EA034945B1 - Outdoor modular dry-type transformer - Google Patents

Abstract

The invention relates to the use of electrical equipment for power conversion, transmission, distribution and transportation, and may be used for production of outdoor modular dry-type transformers based on the latest developments in the area of magnetic cores and insulation materials. The technical result is achieved by the proposed outdoor modular dry-type transformer comprising a support with a clamp, oval amorphous alloy cores in the window of which the main and teaser secondary windings are mounted and connected through a tap, and a primary winding on polyamide frames that is made of aluminium or copper foil with soldered, silicone rubber insulated X-ray cables of the required length, with external winding insulation made of heat shrink polymer tubes which ensure the modular principle of transformer production and operation. The transformer according to the invention eliminates the existing disadvantages in the known transformers and allows arrangement of a "load center" for high voltage loads with reduction of technical power loss in distribution networks by a factor of more than 600 and "commercial loss" and theft level down to zero.

Description

Technical field

The invention relates to the field of application of electrical engineering in the conversion, transmission, distribution and transportation of electricity and can be used in the manufacture of dry transformers for outdoor installation without the use of insulators installed on the transformer case from solid insulating materials such as porcelain, ceramics, etc.

The whole process in the electric power industry from production to consumption goes through the following stages: generation, conversion (increase and several stages of voltage reduction), transmission, distribution and transportation. Moreover, at all stages, these processes occur with losses of electricity on all elements of electric networks. The lion's share of losses is accounted for by distribution networks (voltage levels of 10 and 0.4 kV).

Table 1

Loss structure by networks of Astana-REC JSC for 2016

The stress class. kV Losses for 2016, million kWh the actual value of losses, as a percentage of the volume of electric power included in the enterprise network,% Load loss Idling in power transformer X for own needs of substations in measuring current and voltage transformers and their secondary circuits on the crown At total loss in lines In the forces of the trans forms of the atom X 220 7.10 0.7 1.9 1,1 0.1 2,5 13,4 0.39 110 20.90 6.3 11.5 4.1 0.3 43.1 1.25 10 86.10 46.2 18.1 150,4 4.35 0.4 207.50 207.5 6.01 Total about 321.6 53,2 31.5 5.2 0.4 2,5 414.4 12.00

As you can see, with a total level of losses of 12%, networks of 10 and 0.4 kV account for 10.36% with the cost of 1% loss of 300,000,000 tenge. Theoretically, this problem has always had a solution - transferring consumer power to deep input, 10 kV with individual mast transformers, where the level of technical losses compared to 0.4 kV is reduced by 625 times, commercial losses, i.e. theft of electricity is reduced to zero, as well as the transfer of 10 kV overhead lines (OHL) from bare wire to self-supporting insulated wires (SIP), reducing losses by another 3 times, while the cost of maintaining the line is reduced by 80%.

The main obstacle to the transition to deep entry were bulky and fire hazardous oil and epoxy compound dry indoor transformers with porcelain or polymer inputs.

State of the art

Known oil voltage transformer, measuring type NTMI-10 (Petrov VN Use of voltage transformers for connecting dispatch control equipment to rural distribution networks. Dis. Cand. Tech. Sciences. M., 1972, pp. 39-50).

The disadvantages of the known transformer are:

1) low line voltage in the secondary winding of the transformer, connected by a star, which is 100 V, which does not allow it to be used as a power transformer;

2) installation of bushing porcelain bushings on the transformer case, which reduces its reliability.

Also known is an oil transformer (ed. St. USSR No. 1707634, H01F 27/04, 1992), which is adopted as a prototype.

The disadvantages of the known transformer are:

1) installation of bushing porcelain bushings on the transformer case, which reduces its reliability;

2) the transformer is often damaged during a short circuit due to surge or overlapping by the birds of high voltage bushings on the open parts of the insulators;

3) the presence of transformer oil, because of which it is a source of environmental pollution and fire;

4) requires periodic maintenance.

Also known is a dry transformer OL-10. TU 16-98 OGG.670.121.008TU of the Sverdlovsk plant of current transformers, which is also taken as a prototype.

The disadvantages of this transformer are:

1) the isolation of the entire transformer is carried out in a monolithic, epoxy compound, is subject to solar radiation, aggressive environments and harmful atmospheric influences, which negatively affects

- 1 034945 refers to the insulation of the outer part of the transformer housing;

2) disposability, unsuitability for repair.

The problem solved by the invention is to create a modular dry transformers for outdoor installation using the latest achievements of science and technology in the field of magnetic conductors from amorphous alloys and insulating materials.

