RU2282911C2 - Electric reactor with magnetization - Google Patents

Abstract

FIELD: electric engineering, possible use for electric reactors controlled by magnetization, mounted, for example, in electric network for compensation of reactive power.

SUBSTANCE: electric reactor with magnetization contains magnetic system with rods, upper and lower horizontal yokes, two side yokes, magnetization control windings, positioned on rods, connected oppositely in pairs and connected to source of direct voltage being controlled, network windings, enveloping two adjacent rods with control windings, and magnetic bridges. New in the reactor is the fact that magnetic bridges are made of packets of stripes of electro-technical steel, mounted outside the magnetic system on two sides of reactor and made in form of two closed rectangular frames, enveloping aforementioned windings. Two end parts of each frame are positioned on opposite ends of windings, while two other longitudinal parts of frame are positioned along windings. End parts of bridges efficiently collect magnetic field dissipated by reactor windings and close it by longitudinal parts of bridge-frames.

EFFECT: decreased material costs and losses, simplification of manufacturing and assembling processes.

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Description

The invention relates to the field of electrical engineering and can be used for magnetically controlled reactors installed, for example, in an electrical network to compensate for reactive power.

Known electric reactor with magnetization [1]. This analogue device has a magnetic system with rods, yokes, with two side yokes, there is one network winding covering two adjacent rods with control windings. However, the device has increased eddy current losses arising in structural elements due to the scattering magnetic field.

Partially, the disadvantages [1] are eliminated in the known device [2], which is the closest in technical essence to the invention. As in the analogue [1], in this prototype device there is a magnetic system with rods, upper and lower horizontal yokes, two side yokes, on the rods there are control windings connected to an adjustable constant voltage source, and network windings covering two adjacent rods with control windings included in the opposite direction. Between the ends of the windings and yokes placed massive annular magnetic shunts with a radial cut. Ring shunts are made in a shape corresponding to the cross-sectional shape of the ends of the windings protruding beyond the contours of the magnetic system. The disadvantages of the prototype are the high consumption of steel and increased losses in steel in the rods and yokes, as well as the significant complexity of the design.

The aim of the invention is to reduce the consumption of steel in the rods and yokes of the magnetic system, reduce losses in steel and simplify the design of the reactor by introducing new structural elements - magnetic shunts from packages of strips of electrical steel in the form of closed rectangular frames.

This goal is achieved by the fact that in an electric reactor with magnetization, containing a magnetic system with rods, upper and lower horizontal yokes, two side yokes, control windings located on the middle rods, connected in pairs in the opposite direction and connected to an adjustable constant voltage source, network windings, covering two adjacent rods with control windings, and magnetic shunts. The shunts are drawn from packages of strips of electrical steel, installed outside the magnetic system on both sides of the reactor and made in the form of two closed rectangular frames. Two end parts of each frame are located on opposite ends of the windings, and two other longitudinal parts of the frame are located along the windings.

The proposed electric reactor with magnetization is illustrated by drawings.

In Fig.1 shows the design of the magnetic system of the reactor with windings in cross section along the main axis, Fig.2 - section of the reactor in plan, figure 3 - side of the reactor. Figure 4 is given a shunt in the form of a frame. Figures 4 and 5 show the laden and butt joints of the parts in the corners of the frame; Fig. 6 shows a variant of a fragment of the end part of the shunt with an increased coverage of the area of the end surface of the winding. 7 shows a variant of the frame with longitudinal parts located between the phases of a three-phase reactor. On Fig shows a variant of the reactor in a single-phase design.

The magnetic system of the reactor contains rods 1, two yokes (horizontal) - upper 2 and lower 3, two side yokes 4. On all rods 1 there are control windings 5. In the reactor there are three (by the number of phases A, B and C) network windings 6 , each network winding covers two adjacent terminals with control windings. Two magnetic shunts in the form of rectangular frames covering the windings are installed in the reactor. Parts of each frame - end 7 and longitudinal 8 - are made of packages of strips of electrical steel. The end parts 8 are located at the minimum distance from the windings, which is acceptable under the conditions of ensuring electrical insulation.

For ease of execution and installation, for better cooling, the shunt frames can be solid or composite of several packages, in the latter case, cooling channels 9 are located between these packages, which are shown in Fig.6.

The angles of the shunt-frames at the joints of the end sides 7 with the longitudinal sides 8 can be made laden (figure 4). A butt option is also possible jointing the sides of the frame, in which they are pressed against each other (figure 5).

Figure 6 presents a more complex design of the end parts of the shunt frame with an increased coverage of the area of the end surface of the winding. The increase in the area of the end surface is achieved by installing between packages of steel or between their parts of additional insulating gaskets 10.

The longitudinal parts of the shunt frames can be located not near the extreme phases of the reactor A and C (Fig. 1), but between the phases of the reactor A and B, B and C (Fig. 7).

In addition to the three-phase version, a single-phase version of the design of the electric reactor with magnetization is possible, while all the structural elements of the three-phase reactor are preserved, but the number of rods and windings is accordingly reduced (Fig. 8).

