500 Kva Dry Type Transformer

The 500 kVA Dry Type Transformer functions as the critical node for medium-sized infrastructure, seamlessly bridging the gap between utility grids and building utilization voltages. Unlike smaller branch units, this capacity typically serves as the Main Incoming Transformer for office towers, shopping complexes, or data center IT rows.

As a versatile medium voltage dry type transformers solution, it is engineered to accept primary inputs up to 35kV (commonly 11kV or 13.8kV). By installing this unit directly within the building's load center-rather than in a remote outdoor substation-facility managers can significantly reduce low-voltage cabling costs and distribution losses.

When selecting from various types of dry type transformer, the choice often dictates the unit's environmental resilience. We offer this 500 kVA model in two distinct configurations:

• Cast Resin (CRT): Our standard recommendation for general indoor use. The HV windings are vacuum-cast in a solid epoxy block filled with silica. This structure is F1 Fire Rated (self-extinguishing) and impervious to moisture, making it ideal for basements or humid areas.
• VPI (Vacuum Pressure Impregnated): An alternative "open-wound" design using Class H varnish. This option is lighter and allows for easier recycling at the end of life, often preferred for green building certifications or retrofits with strict weight limits.

Beyond standard step-down duties, this unit is frequently deployed as a dry type step up transformer.

• Application: It is perfectly sized to connect 400kW-500kW rooftop solar arrays or natural gas cogeneration engines (CHP) to the 11kV medium voltage grid.
• Engineering: In this "reverse" mode, the transformer is designed with low inrush current geometry and reinforced insulation on the secondary side to handle the voltage spikes typical of inverter-based generation sources.

Technical Parameter	Specification / Options
Rated Power	500 kVA
Primary Voltage	4160V / 6.6kV / 11kV / 33kV
Secondary Voltage	400V / 480V / 600V
Technology	Cast Resin (Standard) or VPI (Option)
Insulation Class	Class F (155°C) or Class H (180°C)
Cooling	AN (Natural) / AF (Forced Air adds ~40%)
Enclosure	IP23 (Standard Indoor)
Efficiency	Compliant with IEC 60076-20 (Tier 1 / Tier 2)
Vector Group	Dyn11 (Standard)

• Protection Logic: The unit comes equipped with PT100 sensors embedded directly into the hottest spot of the LV windings. These link to a relay that executes a staged response based on Class F limits: Alarm at 130°C (warning operators), Fan Start at 140°C (if equipped), and Trip at 155°C (disconnecting the load to prevent insulation damage).
• Maintenance Reality: Unlike oil units that require dielectric fluid sampling and gas analysis, this solid-state unit removes these variables. Maintenance is strictly mechanical: checking bolt torque and vacuuming dust from the air channels, drastically simplifying facility management schedules.

• Commercial Incomer: Delivering approximately 720 Amps of continuous power, it is the standard specification for powering a typical 10,000 m² office building or a mid-sized data hall.
• Retrofit Projects: Specifically designed to fit through standard double-doors, making it the ideal replacement for aging, hazardous Askarel (PCB) filled transformers in older basement substations without requiring wall demolition.
• Distributed Generation: Acting as the grid-tie point for commercial rooftop solar installations, stepping up 400V inverter output to the 11kV distribution network.

Every  500 kVA Dry Type Transformer is 100% factory tested before shipment, covering:

- Voltage ratio & tap changer verification - ratio tolerance within ±0.5%

- DC winding resistance test - measured at controlled ambient temperature

- Insulation resistance & dielectric withstand test - IR >1000 MΩ @ 1000V

- Performance test - no-load loss, load loss, impedance voltage verified against rated tolerances

- Partial discharge test - controlled to ≤ 4pC across all phases

All testing is conducted per GB1094.11-2022 and GB/T10228-2023.

In March 2025, 2 units of 500 kVA dry type transformers were directly exported to an industrial park project in Qatar. Dry type units are the preferred choice for this type of installation in the region - the epoxy cast resin construction eliminates oil leakage risk and requires no fire-rated bunding, which simplifies compliance for enclosed substations in high-ambient-temperature environments.