40MVA/20kV split auxiliary transformer for factory

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Place of Origin: HeBeiBrand Name:


Model Number:




Phase: Coil Structure:


Coil Number:

3 Winding

Capacity: Rated Voltage:


Connection Symbol:

YNd11 Dyn11 YNyn0d11


Cover type or Bell type


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 the 40MVA/20kV split auxiliary transformer, 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 200-490 tons, and due to the restricted transport conditions, the transportation becomes the critical issue for application of the 40MVA/20kV split auxiliary 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 the 40MVA/20kV split auxiliary 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:630 kilovolt transformer secondary side of the current is how much
630kVA that his rated capacity, it is ideal to say that with the load of 630kW (but actually can not bring so much) Rated current calculation formula: rated current = capacity / rated voltage / root number 3 (for 3-phase transformer) 630 / 0.4 / 1.732 = 909.3 A Pure hand to play, hope to adopt ~
Q:What is the unit of the transformer?
Power transformer capacity unit with KVA, that is, as the power. Most of the power load is inductive load, its apparent power is equal to the sum of active power and reactive power vector. Therefore, the apparent power of the inductive load is greater than the active power. If the active power transformer, the apparent power of the inductive load is greater than the power transformer capacity, the load current to exceed the allowable value of the transformer, so the inductive load must use the apparent power transformer. If the transformer load is all the resistance load, the total power can be equal to the transformer KVA value.
Q:The zero line of the transformer can be connected with the ground wire. Why not leave it?
Transformer at the zero line with the ground line together, called "repeat ground", is to achieve a stable system 220 volts power supply, the advantage is now widely used 380 / 220V system. That connector out immediately, there is a zero sequence current transformer, set in the zero line busbar, mainly to protect the transformer, it will not allow the transformer zero line there is a large current, that is a fault. The substation is coming out again. The general line is the end of the user or equipment, the device is a three-phase five-wire system, there is a main switch, often this switch is with leakage protection function, it does not allow any part of the line ground, the body accidentally touch, Causing the switch off power, can play a role in protecting personal safety. So, this part is not allowed to zero line and ground together, also known as TN-S system.
Q:Transformer input power how to ask?
The significance of no - load power factor of power transformer The power transformer is likely to run without load, while the low power factor will increase the grid supply voltage. When the power transformer is unloaded, the no-load current is mainly used to establish the transformer core excitation and provide the excitation loss. The excitation current is part of the current current is reactive current, the general design, the power transformer power factor is low. When the power transformer winding side of the application of sinusoidal AC, the magnetic field is also sinusoidal changes in the magnetic field. However, the core of the transformer is a non-linear magnetically permeable material, so the field current that produces the magnetic field must be non-sinusoidal. Generally appear as "steeple". Figure 1 for a single-phase transformer no-load current waveform and its harmonic spectrum. Transformer no-load operation, the output power is zero, no-load power is equal to no-load loss. In the case of loss of fixed, the smaller the no-load current, the higher the no-load power factor. Therefore, the power transformer no-load power factor is higher, the better the no-load current is better. Increasing the no-load power factor is one of the main technical research directions of power transformer manufacturers, and reducing the no-load current is an important technical means to improve the no-load power factor.
Q:What is the reason why the dry transformer is loud
500kva below the dry-type transformer noise 56 to 58 dB or so, 630kva above 62 to 65 dB or so! This is our factory data. The dry-type transformer sound is great. Big like cattle called the same, because the core is loose!
Q:Two different impedance of the transformer, parallel load how to allocate?
The impedance voltage is equivalent to the power supply resistance. Two impedance voltage is not equal to the parallel operation of the transformer, the impedance of the load distribution of small, low impedance voltage transformer load distribution. Basically inversely proportional. Generally the same type of transformer, the impedance voltage and capacity is basically inversely proportional to the large transformer impedance voltage is smaller than the small transformer impedance voltage. Parallel operation after the load distribution is basically proportional to the capacity of the transformer. But this ratio is not exactly the same, so even if the same type of transformer, the capacity difference is too large (more than 3 times), it is not allowed to run side by side. If it is different types of transformers, the impedance voltage and capacity is not completely inversely proportional to the capacity. The load distribution is even worse.
Q:Transformer rated capacity 500 / 750KVA (AN / AF) What does it mean?
Transformer under natural cooling conditions, the maximum capacity of 500kVA, air-cooled conditions, the maximum 750kVA A refers to air, N refers to the natural cycle, F refers to forced circulation Transformer (Transformer) is the use of electromagnetic induction principle to change the AC voltage of the device, the main components are primary coil, secondary coil and core (core). The main functions are: voltage conversion, current conversion, impedance conversion, isolation, voltage regulator (magnetic saturation transformer) and so on. According to the purpose can be divided into: power transformers and special transformers (electric furnace change, rectifier, frequency test transformer, voltage regulator, mine transformer, audio transformers, IF transformers, high-frequency transformers, impact transformers, instrument transformers, electronic transformers , Reactors, transformers, etc.). Circuit symbols commonly used as the beginning of the number. Example: T01, T201 and so on.
Q:The difference between the reflection impedance of the ideal transformer and the hollow core transformer is different.
The ideal transformer reflection impedance is the equivalent impedance of the load resistance equivalent to both ends of the primary coil, directly across the primary coil at both ends, in parallel with the primary circuit, and the nature of the reflection impedance and load impedance of the same nature.
Q:Rated capacity of three-phase transformer S = √3 * U * I
Single phase transformer S = UI where U is the phase voltage and I is the phase current. When the composition of three-phase transformer, of course, is the three transformers add up, S = 3UI. Here U is phase voltage, I is the phase current. As the three-phase circuit to use the line current and line voltage calculation, angle and triangular connection is the same, when U is the line voltage, the phase voltage increases the root number 3 (1.732) times.
Q:What is an isolated ring transformer?
Isolated ring-type transformer is mainly focused on its insulation performance, between the primary and secondary must have a double insulation, so that the isolation of its own high efficiency, effective protection of equipment safety.

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