그리드 설계를 담당하는 엔지니어는 변화를 겪을 해안 부지를 계획하고 있었습니다. 200 메가와트의 해상 풍력 발전소가 다양한 220킬로볼트 변전소 중 하나에 연결될 것입니다. 120 메가와트의 태양광 시설과 50 메가와트/100 메가와트시의 에너지 저장소가 또 다른 변전소를 통해 연결될 것이며, 35킬로볼트 연결 시스템이 확장될 것입니다. 모든 새로운 메가와트는 변압기를 필요로 했습니다 – 터빈용 0.69 kV 변압기, 태양광 시스템용 0.4 kV 변압기, 변전소용 33/110 또는 33/220킬로볼트 변압기, 그리고 에너지 저장소에서 충전 및 방전을 처리하는 데 필요한 변압기. 엔지니어의 기계는 그녀에게 한 가지 사실을 끊임없이 상기시켰습니다: 재생 에너지 발전소가 모든 홍보를 받지만, 전체 시스템이 제대로 작동하도록 보장하는 것은 변압기입니다. 변압기가 손실이 증가하거나 스스로 냉각되지 않으면, 바깥의 바람이 아무리 강해도 풍력 발전소는 그 용량을 제대로 사용할 수 없습니다.
이 기사는 새로운 에너지 전력 시스템에서 변압기의 중요성을 강조하며, 위치, 운영 매개변수, 비용 및 저장 시스템 건설을 위한 선택 방법을 포함합니다.
새로운 에너지 시스템에서 변압기의 역할
새로운 에너지 시스템의 운영은 전통적인 전력 시스템과 유사하지만, 분산된 기상 의존 소스를 기반으로 합니다. 전통적으로 변압기는 다섯 가지 주요 기능을 수행합니다:
발전기용 승압 변압기: 수집 시스템의 각 터빈 또는 인버터 문자열에서 나오는 저전압을 더 높은 전압으로 전송합니다;
수집 시스템 변압기: 많은 발전기에서 전력을 변전소로 운반합니다;
승압 변압기: 추가 전송을 위해 수집 전압을 높입니다;
격리 변압기: 발전과 그리드 간의 분리를 수행합니다;
보조 공급 변압기: 변전소에 보조 서비스를 제공합니다.
시스템 토폴로지: 풍력, 태양광, 저장, 하이브리드
변압기 구성은 소스 유형과 발전소 크기에 따라 다릅니다:
| 시스템 | 일반적인 변압기 단계 | 정격 예시 |
|---|---|---|
| 육상 풍력 (20–200 MW) | 터빈 0.69/33 kV → 변전소 33/110–220 kV | 승압 1.5–10 MVA; 변전소 20–100 MVA |
| 해상 풍력 | 터빈 승압 → 해상 변전소 → 육상 변전소 | 승압 5–15 MVA; 변전소 100–400 MVA |
| 유틸리티 태양광 (10–200 MWp) | 인버터 0.4–0.6/33 kV → 변전소 33/110–220 kV | 수집 1–5 MVA; 변전소 20–100 MVA |
| 배터리 저장 (10–100 MW) | PCS 0.4/10–33 kV → 변전소 승압 | PCS 변압기 1–5 MVA |
| 하이브리드 (풍력+태양광+저장) | 위의 모든 것을 하나의 수집 변전소로 | 다중 권선 변전소 변압기 |
각 단계는 손실, 비용 및 고장 모드를 추가하므로 시스템 설계자는 변환 단계 수를 최소화하기 위해 열심히 작업합니다 — 그러나 현대 전송 시스템의 전압 수준은 단계를 피할 수 없게 만듭니다. 변압기는 재생 가능한 전력을 효율적으로 먼 거리로 이동하는 대가입니다.
새로운 에너지 의무: 그리드 의무와의 비교
신재생 에너지 변압기는 그리드 배전 변압기에서는 드문 운영 조건을 처리해야 합니다:
변동 부하: 풍력 및 태양광 출력이 거의 제로에서 전부로 몇 분 만에 변동하여 변압기 권선이 급격한 온도 변화를 겪고 절연체에 스트레스를 줍니다.
