Controlled current injection
Adjustable AC output supports controlled measurement current across different grounding and line conditions.
Utility measurement equipment
AC Current Source for Earth Resistance Testing
A custom high-current AC source developed for controlled injection during earth resistance measurements on powerline distribution infrastructure.
Output current
0-30 A AC
Compliance voltage
up to 200 VAC
Application
Earth resistance
Project overview
Built for repeatable field measurements where ordinary sources fall short.
The device provides a controllable AC current output for earth resistance measurements on distribution line grounding systems. It was designed as a practical instrument: powerful enough for real test conditions, compact enough to bring into the field, and clear enough to operate from a simple front-panel interface.
30 A
maximum AC output current
200 V
maximum AC output voltage
Field
validated on distribution line equipment
Engineering scope
From power electronics to a deployable test instrument.
High-power converter assembly
Custom PCB assemblies, toroidal magnetics, heat sinking, and forced airflow were integrated into a compact enclosure.
Touchscreen operation
The operator interface exposes current setpoint, output status, and measured electrical quantities directly at the instrument.
Bench and field validation
The system was verified with oscilloscope, multimeter, clamp meter, and dedicated field measurement equipment.
Bench validation
Waveform and output behavior checked under controlled load conditions.
R&D process
The final instrument came through schematic and PCB iteration.
The current source was not designed as a single clean drawing. Early revisions were used to prove the sensing, gate drive, isolation, and high-current routing. Each board pass made the system easier to manufacture, easier to debug, and more tolerant of the electrical stress expected during field measurements.
V1.0 REV5
First working power stage layout
REV5 captured the early architecture: current sensing, isolated control signals, gate-drive circuitry, and the high-voltage output path were brought together on a compact PCB. This revision was valuable because it exposed the real constraints of copper width, clearance, component placement, and service access around the high-current sections.
V1.0 REV10
Separated functions and stronger routing discipline
Later development moved toward a clearer separation between measurement, control, and power routing. REV10 shows a more mature board plan with repeated driver sections, larger copper areas, improved connector placement, and mechanical space reserved for magnetics and power components. The schematic also became a map of the complete instrument rather than only a single proof-of-concept stage.
Operating envelope
Designed around the realities of utility testing.
The project combines source power, measurement feedback, operator control, and transportable mechanics into one instrument for grounding system tests.
Output current range
0-30 A AC
Maximum output voltage
200 VAC
Measurement target
Earth resistance on distribution lines
Control interface
Integrated touchscreen HMI
Validation environment
Laboratory bench and outdoor field site
Internal assembly
Custom power stage
Stacked electronics, magnetic components, and heat sinking packaged for service access.
Integration
Field enclosure
Power, cooling, and operator connections organized into a transportable test unit.
Deployment
On-site validation
The instrument was used alongside existing measurement equipment in a real outdoor setup.
Project gallery
Bench work, internal build, and field deployment.
Company project
A purpose-built source for a specialized measurement problem.
The project demonstrates end-to-end development across power electronics, embedded control, mechanical packaging, test validation, and field support.