Pad-mounted Transformer Product Introduction

1. Product Brief Introduction

The Pad-mounted Transformer (also known as American-style substation) is an integrated outdoor prefabricated power distribution equipment designed in accordance with North American IEEE standards. It adopts a "high-voltage switch + transformer + low-voltage power distribution" highly compact structure, with core components including oil-immersed distribution transformer, low-voltage circuit breaker, lightning protection device, and metering module integrated and installed directly on outdoor pads. The equipment features an integrated, outdoor-type, small-footprint, and standardized design, with a compact structure, high reliability, and stable and reliable operation. It is widely used in outdoor distributed power distribution scenarios such as urban power grids, industrial parks, commercial facilities, etc., and is an ideal outdoor power distribution equipment for commercial, industrial, residential, and infrastructure scenarios across North America and the globe.

2. Scope of Application

• Urban power grid: Outdoor distributed power distribution in urban trunk roads, residential communities, municipal green belts, and street power distribution stations, adapting to refined urban construction.
• Industrial and commercial scenarios: Outdoor supporting power distribution in industrial parks, manufacturing plants, commercial complexes, and shopping centers, supporting production and commercial load power supply.
• Infrastructure supporting: Independent power distribution in highway service areas, gas stations, sewage treatment plants, and communication base stations, adapting to remote/independent load supply.
• Residential community power distribution: Outdoor centralized power distribution in residential districts, villa groups, and small town areas, replacing traditional civil-built power distribution rooms.
• Temporary power supply scenarios: Temporary power supply for construction projects, event venues, and emergency backup power supply (movable type available).
• Voltage level configuration: 12kV/24kV/34.5kV high-voltage incoming lines (mainstream North American power grid voltage), 208V/480V low-voltage outgoing lines (North American standard low-voltage level), covering a capacity range of 50kVA-2500kVA.

3. Model Definition (Compiled in Accordance with IEEE Standards, Aligned with American Design Characteristics)

The model number of American-style substation follows North American IEEE standards and industry practices, compiled in the format of "voltage level + capacity + structure type + function expansion". The core model such as PM-34.5/480-1000-OL, with each part defined in line with American equipment labeling habits:

• PM: Pad-mounted Transformer (exclusive code for American-style substation, meaning "pad-mounted transformer"), installed directly on outdoor pads.
• 34.5/480: Rated voltage, 34.5kV (mainstream North American medium voltage)/12kV/24kV on the high-voltage side, 480V/208V (North American standard) on the low-voltage side, voltage unit in kV/V.
• 1000: Rated capacity of the main transformer, unit kVA, common specifications include 50/100/250/500/750/1000/1500/2500kVA.
• Structural type code: OL - Oil-immersed load switch type (mainstream), VCB - Vacuum circuit breaker type, M - Mobile type, S - Sealed type.
• Function expansion code: M - Metering type, P - Protection enhanced type, R - Remote control type, C - Anti-corrosion type, marked for exclusive functions.

4. Working Conditions

4.1 Environmental Conditions (Adapted to North American Outdoor Climate)

• Ambient temperature: -40℃~+55℃ (temperature-designed), withstanding extreme cold and high temperature climates in North America.
• Relative humidity: ≤95% (at 25℃), allowing short-term condensation with built-in anti-condensation device.
• Altitude: ≤1500m (mainstream North American configuration), customizable for altitude >1500m.
• Installation environment: Outdoor open fields, green belts, sidewalk edges, withstanding rain, snow, wind and sand, salt spray (anti-corrosion type optional for coastal areas).
• Vibration requirements: Withstanding transportation and road vehicle vibration (acceleration ≤2g), with anti-vibration base for the cabinet.
• Pollution level: Class III (in accordance with IEEE C57.12.00 pollution grade standard), adapting to industrial dust environments.

4.2 Electrical Working Conditions (Aligned with North American Power Distribution Norms)

• Power frequency: 60Hz (North American standard frequency), compatible with 50Hz (customizable).
• Voltage fluctuation: ±10% on high-voltage side, ±5% on low-voltage side, adapting to North American power grid voltage characteristics.
• Load characteristics: Adapting to commercial resistive loads, industrial inductive loads, and residential mixed loads, supporting long-term full-load operation.
• Installation method: Outdoor direct pad installation (no civil foundation required, installed on gravel/concrete pads), installation site flatness ≤5mm/m.
• Implementation standards: Complying with IEEE C57.12.00 (transformer standard), IEEE C37.74 (switch standard), UL 1558 (power distribution equipment standard), NEC (American National Electrical Code).

5. Main Technical Parameters

5.1 Core Structure & High Voltage Parameters (North American Standard Configuration)

• Core structure: Integrated design of high-voltage switch + transformer + low-voltage power distribution, with tank and cabinet integrated, no independent high-voltage chamber.
• Rated high-voltage: 12kV/24kV/34.5kV (IEEE C57.12.28 standard), rated current: 200A/400A/630A.
• High-voltage switch type: American-style oil-immersed load switch (OL) / vacuum circuit breaker (VCB), with fuse protection, supporting manual operation.
• Short-circuit breaking capacity: 12.5kA/16kA (10s), complying with IEEE C37.74 standard.
• Grounding mode: Neutral ungrounded / grounded via arc suppression coil (North American standard configuration).
• Lightning protection: Class I surge protection device (SPD) on high-voltage side, nominal discharge current ≥60kA.

