Long-distance Power Transmission
Since its establishment, Kerun has focused on the R&D and manufacturing of large power transformers. Backed by mature processes and a robust quality system, we have delivered extensive projects across multiple voltage levels and application scenarios, ensuring stable and proven engineering capability.
Long-Distance Power Transmission Scenario Overview
Kerun provides integrated solutions for long-distance, cross-regional power transmission and grid interconnection, centered on power transformers and complete substation packages. We cover typical voltage levels 0.4kV / 6kV / 6.3kV / 6.6kV / 10kV / 11kV / 13.8kV / 15kV / 20kV / 22kV / 24kV / 33kV / 35kV / 40.5kV / 66kV / 110kV / 132kV / 220kV, and main transformer capacities 10–240MVA (up to 220kV, 240MVA class; customizable upon project requirements). Our portfolio typically includes power transformers, station service/distribution transformers, packaged substations (European/American type), prefabricated containerized substations, MV switchgear/RMU, LV switchboards, and protection–control–communication systems.
Standards & Key Advantages
Solutions can be engineered to comply with major international standards including IEC 60076 (power transformers), IEC 60214 (tap-changers), IEC 62271 (HV/MV switchgear), IEC 61439 (LV assemblies), and IEC 60529 (IP protection), supported by ISO 9001/14001/45001 management systems, with IEC 61850 digital substation/SCADA integration available when required. With proven engineering experience and robust quality control, Kerun delivers strong advantages in insulation and short-circuit withstand capability, low-loss high-efficiency design, modular fast delivery, and lifecycle-friendly operation & maintenance.
| Product (Bold) | Voltage Coverage (kV) | Typical Rating / Capacity Range (Customizable) |
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| Power Transformer (Step-Up / Step-Down Main Transformer) | HV: 66 / 110 / 132 / 220; MV: 33 / 35 / 22 / 20 / 15 / 13.8 / 11 / 10 / 6.6 / 6.3 / 6 | 10–240MVA (ONAN/ONAF, OLTC/DETC optional) |
| Station Service / Distribution Transformer | LV 0.4 ↔ MV 6–35 | 100kVA–5000kVA (as per auxiliary load) |
| Packaged Substation (European / American Type) | MV 6–40.5 / LV 0.4 | 0.5–10MVA (typical for collection/distribution; project-based) |
| Prefabricated / Containerized Substation | MV 6–40.5 / LV 0.4; configurable for 66–220kV substation systems | Project-based configuration (primary & secondary integrated) |
| MV Switchgear / RMU | 6 / 10 / 11 / 15 / 20 / 22 / 24 / 33 / 35 / 40.5 | Project-specified (rated current & breaking capacity) |
| LV Switchboard Assemblies | 0.4 | Project-specified (rated current, feeders, protection) |
| Protection, Control & Communication System | Adaptable to full station voltage levels | Project-specified (interfaces/protocols; IEC 61850 optional) |
Long-Distance Power Transmission Transformers
Kerun has been deeply engaged in the long-distance power transmission sector for many years, with extensive experience in manufacturing and delivering a large number of power transformers across multiple voltage classes, capacity ranges, and application scenarios. We can provide customized design, manufacturing, and testing in accordance with major standards such as IEC 60076, IEEE/ANSI, and GB. By strictly controlling critical parameters—including insulation reliability, short-circuit withstand capability, temperature rise, and losses—we deliver safe, stable, and high-efficiency transmission transformer solutions, supported by full lifecycle services.
Angola National Grid Supply | 180MVA 220kV Three-Phase Five-Limb Power Transformer
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Three-phase five-limb core design: Uniform magnetic flux distribution with improved mechanical rigidity, helping reduce leakage flux, noise, and partial discharge risks—well-suited for long-term utility operation.
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Low-loss & high-efficiency design: Optimized core and winding electromagnetic design to balance no-load and load losses, reducing lifetime operating cost.
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High short-circuit withstand capability: Reinforced clamping and winding support structure to withstand short-circuit electrodynamic forces and transportation/handling stress.