양방향 에너지 흐름(배터리 에너지): 배터리 변압기는 양 방향으로 에너지를 동일한 중요도로 전송해야 하며, 이는 단방향 그리드 변압기가 설계되지 않은 대칭 열 스트레스를 의미합니다.
고조파: 인버터와 컨버터는 변압기 임피던스와 공진을 일으킬 수 있는 추가적인 전력 손실을 초래하는 고조파 전류를 주입합니다.
원거리 위치: 풍력 터빈 변압기는 산꼭대기나 바다의 염수, 극한 기상 조건에서 유지보수를 위한 공간이 제한된 곳에 설치됩니다.
이로 인해 출력 저하, 더 나은 냉각, 고조파 처리를 위한 권선 설계 및 강력한 절연체 사용이 필요합니다. 안정적인 그리드 작업을 위해 설계된 변압기가 신재생 에너지 프로젝트에 설치될 경우, 사양서에 명시된 대로 작동하지 않을 수 있으며, 과열되어 계획보다 빨리 고장날 수 있습니다.
| 운영 조건 | 전형적인 그리드 작업 | 신재생 에너지 작업 | 설계 응답 |
|---|---|---|---|
| 부하 프로필 | 상대적으로 안정적이고 예측 가능함 | 거의 제로에서 전부로의 급격한 변동 | 주기적 부하 정격, 열 여유 |
| 전력 흐름 방향 | 단방향(그리드에서 부하로) | 저장소에서 양방향 | 대칭 권선 및 냉각 설계 |
| 고조파 내용 | 낮음, 대부분 50/60 Hz | 인버터 고조파 존재 | Harmonic-rated windings, extra margin |
| Siting | Substations with service access | Remote, offshore, salt air, extremes | Corrosion protection, sealed designs |
The practical lesson is to specify for the duty, not the voltage. A transformer that perfectly fits a distribution substation can be the wrong choice at the same rating in a wind or solar plant.
Transformer Types and Configurations
The main transformer families in new energy systems, with their design emphasis:
| 유형 | Typical rating | Design emphasis |
|---|---|---|
| Turbine step-up (WTS) | 1.5–15 MVA, 0.69/33 kV | Compact, corrosion-resistant, high vibration tolerance |
| Solar inverter transformer | 1–5 MVA, 0.4–0.6/33 kV | Harmonic-tolerant windings, low load loss at high cycling |
| Battery storage transformer | 1–5 MVA, 0.4/10–33 kV | Bi-directional load capability, high overload margin |
| Collector substation transformer | 10–40 MVA, 33/110–220 kV | On-load tap changer, low losses, high reliability |
| Auxiliary transformer | 50–500 kVA, 33/0.4 kV | Station house loads, compact and reliable |
Dry-type and cast-resin transformers appear increasingly at the inverter and PCS stage for indoor or containerized installations, where fire safety and maintenance access favour solid insulation. Liquid-immersed units dominate the outdoor collection and station stages.
Efficiency and Loss Considerations
The efficiency of new energy transformers is complex in its nature. Losses constitute the energy that the plant is unable to sell, thus decreasing its income. Furthermore, the loss amount depends on the changes in load. To tackle the problem, two design principles should be followed:
No-load loss is the most important factor under low load. When the solar plant is not generating any output at night, the transformers are still functioning, which leads to core losses of 8,760 hours per year;
Load loss is the second factor that can become essential when the load is high. As the harmonics raise the load loss by 5-20%, it is necessary to take this aspect into consideration when elaborating on the design of the transformer winding.
