Hybrid Substation

The ZGS11-Z-35kV American-style prefabricated box-type substation (American-style box-type substation) is a compact, oil-immersed, integrated outdoor power distribution device. Unlike the split structure of European-style box-type substations, this product adopts an integrated oil-immersed structure for the high-voltage load switch, protective fuses, and transformer body , while the low-voltage distribution unit is independently externally arranged. The entire unit integrates four core components: a 35kV high-voltage load switch, elbow-type pluggable cable heads, an oil-immersed main transformer, and a 0.4kV low-voltage distribution cabinet .

The equipment features a compact structure and small size, occupying only about one-third the area of a European-style prefabricated substation of the same capacity. The high-voltage side uses elbow-type cable heads for plug-in connection, eliminating the need for traditional wall bushings. Wiring is convenient, insulation is reliable, and waterproofing and anti-fouling performance are excellent. The equipment undergoes overall assembly, oil filling, withstand voltage testing, and commissioning in the factory. On-site, only hoisting and cable plugging are required for commissioning. Construction is short, and a civil engineering substation is unnecessary. It is widely applicable to 35kV outdoor terminal distribution, new energy photovoltaic and wind power voltage boosting, and industrial and mining enterprise power distribution scenarios.

ZGS11-Z-35 / □

• Z - Combined Substation
• G - High-protection structure
• S - Three-phase oil-immersed
• 11 - Energy efficiency rating 11, low-loss iron core
• Z - Terminal power distribution type
• 35 - Rated high voltage level 35kV
• □ - Transformer rated capacity (kVA), standard: 1000, 1600, 2000, 2500, 3150 kVA

1. Ambient temperature: -30℃～+45℃, suitable for extreme high and low temperature outdoor conditions;

2. Altitude: ≤1000m; for high-altitude areas, customized solutions with enhanced insulation and anti-condensation can be provided.

3. Relative humidity: Daily average ≤95%, monthly average ≤90%, no persistent condensation or icing;

4. Environmental conditions: Outdoor use, no explosive or corrosive gases, no serious dust or salt spray pollution;

5. Installation site: The site should be flat, well-drained, well-ventilated, and have a stable foundation, with no risk of long-term water immersion.

The 35kV American-style prefabricated substation adopts a classic American structure with a front-panel high-voltage plug-in connection , an integrated oil-immersed main body, and a rear-mounted independent low-voltage compartment. It lacks a separate high-voltage cabinet; the high-voltage load switch and current-limiting fuses are all submerged inside the transformer tank, resulting in a highly integrated structure. The entire system is divided into three parts: the high-voltage plug-in connection area, the transformer main body oil-immersed area, and the low-voltage distribution area. It features a compact structure, strong sealing, and few potential failure points.

Overall layout: front-end 35kV elbow cable head + high-voltage load switch wiring area, middle integrated oil-immersed transformer body, rear independent low-voltage distribution cabinet compartment , single-side door operation, convenient operation and maintenance, and minimal footprint.

■ 35kV High Voltage Load Switch (Built-in Oil Immersed Type)

The high-voltage core of this equipment adopts a 35kV oil-immersed high-voltage load switch , which is built into the transformer tank and completely wetted by the transformer oil. It has excellent insulation performance, good arc extinguishing effect, and maintenance-free operation. It is equipped with a built-in current-limiting fuse, forming a "load switch + fuse" combined protection mode, which is suitable for 35kV terminal power grid distribution conditions.

Main functions : Enables the opening and closing of normal load current on 35kV high-voltage lines; can switch on and off unloaded lines, unloaded transformers and load current under load; works with built-in fuses to quickly clear short-circuit and overload faults, providing reliable protection for transformers and downstream low-voltage equipment; has insulation isolation and power outage interlocking functions to ensure maintenance safety.

Structural features : Fully oil-immersed sealed structure, no exposed live parts, anti-fouling, moisture-proof, anti-condensation, extremely strong outdoor weather resistance, long mechanical life, and maintenance-free long-term operation.

■ 35kV elbow cable head (plug-in insulated joint)

The high-voltage incoming line uses a 35kV European-style elbow-type plug-in cable head , a core wiring component exclusive to American-style prefabricated substations, replacing traditional wall bushings. It is a fully insulated, fully sealed, and touch-safe connector. Standard configuration includes an insulating sheath, shielding layer, and stress cone structure, suitable for outdoor high-voltage cable connection.

Main functions : Enables quick plug-in connection between 35kV high-voltage cable and transformer high-voltage body, with simple and standardized wiring; fully insulated and enclosed design with no exposed live parts, effectively preventing electric shock, phase-to-phase short circuit, and creepage discharge faults; waterproof, dustproof, anti-flashover, and anti-aging properties, suitable for harsh outdoor environments, allowing for live plug-in maintenance and segmented isolation, ensuring extremely high operation and maintenance safety.

Structural features : fully insulated structure that can be touched, easy to install, maintenance-free, high insulation strength, good electrical shielding performance, and prevention of high voltage leakage.

■ Oil-immersed main transformer (integrated body)

The transformer is a 35kV low-loss, fully sealed oil-immersed distribution transformer. The core uses high-permeability silicon steel sheets, and the windings use oxygen-free copper wire. The entire system, including the high-voltage load switch and fuses, is integrated into the oil tank. The equipment is optimized for outdoor fluctuating loads and intermittent photovoltaic power generation, featuring overload resistance, impact resistance, low loss, and stable temperature rise. The oil tank employs a fully sealed welded structure, preventing oil leakage, water ingress, and dust ingress.

