As urban scale continues to expand, urban rail transit has gained increasingly widespread application and development due to its large capacity, safety, speed, and excellent environmental performance. The ZQSCB epoxy cast traction rectifier dry-type transformer is a key component of the power rectification system for rail traction locomotives. It adopts the extended delta connection principle, allowing a phase shift of +7.5° or -7.5° by changing the delta connection method. The valve side uses d and y connections so that the line voltage phasors of the valve-side windings of two transformers differ by 15°. Composed of two 6-phase 12-pulse phase-shifting transformers, it forms a 24-pulse DC output through silicon rectifiers. It can also supply power individually through a rectifier to form a 12-pulse rectified DC output, with low harmonic content. This series of products features high insulation heat resistance grade, low loss, low noise, low partial discharge, moisture resistance, and strong overload capacity, fully meeting the requirements of rail Class VI duty, providing reliable power supply quality and effective guarantee for the safe operation of electric locomotives.

Product Features:

1.When two units operate, it forms a 24-pulse system; a single unit can also operate as a 12-pulse system, greatly improving system operation reliability.

2.The 24-pulse rectification system reduces the total harmonic current to the grid by more than 60% compared to 12-pulse systems. Each tap on the grid side shifts phase by 7.5°, resulting in very low harmonic content at all tap positions.

3.Low temperature rise and strong overload capacity, capable of reliable operation under Class VI load conditions.

4.Strong interchangeability: Only the external high-voltage connection sequence of the transformer needs to be changed to achieve ±7.5° phase shift, making it convenient for users.

5.Good balance of key technical parameters, uniform load distribution, effectively reducing non-characteristic harmonic content.

a.Unbalance rate of no-load output voltage between two single units ≤0.3%

b.Unbalance rate of half-through impedance ≤3%

c.Both main and phase-shifting windings have taps, with phase shift angle deviation ≤1.5° at each tap

6.The coils adopt an axial double-split structure, eliminating the need for smoothing reactors. The output DC waveform is smooth, simplifying the grid structure and saving investment.

7.High mechanical strength

8.Excellent moisture resistance

9.Partial discharge less than 5pC

10.Strong resistance to thermal aging and high temperature resistance grade

11.Environmental protection

a.Epoxy resin cast transformers cause no environmental pollution from natural degradation

b.Low noise

c.Low electromagnetic radiation pollution

Technical Parameters

Capacity: 800kVA–4500kVA

Voltage Level: 35kV and below

Voltage Regulation Range: ±2×2.5%

Frequency: 50Hz

Connection Group:

a)Dy11d0 (phase shift +7.5°) and Dy1d2 (phase shift -7.5°);

b)Dy5d0 (phase shift +7.5°) and Dy7d2 (phase shift -7.5°)

Phase Number: Three-phase

Insulation Class: Class F

Other parameters comply with national standards or meet customers’ special design requirements