Solar energy, with its abundant reserves and wide distribution, is the most promising renewable energy source in the 21st century. As global issues such as energy shortage and environmental pollution become increasingly prominent, solar photovoltaic power generation has emerged as a strategic emerging industry prioritized by countries worldwide, thanks to its cleanliness, safety, convenience and high efficiency. In large and medium-sized photovoltaic power stations, centralized PV bases and source-grid-load-storage integration projects, People's 35kV Photovoltaic Combined Transformer/Preassembled Substation undertakes the core functions of power conversion, collection, step-up, protection and intelligent control. It serves as a key hub device connecting photovoltaic arrays, inverters and the public power grid. This article systematically elaborates on the core functions, application scenarios, selection advantages, scientific selection methods and application value of the product, providing professional reference for investment, design, construction and operation & maintenance of photovoltaic power stations.
I. Core Functions of 35kV Photovoltaic Combined Transformer/Preassembled Substation
People's 35kV Photovoltaic Combined Transformer/Preassembled Substation adopts a factory prefabricated, fully integrated and ready-to-install modular design, covering three structural schemes: American-style substation (ZGS-Z structure), Chinese-style substation (YBG structure) and European-style substation (same model as Chinese-style substation). It highly integrates step-up transformers, high-voltage distribution devices, low-voltage distribution units, relay protection systems, intelligent monitoring modules, reactive power compensation components and lightning protection & grounding systems, undertaking multiple irreplaceable functions in photovoltaic power stations:
1.Power Step-up and Long-distance Transmission
It stably boosts the low-voltage alternating current (0.27kV/0.3kV/0.315kV/0.4kV) output by photovoltaic inverters to 35kV/36.75kV/38.5kV grade, with the maximum operating voltage of the high-voltage side reaching 40.5kV. It meets the grid connection voltage requirements, significantly reduces line loss during long-distance power transmission and improves power transmission efficiency, suitable for power transmission needs of centralized PV bases with capacity ranging from 1000kVA to 1250kVA.
2.System Integration and Power Distribution Control
It integrates functions such as high-voltage incoming line, high-voltage outgoing line, transformer protection, low-voltage grid connection interface and electric energy metering, realizing centralized collection, distribution and orderly control of multi-circuit power in photovoltaic fields. Among them, the American-style substation adopts a co-box design, integrating core components such as load switches and fuses into the transformer tank with a compact structure; the Chinese-style and European-style substations are preassembled substations with clear modular partition layout, replacing the multi-device discrete mode of traditional decentralized civil engineering substations and simplifying primary and secondary system wiring.
3.Comprehensive Safety Protection
It is built-in with three core protection components: BYFI-40.5 type high-voltage oil-immersed load switch (rated current 630A, mechanical service life 2000 times, power frequency withstand voltage 95kV), XRNT-40.5 type high-voltage fuse (short-circuit breaking current 31.5kA, fuses can be easily replaced on site) and YH5WZ-51/134 type silicon rubber jacket zinc oxide arrester (gapless design, residual voltage of nominal discharge current ≤134kV, with explosion-proof performance). Combined with protection logic such as overcurrent, differential, zero-sequence, overtemperature and anti-islanding protection, it quickly operates to cut off the fault circuit under working conditions such as overload, short circuit, insulation abnormality and lightning impulse, ensuring the safety of photovoltaic arrays, inverters, substation itself and grid-side equipment.
4.Intelligent Operation & Maintenance and Data Perception
It is equipped with temperature monitoring, partial discharge monitoring and electrical parameter acquisition modules, supporting multi-protocol communication to connect with the power station monitoring platform, realizing real-time upload of operating status, fault early warning and remote switching on/off. Meanwhile, it is configured with SG10 type lighting and maintenance transformer to meet the power supply demand for daily inspection and maintenance of equipment, improving the convenience of operation & maintenance.
5.Power Quality Optimization
The transformer adopts Yd11 and d11 connection group labels, with impedance controlled at 6.5%, effectively suppressing harmonic distortion. Cooperated with reactive power compensation devices, it can stabilize the power factor above 0.98, meeting the mandatory standards of GB/T 19964 for photovoltaic grid-connected power quality and avoiding grid generation limitation and assessment fines.
