240MVA/345kV three-phase OLTC auto-transformer

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Place of Origin: HeBeiBrand Name:


Model Number:






Coil Structure:


Coil Number:

3 Winding

Capacity: Rated Voltage:


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YNd11 Dyn11 YNyn0d11


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MR or ABB or SMS

Packaging & Delivery

Packaging Detail:Mainbody --naked Disassembled parts -- crate
Delivery Detail:3 months



1. CESI certificate
2. High short-circuit withstand
3. Low loss, PD and noise
4. CTQC certificate
5. No leakage




The application of 240MVA/345kV three-phase OLTC auto-transformer can significantly improve the economy of the UHV substation, and matches well with the transmission capacity of UHV lines, which has wide prospect of application. Because of its large capacity and large volume, the whole transportation weight with nitrogen is about 470-490 tons, and due to the restricted transport conditions, the transportation becomes the critical issue for application of the 240MVA/345kV three-phase OLTC auto-transformer. In order to make the products applicable to any UHV substation in our country, the state grid of corporation of China set the "A study of easy-transport large capacity UHV Transformer” as a key scientific research projects, and entrusted BTW to carry out the research.

During the process of research and development, BTW adopted the advanced design technology and modular design, the transformer can be transported disassembly and with advantages of compact core and winding body, less transportation weight and low transportation cost, effectively solves the need of UHV construction in the transportation restricted areas. By using the most advanced 3D magnetic field calculation software, BTW performed detailed analysis and calculation for the magnetic flux leakage and eddy current loss of the transformer coil, iron core and oil tank steel structures. Besides, by using of the advanced electric field calculation software, BTW performed detailed analysis and calculation of main longitudinal insulation, and mastered the arrangement of the main longitudinal insulation of large capacity UHV transformer and the control of distribution of winding magnetic flux leakage. All of which make the products with low loss, low noise, small volume, strong anti short circuit ability, no local overheating and other significant advantages, and guarantee the long-term safe and stable operation.

The world's first on-site assembled large capacity UHV Transformer’s right at the first time once again filled the gap in the field of UHV transformer research after Chinese transformer industry overcame the difficulty of integral transport of 240MVA/345kV auto-transformer, which marks BTW has fully occupied the world transformer industry technical peak. The successful development of the product filled the gaps in the domestic technology and met the urgent need of UHV construction application in our country, greatly improved the technical level and manufacturing ability of BTW in terms of UHV Transformer products.


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Q:National Standard for Transformer Life
I can only give you in the transformer industry, we all agree that the argument: 1, before the transformer, the oil inside the transformer and air direct contact. As the transformer in the thermal expansion and contraction, the oil up and down fluctuations, we called the transformer in the breath, an increase of oil and air contact opportunities. The moisture enters the inside of the transformer. So that insulation is reduced. Under normal operation and maintenance, the transformer is guaranteed to have a life span of 20 years. 2, the current transformer, to take a fully sealed structure, oil pillow with sealed pocket, so that the transformer oil is not in direct contact with the air. Under normal operation and maintenance, the transformer life is 30 years
Q:Transformer Lightning
Dry coil internal coil will burst open, so that the transformer outside the four sides of the shell will be bulging. Cylinders on the porcelain will burn black, porcelain will be black and cracked. The line breaker is tripped.
Q:Know the rated capacity of the transformer, how to calculate its rated current?
If it is a power transformer, its calculation method: rated current = rated capacity ÷ root 3 ÷ output voltage Such as the rated capacity of 1250KVA, the rated current = 1250000 ÷ 1.732 ÷ 400 = 1804A
Q:Power transformer primary current and secondary current
Once refers to the power side, the second refers to the load side
Q:Two Transformers Parallel Operation
The total capacity of the two transformers in parallel is not a simple addition of the capacity of the two transformers. Even if the rated capacity of the two transformers is exactly the same, the impedance of the two transformers can not be exactly the same due to the existence of design / manufacturing errors. Based on the principle of the parallel circuit, the transformer with a small impedance will share a larger current, A transformer has been overloaded and another transformer is not yet fully loaded. Can be based on the measured value of two transformer impedance (on the nameplate). Calculate the transformer with a small impedance to reach full load, the load of another transformer, the sum of the two is the total capacity of the two transformers in parallel. In fact, the transformer capacity selection is usually about 25% greater than the actual load, so the reality is usually not a full load, while the other has been a serious overload situation.
Q:How to calculate non - isolated power transformer parameters
General non-isolated auxiliary windings according to chip drop VCC operating range. T = 1 / f Dmin = Vout / Vin (max) Ton = T * Dmin Id = Io * 0.3 (0.3 for the ripple current coefficient) Inductor voltage V = Vinmin-Vout-0.6 (Schottky voltage drop) Lmin = V * dt / di If there are problems please go to the big bit of the forum electronic transformer plate
Q:Power transformer parameters
B. Transformer efficiency: In the rated power, the transformer output power and input power ratio, called the efficiency of the transformer, that η = (P2 ÷ P1) x100% where η is the efficiency of the transformer; P1 is the input power, P2 is the output power. When the transformer output power P2 is equal to the input power P1, the efficiency η is equal to 100%, the transformer will not produce any loss, but in fact this transformer is not the transformer transmission power always produce loss, this loss is mainly copper Loss and iron loss. Copper loss is the loss caused by the transformer coil resistance.When the current through the coil resistance heat, part of the energy into heat and loss.As the coil is generally wrapped with insulated copper wire, so called copper loss. The iron loss of the transformer includes two aspects: First, the hysteresis loss, when the AC current through the transformer, through the transformer silicon steel wire magnetic field its direction and size changes, making the silicon steel sheet internal friction, release heat, Part of the energy, which is the hysteresis loss. The other is the eddy current loss, when the transformer work, the magnetic core lines through the line, and the magnetic lines perpendicular to the plane will produce induced current, because the current self-closed loop Circulation, and into a spiral, so called vortex. The presence of eddy current heat, energy consumption, this loss is called eddy current loss. Transformer efficiency and transformer power levels are closely related, usually the greater the power, loss and output power is smaller, the higher the efficiency, otherwise, the smaller the power, the lower the efficiency.
Q:What is the vacuum impregnation of the transformer?
In addition, if the conditions can also be limited if the transformer high temperature dipping (100 ~ 120 degrees), you can play the same effect
Q:Transformer and the middle of what is the difference
In the week is the IF transformer or inductance coil, is a fixed resonant circuit with a transformer, the resonant circuit can be fine-tuning within a certain range, so that access to the circuit can achieve a stable resonant frequency.
Q:What is the maximum current of the 800KVA transformer? What is the current? Is how to calculate, ask you master
This type of capacity of the transformer for the distribution transformer, that is, step-down transformer. Voltage combination to 10 / 0.4 for multi-purpose. Transformer high side current 46.19A, low side current 1154.73A. Rated capacity = 1.732 * rated voltage * rated current

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