Introduction: A pole-mounted transformer is a transformer installed on power line poles. It mainly consists of a primary winding, a secondary winding, and a core (magnetic core). It uses the principle of electromagnetic induction to change AC voltage and is used in power systems for voltage transformation, current transformation, impedance transformation, and isolation.
CHBEB GROUP has focused on transformer manufacturing for 60 years. Its products cover various types of transformers, including pole-mounted transformers, oil-immersed transformers, dry-type transformers, and various types of compact substations, meeting the needs of industrial, renewable energy, power distribution, and other application scenarios. Click the link to learn more about our pole-mounted transformers.
In urban and rural distribution networks, a gray metal device can often be seen mounted on utility poles. It operates quietly like a “power transfer station.” This is a pole-mounted transformer. As one of the core pieces of equipment in a distribution network, its operation directly affects whether end users can receive a stable power supply.
Pole-mounted transformers have a simple structure and compact size. They are generally installed in a suspended configuration on a single pole or double poles and are located close to the load. This helps shorten the low-voltage power supply radius and makes them suitable for distributed load supply. They are currently widely used in the United States, Canada, Mexico, Southeast Asia, South America, and other regions.
The working principle of a pole-mounted transformer is based on electromagnetic induction. When the alternating current in the primary winding changes, it produces magnetic flux in the core. The magnetic flux cuts through the secondary winding, thereby inducing an electromotive force in the secondary winding. By changing the turns ratio between the primary and secondary windings, different voltage transformations can be achieved.
Although pole-mounted transformers may appear simple in structure, different active-part configurations, core materials, tank designs, and protection configurations can all affect the design and selection of the product. Faced with different capacities, voltage levels, and energy-efficiency requirements, how should reasonable design and selection be carried out? The following introduces several key aspects.
Pole-mounted transformers can adopt either a core-type structure or a shell-type structure. The core material can be amorphous alloy or silicon steel sheet, and both adopt an open wound-core structure.
The core type adopts a double-winding, single-core structure. The core generally uses a top-opening design, and the winding arrangement is usually low-voltage/high-voltage.
The shell type adopts a single-winding, double-core structure. The core generally uses a side-opening design, and the winding arrangement is usually low-voltage/high-voltage/low-voltage or low-voltage/high-voltage.
The core material can be either amorphous alloy or silicon steel sheet. At present, silicon steel cores are more commonly required.
Amorphous alloy cores adopt a mold-forming and annealing process. Silicon steel cores can be processed in two ways: one is mold forming with annealing, and the other is octagonal bending without annealing.
Both the annealing process and the octagonal bending process have their own advantages and disadvantages, and either can be adopted. Relatively speaking, the annealing process provides more stable performance.
The tank is generally made of 2–3 mm cold-rolled steel plate and formed into a cylindrical shape, while the tank cover is made of 3 mm steel plate.
Since the tank cover requires mold processing, a standard tank diameter should be selected as far as possible during design. The tank cover and tank body can be connected by a clamping band or by a pressure-fastening structure.
Upper and lower mounting lifting plates shall be welded onto the tank body in accordance with standard requirements. The oil level is generally marked inside the tank at 25°C, and an oil level gauge can also be provided if required.
An air gap is reserved at the top inside the tank to accommodate the volume change of transformer oil caused by thermal expansion and contraction. According to performance requirements, radiators can be provided, either corrugated-fin radiators or plate-type radiators.
If CSP protection is required, fuses, circuit breakers, surge arresters, and other components shall be selected according to the transformer capacity and voltage level by referring to the relevant selection tables. The accessory selection of ERMCO in the United States may be used as a reference.
It should be noted that the low-voltage circuit breaker has losses, which need to be taken into account in the load calculation.
With the acceleration of global energy-efficiency initiatives and the transition of industries toward green and low-carbon development, countries are imposing increasingly strict requirements on transformer efficiency.
The specified no-load and load losses are becoming increasingly lower. In some cases where losses are not directly specified, the losses need to be calculated based on the required efficiency.
|
Rated Capacity (kVA) |
HV | LV | Efficiency | |
|---|---|---|---|---|
| DOE(2016) | CSA(2023) | |||
| 5 |
34.5kV/19.92kV 13.8kV/7.96kV 13.2kV/7.62kV 12.47kV/7.20kV or others |
120–240V 240–480V 347V 600V or others |
98.58 | 98.47 |
| 10 | 98.70 | 98.60 | ||
| 15 | 98.82 | 98.73 | ||
| 25 | 98.95 | 98.87 | ||
| 37.5 | 99.05 | 98.97 | ||
| 50 | 99.11 | 99.04 | ||
| 75 | 99.19 | 99.13 | ||
| 100 | 99.25 | 99.19 | ||
| 167 | 99.33 | 99.28 | ||
Pole-mounted transformer installation dimensions drawing
Want to learn more about the technical parameters, overall dimensions, structural configurations, and available options of pole-mounted transformers? Visit our Pole-Mounted Transformer product page for more complete product information.