The technical result of the invention is the ability to transfer distribution consumer electrical networks from 0.4 to 10 kV, leading to at least 3-fold reduction in losses and a significant reduction in electricity tariffs for consumers with high reliability of network elements.

The technical result is achieved by the fact that a modular dry transformer for outdoor installation is proposed, containing a bed with a clamp for attaching twisted oval magnetic cores of amorphous alloys that reduce transformer losses from 4 to 10 times, with an upper oblique cut, in the window of which the main and adjusting secondary windings are mounted, connected through an ansapf switch, and a primary winding for increasing thermal and dynamic stability, wound on polyamide frames made of aluminum or copper foil with flexible inputs soldered to the required length, made by x-ray cables with silicone rubber insulation, which is oil and petrol resistant, frost-resistant (-50; +80; +80 ° C), which can withstand a test voltage of 70 kV, which does not deteriorate in the open air and maintains insulating properties for 30 years, with external insulation of windings made instead of epoxy compounds by heat-shrinkable polymer tubes, resistant to solar radiation, aggressive environments and atmospheric phenomena that are not exposed to harmful atmospheric influences, which provides a modular principle for the production and assembly of dry transformers, which, if necessary, can be overloaded by 50% by installing a cooling fan with start from the temperature sensor.

The claimed transformer eliminates the listed disadvantages existing in known transformers, while new technical properties are obtained, which include:

1) a high level of reliability, a decrease in manual labor and the number of components due to the manufacturability of the manufacturing process, which is preserved during repair work. Repair due to the modularity of the transformer is reduced to replacing damaged elements with certified prefabricated products that do not require post-repair tests and highly qualified repair personnel;

2) resistance to conditions of high humidity and pollution, as well as resistance to solar radiation, high and low temperatures and aggressive environments and atmospheric phenomena;

3) due to the use of amorphous alloys in the manufacture of twisted magnetic cores and winding of foil windings, the energy losses at the transformer are reduced from 4 to 10 times. Accordingly, the overload capacity is increased, the heating of the transformer is sharply reduced and no drastic cooling measures are required;

4) service is completely excluded and is reduced to periodic visual inspection;

5) the overall dimensions and weight of the transformer are reduced due to the elimination of porcelain insulators, which allows them to be suspended on poles as mast substations;

6) the absence of transformer oil eliminates the risk of environmental pollution during its leak. A high level of fire safety is provided. In case of fire, there are no emissions into the environment in the form of toxic and corrosive gases;

7) the service life of the transformer is increased due to the use of two-core flexible cables with silicone rubber insulation, which is oil and petrol resistant and frost-resistant (-50; + 80 ° C). It does not collapse and retains insulating properties for 30 years when the transformer is operated in the open air;

8) provides absolute safety for birds and staff;

9) the number of service personnel is significantly reduced, due to which labor productivity in the electric power industry is increased;

10) allows you to organize deep input to consumers at a high voltage of 10 kV, reducing the length of networks of 0.4 kV, bringing them to the level of transfer from the transformer to the house. At the same time, the level of technical losses of electricity in distribution networks of 10 / 0.4 kV decreases over 600 times, and the level of commercial losses i.e. theft to zero. Also, due to the individual regulation of the voltage level, the consumer sharply increases the quality of electricity.

- 2 034945

Table 2 When converted to SIP-10 kV and a dry transformer with a magnetic core made of amorphous alloys

The stress class. kV Losses for 2016, million kW / h. the actual value of losses, as a percentage of the volume of electric power included in the enterprise network,% Load loss The bachelor on the move in power shuttles for own needs of substations in measuring current transfer and voltage transformers and their secondary circuits on the the crown total loss in line X In power transformer 220 7.10 0.7 1.9 1,1 0.1 2,5 13.40 0.39 110 20.90 6.3 11.5 4.1 0.3 43.10 1.25 10 26.81 11.55 4,525 42.89 1.24 0.4 0.00 0 0 0 0 0 0.00 0 Total about 54.81 18.55 17.93 '5.2 0.4 2,5 99.39 2.9

Reducing losses from 12 to 2.9% in electric networks (i.e., by 9.1%) allows to reduce the cost of electricity, which leads to a decrease in the tariff for transportation for consumers from 3 to 2.09 tg / kWh.

Reducing the level of electricity tariffs, in turn, contributes to the development of small and medium-sized businesses, as well as the economic development of the country.

In turn, a reduction in electricity losses entails a reduction in the need for fuel (coal, gas, uranium, etc.), water and chemicals for water treatment by power generating stations, and consequently, their reduction in harmful emissions into the environment, which favorably affects the environmental situation .