II. Typical Application Scenarios
The product is specially designed for outdoor photovoltaic scenarios, with its operating environmental conditions strictly calibrated, covering the following core scenarios:
1.Large-scale Ground Centralized Photovoltaic Power Stations
It is suitable for desert, Gobi and beach PV bases with altitude ≤1000m, ambient temperature -25℃~+45℃ and wind speed ≤35m/s. The single-unit capacity covers 1000kVA, 1100kVA and 1250kVA, and multiple units can be connected in parallel to realize centralized power step-up and transmission. The equipment meets the seismic grade requirements of horizontal acceleration 0.3m/s² and vertical acceleration 0.15m/s², with pollution prevention grade reaching Level II, and can withstand harsh climates with heavy wind and sand and dust.
2.Photovoltaic + Comprehensive Utilization Projects
It is widely used in composite formats such as agriculture-photovoltaic complementarity, fishery-photovoltaic complementarity and forestry-photovoltaic complementarity. The fuel tank has a protection grade of IP68 (capable of operation when submerged in water), the high and low voltage chambers have a protection grade of IP54, and the high-voltage chamber still maintains IP3X protection when the door is open. It adapts to special environments such as high humidity, salt spray and water accumulation. The equipment installation does not occupy farming and breeding space, realizing "one land for two uses".
3.Large-scale Distributed Photovoltaic Projects in Industrial and Commercial Parks
For distributed photovoltaic projects above 6MW in industrial parks and large commercial complexes, the American-style substation, with the advantages of small size, low loss and convenient installation, is suitable for roof and factory corner spaces; the Chinese-style and European-style substations meet the standardized construction needs of large-scale power stations with high integration, quickly realizing self-consumption and surplus power grid connection.
4.Customized Projects in Special Environments
For scenarios beyond conventional operating conditions such as high altitude, severe cold and extreme heat, the manufacturer can provide personalized design, such as improving insulation level, adding forced ventilation/electric heating temperature control system and adopting heavy anti-corrosion coating, adapting to the construction of special photovoltaic power stations in remote areas, islands and mining areas.
III. Core Advantages of Choosing People Electric Appliance's 35kV Photovoltaic Combined Transformer/Preassembled Substation
Compared with traditional civil engineering substations, 10kV-level box-type substations and discrete equipment combinations, the product has significant advantages in technology, economy, construction period and reliability:
1.Three Structural Schemes to Precisely Match Project Needs
●American-style substation (ZGS-Z structure): Co-box design, with components integrated into the fuel tank, small size, light weight and fast installation speed, suitable for distributed photovoltaic projects with limited space. Daily maintenance does not require professional tools, reducing operation and maintenance costs.
●Chinese-style/European-style substation (YBG structure): Prefabricated modular layout, with high-voltage chamber, transformer chamber and low-voltage chamber independently partitioned, good heat dissipation and strong expansibility, suitable for standardized and large-scale construction needs of large centralized photovoltaic power stations.
2.High Integration, Greatly Shortening the Construction Period
All equipment is assembled, wired, commissioned and type-tested in the factory. On-site only foundation construction, integral hoisting, cable connection and grid connection acceptance are required. The construction period is shortened by 60%—70% compared with the traditional scheme, quickly realizing power station commissioning and power generation, and improving capital turnover efficiency.
3.Super Strong Environmental Adaptability for Outdoor All-weather Stable Operation
The cabin adopts a double-layer heat insulation and anti-corrosion structure, combined with IP68 high protection grade fuel tank, which can resist extreme weather such as floods, salt spray and sand dust. It does not need civil engineering machine room and large-area enclosure, especially suitable for long-term operation in unattended field scenarios.
4.Low Loss Design to Improve the Whole Life Cycle Benefit of Power Station
The no-load loss and load loss of the transformer can be customized and optimized according to customer needs. Combined with low impedance design, the self-loss is reduced by 10%—20% compared with the national standard requirements, improving the electricity revenue of the power station during the 25-year operation period.
