Main Power Transformer General:

The Xiecheng-brand 220kV, 110kV and 66kV low loss Main Power
transformers are independently developed based on advanced domestic and foreign technologies. Featured with reliable low partial discharge level, low loss, low noise, high reliability and strong anti-abrupt short circuit capacity, these products are highly appraised among the vast users and experts with their outstanding performance. The fully sealed products without windlass cover sell well all over the nation.

Partial discharge level: the apparent discharge magnitude under the voltage of 1.5 times the nominal voltage is less than 80pC;
Noise: below 58dB for products of 63MVA and below (AN);
Loss: non-load loss ratio is about 30% lower than IEC standard;
Reliability: none of the in-service products has experienced damage accidents or oil leakage;
Anti-short circuit capacity: SFZ11-50000/132 passed the short circuit bearing capacity test of Holland KEMA and lab of China National Transformer Quality Supervision Testing Center at one time.

 Coil:

High-voltage windings adopt the continuous interleaved structure to improve the distribution characteristics under surge voltage and obtain relatively uniform electric field distribution. The strips and cushion blocks are chamfered to improve the reliability of insulation.

There is winding oil guide structure inside the transformer winding, so that each area within the winding can be fully cooled, thus reducing winding temperature rise and winding hot spot temperature rise and extending the insulation service life.

Separate regulating windings are set for high-voltage and medium-voltage regulation units, so that the ampere-turn of each winding is relatively balanced and the axial electro-dynamic force can be effectively reduced in case of transformer short circuit, hence improving anti-short circuit capacity of the transformers. The windings adopt “0” margin design radially; the part between the iron core and the low-voltage winding cylinder, the part between the low-, medium- and high-voltage windings as well as the part in front of the strips and coaming assembly are fully dried and tightly fitted to ensure that the entire winding has perfect compactness and concentricity.

  Core:

The core material is high-quality cold-rolled high magnetic conductive grain-oriented silicon steel sheets and the advanced automatic cutting line imported from Georg is used for blanking. The burrs at the sheared edges are controlled at smaller than 0.02mm.

The silicon steel sheets adopt the process of non-laminated top yoke and the lap joint of silicon steel sheets is 45° full sloping step. Integrated pressurizing and epoxy adhesive are applied to make the three limbs and two yokes a strong and smooth entity of high vertical accuracy, hence their no-load performance effectively improved and noise reduced.

Brackets are inserted between core limbs and the inner winding to support the core limbs; the iron yokes are strained with glass tapes immersed in epoxy; reaction pressure tap bolts are used between the lower yoke and the lower tank for tightening. In addition, there are three fastening points between the upper yoke and the upper tank and therefore displacement of the transformer body will not occur in the transportation process due to bumps.

  Fuel tank and accessories:

The tank wall adopts wide steel sheets not butt welded; instead, they are corrugated to reduce weld joints and improve mechanical strength. Meanwhile, corrugated tank walls have dissipation effects, thereby reducing noise. The secondary circuit wiring board and control cabinets are all made with stainless steel. Our transformers are beautifully and concisely shaped.

All sealed surfaces are fine finished and sealed with high-quality sealing materials.

The tank edges have dual sealing grooves. The outer sealing material is used to prevent air and ultraviolet ray from damaging the internal sealing material, thereby improving the service life of sealing elements to the maximum extent and ensuring the sealing reliability.

  Group members:

We have established good cooperative relationship with many large transformer component manufacturers and can make diverse components based on different user requirements. Our production, R&D and sales services are strictly performed according to international standard certification and ISO quality management system.