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Wide-range voltage regulation (OLTC optional): Supports stable bus voltage under weak-grid conditions and long-distance transmission voltage fluctuations.
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Tropical/coastal environment readiness: Optional enhanced anti-corrosion coating system, improved sealing and breathing system options for high temperature, humidity, salt mist, and dust.
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Expandable condition monitoring: Interfaces available for top oil temperature, winding temperature, pressure relief, Buchholz relay, bushing monitoring, DGA/online diagnostics (as required).
| Parameter Item | Specifications | Remarks |
|---|---|---|
| Transformer Type | Oil-immersed power transformer, three-phase five-limb | Utility-grade design for long-distance transmission substations |
| Rated Power | 180 MVA | ONAN/ONAF staged rating can be provided if required (e.g., 120/180 MVA) |
| Rated Frequency | 50 Hz | As per Angola grid requirement |
| Phases | Three-phase | |
| HV Rated Voltage | 220 kV | Typical highest voltage Um: 245 kV (project-based) |
| LV/MV Rated Voltage | As per project system voltage | Common options include 60 kV / 33 kV, subject to SLD and specification |
| Cooling Method | ONAN / ONAF | Configured according to ambient temperature and loading profile |
| Voltage Regulation | On-Load Tap Changer (OLTC) (optional) | Tap step, range and number of positions per technical specification |
| Short-Circuit Impedance | Project-specific (typical range 12%–14%) | Final value determined by system short-circuit level and design calculation |
| Insulation Level (LI/BIL) | Project-specific, per IEC 60076 and utility requirement | Defined by grid insulation coordination and specification |
| Applicable Standards | IEC 60076; IEC 60214 (tap-changer) | Additional standards and local requirements supported as per project |
| Management Systems | ISO 9001 / ISO 14001 / ISO 45001 | Quality, environment and OH&S management support |
| Environment Adaptation | Tropical/coastal option available | Enhanced anti-corrosion coating, sealing and moisture protection (optional) |
| Condition Monitoring | Interfaces available (project-based) | Top oil/winding temperature, Buchholz, bushing monitoring, DGA, etc. (optional) |
Kerun Delivery & Service
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Engineering & technical clarification: Fast response for specification review, loss proposal, impedance/insulation coordination, and drawing submission.
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Quality assurance & FAT support: Full routine testing per IEC and contract, with support for customer/third-party inspection and factory acceptance tests (FAT).
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Export-ready packaging & logistics: Seaworthy packing, anti-corrosion/anti-moisture measures, transport securing, and complete documentation pack (test reports, certificates, manuals).
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Spare parts & after-sales: Recommended spares list and responsive service mechanism to ensure reliable operation throughout the lifecycle.
Ukraine Project | 6 × 63 MVA, 150 kV Power Transformers — Practical Highlights, Detailed Parameters & Safe Delivery by Kerun
Product Features
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Built to run “quietly and steadily” on the grid: the core and winding design focuses on stable insulation performance and low partial discharge risk, so the transformer can operate continuously without frequent alarms or nuisance trips.
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Strong mechanical structure for real fault conditions: windings are tightly clamped and braced to resist short-circuit forces; the tank and accessories are arranged to tolerate transport vibration, lifting, and site handling with less risk of deformation or oil leakage.
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Lower losses = lower operating cost: optimized magnetic flux density and winding layout help reduce both no-load and load losses, which directly saves energy cost over years of utility operation.
- Easy installation and maintenance: clear valve layout (drain/filter/sample), accessible marshalling box, straightforward wiring and terminal identification, and maintenance-friendly radiator/fan arrangement (when ONAF is applied).
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Voltage regulation options that match grid reality: OLTC (or DETC) can be configured to keep the bus voltage stable when the network voltage fluctuates, which is common at transmission/distribution interfaces.
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Complete protection & monitoring accessories: standard protective devices (Buchholz relay, pressure relief device, oil/winding temperature indicators, oil level gauge) plus optional online monitoring (DGA, bushing monitoring) to support condition-based maintenance.
