Designing resilience: advanced power strategies for critical infrastructure

In public safety and critical communications, uptime isn’t a feature — it’s a requirement.

From emergency response centres to networked utility sites, infrastructure providers face growing expectations around continuity, compliance and visibility. As these systems evolve, so do the power strategies required to support them — strategies that must integrate not only performance but also thermal stability, diagnostics, and national compliance standards.

Designing power systems for critical infrastructure now involves more than capacity — it requires foresight.

Architecture in transition: matching system topology to risk profile

Power systems in essential networks are shifting from monolithic, centralised models to site-specific architectures. Remote locations typically deploy 48 V DC systems, chosen for their simplicity, redundancy and compatibility with existing telecom infrastructure. These systems often support continuous loads between 100 and 300 W, with autonomy targets of 6–24 hours, depending on site criticality and accessibility.

In contrast, central hubs — such as data exchanges, operations centres or multi-site aggregation nodes — may employ higher-voltage modular DC systems (eg, ±120 or 240 V configurations) to manage larger, more dynamic load profiles and to reduce voltage drop over distance.

Architectural choices must consider:

• load distribution and projected growth
• physical site constraints and footprint
• grid availability and outage frequency
• environmental and service access conditions.
   

No single topology suits every site. System design must reflect the role and risk profile of the location.

Designing for compliance: meeting AS 4044:2024 in practice

The recently updated AS 4044:2024 standard sets new benchmarks for battery charger safety and performance in stationary applications — a major concern for asset managers and engineers alike.

Key technical features of the standard include:

• Neutral current limitation (≤10% of nominal load): This is to reduce heat build-up and system imbalance in three-phase systems.
• Integrated charge regulation: This includes float voltage accuracy within ±1% and compensation for ambient temperature to extend VRLA battery life.
• EMC compliance (AS/NZS CISPR 11 Class A): This ensures operational safety in dense RF environments, especially near transmission sites.
• Cable colour consistency: Standardised marking of DC positive, negative and earth for improved field safety.
• Mandatory diagnostics: Fault detection for input failure, charger fault, output overvoltage, battery disconnect and high temperature.
   

Meeting these parameters requires coordination across system design, component selection and installation practices — not just product certification. Engineers should engage compliance at the design phase, not as a post-installation obligation.

Thermal design and battery selection: engineering for real-world conditions

Batteries in field-deployed systems are exposed to fluctuating environmental conditions that dramatically affect lifespan, charge efficiency and safety. Thermal derating is no longer an optional design consideration — it’s a necessity.

Key design considerations include:

• Ambient temperature ranges: Systems should be validated for operation in -10 to +45°C environments, with battery thermal management strategies above 35°C.
• Float service life vs cyclic performance: Selecting batteries rated for ≥12-year float service and tested for >260 cycles at 80% depth of discharge if frequent cycling is expected.
• C-rate compatibility: Ensure batteries can support typical site discharge rates of 0.1–0.25C while maintaining voltage above minimum system cutoff.
• Enclosure design: This must provide passive ventilation and/or insulation to maintain internal temperatures within ±5°C of rated ambient.
   

As one example, Yuasa’s VRLA batteries are commonly deployed in telecommunications and utility sites for their stability in elevated temperatures and predictable float behaviour — reflecting the company’s engineering standard of ‘Performance, Every Time’.

Intelligent diagnostics: from data collection to predictive maintenance

Predictive diagnostics are now an essential component of power resilience — especially in networks with decentralised assets.

Modern systems should include:

• Real-time telemetry of input/output voltage, battery voltage, internal temperature and current draw.
• State-of-health algorithms to estimate capacity loss based on charge acceptance, impedance trends and temperature correlation.
• Failure mode alerts, including overcharge detection, thermal excursions, cell imbalance and fuse open/failure.
   

These diagnostics integrate with SNMP or Modbus TCP/IP protocols and are increasingly being tied into centralised asset management systems. Not only do they support compliance audits, they reduce downtime by providing failure prediction rather than simple alerts.

Case example: multi-site hybrid deployment in critical comms

In a recent deployment led by Intelepower, a regional public safety agency upgraded its power infrastructure across 14 sites. Remote locations utilised 48 V systems with long-duration autonomy and battery-level telemetry. Central hub locations implemented ±120 V rack-mounted DC systems with integrated monitoring and predictive diagnostics linked to a central dashboard.

Battery strings were selected based on ambient temperature modelling, and charging profiles were adjusted for altitude and thermal deviation. All systems were designed in accordance with AS 4044:2024 and delivered with traceable commissioning data and maintenance plans.

This approach reflected a performance-driven ethos built on engineering precision and risk alignment — a testament to Intelepower’s commitment to ‘Trusted Power. Unmatched Reliability’.

Designing for what’s next

For critical infrastructure, power continuity is more than just runtime — it’s about long-term compliance, data visibility and thermal resilience. As standards tighten and operational risk increases, power systems must be designed with adaptability and insight at their core.

Key principles for engineers and project leads to follow include:

• Match system voltage and architecture to operational risk.
• Select batteries not only on capacity, but on thermal behaviour, cycle profile, and environment.
• Incorporate diagnostics early — not as a retrofit.
• Design for compliance and auditable traceability, not just output.
   

Ultimately, resilient power is engineered — not improvised.

For more information on advanced power strategies for critical infrastructure, visit Intelepower at https://intelepower.co.nz.