5.Complete Certification and Service Guarantee
The product has passed a full set of type tests, and its insulation level and withstand voltage level all meet national standards. The manufacturer provides full-process services such as selection data download, technical scheme customization and on-site installation guidance, with after-sales hotline 400-898-1166 responding quickly to operation and maintenance needs.
IV. Scientific Selection: How to Select a Suitable 35kV Photovoltaic Combined Transformer/Preassembled Substation
Selection should be comprehensively determined based on power station capacity, inverter parameters, grid connection conditions, environmental characteristics and operation & maintenance needs, following the core steps and indicators below:
1. Determine the Structural Scheme and Capacity Matching
♦ For distributed photovoltaic projects and projects with limited space, American-style substation structure is preferred; for large centralized power stations and standardized projects, Chinese-style/European-style substation structure is preferred.
♦ Calculate the rated capacity of a single box-type substation according to the total output power of the inverter, the number of grid connection points and the load coincidence rate. The mainstream specifications are 1000kVA (high voltage 35kV), 1100kVA (high voltage 36.75kV) and 1250kVA (high voltage 38.5kV). Reserve 10%—15% margin to cope with light intensity fluctuations and subsequent capacity expansion.
2. Voltage and Insulation Level Matching
♦ The input voltage of the low-voltage side must strictly match the inverter output (four options: 0.27kV/0.3kV/0.315kV/0.4kV), and the output voltage of the high-voltage side must be consistent with the grid access voltage (35kV/36.75kV/38.5kV).
♦ Confirm that the insulation level meets the project requirements: high-voltage switch power frequency withstand voltage 95kV, transformer body power frequency withstand voltage 85kV, impulse peak withstand voltage 200kV. For high-altitude projects, the insulation margin needs to be additionally verified.
3. Environmental Protection and Structural Selection
♦ For conventional outdoor scenarios, select standard configuration (pollution prevention Level II, seismic grade 0.3m/s²); for coastal salt spray and fishery-photovoltaic complementary scenarios, upgrade to IP68 fuel tank + heavy anti-corrosion coating; for severe cold/extreme heat areas, configure electric heating and forced ventilation temperature control systems.
♦ Prioritize prefabricated cabin-type independent partition structure to improve the convenience of heat dissipation, maintenance and capacity expansion.
4. Selection of Protection Components and Intelligent Configuration
♦ Standard configuration adopts the protection combination of BYFI-40.5 load switch + XRNT-40.5 fuse + YH5WZ-51/134 arrester. For large-scale power stations, add differential protection and arc protection.
♦ Select intelligent monitoring modules on demand, supporting advanced functions such as remote communication, partial discharge monitoring and digital twin, to adapt to the operation and maintenance needs of unattended power stations.
V. Conclusion
Against the backdrop of the global energy structure transformation towards clean and low-carbon, photovoltaic power generation has shifted from a supplementary energy source to a main energy source, with large and medium-sized photovoltaic bases and comprehensive energy projects becoming the mainstream of construction. People's 35kV Photovoltaic Combined Transformer/Preassembled Substation flexibly adapts to diverse scenarios with three structural schemes, and has become the core step-up grid connection equipment of modern photovoltaic power stations with the core advantages of high integration, energy saving and low loss, IP68 super protection and intelligent friendliness.
The product not only effectively solves the problems of power collection and long-distance transmission in large-scale power stations, but also adapts to complex scenarios such as agriculture-photovoltaic, fishery-photovoltaic and industrial-commercial distributed scenarios, playing an irreplaceable role in improving power station efficiency, reducing investment costs, ensuring safe and stable operation and supporting intelligent operation & maintenance. Scientific selection and reasonable configuration are the keys to ensuring the long-term reliable operation of the equipment. It is necessary to make comprehensive decisions from the dimensions of structural scheme, capacity matching, environmental protection, protection logic and manufacturer service, and select high-quality products that meet national standards, grid specifications and project characteristics.
With the continuous iteration of new energy technology and the construction of new power systems, People Electric Appliance's 35kV Photovoltaic Combined Transformer/Preassembled Substation will be upgraded towards higher integration, lower loss and higher intelligence, providing solid equipment support for the high-quality development of the photovoltaic industry and the realization of the "dual carbon" goals.
Post time: Feb-09-2026
