Chile has one of the more developed power standards systems in South America, with a grid architecture shaped by its unique geography. The northern mining and renewable energy hubs, such as the Atacama Desert PV clusters, commonly operate at 34.5kV or 23kV medium-voltage levels, under demanding environmental conditions.
To address high altitude, high salinity, intense solar radiation and long-distance transmission, Rockwill provides customized oil-immersed grounding transformer solutions.
This solution is designed for Chilean distribution networks to establish a reliable artificial neutral point, improving system safety and operational stability for renewable integration, mining power supply and long feeder circuits.
Key Challenges: Why Chile Requires a Customized Approach?
1.Voltage level compatibility
Chile’s medium-voltage distribution networks commonly use 34.5kV and 23kV, rather than the 35kV/10kV systems frequently seen in domestic Chinese projects. Equipment not designed for local voltage levels may face insulation coordination and system compatibility issues.
2.Harsh environments accelerate equipment aging
Northern mining areas are located at high altitude with strong UV exposure, dust and salt mist, while southern coastal regions experience high humidity. Conventional outdoor equipment may suffer from reduced insulation performance, insufficient creepage distance or accelerated corrosion over long-term operation.
3.High capacitive earth fault current on long lines
Chile’s narrow and elongated geography means mine collection circuits and renewable export lines are often long. During a single-phase earth fault, capacitive current can cause intermittent arcing and temporary overvoltages, potentially affecting downstream VFDs, inverters and other sensitive equipment.
4.High O&M costs at remote sites
Mining sites, PV plants and wind farms are often widely dispersed, making manual inspection costly. Customers typically prefer equipment with high reliability, low maintenance requirements and suitability for unattended or lightly attended operation.
Technical Solution: Purpose-Built Design
1.Customized insulation and voltage design
- Rated voltage can be designed for 34.5kV or 23kV system requirements.
- HV bushings can be specified as reinforced porcelain or composite type, with creepage distance optimized for heavily polluted environments.
- As grounding transformers normally operate only during fault conditions, winding design must meet the required zero-sequence current and thermal stability duration.
2.Oil-immersed structure for harsh environments
- Fully sealed corrugated tank or plate radiator design reduces air and moisture ingress, slowing insulation oil aging.
- Tank surfaces can be treated with anti-corrosion coatings to improve resistance to salt mist, humidity and industrial atmospheres.
3.High-altitude derating compensation
- For high-altitude mining sites, air density reduction is considered in temperature rise calculations.
- Radiator area, oil volume and layout can be optimized to maintain stable thermal performance at altitude.
4.Low zero-sequence impedance connection
- ZN,yn11 connection is recommended, providing low zero-sequence impedance and a stable artificial neutral point.
- The transformer can be coordinated with a neutral earthing resistor to limit single-phase earth fault current and enable fast fault clearance by protection relays.
Economic Value: Benefits for End Users
1.Lower lifecycle cost
Although oil-immersed equipment may have a higher initial cost than some simplified dry-type alternatives, the sealed structure reduces insulation oil aging and lowers inspection and maintenance frequency at remote sites, helping reduce long-term O&M expenditure.
2.Reduced unplanned outage losses
Proper earthing resistor coordination helps suppress arcing overvoltages during single-phase earth faults, reducing the risk of damage to downstream crushers, ball mill VFDs, PV inverters and other equipment, thereby minimizing production downtime.
3.Simplified civil works and installation
Rockwill oil-immersed grounding transformers have a compact structure and high protection level. They can be installed on outdoor platforms or under simple shelters, reducing dependence on separate fire-rated buildings or complex climate-control facilities, which helps lower civil costs and footprint.
Compliance and Documentation: Supporting Project Acceptance
- Product design can follow the IEC 60076 series standards.
- Type test reports, material certificates and technical drawings can be provided to support preparation of documentation for Chilean SEC review.
- Seismic conditions can be considered in structural design, with reinforced or flexible arrangements for the base, bushings and lead connections to improve reliability during transport, installation and operation.
- For long ocean shipments to Chilean ports, heavy-duty wooden crates with moisture protection measures can be used to reduce the risk of moisture ingress.
Typical Applications and Delivery Support
Typical Applications
- Neutral earthing for 34.5kV distribution networks in large copper and lithium mines.
- Earthing for 23kV/34.5kV booster stations in Atacama PV plants.
- Neutral earthing for wind farm collection systems.
- Long-distance overhead line and cable hybrid supply systems.
Delivery and After-Sales Support
- Spanish installation and maintenance manuals can be provided.
- Common spare parts such as sealing gaskets, silica gel for breathers and pressure gauges can be supplied with the equipment.
- Remote video support is available for installation, commissioning and operational checks.
Key Technical Parameters
| Item |
Typical Configuration |
| Rated voltage |
23kV / 34.5kV |
| Vector group |
ZN,yn11 |
| Rated output |
Customized per system requirement |
| Thermal stability duration |
10s / 30s / 60s optional |
| Insulation level |
Compliant with IEC 60076 requirements |
| Protection class |
IP54 / IP55 optional, subject to enclosure or installation arrangement |
| Service environment |
High altitude, high salinity, strong UV, humid areas |
| Corrosion protection |
Configurable for coastal or industrial environments |
| Packing |
Heavy-duty wooden crate with moisture protection measures |
Request Technical Documents
For the 34.5kV/23kV oil-immersed grounding transformer selection chart, technical data sheet or Spanish version of this solution, please contact the Rockwill technical team.
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