What are the uses of dry-type cast resin transformers in cities?

Dry-type cast resin transformers stand out as advanced power distribution solutions, boasting exceptional electrical insulation capability, superior thermal stability, and robust mechanical durability—traits that stem from their innovative construction using high-grade epoxy resin encapsulation. Unlike oil-immersed transformers, their core and windings are fully encapsulated in vacuum-cast epoxy resin, which not only enhances electrical performance by preventing partial discharge but also delivers remarkable resistance to extreme temperatures (typically rated for F-class or H-class thermal operation) and mechanical stress, such as vibration or impact during transportation and operation. This design ensures long-term reliability even in harsh operating conditions, making them a trusted choice for critical power infrastructure.

Engineered to meet stringent safety and performance standards, these transformers are the go-to option for urban power grid modernization initiatives, where upgrading aging infrastructure demands equipment that balances efficiency and safety. They excel in environments requiring strict explosion-proof, fire-retardant, and moisture-resistant properties—making them indispensable for high-rise buildings (where space constraints and fire safety risks are paramount), power generation plants (ensuring stable energy conversion), airports (supporting uninterrupted power for navigation and passenger services), and commercial centers (catering to high-density power loads with minimal downtime). Beyond these core applications, they also serve as reliable solutions for terminal power supply systems and ring network power distribution, where quick installation and flexible operation are key. Their ability to maintain consistent performance across diverse use cases underscores their versatility in modern power systems.

One of the most notable benefits of dry-type cast resin transformers is their elimination of the need for dedicated transformer rooms, a feature that revolutionizes installation flexibility. These units can be directly deployed indoors (such as in building basements or equipment closets), outdoors (in open industrial yards or utility areas), or even integrated into street greenbelts—blending seamlessly with urban landscapes while preserving valuable land resources. This adaptability not only reduces construction costs associated with building specialized enclosures but also enhances safety: the epoxy resin encapsulation prevents leakage of flammable or toxic substances, protecting both personnel and surrounding environments. Additionally, their compact design, low noise emission (typically below 55dB), and aesthetically pleasing profile make them ideal for residential areas or public spaces where environmental harmony is a priority. The combination of reliable power supply performance and user-friendly installation ensures operational flexibility without compromising on safety or efficiency.

Transformer impedance is a critical parameter that directly impacts voltage regulation, short-circuit current limitation, and overall system stability—and its value is inherently determined by the transformer’s physical and design characteristics. Key factors shaping impedance include the type and grade of core material (e.g., high-permeability silicon steel sheets, which influence magnetic flux density), the quantity of core laminations, and the structural design of the windings (such as conductor cross-sectional area, winding pitch, and insulation thickness). Additionally, the degree of magnetic coupling between the primary and secondary windings, as well as the number of turns in each winding, plays a pivotal role in determining impedance levels. Understanding these factors is essential for optimizing transformer performance to match specific grid requirements, as impedance directly affects how the transformer responds to load changes and fault conditions.

Impedance in dry-type cast resin transformers is typically expressed as a percentage relative to the transformer’s rated voltage and power. The standard measurement process involves a systematic short-circuit test: first, the low-voltage winding is short-circuited using a high-capacity conductor to ensure full current flow. Next, a variable voltage is applied to the high-voltage winding, gradually increasing until the low-voltage winding current reaches its rated value (or a specified percentage thereof, such as 100% rated current). At this point, the impedance value is derived from the measured voltage and current data, and further calculations are performed to determine the impedance percentage relative to the high-voltage winding’s rated voltage. This measurement is critical for verifying that the transformer meets design specifications, ensuring stable voltage output under varying loads, and safeguarding the entire power system from excessive short-circuit currents. Accurate impedance testing is a cornerstone of quality control in dry-type transformer manufacturing, guaranteeing consistent performance across all operational scenarios.