A solar power facility of 200 MW in size located on a windy plateau in the northwest of China was about to be connected to a grid but there was an issue with one of its contractors. The inverter needs to reach the high-voltage substation but the path leading there goes over three kilometers of difficult terrain and needs to be accomplished in a matter of weeks. It was decided to send a group of specially made substations made by Jiangsu Subian Electric Power to the cited solar station in order to be connected to the grid on time.
In this article, you can learn about the differences between the typical substation produced in China and similar ones designed by engineers from Europe and North America. There will be a lot of useful information included, such as the characteristics of the unit, the testing process, and the reasons for using this type of equipment being sold to suppliers.
The Delivery Milestone
The supply of the project described above consisted of forty-two specific substation photovoltaic units equipped with 2,000 kVA transformers with step-up functions (35 kV / 0.69 kV), industrial RMUs on the networks, LV switchboards with inverter terminations, numerical relays for protection, as well as instruments for measurement and full operation. Each assembly was undergoing factory type testing, namely temperature rise under functioning condition, short-circuit resistance, voltage test, as well as the capability of withstanding an internal arc discharge. Each unit had certification for routine tests, cover GB standards, as well as full instrumentation for the EPC contractor to deliver it to the owner.
Completion of the delivery of such milestones is significant from a broader perspective than just that of the project. It proves that the complete and certified PV interconnection point may be manufactured and tested, instead of requiring construction work from the construction side.
What Is a Chinese-Style PV Substation?
The Chinese-style photovoltaic substation has been developed in view of China’s massive local solar market, which has necessitated standardization of substation designs by substation makers. The Chinese-type substation bears the following characteristics compared with its European and American counterparts:
Integrated inverter station: The low-voltage section has been designed around the inverter output, which usually is between 800 — 1,500 V direct current input and 400—690 V alternating current output. It may either Europe- or America-made inverter, which minimizes cable runs due to the fact that the inverter is often located in the same skid or adjacent enclosure.
Standardized medium-voltage/low-voltage architecture: Two- or three-compartment layout (medium-voltage, transformer, low-voltage sections) with standard modular dimension, which allows developers to order the same substation all the time.
Double standard compliance: Designed to GB/T standards and allowed by IEC 62271-202 and IEC 60076.
Fast delivery model: Thanks to the standardization of the design, fabrication scheduling is shorter — 10-16 weeks — and costs lower than in Europe.
Grid code-ready: Integrated numerical relays carry the anti-islanding function, and directional overcurrent and voltage/frequency ride-through functionality prepared for the market.
As for international buyers, the term “Chinese-style” means a well-established type of design, which combines the compact and prefabricated substation design features and specific photovoltaic engineering, and thus, is worth considering along with European and American models.
Structure and Key Components
| Compartment | Main Equipment | Typical Rating |
|---|---|---|
| LV inverter-side compartment | LV switchboard, AC breakers, surge arresters, protection relays, inverter terminations | 400–690 V, 2,000–4,000 A |
| Transformer compartment | Step-up transformer, oil containment, temperature monitoring, forced-air cooling option | 630–4,000 kVA, 35/0.69 kV |
| MV grid-side compartment | Solid-insulated or SF6 RMU, vacuum breaker option, metering CTs/VTs, arresters | 10–40.5 kV, 630 A |
| Control and auxiliaries | DC supply, heaters, SCADA/RTU, telecommunication links, anti-condensation control | — |
Constructive specifics for solar applications include derating curves computed for high ambient temperature conditions (up to 50 °C), design of transformer capable of thermal cycling on a daily basis, dust-filtered ventilation for dry places, and corrosion protection system used in desert and coastal zones. Those details allow a unit to operate efficiently for 25 years under conditions of daily solar cycles.
Why Solar Plants Need a PV-Specific Unit
Four factors indicate that a solar plant should not rely on a generic distribution substation.
Firstly, the load pattern of a solar installation will affect the transformer loading due to solar irradiance levels which will peak at noon and drop nearly to zero during the night. If a power facility design does not take that into account, the insulation will wear out rather faster than usual due to continuous thermal cycling.
Secondly, grid regulations establish requirements regarding anti-islanding schemes, directional overcurrent protection, voltage and frequency rides through, including wait times and time-current characteristics, that are hard to meet using standard distribution relays.
Thirdly, reactive power equipment is necessary to ensure proper voltage across the grid line by supplying regulated reactive power to the grid.
Fourthly metering is carried at the interconnection point of the solar installation and has to comply with the prescribed accuracy classes (0.2s/0.5s) with the full SCADA documentation processed.
PV-based transmitters combine all four areas of technology. This is what Subian equipment does, so it could be delivered without being customized on site.