In FIG. 1 is a side view and in FIG. 2, a top view shows an outdoor modular dry-type transformer containing a frame 1, a twisted oval amorphous alloy magnetic circuit with an oblique cut of the upper part 2, into the window of which the primary winding 3, the main secondary winding 4 and the secondary adjusting winding 5 are mounted. FIG. 3 and 4, cable entries of the secondary windings with silicone rubber insulation 8, interconnected on an ansapf switch, in FIG. 5. In FIG. 1 magnetic circuit 2 with windings by means of a clamp 7 is attached to the frame 1.

Modular dry transformer outdoor installation operates as follows.

The primary winding with flexible cable entries made of organosilicon insulation is connected to a 10 kV network through a high-voltage fuse, and the secondary windings are connected to the consumer load through a circuit breaker. Further, the function and operation of a modular dry transformer in normal mode does not differ from other types of transformers. Only during repair does the damaged element change to a serviceable certified factory-ready element, without after-repair tests. This operation does not require highly qualified personnel and a lot of time.

Findings.

1. 17-year experience in operating a sample of cable gland with silicone rubber insulation of an oil transformer in real conditions at the objects of the Kazakhstan railway confirmed its operability.

2. At present, magnetic cores made of amorphous alloys are widely used in world practice, which give large reductions in energy losses at transformers.

3. Instead of filling the winding with an epoxy compound, which cracks and does not withstand prolonged solar radiation during severe frosts, the proposed insulation of coils with windings with heat-shrinkable tubes by RICHEM does not have these drawbacks and is widely used in world practice.

4. The proposed modular principle in transformer construction coincides with the global practice of modular product design and provides great opportunities and benefits in production, operation and repair.

Recommendations are given for the release of an experimental series of transformers.

The modular dry transformer for outdoor installation contains primary and secondary windings, which are mounted in the window of two twisted oval magnetic cores of amorphous alloys forming an armored core. To ensure air circulation between the cores, you can arrange a gap that does not affect the characteristics of the magnetic circuit. Twisted magnetic cores from an amorphous alloy of the necessary size and magnetic properties are bought from world manufacturers.

- 3 034945

To protect against corrosion, the magnetic circuit can be painted with anti-corrosion paint.

Winding frames are made of polyamide polymer with vertical stiffeners on the side of the magnetic circuit, forming channels for air circulation, provide cooling of the windings. To ensure dynamic stability during short circuits and reducing the magnitude of interlayer voltage and interlayer insulation of the winding, it is necessary to wind aluminum or copper foil, previously sealing cable glands with silicone insulation. Cable glands with lugs of the required cross section and of sufficient length (for connecting the high-voltage winding to fuses, and the low-voltage winding to the meter) are made of x-ray cables with silicone rubber insulation manufactured by the Mtishchensky cable plant. On the surface of the wound coil, stick a paper nameplate with information about the manufacturer and the parameters of the transformer winding. Insulate the coil from the outside with a transparent heat-shrinkable polymer tube with a high insulating property on the inner surface closer to the ends with adhesive or sealant. Warming up the polymer tube from the center in both directions, we shrink. Shrinkage is considered complete when the sealant or glue comes out from under the ends of the tube. The transparency of the tube additionally provides visual control over the state of the winding. If necessary, the windings can be made concentric. In this case, the properties and principle of operation of the transformer does not change.

Ansapf switch is assembled on a getinax or textolite tile.

The clamp is made of stainless steel tape with fasteners.

The bed is stamped from sheet steel and coated with a corrosion-resistant coating.

The magnetic core with windings is installed on the bed and secured with a clamp. Ansapf switch is fixed on the bed with screws. The terminals of the low-voltage (main and adjusting) windings are connected to the ansapf.

Claims (1)

CLAIM An outdoor dry modular transformer containing a bed with a clamp for attaching twisted oval magnetic circuits made of amorphous alloys that reduce transformer losses by 4 to 10 times, with an upper oblique cut, in the window of which the main and adjusting secondary are mounted, connected through the switch, and the primary windings characterized in that for thermal and dynamic stability, these windings, wound with separate modules on polyamide frames, are made of aluminum or copper foil with flexible bushings soldered to the required length, made of x-ray cables with silicone rubber insulation, which is oil and oil resistant, frost-resistant (- 50, + 50 ° С), withstanding the test voltage of 70 kV, not destroying in the open air and maintaining insulating properties for 30 years, as well as the fact that the outer insulation of the windings is performed instead of epoxy compounds by heat-shrinkable polymer tubes that are resistant to solar radiation, aggressive environments and atmospheric phenomena, not subject to harmful atmospheric influences, which provides a modular principle for the production and assembly of dry transformers, which, if necessary, can be overloaded by 50% by installing a cooling fan with start from the temperature sensor.