Daelim helps you to know more about pole mounted transformer
What is pole mounted transformer
The so-called pole-mounted transformer refers to its installation form only, not the transformer classification form. Generally, the transformer installed on the pole has a capacity of not more than 250kVA.
Transformers are generally divided into oil-type transformers and dry-type transformers. According to the environment, they are divided into indoor and outdoor types. According to the voltage regulation structure, they are divided into on-load voltage regulation and no-load voltage regulation.
What you are asking here should be what type of transformer should be selected for pole-mounted transformers. It is recommended that after determining the capacity of the transformer according to the load, the type and installation form of the transformer should be determined according to the capacity of the transformer.
There is no difference in their effect, but the pole-mounted transformer is used outdoors, and its structure is more convenient for outdoor installation.
The transformer on the pole is generally a small transformer, which can convert the high voltage above 10KV into 220V civilian power to supply electricity to several households nearby, without pulling a long line from the terminal transformer to save investment.
Other transformers need a platform and a power distribution room, and the pole mount transformer is fixed on the pole, so it is called a pole mount transformer.
Pad-mounted Transformer
Dry-type Transformer
Oil immersed transformer
Table of Content
What size are pole transformers?
It depends on single phase pole mount transformer or three phase pole mount transformer. And also depends on the capacity, please check this link for more detailed information of our transformer.
Keep on reading 110 kv Oil Filled Power Transformer – DAELIM BELEFIC
What are the requirements of installing the pole-mounted transformer?
Pole-mounted transformer construction process 1:
Construction preparation
Conduct on-site surveys, determine construction plans, and write construction standard work cards.
Conduct electrical tests on electrical equipment to ensure that the equipment is qualified.
Check whether the construction tools and equipment are sufficient and intact, and whether the mental state of the personnel is suitable for the construction operation.
Check whether the double-pole assembly is upright, whether the buried depth meets the specification requirements, the double-pole root opening error should not exceed ±30mm, and the double-pole height difference should not exceed ±20mm.
Check whether the grounding production meets the specifications and whether the grounding resistance meets the design requirements.
The construction process of the transformer on the column 2:
Installation of the cross arm
The cross arm should be made of galvanized angle steel and channel steel, and the cross arm should be installed in the order from top to bottom.
For the double-pole cross-arm, the height difference between the cross-arm and the pole should not be greater than 5/1000 of the connection distance, and the left and right skew should not be greater than 1/100 of the length of the cross-arm.
The distance between the cross arm of the drop fuse and the transformer channel steel should not be less than 2.5m, to ensure that the fuse tube of the drop fuse can maintain a sufficient distance from the distribution transformer when it falls off.
Bolt passing through: three-dimensional structure: the horizontal direction is from the inside to the outside, and the vertical direction is from the bottom to the top.
Planar structure: along the line direction, the double-sided components are from the inside to the outside, the single-sided components are penetrated from the power transmission side or in the same direction;
in the horizontal line direction, the two sides are from the inside to the outside, and the middle is from left to right (facing the power receiving side) or Press uniform direction; vertical direction, from bottom to top.
When the screw must be gasketed, each end should not exceed 2 gaskets. The bolts should be perpendicular to the plane of the member and should not have gaps.
Transformer construction process on the column 3:
Transformer hoisting
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Three-phase pole mount transformer
The capacity of the three-phase transformer installed on the phase transformer column should not exceed 400KVA.
First, conduct visual inspection of the transformer to ensure that all components are in good condition, the oil level is normal, the casing is clean, and the breathing passage is unobstructed, which meets the operating requirements.
According to the weight of the transformer and the terrain, determine the hoisting plan. Select the wire rope sleeve that matches the weight of the transformer, and hook it on the lifting point of the transformer.
Do not hang it on the cooling fin or the oil tank to avoid damage to the transformer. When hoisting, it should be kept horizontal, and caution should be taken during the hoisting process to avoid bumping the fuel tank or the casing.
The angle of the hoisting steel cable should not be greater than 60 degrees, and overload lifting is strictly prohibited.
When the transformer is about 0.1m off the ground, the lifting should be suspended and checked by a special person, and the lifting can be continued after confirming that it is normal.
The transformer is fixed on the channel steel by clip iron, and the distance between the transformer and the ground is not less than 2.5m.
The distribution transformer should be installed upright, the horizontal inclination should not be greater than 1/100 of the root opening, and an appropriate distance from the cement pole should be maintained.
For the installation of arrester, please refer to the “Construction Technology of Arrester on Column” that we will introduce soon.