In terms of application scenarios, pole-mounted substations are suitable for areas where appearance is not a major concern and the terrain is relatively open, such as remote rural areas or large farms.
Their advantage is low construction cost, making them an economical and practical solution. For example, on a large farm, a pole-mounted substation can supply power to numerous dispersed agricultural devices, achieving efficient power distribution through its low cost and simple layout.
Choosing the right power transformer supplier not only affects equipment performance, but also directly influences the safety and economic efficiency of the power system. So, how can you choose a truly reliable transformer manufacturer? As a transformer manufacturer with more than 60 years of production history, CHBEB GROUP has summarized the following criteria based on our experience and practice.
A reliable transformer manufacturer must first operate legally and compliantly and obtain recognition from authoritative certification systems. This is important evidence of the company’s strength and product quality, and it is also a prerequisite for participating in major project tenders.
CHBEB GROUP has advanced production and testing equipment, comprehensive testing processes, and a modern management system. We adhere to innovative development and have passed ISO9001 Quality Management System Certification, ISO14000 Environmental Management System Certification, ISO45001 Occupational Health and Safety Management System Certification, CE Conformity Report, Low Voltage Directive Conformity, and GOST Declaration of Conformity, to meet the requirements of different markets and projects.
The technical advancement of transformers is directly related to the operating efficiency and stability of a project over the coming decades. A reliable manufacturer must have solid technical expertise and advanced product support.
As a National High-Tech Enterprise, CHBEB GROUP has certification from the National Transformer Quality Supervision and Inspection Center, CCC certification, 5 invention patents, and more than 120 patent certifications.
We provide high-quality products and solutions for State Grid Corporation of China and industries around the world, including power, metallurgy, steel, petrochemical, machinery manufacturing, and pharmaceuticals.
During 60 years of development, CHBEB GROUP has established its Beijing headquarters as the center for technical research and development, with three major production industrial parks in Nanjing, Jiangsu and Yueqing, Zhejiang. The company specializes in the production of transformers, compact substations, wind power substations, solar photovoltaic substations, high- and low-voltage switchgear assemblies, ring main units, pole-mounted outdoor circuit breakers, outdoor vacuum circuit breakers, power transmission and distribution supporting equipment, as well as power engineering contracting and installation.
A high-quality transformer product depends not only on reliable raw materials, but also on strict control of every production process.
CHBEB has always attached great importance to quality control throughout the entire production process and insists on working with leading raw material suppliers in the industry. From silicon steel sheets, copper wire, and insulation materials to transformer electrical accessories, product quality and stability are ensured from the source.
In terms of manufacturing processes, automatic winding equipment is used for the windings, with strict control over winding dimensions and conductor arrangement. The double vacuum casting process can effectively remove air bubbles and moisture from the coils, greatly improving the insulation strength of the transformer. During assembly, the coils and core are fitted tightly, the silicon steel laminations are stacked evenly, and strict operating standards are applied to the connections of leads, bushings, and switches.
During final inspection, every CHBEB product undergoes rigorous quality testing. Key tests such as no-load and load tests, partial discharge tests, and lightning impulse tests are strictly controlled.
Pole-Mounted Transformers are widely used in urban and rural distribution networks, remote areas, farms, and other distributed-load applications due to their compact structure, flexible installation, proximity to load centers, and relatively low construction cost. In practical selection, factors such as capacity, voltage level, core and tank structure, CSP protection, efficiency and loss requirements, local standards, and operating environment should be considered comprehensively to ensure long-term stable and reliable operation.
CHBEB GROUP has been deeply engaged in the transformer industry for more than 60 years, with a complete R&D, manufacturing, and testing system. We can provide parameter selection, structural configurations, and customized solutions for Pole-Mounted Transformers according to the requirements of different countries and projects. If you are looking for a suitable pole-mounted transformer for your project, please contact us for further technical support.
The common capacity range of pole-mounted transformers is generally 25–500 kVA. Capacity ratings such as 100 kVA, 160 kVA, 200 kVA, and 315 kVA are widely used in rural and urban-rural distribution networks.
Common high-voltage ratings include 6.6 kV, 10 kV, and 11 kV, while the low-voltage side is usually 0.4 kV or 0.415 kV. Depending on the distribution systems used in different countries and regions, voltage combinations such as 6.3–10 kV/0.4 kV can also be adopted.
The main reference standards include IEEE Std C57.12, IEC 60076, CAS C2.2:06, etc. The applicable standards vary depending on the country and region of use.
Taking a common 100 kVA, 11 kV/0.415 kV pole-mounted transformer as an example, its overall dimensions are typically about 1,200–1,400 mm in length, 750–950 mm in width, and 1,400–1,600 mm in height, with a weight of approximately 900–1,100 kg.
Smaller 25–50 kVA models are generally more compact, with a length of about 950–1,200 mm and a weight of approximately 300–550 kg. Larger-capacity models such as 200–500 kVA transformers will increase accordingly in size and weight.
The above data are only reference ranges for common specifications. Specific dimensions and weight should be based on the manufacturer’s actual design and model parameters.
