CN104505238A - Equivalent air gap adjustable reactor - Google Patents

Abstract

The invention discloses an adjustable equivalent air gap reactor, which includes an iron core, an AC working winding and several groups of DC equivalent air gap windings; the iron core is a closed ring structure, and a rectangular coordinate system is established with the center point of the iron core as the origin, The two sides of the iron core are symmetrical with the Y axis; the middle of the iron core on the left side of the Y axis is wound with an AC working winding, and the middle of the iron core on the right side of the Y axis is provided with several pairs of core holes, and the pairs of iron core holes are arranged symmetrically on both sides of the X axis. A set of DC equivalent air-gap windings are wound on two adjacent core holes, and each set of DC equivalent air-gap windings are reversely connected in series; the DC equivalent air-gap windings are all along the X-axis direction or both along the Y-axis direction Winding. In the present invention, the local saturation phenomenon generated by controlling the magnitude of the DC current is regarded as an equivalent air gap to replace the mechanical device to control the air gap, which simplifies the core structure, reduces the response time of the reactor, and at the same time ensures the linearity of the reactance value of the reactor, and has a large Adjustment range.

Description

An Equivalent Air Gap Adjustable Reactor

technical field

The invention relates to a reactor, in particular to an equivalent air gap adjustable reactor.

Background technique

In high-voltage and ultra-high-voltage power grids, the purpose of reactive power compensation is to support the voltage of the grid pivot point, improve the stability of the grid, increase the transmission capacity of the line and reduce the line loss, suppress the power oscillation of the grid and the power frequency overvoltage, and adjust the voltage. And optimize reactive power flow, etc. Reactive power balance is an important guarantee for the safe, stable and economical operation of the power grid, especially for the ultra-high voltage long-distance transmission network. Studies have proved that the capacity of the adjustable reactor can not only change with the size of the transmission power, smoothly adjust the reactive power of the system, realize flexible power transmission, but also suppress power frequency and operating overvoltage, reduce line loss, and thus greatly improve The stability and safety of the system, so the adjustable reactor plays a significant role in improving the operating performance of the power system.

Common adjustable reactors include turn-adjusting controllable reactors, air gap size-adjusting controllable reactors, thyristor control reactors and saturable reactors. There are two types of controllable reactors that are most widely used: thyristor-controlled reactors (TCR) in thyristor-controlled reactors, and magnetic valve reactors (MCR) in saturable reactors. In recent years, due to the rapid development of power electronics, thyristor-controlled reactors have been widely used. Although thyristor-controlled reactors have a fast response speed and relatively mature technology, they are expensive, difficult to maintain, and have serious harmonic pollution. Large-scale applications are still subject to many Restrictions: The magnetic valve type controllable reactor has simple manufacturing process, low cost, and high reliability. The main iron core of the magnetic valve type reactor is always in the ferromagnetic linear region within the entire capacity adjustment range, and the magnetic valve can be designed close to the limit. Saturation, so the linearity of the reactor is better, and the core harmonic is about half of that of the thyristor-controlled reactor. However, because its capacity has reached the limit value, the overload capacity of the magnetic valve controllable reactor is poor.

The air gap size adjustable reactor adopts an electric structure to drive the transmission shaft to control the size of the air gap. The change of the air gap leads to the change of the magnetic flux in the iron core, so as to achieve the purpose of continuously changing the reactance value of the working winding. Although it has a transformer-like iron core like MCR, it has high stability and reliability, and the reactance adjustment range is large and the harmonics are small, but the response speed of the mechanical device to control the size of the air gap is slower than that of MCR and TCR, so Has not received enough attention and promotion application.

Contents of the invention

Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides an equivalent air gap adjustable reactor, which can adjust the DC current in the DC equivalent air gap winding to replace the mechanical device to control the size of the air gap. While improving the linearity and adjustment range of the reactor, the reliability and response speed of the reactor are improved.

