To modernise ageing grid infrastructure that chokes mining productivity, a National University of Science and Technology (NUST) student, Weston Mabota, has developed a smart hybrid transformer designed to eliminate oil-filled failures and enable bidirectional power flow from onsite solar plants and electric haulage systems, Mining Zimbabwe can report.
By Rudairo Mapuranga
Exhibited at the 66th Zimbabwe International Trade Fair (ZITF) under the theme “Connected Economies, Competitive Industries,” Mabota’s prototype directly confronts a growing technical barrier: legacy transformers cannot handle reverse power pushed back by solar panels, nor can they supply the harmonic-free voltage required by sensitive mineral processing equipment.
“Old transformers can’t handle modern grid technologies, there are more power plants, more electric vehicles in mining, and more sensitive electronic drives,” Mabota said. “Our system uses power electronics, so there is no oil. It’s light, and it comes with a remote monitoring dashboard.”
Conventional distribution transformers in Zimbabwean mines rely on mineral oil for insulation and cooling—a fire and environmental hazard that degrades rapidly under fluctuating loads. Mabota’s hybrid topology replaces the oil with forced-air cooling and a power electronic shunt module integrated with a magnetic core. The weight reduction permits modular deployment in underground drifts or confined surface substations.
The embedded dashboard continuously monitors thermal stress, insulation resistance, and harmonic distortion.
“Someone in Harare can monitor a mining operation here in Bulawayo and detect faults before they happen,” Mabota said.
Unstated Technical Measures Critical for Mining
While not detailed in Mabota’s public demonstration, the architecture implies several mining-specific technical specifications:
- Bi-directional power conversion: Enables seamless islanding and reverse-energy handling from solar PV or regenerative braking on haul trucks, preventing nuisance overvoltage tripping.
- Solid-state tap-changing (no mechanical OLTC): Eliminates arcing and spark risk in potentially gassy or dust-laden environments—a key requirement for underground mine safety.
- Grid-forming control logic: Allows the transformer to sustain voltage and frequency during utility outages, maintaining continuous ventilation and hoisting.
- Embedded harmonic filtering (IEEE 519-compliant): Protects variable-frequency drives (VFDs) and automated drilling rigs from current waveform distortion caused by non-linear loads.
- Partial discharge monitoring: The dashboard’s “faults before they happen” capability likely uses high-frequency current transducers to detect incipient insulation breakdown, providing weeks of lead time for scheduled maintenance.
Zimbabwe’s mining sector is accelerating captive solar and battery storage adoption. According to a 2025 industry survey, more than 40% of new mining projects now incorporate hybrid power, yet most installed transformers lack the bidirectional and power-quality capabilities required. Mabota’s hybrid approach, validated in low-cost power electronics research, offers a retrofit path without the expense of full solid-state transformers.
The 2026 ZITF, running from 20–25 April, has drawn over 400 exhibitors. Mabota’s innovation appears in the pavilion for local energy solutions. Later this year, Zimbabwe’s inaugural Mining Week (17–19 November, Harare) will address grid-edge interconnection standards policy that could accelerate field trials.
Mabota plans to file a patent through NUST’s technology transfer office and begin pilot tests at a platinum operation on the Great Dyke by the second quarter of 2027.
“The transformer isn’t just a laboratory project, it has to survive the hammer of real-world mining,” he said.
