Huanghua Group Co., Ltd. 
YB27-40.5 New energy Pad mounted Transformer
Product Overview
Huanghua Group’s HKYB27 series Pad-Mounted Transformer is a fully factory-assembled, outdoor-rated power distribution unit integrating MV switching equipment (LBS), oil-immersed transformer, and LV switchgear (ACB/MCCB) within a single sealed enclosure. Engineered with a low-profile, tamper-resistant design featuring no externally accessible bolts, hinges, or fasteners, the unit provides a self-contained, maintenance-free solution requiring no perimeter fencing or additional protective structures.
Available up to 40.5kV, 1600kVA (YB27-12) and 40.5kV, 2000kVA (YB27-40.5), the pad-mounted transformer delivers reliable power distribution for urban high-rise buildings, residential communities, small-to-medium industrial facilities, commercial complexes, and infrastructure projects. The proven design combines compact footprint, reduced installation cost, and enhanced public safety—making it the preferred choice for space-constrained urban environments.
All units are designed and manufactured in accordance with IEC 60076, with base configuration compatible with ANSI-IEC-DIN mounting centerlines, qualifying the product for global EPC procurement and utility tenders.
General Specifications
| Parameter | YB27-12 Series | YB27-40.5 Series |
| Rated Power Range | 30 – 1600 kVA | 50 – 2000 kVA |
| HV Voltage Class | 6.3kV / 10kV / 11kV | 33kV / 34.5kV / 35kV / 38.5kV |
| LV Voltage | 400V / 690V (customizable) | 400V / 690V (customizable) |
| Frequency | 50Hz / 60Hz (optional) | 50Hz / 60Hz (optional) |
| Tap Changer | ±2×2.5% Off-Load Tap Changer (±5% optional) | ±2×2.5% Off-Load Tap Changer (±5% optional) |
| Vector Group | Dyn11 / Yyn0 | Dyn11 / Yyn0 |
| Cooling | ONAN | ONAN |
| Winding Material | Copper standard; Aluminum optional | Copper standard; Aluminum optional |
| Avg. Temperature Rise | 65°C (55°C / 60°C optional) | 65°C (55°C / 60°C optional) |
| Noise Level | ≤ 55 dB | ≤ 55 dB |
| Protection Degree | Weather-resistant cabinet, tamper-proof latching | Weather-resistant cabinet, tamper-proof latching |
| Enclosure Features | No external bolts/hinges/screws; 3-point terminal compartment locking | No external bolts/hinges/screws; 3-point terminal compartment locking |
| Applicable Standards | IEC 60076 · ANSI · IEC · DIN | IEC 60076 · ANSI · IEC · DIN |
| Compliance | ISO 9001:2015 | ISO 9001:2015 |
Technical Performance Data
YB27-12 (up to 12kV)
| Rated Power (kVA) | HV (V) | LV (V) | No-Load Current (%) | No-Load Loss (W) | Load Loss @120°C (W) |
| 30 | 6000 / 6300 / 10000 / 11000 | 400 / 690 | 2 | 100 | 630 |
| 50 | — | — | 1.8 | 130 | 910 |
| 63 | — | — | 1.5 | 150 | 1090 |
| 80 | — | — | 1.2 | 180 | 1310 |
| 100 | — | — | 1.1 | 200 | 1580 |
| 125 | — | — | 1 | 240 | 1890 |
| 160 | — | — | 0.8 | 280 | 2310 |
| 200 | — | — | 0.7 | 340 | 2730 |
| 250 | — | — | 0.7 | 400 | 3200 |
| 315 | — | — | 0.6 | 480 | 3830 |
| 400 | — | — | 0.6 | 570 | 4520 |
| 500 | — | — | 0.6 | 680 | 5410 |
| 630 | — | — | 0.5 | 810 | 6200 |
| 800 | — | — | 0.5 | 980 | 7500 |
| 1000 | — | — | 0.5 | 1150 | 10300 |
| 1250 | — | — | 0.85 | 1360 | 12000 |
| 1600 | — | — | 0.85 | 1640 | 14500 |
HKS11 series losses shown. Lower-loss solutions available on request.
YB27-40.5 (up to 40.5kV)
| Rated Power (kVA) | HV (V) | LV (V) | No-Load Current (%) | No-Load Loss (W) | Load Loss @75°C (W) |
| 50 | 33000 / 34500 / 35000 / 38500 | 400 / 690 | 1.3 | 160 | 1200 |
| 100 | — | — | 1.1 | 230 | 2010 |
| 125 | — | — | 1.1 | 270 | 2370 |
| 160 | — | — | 1 | 280 | 2820 |
| 200 | — | — | 1 | 340 | 3320 |
| 250 | — | — | 0.95 | 400 | 3950 |
| 315 | — | — | 0.95 | 480 | 4750 |
| 400 | — | — | 0.85 | 580 | 5740 |
| 500 | — | — | 0.65 | 680 | 6910 |
| 630 | — | — | 0.65 | 830 | 7860 |
| 800 | — | — | 0.65 | 980 | 9400 |
| 1000 | — | — | 0.6 | 1150 | 11500 |
| 1250 | — | — | 0.6 | 1400 | 13900 |
| 1600 | — | — | 0.55 | 1690 | 16600 |
| 2000 | — | — | 0.85 | 1990 | 19700
|
HKS11 series losses shown. Lower-loss solutions available on request.
