RHM International
Re-Engineering High-Voltage Interfaces at Scale

RHM International eliminates failure points at the high-voltage grid interface, enabling utilities to modernize aging infrastructure without increasing operational exposure.

Why are high-voltage grid interfaces increasingly critical for utilities?

That capability has become increasingly critical as transmission networks are pushed to deliver greater capacity and reliability under tighter environmental, safety and regulatory constraints. Utilities are expected to extend the service life of assets designed for earlier grid conditions, while maintaining predictable performance across decades-long lifecycles.

A persistent source of risk lies at the interface layer. Engineered for traditional grid environments, interface components have historically relied on oil- and SF₆-based insulation. Over time, these media introduce leakage, insulation degradation and maintenance exposure, increasing failure probability and complicating asset management. Growing restrictions on SF₆ under international environmental frameworks further elevate compliance and replacement risk in an already failure-prone category.

RHM International re-engineered the interface layer of the high-voltage power grid. The family-owned specialist innovation company replaced oil- and gas-based insulation with a proprietary dry-type medium that operates without pressurization, combustion risk or routine servicing. Developed entirely in-house, the insulation system eliminates explosion risk and fluid-related failure modes while reducing long-term maintenance requirements within existing substations.

“When interface assets behave as predictable, long-life infrastructure rather than high-risk failure points, the entire grid becomes easier to manage,” says Eric Euvrard, founder and president.

We don’t just replace legacy equipment. We future-proof the grid with technology we invented ourselves.

This creates a practical path for utilities to modernize incrementally as they transition toward digitally enabled grid architectures.

Built to Last for Decades, Delivered Fast

How does dry insulation change asset lifecycle predictability?

For utilities, interface equipment is treated as critical infrastructure, with lifecycle expectations measured in decades. In practice, legacy insulation technologies undermine those expectations by introducing unpredictable degradation and rapid escalation of failure, directly affecting crew safety, outage planning and asset strategies.

RHM’s dry insulation technology changes how high-voltage interface assets age and fail. Degradation progresses slowly and detectably, reducing the likelihood of sudden failure or collateral impact on adjacent equipment. For asset managers, this predictability supports clearer lifecycle modeling, fewer reactive interventions and more confident long-term planning.

RHM applies the same dry insulation architecture across instrument transformers, bushings and cable terminations, forming a unified interface system. While each plays a critical role in grid operation, bushings have historically been among the most failure-prone elements in high-voltage systems. They are a central focus of RHM’s solution portfolio.

Over the past 25 years, more than 24,000 RHM RIF® bushings and 23,000 RHM HV_DryShield® current transformers have been installed worldwide and have experienced an exceptionally low failure rate. That track record has been sustained through close engineering engagement, from specification through commissioning.

RHM typically ships dry-type interface equipment within 16 to 18 weeks. By contrast, power transformer lead times now extend into multiple years, and many high-voltage components exceed 80 weeks, placing reliability and modernization schedules at risk during failures or emergency replacements.

Shorter lead times allow utilities to maintain service continuity when extended outages are not an option, particularly during failure recovery.

The Fastest Path Off Fluids

How can utilities transition from fluid-insulated components incrementally?

RHM supports utilities across a wide range of operating scenarios. Some utilities execute multi-year programs to phase out fluid-insulated interface assets across their networks. Others engage RHM when a single interface failure threatens a local station or transformer and no direct replacement exists. A key advantage of RHM’s processes is the ability to propose custom designs to address these varied needs efficiently.

In every scenario, dry insulation alters how interface equipment is specified and maintained, shifting it from a recurring maintenance obligation to a long-life infrastructure asset.

RHM’s dry-type interface products are designed as like-for-like replacements for oil- and gas-insulated components. Utilities can upgrade individual assets through routine maintenance cycles or planned capital replacement programs without redesigning existing substations or interrupting operations. Modernization proceeds incrementally, aligned with real-world grid constraints.

The interface strategy extends into digital applications. RHM’s digital variants replace analog outputs with digital signals, enabling interface equipment on transmission networks to connect directly with modern protection and monitoring systems and support more precise grid oversight. As utilities transition toward digitally managed transmission networks, these digital outputs improve system visibility and support more predictive grid operation.

In selected digital applications, RHM also consolidates multiple functions within a single interface asset, including bushings that perform instrument transformer roles. Integrating functions traditionally handled by separate components reduces equipment count and supports more compact substation layouts, an increasing advantage as space, permitting and system complexity tighten.

“We don’t just replace legacy equipment,” says Euvrard. “We future-proof the grid with mature, innovative technologies that deliver long-term value.”

Custom Engineering at Grid Scale

What enables RHM to engineer replacements for legacy OEM equipment?

A defining characteristic of RHM is its engineering-led approach to product development. Rather than solely relying on standard catalog models, it designs each product to meet specific customer requirements. This is enabled by flexible manufacturing processes that accommodate new configurations without requiring dedicated tooling.

This approach addresses a widespread challenge across aging grids, where substations rely on equipment installed decades ago, and often supplied by manufacturers that no longer exist. When these components fail, utilities are left without replacements.
“The real value for customers goes beyond environmental compliance,” says Euvrard. “It’s about protecting maintenance crews and removing decades of built-in maintenance and refurbishment risk.”

RHM engineers work directly from customers' original OEM drawings, particularly for bushings, to design precise dry-type replacements. Each design is developed by evaluating physical envelope constraints alongside electrical performance requirements, ensuring compatibility with the existing installation. Designs are reviewed and validated with customers prior to production, reducing installation uncertainty.

To date, the company has developed more than 3,000 distinct bushing designs, evolving from one-off customization to repeatable engineering at scale.

Execution Built for Utility Timelines

A flat organizational structure keeps decision-making close to engineering and manufacturing teams. Initial technical and commercial inquiries are typically acknowledged within 24 hours. Specifications are then reviewed directly with the customer, followed by a complete technical, design and shipping quotation, usually delivered within a week to 10 days. Once a purchase order is received, production begins immediately. Responsiveness is embedded as a company-wide operating principle.

Documentation and installation guidance are developed in parallel with the equipment itself, simplifying deployment and reducing downstream complexity for utility teams.

RHM operates two manufacturing facilities in China, maintaining direct control over engineering and production as a private company. Key components are manufactured in-house, supported by local supplier partnerships, forming a self-contained industrial ecosystem.

Western engineering practices combined with localized production strengthen supply independence while maintaining consistent quality, shorter lead times, and global technical support.

Innovation remains continuous. Over the past six years, RHM has introduced multiple new products, with development focused on deeper digital integration and greater functional consolidation at the interface level. The company grows organically alongside its customers, treating long-term relationships as a core part of advancing technologies that measurably improve how power grids operate over time.

This shift is reflected in RHM International’s recognition as the Top High-Voltage Power Grid Equipment Manufacturer 2026. For utilities modernizing aging infrastructure and transitioning toward digital transmission networks, RHM International serves as a specialist partner for long-life, high-voltage interface systems designed for safe, decades-long operation.