO-1 interface device. This purpose-built combination creates the industry’s only monitoring solution specifically designed for the unique challenges of underground vault transformers.”
The AVO-1 interface enables reliable data collection and communication from previously inaccessible locations, supporting utilities’ transition from uncertainty to one that allows them to prioritize their field teams based on real data. This field-proven solution provides continuous transformer monitoring that alerts the network’s teams to the presence of an incipient fault (starts small and escalates over time) in the transformer as it occurs, allowing field teams to address issues before they escalate into potentially dangerous situations.
Unlike adapted technologies that can underperform or fail to withstand these harsh environments, HY-VAULT was specifically designed with an IP rating for these conditions, including the abnormally high hydrogen fault gas concentrations that would damage standard monitoring sensors.
Also, Marais notes the traditional issue of accomplishing any underground transformer monitoring economically.
“Historically, every design I’ve seen struggled to find a way to do the measurement in any type of cost-effective manner, not just for one transformer, but across the whole fleet,” explains Marais. “What we’ve managed to create is a solution that is a fraction of the cost of prior attempts to deliver solutions, and is also a fraction of the cost of the transformer itself. More importantly, the reliability of our offering not only provides operational and safety benefits. It reduces OPEX spend.”
Designed for the Harshest Environments
The typical transformer monitors for above-ground (substation) applications do not work in underground environments. Underground network transformers face unique challenges—they run hot due to heavy loading and confined spaces, accelerating the breakdown of insulating liquids and generating significant amounts of hydrogen gas.
“These are not average transformers,” notes Marais. “The amount of hydrogen in these transformers is significant, so much so that it would damage one of our standard sensors. Furthermore, the concern is not only with the absolute level, but the hydrogen change rate.”
The GRIDSCAN 5015 sensor technology was engineered explicitly for the HY-VAULT system to withstand these extreme conditions, measuring absolute hydrogen levels and the rate of change, a critical indicator of developing transformer abnormalities. This capability allows utilities to distinguish between normal operating conditions and potentially dangerous situations that require immediate attention.
Transforming Utility Maintenance Practices
“Consider again how the network transformer condition is determined. Personnel enter the vault annually, bi-annually or even less frequently to collect oil samples. We know empirically that the time from first gassing to the transformer failure is 6 months,” states Marias. “Even when manual sampling occurs, there are blind spots where the condition of the transformers is unknown”. HY-VAULT solves that by providing continuous fault gas measurements.
Once a HY-VAULT is installed, it operates maintenance-free, delivering consistent data without the need for periodic calibration or adjustment for ten+ years.
Addressing Industry-Wide Challenges
The HY-VAULT system is critical for utilities managing urban power infrastructure. With workforce shortages affecting the industry, aging infrastructure requiring more attention than ever, and increasing power demands stressing the grid, traditional oil sampling methods and approaches are stretched to their limits and are inadequate.
“We’re seeing reports of up to 120 weeks of lead time on transformers. Part of the problem is that there’s a growing demand due to renewable energy, more data centers, and increasing electrification. Add to that the issues of supply chains and raw goods, and you can see the importance of taking care of the transformers in your fleet and not “running to fail,” which has been a traditional operational method,” said Marais.
“Single gas (hydrogen) monitoring offers the most reliable early indicator of developing transformer faults within these critical components, allowing maintenance teams to identify and address issues long before they lead to serious transformer incidents.”
Take Control of Your Underground Transformer Fleet Today
Don’t wait for a serious network transformer failure to expose the vulnerabilities in your condition awareness. The HY-VAULT system offers an immediate path to improved safety, reliability, and operational efficiency for your most challenging assets.
Contact H2scan today to learn how this field-proven monitoring system can transform your approach to underground vault transformer management and help you build a safer, more resilient urban grid.
