50 kva pole mount transformer is mounted on an electrical service pole

50 kva pole mount transformer

is mounted on an electrical service pole, usually at the level of the overhead cables but occasionally at ground level. Pole-mounted transformers are the common breadbox transformers used for converting distribution voltage to the 120/240 volt power used by homes and low-volume commercial installations.
50kva transformer is used in extensive rural area. These transformers range from 16 kVA to 100kVA and transform 11,000 to 33,000 volts down to a low voltage of 400 volts. Pole mounted transformers are reasonably small in size and mass so that it is easy to install them on single pole structures, and larger units on two-pole structures, approximately 5 meters above the ground. This makes the transformers inaccessible, reducing the risk of injury to animals and people and minimizing vandalism.

50 kva pole mount transformer is used to step-down distribution voltage to the final voltage used for residential

50 kva pole mount transformer is used to step-down distribution voltage to the final voltage used for residential, industrial, and commercial applications. pole transformers are mounted to a utility pole where service drop wires are run underground or overhead to a customer’s location to supply power. Multiple customers can be serviced from one transformer depending on the load each customer demands. Pole Mount Transformers can be built for 1 Phase or 3 Phase applications.

Basic knowledge of rated capacity of power transformers

The main function of the transformer is to transfer electrical energy, therefore, the 100kva distribution transformer rated capacity is the main parameters of the transformer. The nominal capacity of the transformer is a nominal value of the power of the performance. It is the magnitude of the transmitted energy, expressed in kVA or MVA, and is used to determine the rated value of the temperature rise limit under the specified conditions when the rated voltage is applied to the transformer Current. conventional pole transformer capacity size and voltage level is also closely related. Voltage is low, the capacity is large, the current is large, loss increases; high voltage, capacity, insulation ratio is too large, the transformer size relative increase, therefore, low voltage capacity will be small, high voltage capacity will be large. The rated capacity of the two-winding transformer is the rated capacity of the winding. (Due to the high efficiency of the transformer, usually the rated capacity of the primary and secondary sides is designed to be equal).

Overload Analysis of Power Transformer

Overload normal load and accident over load two cases. Normal overload is in the normal power supply, the user caused by increased power consumption. It will cause the oil immersed distribution transformer temperature rise, causes the transformer insulation to accelerate the aging, the service life reduces, therefore, under normal circumstances does not allow the overload operation. Special circumstances Transformer can be overloaded in a short time, but in winter shall not exceed the rated load of 30% in summer shall not exceed 15% of rated load. In addition, the transformer should be based on the temperature rise and the provisions of the manufacturer to determine the overload capacity of the transformer. When the power system or the user substation accident, in order to ensure the continuous supply of important equipment, it allows the transformer short-term overload operation, that is, accident overload, accident overload will cause the coil temperature exceeds the allowable value, so the insulation in terms of Faster than normal aging conditions. But less chance of accident overload, under normal circumstances the Amorphous Core Transformer is under-load operation, so short-term overload caused by damage to the transformer insulation. The time and the multiples of the accident overload shall be carried out in accordance with the provisions of the manufacturer.

New type transformer special equipment

pad mount transformer production process is characterized by a large number of non-standard special equipment, so the level of its level depends mainly on the level of special equipment used. Product quality assurance, production efficiency, but also through advanced special equipment to achieve. Transformer product upgrading, but also rely on special equipment to support.
80 years of the 20th century, before importing foreign equipment, China's dry power transformers special equipment, the overall level of technology is relatively low, in addition to winding equipment, professional production plant production, the rest of the vast majority of self-made relatively simple equipment.

The Simplest Phase - shifting Method of Transformer

three phase pad mounted transformer The simplest phase-shifting method The simplest phase-shifting method is to use the secondary side of the amount of two-angle connection of the winding, can make the rectifier furnace pulse wave number doubled. For high-power rectifier equipment, the need for more pulse wave number, pulse wave number 18,24,36 applications such as increasing, which must be set in the primary side of the rectifier transformer phase shift phase shift. Phase-shifted winding and the main winding connection in three ways, namely, zigzag, hexagonal and Yanbian triangle. For the electrochemical industry, rectifier transformer voltage range is much larger than the electric furnace transformer, for chemical salt electrolysis, rectifier transformer voltage range is usually 56% - 105%, for aluminum electrolysis, the voltage range is usually 5% - 105%. Commonly used voltage regulation methods such as electric furnace transformer has variable magnetic flux regulator, series single phase step down transformer voltage regulator and auto-regulator voltage regulator. In addition, due to the characteristics of the rectifier element, the rectifier can be directly on the valve side of the rectifier silicon rectifier conduction phase angle, can be adjusted smoothly the average of the rectified voltage, this regulator called phase-controlled voltage regulator. To achieve phase-controlled voltage regulator, the use of crystal valve, the second is the use of self-saturable reactor, self-saturation reactor is basically composed of a core and two windings, one is the working winding, which is connected in series rectifier transformer two The secondary winding and the rectifier between the load current, the other is the DC control winding is provided by another DC power supply DC current, the main principle is the use of non-linear changes in ferromagnetic materials, the work winding reactance value is very large The change. Adjust the DC control current, you can adjust the phase angle α, which adjusts the average rectified voltage.