Add transformer nameplates and warning signs to the conspicuous positions on both sides of the transformer.
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Single-phase pole mount transformer
The capacity of the single-phase transformer installed on the column should not exceed 100kVA.
First, conduct visual inspection of the transformer to ensure that all components are in good condition, the oil level is normal, the casing is clean, and the breathing passage is unobstructed, which meets the operating requirements.
According to the weight of the transformer and the terrain, determine the hoisting plan. Select the wire rope sleeve that matches the weight of the transformer, and hook it on the lifting point of the transformer.
Do not hang it on the cooling fin or the oil tank to avoid damage to the transformer. When hoisting, it should be kept horizontal, and caution should be taken during the hoisting process to avoid bumping the fuel tank or the casing.
The angle of the hoisting steel cable should not be greater than 60 degrees, and overload lifting is strictly prohibited.
When the transformer is about 0.1m off the ground, the lifting should be suspended and checked by a special person, and the lifting can be continued after confirming that it is normal.
The transformer is fixed on the cement pole with a hoop, and the distance between the transformer and the ground is not less than 4.5m.
The installation of the transformer should be straight and firm. For the installation of arrester, please refer to the “Construction Technology of Arrester on Column” that we will introduce soon.
Add transformer nameplates and warning signs to the conspicuous positions on both sides of the transformer.
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Column-mounted transformer construction process 4
Distribution box hoisting
Check the appearance of the distribution box first to ensure that all components are in good condition and the wiring is correct.
According to the weight of the distribution box and the terrain, determine the hoisting plan.
Select the wire rope sleeve that matches the weight of the distribution box, keep the distribution box level when hoisting, and be careful during the hoisting process to avoid bumping the box.
The included angle of the hoisting wire rope should not be greater than 60 degrees, and overload lifting is strictly prohibited.
When the distribution box is about 0.1m off the ground, the lifting should be suspended and checked by a special person, and the lifting can be continued after confirming that it is normal.
The distribution box is fixed and hoisted under the channel steel with iron clamps, and the distance between the distribution box and the ground is not less than 2m.
The distribution box should be installed flat and firm. Paste the name of the station area and warning signs on the conspicuous positions on both sides of the distribution box.
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The construction process of the transformer on the column 5
The connection of the drainage line
The connection between the lead wire and the overhead line should use parallel groove wire clips or insulation piercing wire clips, the number of wire clips should not be less than 2, the type of wire clips should match the wires, and the connection parts of wires and drainage wires should be removed before overlapping
The oxide layer ensures that the contact is tight and good. The high-voltage leads of drop fuses, transformers and arresters should be connected with insulated wires, and the cross-section should not be less than 35mm2.
The neutral point of the transformer and the casing, the casing of the distribution box and the grounding down-conductor of the arrester should be connected with multi-strand copper core wires, the protective grounding and the working grounding should be grounded separately, and the cross-section should not be less than 25mm2.
The lead on the low-voltage side of the transformer should be selected according to the distribution capacity and load.
The large-capacity one should be connected by a single-core copper cable, and the small-capacity one should be connected by a four-core copper cable or insulated wire. The lead wires are distinguished by color codes.
The leads should be arranged neatly with proper spacing, and the lead connections should be terminals, and the connection should be coated with electrical compound grease.
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The construction process of the transformer on the column 6
Install the insulating cover
Install insulating covers on the transformer high and low voltage pile heads and arresters. The color of the insulating cover should correspond to the color of the line.
The construction process of the transformer on the column 7
Quality acceptance
There should be product manuals, factory test reports, qualification certificates, handover test reports and relevant completion materials for electrical equipment.
The electrical equipment and lead-to-ground and phase-to-phase distances meet the specification requirements.
The appearance of the electrical equipment should be complete without damage, and the electrical connections should be tight, reliable and in good contact.
The fuse should be flexible in operation and the fuse configuration should meet the requirements.
The grounding resistance meets the specification requirements, and the grounding connection is tight and reliable.
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How much copper is in a pole mounted transformer?
For oil-type transformers, the copper-containing weight is 20% of the total weight of the transformer.
Why is it necessary to ground the neutral of a pole mounted transformer?
Grounding the neutral point can return the phase wire of the equipment in which the accident occurs to the “shell” to the transformer through the ground and the ground wire connected to the neutral point,so that a short-circuit fault occurs in the system, thereby forcing the air circuit breaker or fuse to disconnect, protecting the human body safety.