An energy-efficient transformer for the solar station can save from 30% to 50% of the total losses of the energy transformer that has the same power. In monetary equivalent, it can be equal to $10,000 to $40,000 per year considering the energy cost of $0,08 to $0,10 per kWh.
| Plant size | Typical transformer fleet | Annual loss-energy saving vs generic spec | Annual value at $0.09/kWh |
|---|---|---|---|
| 10 MW solar | 10 × 1 MVA collection units + 1 station unit | 30,000–60,000 kWh | $2,700–$5,400 |
| 50 MW solar | 25–30 collection units + station | 110,000–440,000 kWh | $10,000–$40,000 |
| 30 MW wind | 20 × 1.5 MVA turbine units + station | 90,000–250,000 kWh | $8,100–$22,500 |
| 50 MW / 100 MWh storage | 10–20 PCS units + station | 70,000–200,000 kWh | $6,300–$18,000 |
The saving scales with plant size and worsens when generic transformers are used, which is exactly why the plant-level loss model has become part of renewable project engineering.
Protection, Monitoring, and Reliability
Transformers play an auxiliary role if they are operational. Because of this, new power plants use several instruments along with the transformers such as:
– Protective relays: station transformers equipped with both differential and overcurrent relays, and fuse protection and circuit breakers at collection system level.
– Dissolved gas analyzer: the use of oil sampling according to IEC 60599 in order to identify early failures that can be vital in the case of how the remote equipment is operated.
– Temperature and pressure monitoring: top oil and winding temperature sensors.
– On-load tap changers: as a part of transformer station equipment to assist in the maintenance of voltage levels during power plant operation.
– Smart monitoring system: now a customary aspect allowing for the collection of the above data and optimizing dispatching process.
Economics of reliability are straightforward: when the 30 MVA power assembles fail, the generation of 30-100 MW via weeks can be delayed at a cost of millions of dollars. The transformers are only a minor cost against the risk associated with such inconveniences leading to the quality of equipment used in the projects.
Sizing and Selecting for Renewable Projects
When choosing transformers for a new energy system, it has to follow the steps outlined below.
1.lotting the load profile: this involves obtaining hourly output from the generation model, and it refers to the output profile derived from wind speed or solar irradiance series, and charge/discharge schedule.
2.Determining the size of each transformer stage using derating methods: here the harmonic derating has to be applied, which is usually 5–10%, as well as derating methods for the ambient temperature.
3.Finding out the loss balance: this step consists in running the loss capitalization via tariff and output.
4.Determining protection and monitoring devices which have to be included into the solution, such as relays and DGA.
5.Defining environmental specifications: this includes noise regulations, oil type and corrosion protection.
6.Testing the devices according to standards.
Manufacturers and Price Ranges
Indicative FOB pricing for new energy transformers by brand and stage:
| 브랜드 | Origin | 1 MVA collection unit | 30 MVA station unit |
|---|---|---|---|
| 히타치 에너지 | Japan/Global | $9,000–$14,000 | $95,000–$160,000 |
| ABB | Switzerland/Global | $8,500–$13,500 | $90,000–$150,000 |
| Siemens Energy | Germany/Global | $8,000–$13,000 | $85,000–$145,000 |
| 슈나이더 일렉트릭 | France/Global | $7,500–$12,500 | $80,000–$140,000 |
| Toshiba / Hyundai | Japan/Korea | $7,000–$11,500 | $75,000–$130,000 |
| Jiangsu Subian Electric Power | 중국 | $4,000–$7,500 | $45,000–$120,000 |
Prices vary with rating, voltage ratio, loss class, tap changer, oil type, copper prices, and delivery terms; treat these as planning ranges, not firm quotes.
The premium tier anchors the market with global type-test programs and offshore-track records. The Chinese tier offers the same IEC 60076 evidence and new-energy-specific designs at 40–50% lower cost, which has made it a leading source for onshore wind, solar, and storage projects across Asia, Africa, the Middle East, and South America. Jiangsu Subian Electric Power is a Chinese transformer manufacturer and energy-saving transformer producer supplying turbine step-up, solar collection, storage, and station transformers from 10 kVA to 63 MVA, with harmonic-tolerant windings, on-load tap changers, amorphous-core and natural-ester-oil options, all tested to IEC 60076 and shipped with routine test reports. Subian has supplied renewable and storage projects internationally; the range is documented at subian-electric.com.