Chinese-Style vs. European vs. North American Designs
| 要因 | Chinese-Style | European Style | North American Style |
|---|---|---|---|
| Base standard | GB/T + IEC 62271-202 | IEC 62271-202 | IEEE C57 / UL |
| Inverter integration | Common on one skid | Separate enclosure typically | Separate station typically |
| Typical rating | 630–4,000 kVA | 630–2,500 kVA | 75–5,000 kVA pad-mounts |
| Voltage levels | 10–40.5 kV / 400–690 V | 10–36 kV / 400–690 V | 15–35 kV / 480–690 V |
| エンクロージャ | IP54, skid or cabinet | IP54, cabinet | Tamper-resistant cabinet |
| Price level | Lowest cost tier | Premium tier | Premium tier |
| Lead time | 10–16 weeks | 16–28 weeks | 20–35 weeks |
Every style is effective for its market. The Chinese version excels at integration density, price, and lead time. Meanwhile, the European and North American approaches have local qualifications and service. For global solar projects where price and time are the most important, the Chinese-style solar station is the most attractive.
Typical Specifications
Representative specification for the delivered Subian PV substation unit:
| パラメータ | 典型的な値 |
|---|---|
| Transformer rating | 2,000 kVA, oil-immersed, ONAN |
| Voltage ratio | 35 kV / 0.69 kV (10/20/33 kV options) |
| ベクトルグループ | Dyn11 or Dyn5 |
| 無負荷損失 | ~2.2–3.0 kW |
| Load loss at 75°C | ~16–20 kW |
| インピーダンス電圧 | 6%–8% |
| LV switchgear | 2,500–4,000 A ACB, inverter terminations |
| MV switchgear | Solid-insulated or SF6 RMU, 20–25 kA/3s |
| 保護 | Numerical relay: 50/51, 50N/51N, 27/59, 81, anti-islanding, directional |
| Metering | Class 0.5s or 0.2s, CTs/VTs |
| エンクロージャ | IP54, hot-dip galvanized base, anti-corrosion coating |
| Ambient design | Up to 50°C with derating curve |
| 規格 | GB/T + IEC 62271-202 + IEC 60076 + IEC 60529 |
Standards and Grid-Code Compliance
| 標準 | 範囲 | Relevance |
|---|---|---|
| IEC 62271-202 | Prefabricated transformer substations | Complete-unit design, enclosure, type testing |
| IEC 60076 | 電力変圧器 | Transformer ratings, losses, tests |
| IEC 60529 | IP enclosure protection | IP54/IP55 outdoor ratings |
| GB/T 17467 | Chinese prefabricated substation standard | Domestic design basis in China |
| IEEE 1547 / EN 50549 | Grid interconnection (regional) | Configured anti-islanding and ride-through |
Buyers should confirm which grid-code settings ship with the relays and request a relay coordination study for the site. The same hardware can often meet EN 50549 (Europe), IEEE 1547 (North America), and various national codes with a firmware/settings change.
Factory Testing and Documentation
All units received through the delivery process went through a complete factory test program.
The transformers were examined (in part and completely) in compliance with IEC 60076, which included the following tests: ratio; winding resistance; losses; impedance; and dielectric tests.
In addition to the standard transformer inspections, the complete unit underwent routine type tests according to IEC 62271-202. The testing included during operation tests such as: temperature rise with housing; short circuit resistance to internal arc; and dielectric.
The switchgear also underwent routine tests, including mechanical operation tests; contact resistance; insulation tests; and protection function tests.
In addition to these routine tests, protection relays were checked to ensure that their configuration settings conformed to the project grid codes.
Before the shipment, each unit was inspected to confirm that they complied with all requirements, including: construction; terminals; level of oil; painting; and documentation compliance.
Every unit came with a routine report; type testing report; test reports for the used materials; and a full package of documentation so that they would have everything necessary for the end users.
Costs and Price Ranges
Indicative prices for complete PV-specific substation units in the Chinese-style configuration (step-up transformer, MV and LV switchgear, protection, metering, IP54 enclosure):
| 定格 | Voltage Class | 典型的な価格（USD） | リードタイム |
|---|---|---|---|
| 630–1,000 kVA | 10–35 kV | $12,000–$25,000 | 10–14 weeks |
| 1,250–2,000 kVA | 10–35 kV | $16,000–$35,000 | 10–16 weeks |
| 2,500–3,150 kVA | 10–40.5 kV | $30,000–$60,000 | 12–18 weeks |
| 3,550–4,000 kVA | 10–40.5 kV | $45,000–$90,000 | 14–20 weeks |
Add 15–30% for stainless-steel or high-corrosion enclosures, 10–20% for dry-type transformers, and $1,500–$5,000 for advanced relays, class 0.2s metering, and full SCADA. Prices are FOB indicative and vary with specification and region.
