RU-2861397-C1 - TRANSFORMER WITH TWO-PHASE COOLING SYSTEM

RU2861397C1RU 2861397 C1RU2861397 C1RU 2861397C1RU-2861397-C1

Abstract

FIELD: electrical engineering. SUBSTANCE: invention relates to cooling systems for high-voltage and/or high-current electrical equipment using two-phase immersion cooling. The technical result is achieved due to the fact that the two-phase cooling system for a transformer disc winding with a coolant comprises a disc winding made of conductors, a cavity with a coolant, and a heat exchanger. Distinctive features are: the installation between the winding discs of two-phase spacers with vertical slots and holes for separate phase movement, the presence of wide vertical channels inside the winding for vapour rise, the design of the heat exchanger as a block with microchannels and micro-ribs for condensation, and also a microporous layer coating of the winding conductors to intensify boiling. EFFECT: significant increase in heat removal efficiency and reduction in equipment operating temperature by optimising two-phase heat exchange, which leads to an increase in power density, reliability, and service life, as well as a reduction in system dimensions. 8 cl, 5 dwg

Inventors

BASHIROV MUSSA GUMEROVICH
Khismatullin Azat Salavatovich
KOROLEV MIKHAIL ALEKSANDROVICH
Bulatov Albert Damirovich
Sajdashev Marat Rustemovich

Dates

Publication Date: 20260505
Application Date: 20251119

Claims (8)

1. A transformer comprising cooled disc windings, characterized in that between the flat toroidal discs of the winding there are installed two-phase spacers made of heat-resistant dielectric with vertical slots and openings ensuring separate movement of the vapor and liquid phases of the coolant; vertical channels are formed inside the winding, connecting the space of the winding with a heat exchanger mounted on the outer surface of the winding, made in the form of a block with microchannels and microfins; the conductors of the winding are covered with a microporous layer; the cavity inside the transformer housing is filled with a coolant.
2. A transformer according to paragraph 1, characterized in that the two-phase spacers are made of a dielectric polymer, for example, polytetrafluoroethylene or polyetheretherketone.
3. A transformer according to paragraph 1, characterized in that vertical slots with a width of 0.5-1.0 mm and openings with a diameter of 1.5-2.0 mm are made in the two-phase spacers.
4. A transformer according to paragraph 1, characterized in that vertical channels with a diameter of 3-5 mm are formed inside the winding.
5. A transformer according to paragraph 1, characterized in that the vertical channels are located along four segments of the disk winding in the center of each segment and/or in the corners of the disk assembly.
6. A transformer according to paragraph 1, characterized in that microchannels with a width of 100-300 μm and microfins with a height of 200-500 μm are made on the surface of the heat exchanger.
7. A transformer according to paragraph 1, characterized in that the microporous layer of conductors is made with a pore size of 1-10 μm.
8. A transformer according to claim 1, characterized in that the microporous layer of conductors is made by the method of electrochemical deposition of nanoporous aluminum oxide or PVD sputtering of silicon oxide.

Description

The invention relates to the field of electrical engineering, in particular to cooling systems for high-voltage and/or high-current electrical equipment, such as transformers, reactors, electrical machines, etc., using two-phase immersion cooling. A transformer is known [Russian Federation patent for invention No. 2433495, published on 20.11.2011], containing a magnetic circuit, disk windings and a cooling system, made in the form of a device for liquid cooling of windings, using vertical channels for circulation of cooling liquid. A drawback of this prototype is the limited efficiency of heat removal from the windings, due to the use of single-phase cooling and the lack of specialized elements to intensify heat exchange and optimize two-phase circulation. This leads to the formation of localized "hot spots," reduces the transformer's maximum power density, and requires the use of forced circulation to achieve the required performance. The technical problem of the invention is the creation of a transformer with a two-phase cooling system with the achievement of the following technical result: increasing the speed and efficiency of heat removal from electrical equipment while simultaneously reducing its operating temperature. The claimed technical result is achieved by the fact that in a transformer including cooled disk windings, according to the invention, two-phase spacers made of a heat-resistant dielectric with vertical slots and holes are installed between the flat toroidal disks of the winding, ensuring separate movement of the vapor and liquid phases of the coolant. Vertical channels are formed inside the winding, connecting the winding space with a heat exchanger mounted on the outer surface of the winding, made in the form of a block with microchannels and microfins; the winding conductors are covered with a microporous layer; the cavity inside the transformer housing is filled with a coolant. Moreover, the two-phase spacers are made of a dielectric polymer, for example, polytetrafluoroethylene or polyetheretherketone. In the two-phase spacers, vertical slots with a width of 0.5-1.0 mm and holes with a diameter of 1.5-2.0 mm are formed. Inside the winding, vertical channels with a diameter of 3-5 mm are formed, which are located along the four segments of the disk winding, in the center of each segment and/or in the corners of the disk assembly. The heat exchanger surface is provided with microchannels 100-300 μm wide and microfins 200-500 μm high. The microporous conductor layer, with pore sizes of 1-10 μm, is fabricated using electrochemical deposition of nanoporous aluminum oxide or PVD sputtering of silicon oxide. Fig. 1 shows a general view of the two-phase cooling system for the transformer winding. Fig. 2 shows a fragment of the disk winding with two-phase spacers. Fig. 3 shows an enlarged view of the two-phase spacer. Fig. 4 shows a fragment of the conductor with a microporous layer. Fig. 5 shows a fragment of the heat exchanger surface with microchannels and microfins. The system contains a transformer housing (tank) 1, inside which is located the active part 2, which includes a disk winding 3. The internal cavity 4 of the housing 1 is filled with a coolant. A heat exchanger 5 is installed in the upper part of the system. Winding 3 consists of separate flat toroidal disks 3.1, between which two-phase spacers 6 are installed, which have vertical slots 6.1 and holes 6.2, providing separate movement of steam upward and liquid downward. Two-phase spacers 6 are made of heat-resistant dielectric (for example, polytetrafluoroethylene (PTFE) or polyetheretherketone (PEEK)), vertical slots 6.1 are made 0.5-1.0 mm wide and holes 6.2 are made 1.5-2.0 mm in diameter. Steam rises through vertical slots 6.1 and holes 6.2, condensate flows down solid part 6.3 (see Fig. 3). Inside the winding 3, vertical channels 7 with a diameter of 3-5 mm are formed, serving as the main paths for the rise of steam, located, for example, along four segments of the disk winding (in the center of each segment and/or in the corners of the disk assembly), which connect the winding space with the heat exchanger 5 and serve as the main paths for the rise of the steam phase, ensuring thermosiphon circulation. Conductors 3.2 of winding 3 are coated with a microporous layer 8 with pores 8.1 measuring 1-10 μm. Layer 8 promotes uniform nucleation of steam nuclei, accelerates condensate outflow, intensifying the boiling process, and promotes the intensive formation of steam bubbles 9, increasing heat exchange efficiency. On the outer surface of winding 3, a heat exchanger 5 is mounted, made in the form of a block with microchannels 10 with a width of 100-300 μm and microfins 11 with a height of 200-500 μm, which ensures highly efficient condensation of the vapor phase and the return of condensed refrigerant 12 to winding 3. Fluorinated ketone is used as a coolant, which has a dielectric strength of ≈ 30 kV/mm, a boiling point of ≈ 4