Technical Specifications
| Parameter | Value |
|---|---|
| Model | SZ20-8000/120 |
| Product Code | 1ZX.710.8802 |
| Rated Capacity | 8000/8000 kVA |
| Voltage Combination | 120±8×1.25%/10.5 kV (17-position OLTC) |
| Vector Group | YNd11 |
| Cooling Method | ONAN / 100% |
| Phases / Frequency | 3-Phase, 50 Hz |
| Service Condition | Outdoor |
| Impedance Voltage | 10% |
| Load Loss / No-Load Loss | 37.86 kW / 6.15 kW |
| No-Load Current | 0.51% |
| Insulation Level — HV | LI/AC 480/200 kV |
| Insulation Level — HV Neutral | LI/AC 325/140 kV |
| Insulation Level — LV | LI/AC 75/35 kV |
| Total Weight | 27.8 t (22.9 t oil-filled transport / 17.5 t N₂-filled transport) |
| Standard Codes | GB1094.1, 2-2013; GB1094.3-2017; GB/T6451-2023; GB20052-2024 |
This unit complies with GB20052-2024 as standard. Zhongxin General can also produce Grade 1 energy efficiency versions upon request, with technical standards equivalent to or higher than COMMISSION REGULATION (EU) No 548/2014 and Commission Regulation (EU) 2019/1783 of 1 October 2019. As a manufacturing factory, we also offer aluminium winding as an alternative to the standard copper winding configuration.
An OLTC Transformer at 120kV Class — What Sets 8000 kVA Apart
At 8000 kVA and 120kV class, the SZ20-8000/120 sits well above standard distribution capacity. The on-load tap changer allows voltage regulation under full load without any interruption to supply — essential for industrial and power-station applications where downtime is not an option. The 17-position tap range (120±8×1.25%) gives wide adjustment capability to accommodate grid voltage fluctuations at this class. Every image below documents this specific 8000 kVA unit through production — not a different capacity substituted to represent it.
At this capacity, final assembly requires coordinated teamwork rather than a single technician — tank fitting, bolt torque verification, and enclosure alignment are checked in sequence before the unit proceeds to testing.
Completed Unit
The finished 8000 kVA unit is difficult to appreciate in photographs alone — the scale only becomes clear standing next to it. The three tall composite HV bushings, the conservator tank on the left, and the corrugated tank body together form a unit built for decades of outdoor 120kV-class service.
HV Side & Bushing Detail
The three HV bushings use composite silicone rubber insulators, chosen for superior anti-pollution flashover performance versus porcelain in outdoor installations, along with lighter weight and better mechanical resilience during transport and handling.
Bushing turret assemblies are prepared and quality-checked as standalone components before final mounting — a stage most suppliers never photograph, since it requires disassembling or interrupting a production run to document.
OLTC & Control Systems
The motor drive mechanism executes tap changes automatically or manually via the operating handle, with the position dial giving a clear local indication at all times. This mechanism is what allows the SZ20-8000/120 to regulate output voltage under full load — the defining feature separating an OLTC transformer from a fixed-tap unit.
The stainless steel control cabinet houses the terminal wiring for protection devices, monitoring instruments, and the tap-changer control circuit. Clean, labeled cable routing at this stage directly affects long-term maintenance ease and fault-finding speed on site. The nitrogen cylinder supports the nitrogen-sealed conservator option — recommended for long-distance sea freight to prevent oil oxidation and moisture ingress during transit.
Packing & Dispatch
Every 8000 kVA transformer we dispatch has completed the full routine test programme, with accessories packed separately in export-grade wooden crates and full documentation prepared before the unit leaves the factory bound for port.
Why Zhongxin General — Our Advantages Over Other Suppliers
Real product photographs of the actual 8000 kVA unit. Every image on this page documents this specific SZ20-8000/120 transformer through production — from tank assembly to HV bushing installation to final dispatch. This is fundamentally different from suppliers who substitute photographs of larger-capacity dry-type transformers to represent oil-immersed products they haven’t actually built at this capacity and type. What you see here is what left our factory.
Complete capacity-range production tooling. Zhongxin General holds production tooling covering the full oil-immersed transformer range — 30 kVA to 100 MVA — including OLTC configurations at 120kV class. The 8000 kVA unit is built with purpose-matched tooling, not adapted from a different capacity, giving consistent dimensional precision and predictable delivery timelines.
OLTC engineering in-house. On-load tap-changer integration, motor mechanism calibration, and full-load voltage regulation testing are all performed at our Sichuan facility — not outsourced to a third-party OLTC supplier for final assembly.
Full in-house manufacturing cycle. Winding, active-part assembly, insulation drying, oil treatment, tank fabrication, bushing installation, and factory acceptance testing all take place on one site.
All energy efficiency grades available. Standard and Grade 1 versions can be supplied to GB20052-2024, with Grade 1 units meeting and exceeding EU Commission Regulation No. 548/2014 and 2019/1783 requirements for international projects.
Copper and aluminium winding both available. As a manufacturing factory rather than a trading company, we can configure either winding material to match project budget and specification.
Full routine testing, every unit, test report as standard. No transformer leaves our factory without passing the complete routine test programme, documented and issued as standard order documentation — not provided only on request.
Applicable Standards & Testing
Routine tests (every unit): winding resistance measurement; voltage ratio and vector group verification; no-load loss and no-load current; load loss and short-circuit impedance; induced overvoltage withstand test; separate-source AC withstand test; on-load tap changer operation test.
Type tests (reports available on request): temperature rise test; lightning impulse test.
Special tests (available on request): partial discharge measurement; sound level (noise) measurement; short-circuit withstand test.
All tests are conducted to IEC 60076 and GB1094 / GB/T 6451. Factory Acceptance Test (FAT) with client witness is supported.
Available Options & Configurations
- Winding material: copper (standard) or aluminium
- Voltage class: HV customizable to match local grid standards
- Frequency: 50 Hz (standard) or 60 Hz
- Energy efficiency grade: GB20052-2024 standard or Grade 1
- Tap changer: on-load (OLTC) as standard on this model
- Conservator sealing: oil-filled (standard) or nitrogen-sealed for long-distance sea freight
- Export wooden crating with full documentation package
Typical Applications
The 8000 kVA 120kV-class OLTC transformer is specified for industrial production bases, power station step-down applications, mining and heavy-industry supply, and any project requiring stable voltage regulation under full load at this capacity — where fixed-tap transformers cannot meet grid voltage variation requirements.
Inquire About 8000 kVA OLTC Transformer
Need a quotation, technical datasheet, or Factory Acceptance Test arrangement? Tell us your grid voltage, required LV output, frequency, efficiency grade, and installation conditions — and we will configure the right unit for your project.
Contact Us for Price & Datasheet
About Zhongxin General — Oil-Immersed Transformer Manufacturer & Factory
Zhongxin General (Sichuan Zhongxin General Electric Energy Co., Ltd.) is a China-based manufacturer and factory specialising in oil-immersed power transformers and dry-type power transformers, HV/MV/LV switchgear, prefabricated substations, and energy storage systems.
Headquartered in Xinjin District, Chengdu, Sichuan Province, the company holds National “Little Giant” Enterprise status alongside National High-Tech Enterprise certification. Our oil-immersed transformer portfolio covers 30 kVA to 100 MVA, including OLTC configurations at 120kV class, in both GB and IEC standard configurations. Every transformer undergoes full routine testing before dispatch, with test reports issued as standard documentation.
Browse all case studies — including our 8000kVA 120kV OLTC transformer exported to DR Congo — and company news to evaluate Zhongxin General as a supplier.