Top Brands & Price Comparison
| ブランド | Country | Strength | Indicative Price — 2,000 kVA (USD) |
|---|---|---|---|
| シュナイダーエレクトリック | France | Integrated solutions, global service | $38,000–$60,000 |
| Siemens | Germany | Digital grid, utility references | $40,000–$65,000 |
| ABB / Hitachi Energy | Switzerland | Broad portfolio, strong solar references | $38,000–$62,000 |
| Sungrow / Huawei | 中国 | Inverter + station packages | $32,000–$58,000 |
| 江蘇省蘇辺電力 | 中国 | Chinese-style PV substations, IEC/GB certification, OEM | $16,000–$35,000 |
The major players in Europe and the makers of inverters join forces with local teams of support and compliance teams to make substations appealing for major bids. Jiangsu Subian Electric Power brings to the table the PV substation in full Chinese style with step-up transformers, MV/LV switchgear, grid code protection, and SCADA-ready metering at 40-55% of European prices, including factory-testing, certification in GB/T and IEC, and OEM customization. This combination of testing, density-integrated solutions, and price sustainability guarantees that Subian ranks high on the list of candidates for the tenders run by EPC industries that embrace various solar projects.
How to Specify and Buy
To get the appropriate output of your inverter AC, sum the AC inverter output(kVA) with 10 – 20% margin considering environmental derating factor.
To ensure a smooth project setup, check with utility company in advance the export voltage as well as connection point.
Decide transformer type – oil-immersed for open ground units and dry-type for limited space or fire sensitive locations.
Confirm with utility specifications of grid code – times for anti-islanding, ride-through and reactive power according to your country` laws.
Request for tests for complete unit operations in accordance with requirements provided in IEC 62271-202.
For underwater or especially important projects, ask for the relay coordination project in case you have more than 1 MW of power output.
Select the company based on evaluated operations cost of 25 years instead of cost incurred for getting the generator.
Confirm local resources and company support.
よくある質問
What is a Chinese-style PV substation?
It is a factory-assembled MV/LV substation purpose-built for solar plants, developed for China’s high-volume domestic market and now exported. It integrates a step-up transformer (630–4,000 kVA), MV switchgear, LV inverter-side switchgear, grid-code protection, and metering in one IP54 enclosure per IEC 62271-202, often with the inverter station on the same skid.
How much does a Chinese-style PV substation cost?
Complete units range from $12,000–$25,000 (630–1,000 kVA) to $45,000–$90,000 (3,550–4,000 kVA). This is roughly 40–55% below European pricing for comparable scope. Stainless enclosures add 15–30%, dry-type transformers add 10–20%, and SCADA adds $1,500–$5,000. Prices are FOB indicative and vary by specification and region.
What tests should I require before accepting delivery?
Require transformer routine tests per IEC 60076 (ratio, winding resistance, losses, dielectric), switchgear mechanical and insulation tests, and the IEC 62271-202 complete-unit type tests — temperature rise with the enclosure fitted, short-circuit withstand, and internal arc. For export, add a factory test witness and pre-shipment inspection.
Is the Chinese-style design compliant with international standards?
Yes. The units are built to GB/T national standards and tested to IEC 62271-202, IEC 60076, and IEC 60529. Protection relays ship with grid-code settings configurable for EN 50549, IEEE 1547, or national codes, and metering meets class 0.5s/0.2s accuracy requirements.
How long is the lead time for a full delivery?
Standard ratings ship in 10–16 weeks; larger units (2,500–4,000 kVA) take 14–20 weeks. Because the Chinese-style design is standardized, production slots are shorter than bespoke European builds. Confirm slots in writing early, especially for multi-unit programs.
参考文献
- IEC 62271-202 — Prefabricated substations — governing standard for complete-unit design and type testing.
- IEC 60076 series — Power transformers — base standard for the step-up transformer.
- IEC 60529 — IP Code — defines IP54/IP55 enclosure protection.
- IEEE 1547 — Interconnection of Distributed Energy Resources — North American grid interconnection requirements.
- IRENA — Renewable capacity statistics — data on global solar deployment and interconnection demand.
- U.S. DOE — Solar interconnection guidance — interconnection requirements for utility-scale solar.
- Jiangsu Subian Electric Power — official site — manufacturer and exporter of PV-specific substations.
結論
The introduction of Subian’s facility-specific substations in the market represents a significant milestone on the way to the establishment of the supply of solar balance of plants. The new facility represents a fully certified delivery point for solar substations, whose essential components — transformers, switchgear, protection, and metering — are manufactured, tested, and delivered as standard equipment. This means that both project developers and contractors must keep their schedules and reduce costs with no compromise on the site quality.
The basic novelties include:
– New types of Chinese PV substations combine converter-connected transformers and LV, MV switchgear into one tested piece of equipment.
– Trailed devices must pass IEC 62271-202 tests and comply with the requirements of the grid code.
– Their price range varies from $12,000 to $90,000 depending on the rating, which is 40–55% lower than that of similar European equipment.
– It is important to compare the losses and total cost over 25 years and agree on delivery time in advance.
– Compare the brands — Schneider, Siemens, and ABB against approved manufacturers like Jiangsu Subian Electric Power.
For PV substation pricing, specifications, and export support, contact Jiangsu Subian Electric Power at www.subian-electric.com.