High-voltage line relay protection for the three-stage:

For high-side side of the 6 ~ 10KV substation main transformer substation, usually equipped with time-limited over-current protection; such as over-current protection action time is greater than 0.5 ~ 0.7s, should also be installed current quick-break protection. amorphous transformer with capacities of 800 KV · A and above and oil-immersed transformers in workshops of 400 KV · A and above shall be equipped with gas protection (also called gas relay protection) according to regulations. Transformers with capacities of 400 KV · A and above shall be fitted with overload protection according to the possible overload conditions when several units are operated in parallel or in a single operation and as a standby power source for other loads. Overload Protection and Gas Protection In the event of a minor fault (known as "light gas"), the signal is acted on, while others, including gas protection, are normally tripped in the event of a serious failure (commonly known as "heavy gas").
For high voltage side of the plant 35KV and above the total transformer substation main on load tap changer transformer, it should be installed over-current protection, current quick-break protection and gas protection; in case of possible overload, also need to install overload protection. However, if a single transformer with a capacity of 10,000 KV · A or more and a transformer operating in parallel with each capacity of 6300 KV · A and above is installed, a pilot differential protection is required to replace the current quick-break protection.

The output of the transformer

With the sustained and healthy development of China's economy, power demand continues to grow rapidly. In 2011, the nation's total electricity consumption of 4.69 trillion kwh, up 11.7% over the previous year, consumer demand is still strong. Per capita electricity consumption of 3483 kwh, an increase of 351 kwh than the previous year, more than the world average.
China's rapid development of power construction led the development of China's substations and transformers manufacturing industry. In 2011, the national transformer production reached 1.43 billion KVA, an increase of 6.86%. In 2011, China's transformer manufacturing industry scale (main business income of more than 20 million yuan) 1461 companies; sales of 291.01 billion yuan, total profit of 16.608 billion yuan, assets of 263.84 billion yuan, the product Sales profit of 33.972 billion yuan.
China's transformer industry is highly competitive, foreign multinational companies to seize a large market share, the number of domestic transformer manufacturers are also rapid growth. In the low-end transformer market is highly competitive, with 220KV pole mounted distribution transformer production capacity of more than 20 enterprises, with 110KV transformer production capacity of more than 100 enterprises. The production of more than 500KV transformer enterprises through technology and capacity to build a very high barriers to entry, the market tends to stabilize the pattern.

Cause of Leakage of Transformer

Leakage caused by two main reasons: one is in the transformer design and manufacturing process latent down; the other is due to the improper installation and maintenance of the pad-mounted transformers caused. Transformer main leakage parts often appear in the radiator interface, flat disc valve cap, casing, porcelain, weld, trachoma, flanges and other parts.
1, out of the air
Out of the air is an invisible form of leakage. For example, the casing head, the oil storage cabinet diaphragm, the airway glass, weld trachoma and steel sand and other parts of the air out of sight are invisible. Over the years, the main power system accidents are mostly winding winding accidents and low-voltage transformer outlet short-circuit the body of the serious damage.
2, the classification of oil leakage
Transformer oil leakage can be divided into two kinds of leakage and leakage, and leakage can be divided into weld seepage and sealing surface leakage of two.
1) Endoleak: The most common internal leakage is the oil in the oil-filled casing and the on-load tap-changer oil in the diverter switch housing leaks into the transformer body.
2) leakage: Leakage is divided into weld seepage and sealing surface leakage of two:
Weld seepage: weld seepage is caused by the existence of trachoma in the welded parts of the steel plate.
Sealing surface leakage: sealing surface leakage is more complex, to specific issues specific analysis. In the single phase step down transformer overhaul or installation process should prevent the sealing surface leakage as an important task.