750 KVA Ground Loop Transformer-24.94/0.6 KV | Canada 2026

Easy to install, tough to beat - pad mounted transformer keeps your grid running safe and neat.

01 General

1.1 Project Description

This Pad-Mounted Transformer is designed for demanding outdoor environments where reliable step-down power distribution is critical. Its low-profile, compartmentalized design mounts directly on concrete pads, offering a space-saving installation without additional protective enclosures while enabling safe transformation from underground primary cables.

Delivering an outstanding efficiency rating of 99.15%, this ground loop transformer ensures minimal energy losses in daily operation. A top oil temperature gauge with two sets of contacts continuously monitors thermal conditions, providing alarm/trip signals to facilitate preventive maintenance and protect your system from overheating risks. A single-component, isocyanate-free acrylic coating-finished in Equipment Grey-is standard on all exterior surfaces. This durable, UV- and weather-resistant finish provides excellent corrosion protection while eliminating the health hazards typically associated with isocyanate-cured systems. In addition, a Kirk key trapped-key interlock mechanism mandates a specific sequence of operations, ensuring that the cabinet can be opened only after upstream power isolation is completed. This mechanical failsafe delivers both security against unauthorized access and positive protection for maintenance crews.

1.2 Key Specifications

This transformer offers a smart combination of high efficiency, intelligent monitoring, worker-focused safety, and long-lasting durability-ready for service in your distribution system.

1.3 Technical Specification

750 kVA ground loop transformer specifications type and data sheet

1.4 Drawings

750 kVA ground loop transformer diagram drawing and size.

02 Manufacturing

2.1 Core

The core is manufactured using high-permeability cold-rolled grain-oriented silicon steel (CRGO), with parameters fully matching the 750kVA rating, 5.75% impedance, and 1.18kW guaranteed no-load loss. The core assembly is tightly controlled with in-process inspections for burrs and air gaps, and verified by a no-load test showing actual no-load loss of 1110W (below guarantee) and exciting current of 0.81%, proving excellent magnetic performance. The design complies with CSA C227.4‑21 for three‑phase pad‑mounted transformers, and the test results confirm its reliability under the CSA C802.1 efficiency standard. Manufacturing highlights include 100% in‑process inspection of lamination stacking and core loss measurement before final assembly.

2.2 Winding

All windings are copper, with primary line voltage 24.94GrdY/14.4kV, secondary 0.6GRDY/0.347kV, vector group YNyn0, and BIL ratings of 125kV (HV) and 30kV (LV), exactly matching the order specifications. The measured ratio deviation is between -0.07% and +0.09% (far better than ±0.5%), the LV resistance unbalance is 3.08% (≤3% requirement), and the phase relation is verified as YNyn0, all in full compliance with CSA C227.4‑21. Load loss corrected to 85°C is 8501W (tolerance +6%), short‑circuit impedance is 5.96% (tolerance ±7.5%), and efficiency is 99.19% (≥99.15%), demonstrating reliable electrical and thermal design. Manufacturing quality is ensured by CNC winding machines with tension control, inter‑turn insulation checks, and 100% DC resistance and turns ratio tests to avoid shorted turns or wiring errors.

2.3 Tank

The tank is a sealed design with a bolted cover, made of mild steel for both the main tank and the HV/LV compartments, meeting CSA mechanical strength requirements for liquid‑filled transformers. A 20kPa pressure leak test for 12 hours showed no leakage or permanent damage; oil tests further confirmed reliability with moisture content 12.1 mg/kg, dissipation factor 0.103%, and dielectric strength 65.4 kV. Manufacturing highlights include 100% weld pressure testing (under water or soap solution), hot oil circulation flushing, and vacuum oil filling to ensure internal cleanliness and insulation integrity, fully complying with CSA C227.4‑21 tank integrity requirements.

2.4 Final Assembly

Final assembly includes separable insulated high‑voltage connectors (dead‑front, radial feed), resin‑cast low‑voltage spade terminals, a no‑load tap changer (±2×2.5%), three bayonet fuses, three ELSP fuses, and a two‑position load break switch. The external finish is a single‑component, isocyanate‑free acrylic paint in Equipment Grey, which is environmentally friendly and weather‑resistant. Key highlights: top oil thermometer with two sets of contacts (redundant alarm or remote temperature signal), and Kirk‑key interlock system for enhanced operational safety. All mechanical and electrical connections are double‑checked against drawings, and the assembly complies with CSA C227.4‑21 requirements for terminals, grounding devices, and safety markings.

03 Testing

All routine tests are performed according to CSA C227.4‑21 and CSA C802.1‑13, covering resistance measurement, ratio, phase relation, no‑load loss, load loss / impedance / efficiency, applied voltage, induced voltage, leak test, insulation resistance, and oil tests. Key results: no‑load loss 1110W, load loss 8501W (85°C), impedance 5.96%, efficiency 99.19%, ratio deviation -0.07~+0.09%, insulation resistance HV&LV to ground 25.0GΩ, oil dielectric strength 65.4kV, moisture 12.1 mg/kg, dissipation factor 0.103%, and dissolved gas analysis with total hydrocarbon 0.57μL/L and C₂H₂ = 0. All tests passed without breakdown or leakage, proving electrical strength and insulation reliability well above guaranteed values.

04 Packing and Shipping

4.1 Packing

Packing is designed for export shipment: all separable HV connectors, LV terminals, tap changer handle, and oil level gauge are protected with industrial stretch film and dedicated caps; oil valves and filler ports are sealed with threaded protective plugs, and tap positions are clearly marked. The transformer is securely fastened to a heavy steel‑reinforced wooden skid with cushioning material on the sides and steel strapping. Overall dimensions and total weight follow the drawing, and the wooden crate is fumigated/heat‑treated, rainproof and moisture‑proof, ensuring no damage, leakage, or corrosion during long‑distance transport and multiple handling.

4.2 Shipping

The transformer is shipped in a 40‑foot high‑cube container or as breakbulk, with a final visual inspection and checklist of accessories (including oil thermometer, Kirk‑key, nameplate, etc.) before loading. It is kept upright and well‑secured to avoid shock during transit. The shipment includes the complete factory test report, certificate of conformance, installation and maintenance manual, and a statement of CSA standard compliance. A quality control release and, if required, third‑party survey are performed before dispatch. All documents are sent together with the goods to ensure smooth receipt and acceptance at the customer site.

05 Site And Summary

In summary, this 750kVA ground loop transformer fully matches the contract parameters in design, manufacturing, testing, packing and shipping, and strictly complies with CSA C227.4‑21 and CSA C802.1‑13. Key test results – no‑load loss, load loss, impedance, efficiency, and insulation performance – are excellent, thoroughly verifying reliability. Quality is ensured by CRGO core precision stacking, CNC copper winding, hot oil circulation with vacuum filling, and 100% routine testing. Manufacturing highlights include an environmentally friendly isocyanate‑free acrylic paint (Equipment Grey), a top oil thermometer with two sets of contacts, a Kirk‑key interlock system, and optional accessories. The transformer meets all North American safety and efficiency requirements for pad‑mounted distribution transformers and is ready for reliable service.