Hiko Enhancing Monitoring with Smart Meter Integration and Live CT Retrofitting.
The challenge: Load monitoring without outages
WEL Networks aimed to modernise monitoring across its distribution transformers, particularly in rural areas where traditional approaches proved infeasible. Traditional distribution network MDI monitoring records the highest peak measured by the device which does not provide sufficient data to make meaningful decisions for a future data enabled network. The MDI design was not widely used across the existing transformer fleet which results in low availability of current transformers (CTs) fitted in the low voltage distribution frame. Not having the CTs has hampered efforts to retrofit smart meters for load distribution analysis for new customer connections and asset planning. The meters are also used for near real time fault detection.
In urban networks, ground-mounted transformers are often pre-fitted with CTs during installation, but WEL’s older infrastructure lacked this provision. Installing new CTs using whole-current designs required HV outages—disruptive and costly, especially in sensitive areas like schools or industrial and commercial areas.
Technical barriers: Environment and installation
The logistical and electrical environment presented three key challenges:
Live installation required
Transformers couldn’t be taken offline without significant planning and cost.
Smart meter integration
CTs needed to interface reliably with WEL’s 5A-input smart meters.
Rural placement
Transformers in valleys or remote farms meant traditional comms layouts were unworkable, necessitating pole-mounted smart meters and thus waterproof, IP-rated CTs.
WEL’s interim efforts and the shift to split-core CTs
Initial attempts included whole-current CT installations at select locations. However, these required complete shutdowns for installation, often at night or providing alternative generation which incurred high labour and material costs. The team trialled several solutions, including overseas-sourced CTs, but lead times and form factor issues delayed progress.
The search shifted toward a split-core design that could be safely installed around energised conductors. Hiko’s IP67-rated split-core CTs, already known to some in the industry for ease of installation, emerged as a practical alternative. While not as accurate as metering class CTs, they offered sufficient resolution for operational monitoring needs for a distribution network.
The Solution: Live Retrofit with IP-Rated Split-Core CTs
Hiko’s split-core CTs were retrofitted across transformers without needing power interruptions. The clamshell design enabled live, safe installation around busbars or cables. With a form factor compatible with smart meters, and environmental robustness (IP67-rated), they met WEL’s unique deployment needs.
This approach:
Eliminated service disruptions during install.
Enabled load and performance data collection in areas previously inaccessible.
Standardised install procedures into a templated four-hour workflow suitable for field teams or contractors.
Reduced installation costs and allowed better resource planning.
Impact: A Practical Monitoring Framework for Rural Networks
By enabling live retrofits, WEL could finally integrate transformer smart metering at scale—even in remote, topographically difficult areas. The smart meters, now fed by reliable current inputs, provide near real-time insights into transformer performance. Engineers can better rationalise asset upgrades, balance loads across feeders, and anticipate emerging faults before they impact service.
Field and Technical Feedback
WEL’s engineers and field teams report improved safety, efficiency, and ease of use. With no need for outages or complex scheduling, the retrofit programme progressed swiftly. The waterproof, rugged design also avoided failures in exposed locations.
Looking Ahead: Scalability and Lessons Learned
Although the solution was tailored to specific WEL constraints, the principles apply broadly to other networks facing rural deployment or retrofit challenges. Future regulatory shifts may increase demand for such solutions, and WEL is now better positioned to adapt.