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Export-ready and site-ready design: bushings and sensitive accessories can be shipped separately in reinforced cases; moisture control and corrosion protection are applied for long-distance transport and outdoor installation.
| Parameter Item | Specifications | Remarks |
|---|---|---|
| Project / Quantity | Ukraine / 6 Units | Batch supply with unified design, drawings and documentation |
| Transformer Type | Oil-immersed power transformer | Designed for transmission/distribution substation duty |
| Rated Power | 63,000 kVA (63 MVA) | Staged rating available if required (e.g., ONAN/ONAF) |
| Cooling Method | ONAN (standard) / ONAF (optional) | Fan control and staging per contract |
| Phases | 3 Phase | |
| Frequency | 50 Hz | As per Ukraine grid requirement |
| HV Rated Voltage | 150 kV | 150 kV class; highest voltage Um typically 170 kV |
| HV Rated Current (Approx.) | ≈ 242 A | Calculated at 63 MVA / (√3 × 150 kV) |
| LV Rated Voltage | As per project SLD | Typical applications may be 150/35 kV or 150/20 kV (final per contract) |
| Vector Group | As per project/utility specification | Common utility practice: YNd11 / YNyn0 (final per system design) |
| Tap Changer | OLTC (optional) / DETC (optional) | Type and location (HV/MV) per contract |
| Tapping Range / Step | Project-specific | Typical OLTC options: ±10% or ±8×1.25% (17 positions), as required |
| Short-Circuit Impedance | Project-specific (typical 10%–14%) | Set by system fault level and design calculation |
| Guaranteed Losses | As per loss schedule / tender requirement | No-load loss and load loss to be guaranteed in contract documents |
| HV Insulation Level (Typical) | Um 170 kV: LI/AC = 750/325 kV | Typical IEC practice for Um 170 kV class (final per utility spec) |
| Temperature Rise Limits | As per IEC 60076 / contract | Typical practice: top oil / winding rise per agreed limits |
| Insulation System | Oil-paper, Class A (105°C) | Proven insulation system for long-term utility operation |
| Oil Type | Mineral insulating oil (standard) | Alternative fluids available upon request and approval |
| Oil Preservation | Conservator type | Breather/moisture control options per project |
| Core & Winding Design | Optimized low-loss core + robust winding bracing | Designed for low loss and high short-circuit withstand capability |
| Standard Accessories | Buchholz relay, PRD, OTI/WTI, oil level gauge, marshalling box | Plus valves for filling/draining/sampling and earthing terminals |
| Optional Monitoring | Online DGA, bushing monitoring, temperature/pressure trending | Selectable for condition-based maintenance strategy |
| Painting / Corrosion Protection | Export-grade coating system | Configured for transport duration and site environment |
| Applicable Standards | IEC 60076 (Transformer), IEC 60214 (Tap-changer) | Additional project/utility standards supported as required |
| Factory Testing | Routine tests per IEC 60076; additional tests as specified | FAT witness by customer/third party supported |
Inside Quality Matters — Built for Long-Term Reliable Operation
At Kerun, a transformer’s value is not only in its appearance, but in the details you can’t see after energization. From the active part assembly (core & windings) to lead routing and insulation finishing, we use solid materials and disciplined workmanship: carefully wrapped insulation, tidy and well-supported conductors, reinforced clamping structures, clean and controlled assembly areas, and strict torque/process checks at every key step. Each unit then goes through vacuum drying, oil processing and comprehensive factory testing to verify performance before shipment. This “inside-first” quality philosophy—supported by skilled workers and rigorous process control—provides strong assurance for stable, long-life operation under real grid conditions.
Kerun Service — Safe Delivery Workflow (Designed for “Arrive Intact, Ready to Energize”)
Transport feasibility review (before shipment): confirm lifting points, transport dimensions/weight constraints, road/bridge limits, port handling capability, and site unloading conditions—then issue a clear method statement.
Shipping configuration to reduce damage risk: remove bushings, radiators, fans, instruments (as needed) and pack them in reinforced, moisture-proof crates; protect all flange faces and sealing surfaces.
Moisture & insulation protection: apply vacuum treatment/oil processing as required; for long transit, implement moisture control and (if specified) nitrogen blanket / sealed protection to keep insulation dry.
