SC(B)12-14-18 epoxy resin cast dry-type transformer

Overview

Epoxy resin-cast dry-type transformers can be manufactured with conventional, standard enclosed busbar, and side-outlet options to suit various interface configurations. Special design options can also be customized to meet customer requirements.

The coils are wound on a high-precision winding machine. Glass fiber is applied to the inner and outer layers of the coils during winding. Ventilation ducts are designed for larger transformers. After winding, the coils are vacuum-dried. The entire casting and curing process is completed according to process curves transmitted from the process department to the casting control terminal via a computer network. All processes can be monitored at the computer terminal and automatically adjusted accordingly. The precise manufacturing process ensures that the coils are free of bubbles and voids.

The main components include spacers, cooling ducts, high-voltage coils, low-voltage coils, core, lifting rings, temperature control, high-voltage copper busbars, upper yoke, high-voltage insulators, high-voltage connecting rods, high-voltage taps, high-voltage connecting plates, fans, and a base.

Product Specifications

High Dielectric Strength

Pouring epoxy resin has an insulation breakdown field strength of 18-22 kV/mm and offers roughly the same lightning impulse strength as oil-immersed transformers of the same voltage level. It also has an insulation temperature rating of F, a maximum allowable temperature of 155°C, and a winding temperature rise limit of 100 kV.

Strong Short-Circuit Resistance

Due to the resin's material properties and the fact that the windings are integrally cast and then heat-cured to form a steel body, the resulting structure offers exceptional mechanical strength. Sudden short-circuit tests have shown that cast dry-type transformers rarely experience damage from short circuits.

Excellent Environmental Performance

Epoxy resin is a chemically extremely stable material, resistant to moisture and dust. It operates reliably even in polluted environments, even at 100% humidity. It can be put back into operation after an outage without requiring drying or preheating.

Maintenance-Free

Thanks to a comprehensive temperature control and display system, epoxy-cast dry-type transformers are now maintenance-free, significantly reducing the burden on operators and lowering operating costs. They offer low operating losses, high efficiency, low noise levels, and are compact, lightweight, and easy to install and commission. They eliminate the need for a separate transformer room and core inspection, saving floor space and correspondingly reducing construction investment.

Strong Overload Capacity

The SC(B)10-12 series can withstand a long-term overload of 1.16 times the rated load at an ambient temperature of 20°C, and a 1.5 times overload for up to 60 minutes. If a fan is used to operate the transformer in forced air cooling (AF), it can withstand a short-term overload of 1.5 times the rated load. [Note: The overload capacities of the transformer's high and low voltage inlet and outlet switches and busbars must match.]

Outstanding Disaster Prevention

Epoxy resin is flame-retardant, self-extinguishing, and non-flammable, preventing secondary hazards such as explosions.

Main technical parameters

Rated voltage: The voltage between the transformer's high-voltage input and low-voltage output (35kV/0.4; 20kV/0.4; 10kV/0.4).

Rated frequency: my country's power grid frequency is 50Hz; overseas, it's 60Hz.

Short-circuit impedance: A basic parameter for voltage transformation (normally 4% or 6%).

No-load loss (Po): The loss generated when the transformer operates without load. This loss occurs in the transformer core and is sometimes referred to as iron loss. The transformer's no-load loss is not directly related to temperature; it remains constant at all temperatures.

Load loss (Pk): The loss generated in the windings when the transformer is operating at rated load. This also includes losses in the structural components caused by leakage magnetic fields. This loss occurs primarily in the copper conductors of the windings and is therefore also referred to as copper loss. The transformer's load loss varies with temperature because the conductor's resistance changes with temperature. Therefore, the loads of different transformers must be converted to the same temperature. The reference temperature for oil-immersed transformers is 80°C, for Class F dry-type transformers it is 120°C, and for Class H dry-type transformers it is 145°C.

Insulation level: The electrical strength a transformer must withstand, primarily including lightning strike resistance and power frequency withstand voltage.