5.2 Transformer Part (American-style Special Oil-immersed Design)

• Type: Hermetically sealed oil-immersed transformer (complying with IEEE C57.12.00 standard), fully sealed structure, maintenance-free.
• Rated capacity: 50kVA-2500kVA, connection group: Dyn11/Yyn0 (North American common).
• Impedance voltage: 4%~6% (12kV side), 6%~8% (24kV/34.5kV side).
• Insulation grade: Class A (oil-immersed standard), temperature rise limit: top oil temperature ≤65K, winding ≤80K.
• Cooling method: Natural cooling (ONAN), large-capacity models can be forced air cooling (OFAF).
• Tank material: Cold-rolled steel plate, sealed structure, with oil level gauge, pressure relief valve, service life ≥25 years.
• Noise level: ≤55dB (1m from the cabinet), complying with North American environmental noise standards.

5.3 Low Voltage Parameters (North American Standard Low Voltage Configuration)

• Rated voltage: 208V/480V (three-phase), 120V/240V (single-phase), complying with North American NEC standard.
• Rated current: 400A/630A/1250A/2000A.
• Rated short-circuit breaking capacity: 25kA/50kA (complying with UL 489 standard).
• Outgoing circuits: 4-12 circuits (customizable), switch configuration: American-style molded case circuit breaker (MCCB), with overload and short-circuit protection.
• Metering function: Built-in North American standard intelligent meter (complying with ANSI C12.20 standard), supporting time-sharing metering and data remote transmission.
• Protection grade: IP44 for low-voltage chamber, IP54 for the whole cabinet (outdoor waterproof and dustproof).

5.4 Cabinet & Auxiliary Parameters

• Cabinet material: Carbon steel/Q235 cold-rolled steel plate, surface treated with sandblasting + electrostatic spraying + anti-UV coating, thickness ≥3.0mm.
• Cabinet structure: Integrated sealed design, with ventilation louvers, rainproof cover, anti-theft door lock, suitable for unattended outdoor use.
• Auxiliary configuration: Built-in oil level monitoring, oil temperature alarm, anti-condensation heating device, optional remote control module.
• Installation size: Compact design, floor area ≤3.5㎡, height ≤2.3m, weight ≤5000kg (1000kVA model).

6. Performance Characteristics

• Integrated compact design, minimal footprint: High-voltage switch, transformer, and low-voltage power distribution are integrated into a single cabinet with no independent high-voltage chamber, occupying only 60% of the area of traditional substations. It can be directly installed in green belts and sidewalks, perfectly adapting to urban small spaces.
• Fully sealed and maintenance-free, optimized operation: The transformer adopts an American-style fully sealed structure with oil-free design, achieving lifelong free oil change; the high-voltage switch is maintenance-free, and the low-voltage chamber is waterproof and dustproof, with an overall maintenance-free period ≥10 years, greatly reducing operation and maintenance costs.
• North American standard compliance, localized adaptation: Fully compliant with IEEE, UL, NEC and other North American core standards, with voltage levels, frequency, and interfaces meeting North American power grid requirements, enabling direct access to North American power grids without modification.
• Weatherproof protection, all-round safety: The cabinet has IP54 protection grade, with anti-UV, anti-corrosion, and anti-salt spray treatment, withstanding extreme climates of -40℃~+55℃, adapting to diverse climates and industrial/commercial complex environments in North America.
• Fast and convenient installation, high efficiency: No civil foundation required, direct outdoor pad installation, factory pre-assembly and commissioning completed, on-site commissioning in 1-2 days, greatly shortening the power distribution project cycle.
• Upgraded safety protection, reliable operation: Double protection of high-voltage load switch + fuse, low-voltage overload/short-circuit protection, anti-theft cabinet sealing, and explosion-proof design of transformer pressure relief valve, providing all-round protection for equipment and personnel safety.
• Compatible with intelligent expansion, modern operation: Supporting North American standard remote control modules (complying with ANSI C12.18 standard), realizing remote monitoring of voltage, current, power, oil temperature and other parameters, adapting to smart grid upgrade needs.
• Robust and durable structure, long service life: The cabinet is made of thick steel plate with fully sealed transformer design, core components are selected from North American certified products, shock-resistant and corrosion-resistant, with a service life ≥25 years, far exceeding industry average levels.
• Flexible customization, wide application: Voltage levels, capacity, and outgoing circuits can be customized on demand, supporting North American low-voltage specifications such as 208V/480V, adapting to power distribution needs of commercial, industrial, residential, and infrastructure scenarios.
• Significant cost advantage, maximized cost-effectiveness: Integrated design reduces redundant components, with civil construction and maintenance-free features lowering long-term investment; the overall procurement and operation cost is 20%~30% lower than traditional power distribution equipment, with outstanding cost performance.