Technical scheme: in order to achieve the above object, the technical scheme adopted in the present invention is:

An adjustable equivalent air gap reactor, comprising an iron core 1, an AC working winding 2, and several groups of DC equivalent air gap windings; the iron core 1 is a closed ring structure, and a rectangular coordinate is established with the center point of the iron core 1 as the origin The two sides of the iron core 1 are symmetrical with the Y axis; the middle part of the iron core 1 on the left side of the Y axis is wound with an AC working winding 2, and the middle part of the iron core 1 on the right side of the Y axis is provided with several pairs of iron core holes 4, and the pairs of iron core holes are arranged symmetrically. On both sides of the X-axis, a set of DC equivalent air-gap windings are wound on two adjacent iron core holes, and each set of DC equivalent air-gap windings are reversely connected in series; in the direction of the X-axis and the direction of the Y-axis , the distance between two adjacent core holes is equal; the DC equivalent air gap windings are all wound along the X-axis or both along the Y-axis.

Further, 2n rows of core holes are arranged along the X-axis direction, where n is a natural number.

Further, the core hole 4 is a square hole or a round hole.

Further, the several pairs of iron core holes 4 are 2 or 4 groups.

Further, the iron core 1 is formed by laminating electrical silicon steel sheets.

Beneficial effects: an equivalent air gap adjustable reactor provided by the present invention:

1) The AC working winding and the DC equivalent air gap winding share one iron core, which greatly simplifies the structure of the iron core and reduces the amount of silicon steel materials.

2) Since the DC equivalent air gap winding only generates magnetic flux locally in the iron core to saturate the iron core locally, the local saturation effect can be regarded as an equivalent air gap. The equivalent air gap controlled by direct current is used to replace the mechanical device to control the air gap, so as to improve the reliability and response speed of the equipment.

3) Multiple groups of DC equivalent air-gap windings are used in reverse series to reduce the AC voltage component induced in the DC equivalent air-gap winding, thereby reducing the influence of the AC voltage component on the DC power supply.

4) There is no electrical connection between the AC working winding and the DC equivalent air gap winding, which avoids the influence of high voltage and high current on the grid side on the control circuit and improves the reliability of the reactor.

5) A separate DC power supply is used to supply power to the DC equivalent air gap winding in the equivalent air gap adjustable reactor, so the wiring is simple. The reactance of the reactor is only related to the DC equivalent air gap winding, and the control is simple.

Description of drawings

Figure 1 is a schematic diagram of a four-hole equivalent air gap adjustable reactor;

Figure 2 is a schematic diagram of an eight-hole equivalent air gap adjustable reactor;

Figure 3 is a schematic diagram of a square hole equivalent air gap adjustable reactor;

Figure 4 is a schematic diagram of the winding direction of the four-hole equivalent air gap adjustable reactor;

Figure 5 is a schematic diagram of the winding direction of an eight-hole equivalent air gap adjustable reactor;

Figure 6 is a schematic diagram of the winding direction of the square hole equivalent air gap adjustable reactor;

In the figure, there are: iron core 1, AC working winding 2, DC equivalent air gap winding 3, iron core hole 4, local magnetic flux 5, beam 6, side column 7.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

Embodiment one:

A structural diagram of the equivalent air gap adjustable reactor of the present invention is shown in Figure 1, including an iron core 1, an AC working winding 2 and several groups of DC equivalent air gap windings; the iron core 1 is a closed ring structure, A Cartesian coordinate system is established with the center point of the core 1 as the origin, and the two sides of the core 1 are symmetrical with the Y axis; the middle part of the core 1 on the left side of the Y axis is wound with an AC working winding 2, and the middle part of the core 1 on the right side of the Y axis is provided with several pairs of Iron core holes 4, pairs of iron core holes are symmetrically arranged on both sides of the X axis, a set of DC equivalent air gap windings are wound on two adjacent iron core holes, and each group of DC equivalent air gap windings is reversely connected in series ; In the X-axis direction and the Y-axis direction, the distance between two adjacent iron core holes is equal; the DC equivalent air gap windings are all wound along the X-axis direction or both along the Y-axis direction. The upper and lower windings or the left and right windings shown in Fig. 4 represent two sets of DC equivalent air gap windings: 3A and 3B; each set of DC equivalent air gap windings are reversely connected in series. The shaded part in Figure 1 represents the flow range of the local magnetic flux 5, and the resulting local saturation can be regarded as an equivalent air gap: because when a DC current passes through the DC equivalent air gap winding, the core 1 is locally generated around the side of the core hole 4 Magnetic flux saturation, the greater the magnitude of the passing current, the higher the degree of magnetic flux saturation, that is, the smaller the magnetic permeability, until it is close to the magnetic permeability of air, so the current passing through the DC equivalent air gap winding can be regarded as Equivalent air gap with variable length; the effect is: by adjusting the size of the equivalent air gap, the reluctance of the entire core 1 can be controlled. Since the main magnetic flux is inversely proportional to the reluctance of the main magnetic circuit, the main magnetic flux can be controlled. pass size.