The Outlook: Transformers in Future Power Systems
The functions of transformers will be determined by three trends in the domestic renewable energy system over the next ten years. First, there will be a rapid expansion of renewable energy transformer installations, which is necessary taking into account that global estimates predict an increase of share of the renewable energy in the electricity productions at major markets from 30% to as high as 50-70%, which in its turn means that each installed gigawatt of capacity will require dozens of transformers. Second, efficiency will tighten further as efficiency grades and green procurement continue to ratchet, making green transformer designs the default. Third, smart monitoring will become standard, because in a system where output is variable and remote, the data that keeps transformers healthy is the data that keeps renewable power flowing.
The transformers will remain in the background of the energy transition — but the transition simply does not happen without them.
Frequently Asked Questions
What transformers are used in wind and solar plants?
Typically three stages: generator/inverter step-up transformers (0.69/33 kV or 0.4–0.6/33 kV, 1–15 MVA), collection-network units, and a station step-up transformer (33/110–220 kV, 20–400 MVA). Battery storage plants add bi-directional PCS transformers at 0.4/10–33 kV.
How much do transformers for renewable plants cost?
A 1 MVA collection transformer runs about $4,000–$7,500 FOB from Chinese manufacturers; a 30 MVA station transformer runs $45,000–$120,000. Premium international brands price 50–80% higher. Prices vary with rating, loss class, tap changer, and copper prices.
Why are transformer losses important in new energy systems?
Because every kilowatt lost is renewable output that can never be sold. A solar plant’s station transformers stay energized at night when output is zero, so no-load losses matter more than their small size suggests. On a 50 MW plant, the right specification can save $10,000–$40,000 a year in loss energy.
Are renewable transformers different from normal grid transformers?
Yes, in duty. They see variable and bi-directional loading, harmonics from inverters, and remote or harsh siting. That requires harmonic-rated windings, derating, better cooling, and corrosion protection. Using a standard grid transformer without derating shortens its life.
What is the lifespan of a transformer in a renewable plant?
20–35 years, depending on loading severity, ambient conditions, and maintenance. Variable loading and harmonics shorten life unless the unit is derated and monitored. Annual DGA per IEC 60599, temperature monitoring, and keeping hot-spot temperature within IEC 60076-7 limits are the strongest levers on lifespan.
References
- IEC 60076-1: Power transformers – General — International rating and testing baseline for all renewable-system transformers.
- IEC 60076-5: Ability to withstand short circuit — Short-circuit design verification for station transformers.
- IEC 61936-1: Power installations exceeding 1 kV a.c. — Installation requirements for medium- and high-voltage renewable plants.
- IEA Renewables 2023 — Global renewable growth data underpinning transformer demand.
- IRENA renewable energy technology — Technology outlook for wind, solar, and storage integration.
- GB 20052: Energy efficiency grades for power transformers — Efficiency grades relevant to renewable transformer specification.
- Jiangsu Subian Electric Power official site — Renewable and storage transformer range with test reports.
Conclusion
Transformers are important elements in contemporary energy power systems — in the structural rather than optional sense. Each wind turbine, solar field, and battery facility relies on transformers to step up voltage, gather power and connect to the grid, and each transformer must therefore be engineered to withstand the ordeal these systems impose: changing loads, distortion, two-way traffic, and remote locations.
Key takeaways:
- Renewable systems need three transformation stages: generation step-up, collection, and station step-up.
- New energy duty is harder than grid duty — derating, harmonic tolerance, and monitoring are non-negotiable.
- Efficiency specification saves 30–50% of annual loss energy versus a generic unit; worth $10,000–$40,000/year on a 50 MW plant.
- Budget $4,000–$7,500 for 1 MVA collection units and $45,000–$120,000 for 30 MVA station units from Chinese manufacturers.
If you are building or expanding a wind, solar, storage, or hybrid project, Jiangsu Subian Electric Power supplies renewable-grade transformers from 10 kVA to 63 MVA — harmonic-tolerant, tested to IEC 60076, with amorphous-core and ester-oil options — at export-friendly prices. Review the range at subian-electric.com.