Main functions : step down 35kV high-voltage power to 0.4kV low-voltage power to provide a stable standard power supply for downstream electrical equipment; integrated oil-immersed heat dissipation design, uniform heat dissipation, low temperature rise, can operate continuously at full load for a long time, and is suitable for the long-term operation needs of power grid and new energy power plants.

■ Low-voltage switchgear (independent external enclosure)

The low-voltage switchgear is an independent, externally sealed compartment, completely isolated from the high-voltage oil-immersed area. It consists of a low-voltage incoming cabinet, an outgoing cabinet, a metering cabinet, and a reactive power compensation cabinet. The main switch uses a frame circuit breaker, and the branch circuits are equipped with molded case circuit breakers. It is equipped with intelligent meters, energy metering devices, surge protectors, indicator lights, and other components. The wiring inside the cabinet is neat and modular.

Main functions : It collects 0.4kV low-voltage power output from the transformer to achieve multi-load distribution and voltage stabilization; it has comprehensive protection against short circuit, overload, leakage, and lightning surge; it can perform power metering, power factor compensation, power quality optimization, and real-time monitoring of low-voltage operating parameters to ensure safe and stable power supply on the low-voltage side.

1. Highly integrated: The high-voltage load switch, protective fuse, and transformer oil immersion are integrated into one unit, eliminating the need for complex separate cabinets. The structure is extremely simple and the failure rate is extremely low.

2. Safe wiring of elbow-shaped cable heads: Fully insulated, touch-accessible pluggable structure, no exposed live parts, protection against electric shock, flashover, water and moisture, and extremely high safety factor for operation and maintenance;

3. Compact size and small footprint: It occupies only 1/3 of the area of a European-style box-type transformer, making it suitable for scenarios with limited space, narrow roads, and scattered outdoor power distribution.

4. Oil-immersed sealing, maintenance-free: The core high-voltage components are fully oil-immersed and sealed, with excellent insulation, arc extinguishing, and heat dissipation performance, and strong outdoor weather resistance;

5. Comprehensive protection configuration: high-voltage protection with load switch + fuse combination, low-voltage multi-stage circuit breaker protection, and fast and reliable fault clearing;

6. Quick installation and construction: The plug-in cable connection eliminates the need for complex high-voltage wiring, allowing for immediate commissioning upon on-site hoisting, significantly shortening the construction period;

7. Low loss and energy saving: It adopts a new type of low loss transformer core, with low no-load loss and low load loss, and good long-term economic performance.

1. Foundation construction: Pour a level concrete foundation according to the equipment drawings, and reserve the positions of cable wells, cable channels and grounding electrodes to ensure that the foundation is unobstructed and free of water accumulation;

2. Equipment placement: The main body of the American-style prefabricated transformer is hoisted smoothly, leveled, adjusted, and secured to ensure that the transformer is upright and without tilting;

3. Wiring and installation: Low-voltage cables should be connected to the low-voltage cabinet according to specifications; 35kV high-voltage cables should be accurately plugged in and unplugged with elbow-shaped cable heads, and proper insulation and sealing treatment should be performed; reliably connect to the entire station grounding system, with a grounding resistance ≤4Ω;

4. Overall commissioning: Conduct insulation resistance testing, power frequency withstand voltage testing, protection setting verification, circuit continuity testing, and check the insulation sealing of cable heads;

5. Phased trial operation: After no-load trial operation without any abnormalities, gradually increase the load to confirm that the equipment temperature rise, sound, and parameters are normal before officially putting it into operation.

1. During the operation of the equipment while it is energized, non-professionals are strictly prohibited from touching the elbow cable head and high-voltage area. High-voltage operations must be carried out by certified personnel.

2. Routine inspection: Check the enclosure's sealing, oil temperature, operating noise, and low-pressure instrument parameters; check the elbow cable heads for damage, aging, leakage, and discharge marks.

3. Quarterly maintenance: Tighten low-voltage terminals, clean dust from low-voltage cabinets, check grounding reliability, verify the status of protection devices; check the integrity of cable head insulation sheaths;

4. Annual maintenance: Inspect transformer oil quality and level, calibrate high-voltage protection and low-voltage circuit breakers, comprehensively test cable head insulation performance, and investigate potential aging hazards.

1. The equipment should be transported upright throughout the entire process. Tilt, inversion, impact, and heavy pressure are strictly prohibited. During transportation, rainproof, shockproof, and collision-proof protection should be provided to protect the elbow cable interface from damage.

2. The equipment should be stored in a dry, ventilated, flat, and non-corrosive place, avoiding long-term exposure to sunlight, rain, and sand accumulation. For long-term storage, the sealing and insulation conditions should be checked regularly.

1. This product is manufactured in strict accordance with national and industry standards. It undergoes a full range of insulation, withstand voltage, and protection tests before leaving the factory and can only be shipped after passing the inspection.

2. Product warranty period: 12 months from the date of formal commissioning of the equipment or 18 months from the date of manufacture (whichever comes first). During the warranty period, free repair and replacement of parts will be provided for non-human-caused damage.

3. The manufacturer provides a full range of after-sales services, including on-site hoisting guidance, cable connection and commissioning, equipment operation and maintenance training, and fault technical support.

Manufacturer : Jiangshan City Da'an Power Equipment Co., Ltd.