Embodiment two:

The structural diagram of an equivalent air gap adjustable reactor according to the present invention is shown in Figure 2. Compared with the first embodiment, the structure has eight circular iron core holes 4 for winding four sets of DC equivalent air gap windings. , to produce a more uniform equivalent air gap. Fig. 5 shows the second embodiment, four sets of DC equivalent air gap windings: 5A, 5B, 5C and 5D. The four DC equivalent air gap windings are connected in reverse series as shown in Figure 5. There are many combinations of winding methods. Figure 5 shows two of the winding methods. The principle of winding is four sets of DC equivalent air gaps The AC magnetic forces induced in the windings cancel each other out. The shaded part in Figure 2 is the flow range of the local magnetic flux 5, and the resulting local saturation can be regarded as an equivalent air gap.

Embodiment three:

A structural diagram of the equivalent air gap adjustable reactor of the present invention is shown in Figure 3. Compared with the structure of the first embodiment, there are two groups of square core holes 4 of the same size arranged longitudinally on one side of the core 1, wherein The vertical distance between the group of square core holes 4 in the middle and the X-axis is zero; that is, the combined cross-sectional area of the middle core holes 4 is twice the cross-sectional area of the upper core hole 4 or the lower core hole 4 . A set of DC equivalent air gap windings is wound on adjacent square core holes 4, that is, two sets of DC equivalent air gap windings are required. If the two square iron core holes 4 in the middle are separated, the magnetic flux generated between the two square iron core holes 4 due to the winding mode of the DC equivalent air gap winding cancels each other, and the magnetic flux is zero, which is equivalent to non-existence. Two sets of DC equivalent air gap windings are wound on the beams 6 between the square iron core holes 4 , as shown in FIG. 6 , the connection modes 6A and 6B of the two DC equivalent air gap windings. The shaded part in Figure 3 is the flow range of the local magnetic flux 5, and the resulting local saturation can be regarded as an equivalent air gap.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications are also possible. It should be regarded as the protection scope of the present invention.

Claims (5)

1. an effective air gap Regulatable reactor, is characterized in that: comprise iron core (1), alternate current operation winding (2) and some groups of direct current effective air gap windings; Described iron core (1) is the loop configuration closed, and is that initial point sets up rectangular coordinate system with the central point of (1) unshakable in one's determination, and the both sides of (1) unshakable in one's determination are symmetrical with Y-axis; Iron core (1) middle part on the left of Y-axis is wound with alternate current operation winding (2), iron core (1) middle part on the right side of Y-axis is provided with some to hole unshakable in one's determination (4), paired hole unshakable in one's determination is symmetricly set on X-axis both sides, adjacent two holes unshakable in one's determination are wound with one group of direct current effective air gap winding, differential concatenation between each group direct current effective air gap winding; In the X-axis direction with in Y direction, the spacing in adjacent two holes unshakable in one's determination is equal; Direct current effective air gap winding is all along X-direction or all along Y direction coiling.

2. a kind of effective air gap Regulatable reactor according to claim 1, it is characterized in that: X-direction is provided with 2n and arranges hole unshakable in one's determination, n is natural number.

3. a kind of effective air gap Regulatable reactor according to claim 1, is characterized in that: described hole unshakable in one's determination (4) is square hole or circular hole.

4. a kind of effective air gap Regulatable reactor according to claim 1, is characterized in that: the right hole unshakable in one's determination (4) of described some compositions is 2 groups or 4 groups.

5. a kind of effective air gap Regulatable reactor according to claim 1, is characterized in that: described iron core (1) is overrided to form by electrical steel sheet.