Compartment Configuration
1 HV Compartment (Left Side)
Primary Entrance: Live front cast resin bushings or dead front configuration (optional)
Tap Changer: Off-load tap changer for HV voltage adjustment
Fuse Protection: HV current-limiting fuse for transformer fault protection
Load Switch (LBS): Optional load break switch for circuit isolation
Grounding Point: Dedicated grounding terminal
Oil Drain Valve: Accessible from HV compartment
2 Transformer Compartment (Center)
Core & Coil: Low-loss grain-oriented silicon steel core; copper winding standard
Liquid Preservation System: Sealed tank with conservator or fully-sealed design
Insulation Oil: Thermally upgraded insulating oil
Pressure Relief Valve: Automatic pressure relief under fault conditions
Oil Level Gauge: Visual indication of oil level
Oil Thermometer: Dial-type thermometer for temperature monitoring
Sudden Pressure Surge Relay: Optional protection device
Radiator: Natural convection cooling; radiator valves for maintenance isolation
3 LV Compartment (Right Side)
LV Switchgear: ACB and/or MCCB provisions per customer specification
Power Compensation: Capacitor bank for reactive power correction (optional)
Metering: Energy meter and CT/PT measurement provisions
Three-Point Terminal Latching: Tamper-resistant locking mechanism preventing unauthorized access
CTs & PTs: Current and voltage transformers for protection and metering
Outline Dimensions (mm)
YB27-12 Series
| Rated Power (kVA) | A | B | C | D | E | F | H |
| 100 – 250 | 2400 | 1650 | 1350 | 800 | 650 | 1610 | 1450 |
| 315 | 2400 | 1650 | 1250 | 800 | 600 | 1560 | 1450 |
| 400 – 500 | 2400 | 1750 | 1450 | 800 | 650 | 1640 | 1550 |
| 630 | 2400 | 1750 | 1550 | 800 | 700 | 1730 | 1550 |
| 800 | 2400 | 1850 | 1550 | 800 | 700 | 1790 | 1650 |
| 1000 | 2400 | 1850 | 1650 | 800 | 700 | 1790 | 1650 |
Dimensions subject to final engineering drawing confirmation.
Engineering Options & Accessories
| Category | Available Options |
| Winding Temperature Rise | 55°C / 60°C / 65°C (standard) |
| Primary Entrance | Dead front / Live front |
| Basic Impulse Level | Adjustable on request |
| Monitoring Devices | Dial thermometer / Liquid level valve / Pressure vacuum gauge / Radiator valves |
| Protection Devices | Sudden pressure surge relay / Pressure relief valve |
| Transformer Options | Lower loss core & coil / Non-standard HV taps / Special impedance / Special noise levels / Electrostatic shields |
| LV Configuration | Reactive power compensation / Energy metering / Custom LV panel types |
| Environmental Adaptations | Special ambient conditions / High-altitude versions (>1000m) / Coastal anti-corrosion coating |
| Paint Finishes | Standard RAL 7035; custom RAL colors available |
| Mounting Base | Designed for rolling in accordance with ANSI-IEC-DIN segment center lines |
Key Features
Tamper-Resistant Security — No externally accessible bolts, hinges, screws, or fasteners. Three-point terminal compartment latching prevents unauthorized access without requiring perimeter fencing.
Fully Factory Assembled — Shipped as a single integrated unit with lifting lugs pre-installed. Single-piece transport and placement eliminates on-site assembly.
Low-Profile Urban Design — Compact footprint suitable for sidewalks, green belts, residential courtyards, and other space-constrained locations without obstructing sightlines.
Weather-Resistant Construction — Bolted weather-resistant cabinet protects internal components from rain, dust, UV, and environmental contaminants.
Maintenance-Free Operation — Sealed tank design with liquid preservation system requires no routine oil maintenance. Reduced lifecycle costs compared to conventional substations.
Flexible Configuration — Independent HV/LV compartments allow customization of switching equipment, protection schemes, and LV distribution to match project requirements.
Global Standard Compatibility — Base design aligns with ANSI-IEC-DIN mounting centerlines, supporting deployment across North American, European, and international markets.
Applications
| Sector | Recommended Configuration | Rationale |
| Residential Communities | YB27-12, 315–800 kVA | Low profile, tamper-resistant, minimal visual impact |
| Urban High-Rise Buildings | YB27-12, 630–1250 kVA | Compact footprint, indoor/outdoor flexible placement |
| Commercial Complexes | YB27-12 / YB27-40.5, 800–1600 kVA | Reliable power distribution, low maintenance |
| Small & Medium Industrial Plants | YB27-40.5, 1000–2000 kVA | Higher voltage class reduces transmission losses |
| Infrastructure (Airports, Railways, Docks) | YB27-40.5, 1250–2000 kVA | Robust construction, weather-resistant |
| Green Belts & Parks | YB27-12, 100–630 kVA | Aesthetic integration, no perimeter fencing required |
| Utility Distribution Networks | YB27-12 / YB27-40.5 | ANSI-IEC-DIN compatible mounting |
