The ZQSCB series Epoxy Cast Dry-Type Traction Rectifier Transformer is a high-reliability dry-type transformer designed specifically for urban rail transit and industrial rectification systems. Utilizing an epoxy resin vacuum casting process, this product offers equivalent 24-pulse rectification capability, supporting dual-unit 24-pulse operation or single-unit 12-pulse operation. It combines energy-saving, environmentally friendly, low harmonics, and high overload capacity advantages, making it widely used in rail transit traction power supply and other demanding industrial scenarios.
1.High-Voltage Winding
The high-voltage winding utilizes a fully cast structure with thin insulation and minimal filler, wound in a segmented cylindrical manner. The conductor is 100% oxygen-free copper wire. A special epoxy resin is poured into the winding under vacuum to fully remove internal gases and maintain stable partial discharge within 10pC. This casting results in a fiberglass-like solid structure with strong integrity and high mechanical strength. It offers excellent moisture resistance and supports immediate power-up and operation. Both the high-voltage extended winding and the main winding are equipped with taps to ensure a constant phase shift angle during voltage regulation and consistent harmonic characteristics.
2. Low-Voltage Winding
The low-voltage winding is wound with copper foil, using epoxy prepreg insulation between layers. Axial heat dissipation ducts are provided in the center, with internal support ribs to enhance mechanical strength and heat dissipation efficiency. The winding is cured at high temperature to form a single structure, and both ends are sealed with resin. The winding features balanced ampere-turn distribution, strong current carrying capacity, and excellent short-circuit shock resistance.
3. Vacuum Casting Process
The fully automated vacuum casting equipment is equipped with a multi-stage degassing system, a precision metering pump, and a dynamic mixing system to ensure accurate epoxy resin mixing and uniform mixing. The vertical casting process facilitates the removal of bubbles, and the vacuum level is controlled in real time during the casting process, eliminating defects and improving the winding's mechanical strength and electrical performance.
4. Core Structure
The core is constructed from high-quality cold-rolled, grain-oriented silicon steel sheets from Baowu Group or imported from abroad. Precision sheared on a German GEORG production line, the core exhibits minimal burrs. A seven-stage stepped stacking structure with 45℃ fully beveled seams effectively improves magnetic flux distribution and reduces no-load losses, no-load current, and operating noise. The core surface is resin-coated for moisture and corrosion resistance and low vibration. 5. Product Inspection and Testing
5.In addition to factory testing, each product undergoes the following tests:
1) Phase shift angle test;
2) Harmonic characteristics test: Ensure that the total harmonic current of a 24-pulse system is at least 60% lower than that of a 12-pulse system.
Load test: Includes verification under Level VI load conditions (100% continuous, 150% for 2 hours, 300% for 1 minute).
1. Multi-pulse operation, high system reliability: Supports dual-unit 24-pulse operation or single-unit 12-pulse operation, providing strong system redundancy and significantly improved reliability.
2. Excellent harmonic suppression: The total grid-side harmonics of the 24-pulse rectifier system are at least 60% lower than those of a 12-pulse system. The phase shift angle of each tap is 7.5℃, ensuring consistently low harmonic levels.
3. Strong overload capacity and excellent temperature rise control: Reliable operation under Level VI load conditions meets the requirements of rail transit operating conditions with sudden and frequent load changes. 4. Convenient Phase Shift Adjustment: ±7.5℃ phase shift can be achieved simply by changing the high-voltage external wiring sequence. Flexible operation facilitates user use and system adjustments.
5. Balanced Parameters and Reduced Harmonics: Excellent symmetry of technical parameters ensures uniform load distribution, effectively suppressing non-characteristic harmonics and improving grid quality.
6. Simplified Structure and Reduced Investment: The axial double-split coil structure eliminates the need for balancing and smoothing reactors, resulting in a smooth DC output waveform, a simple system structure, and outstanding cost-effectiveness.
7. Fireproof, Safe, Environmentally Friendly, and Maintenance-Free: Using air as the cooling medium and epoxy resin as insulation, the product is non-flammable, non-explosive, non-toxic, and non-polluting, making it suitable for fire and explosion-proof applications.
Implementation Standards: IEC60146, IEC60076
Grid Side: 10kV, 20kV, 35kV, or Customized
Valve Side: 1.18kV–1.22kV, or Customized
Capacity Range: 1000–5000kVA
Voltage Regulation Range and Method: ±5%, ±2×2.5%, Off-Excitation Voltage Regulation
Frequency: 50Hz
Transformer Combination: Two units, 12-phase, 24-pulse
Connection Group: Dy11d0 (+7.5℃) and Dy1d2 (+7.5℃) or customizable
Partial discharge: <=10pC
3kV and below: Power frequency withstand voltage 10kV, impulse withstand voltage 20kV
10kV: Power frequency withstand voltage 35kV, impulse withstand voltage 75kV
35kV: Power frequency withstand voltage 70kV, impulse withstand voltage 170kV
The Epoxy Cast Dry-Type Traction Rectifier Transformer is particularly suitable for applications with stringent requirements for harmonics, reliability, fire and explosion resistance, such as urban rail transit traction power supply systems, ship electric propulsion systems, and port shore power. Its excellent environmental adaptability and maintenance-free design make it an ideal choice for modern green grids and intelligent transportation systems.