Network windings 6 of three phases can be connected to a star with zero (or to another three-phase circuit) and connected to a three-phase AC voltage network.

The control windings 5, by means of which the reactor power is controlled by magnetizing the cores, are connected to an adjustable constant voltage source, while various options for connecting the control windings are possible. For example, each pair of control windings 5 covered by its network winding 6 can be connected in series in the opposite direction, and all three pairs of control windings of the three phases of the reactor can be connected in parallel.

An electric magnetization reactor, made in accordance with the claims of the invention, operates as follows.

The network windings 6 are connected to an electrical AC network. In this case, an alternating magnetic flux occurs inside the area of the network winding. The reactor power control is carried out by connecting to a magnetizing control windings 5 an adjustable constant voltage source, for example, an adjustable converter (rectifier). Since a constant voltage source is connected to the control windings, a current with a constant component arises in the windings 5, this current leads to the appearance of a bias constant current in the rods in time. In adjacent rods, this flow is directed in different directions (due to the on-off switching of the control windings), therefore, it closes mainly along the shortest path through sections of the yoke located between the rods 1 of one phase. Since an alternating flux is superimposed on the magnetization flux, the resulting flux is shifted to the steel saturation region, i.e. the rods are saturated for some part of the period. In turn, the saturation of the rods is the cause of the current in the network winding 6. This is the operating current of the reactor.

During the operation of the reactor, in addition to the magnetic field, a magnetic field arises in the steel of the rods in the region of the windings, which is created by the current of the windings. This magnetic field has a maximum induction in the region of the middle of the height of the windings, and it closes outside the windings, passing mainly through the ends of the windings. If the magnetic field is not directed by certain constructive measures, then, breaking out, it will induce eddy currents in all metal components of the structure (pressing beams, yokes, tank walls, etc.). These eddy currents will lead to a significant increase in power losses in the reactor, to dangerous local heating. For powerful reactors, they threaten their complete inoperability.

A part of the magnetic field flux of the windings passes through the surfaces of the upper and lower yoke, overlapped by part of the area of the end zones (in Fig. 2, the overlapped area is highlighted by oblique hatching). This part of the magnetic flux enters the narrow sides of the steel sheets and does not cause additional eddy current losses. Together with the flow of the rod, this flow closes by the yokes of the magnetic system.

The second part of the magnetic flux of the field of the windings (it can be arbitrarily called the scattering flux) is sent to the end parts 7 of the shunt-frames (in the lower and upper). The scattering flux collected by these shunts is closed in the longitudinal parts of the shunts 8 (the magnetic flux leaves the winding region, enters the upper end parts of the shunts, passes along the longitudinal parts of the shunts, and leaves the lower end parts in the region of the windings). The magnetic field directed to the narrow sides of the stripes of shunt packets does not cause additional eddy current losses in the reactor construction details.

The proposed reactor has several advantages compared with the prototype reactor.

Both in the proposed reactor and in the prototype there are magnetic shunts for directing the scattering flux. In the proposed reactor, the shunt frames are outside the magnetic system. In the prototype, massive ring shunts are located in the window of the magnetic system, so the magnetic system has an increased length of the rods and side yards, which increases the consumption of steel and steel loss compared with the proposed reactor.

In the proposed reactor, the magnetic flux of scattering is closed by the longitudinal sides of the shunts - frames, i.e. magnetic flux scattering does not load the magnetic system. In the prototype, the scattering magnetic flux collected by the ring shunts passes into the upper and lower yokes and closes through the side yokes of the magnetic system, i.e. additionally loads them. Thus, it is possible to reduce the cross-section of the lateral yoke of the magnetic system and further reduce the consumption of steel compared to the prototype.

The proposed reactor design is simpler to manufacture and assemble compared to the prototype, in which there are complex multilayer ring shunts wound from electrical steel tape with cuts to eliminate the closed loop.

The performance of the proposed bias-controlled electric reactor and its high technical and economic indicators are confirmed by calculations and physical modeling. Compared with the analogue and prototype, the present invention has a clear advantage - reducing material consumption and losses.

Literature

1. Core for electrical apparatus. Paul A. Vanse. U.S. Patent No. 2,267,382. Application Juli 23, 1940, Serial No 346, 904. Patendet Dec. 23, 1941.

2. An electric reactor with magnetization. RF patent №2217829. H 01 F 29/14. Invention Bulletin No. 33 of 2003

Claims (1)

An electric magnetization reactor containing a magnetic system with rods, upper and lower horizontal yokes, two side yokes, control windings placed on the rods, connected in pairs in the opposite direction and connected to an adjustable constant voltage source, network windings covering two adjacent rods with control windings, and magnetic shunts, characterized in that said shunts are selected from packages of strips of electrical steel, are installed outside the magnetic system on both sides of the reactor, and are made s in the form of two closed rectangular frames covering these windings, with two end parts of each frame placed on opposite ends of the windings, and two other longitudinal parts of the frame located along the windings.

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