RU2037224C1 - Electric reactor with superposed magnetization - Google Patents

Abstract

FIELD: electrical engineering; electrical power engineering. SUBSTANCE: electric reactor has coils of main winding 1, coils of control winding 2 and magnetic system with rods and yokes 3. Rods of magnetic system are manufactured in the form of individual armored cores 4 with central bars and side yokes placed orthogonally to axes of coils of main winding. Central rods of armored cores carry coils of control winding, cores proper are isolated from with the aid of nonmagnetic gaps. Electric reactor is provided with additional cores 5 having correction winding 6 and magnetic shunts 7 put on them. Yokes 3 of magnetic system on side of external front part of control winding are fitted with protrusions 8 of electrical-sheet steel located on both sides of system. Cores 5 with windings 6 are placed between protrusions 8 of yoke 3 and magnetic shunts 7 positioned over entire height of electric reactor. Windings 6 are connected in series with coils of control winding. Shunts 7 are separated from cores 5 by nonmagnetic gaps. EFFECT: diminished harmonics in working current of reactor over the whole range of adjustment, reduced additional losses. 2 cl, 4 dwg

Description

 The invention relates to electrical engineering and energy, in particular to electric induction devices with smooth regulation of inductance by magnetization.

A known design of an electric reactor controlled by transverse magnetization, containing the main windings and a magnetic system with rods made in separate sections, each of which consists of two contacting ferromagnetic cylinders covered by a section of the control winding in the area of their contact, and the frontal sections of the sections are located inside the ring ferromagnetic inserts [1]
The disadvantages of this design are the great technological complexity of manufacturing, the presence in the operating current of the reactor of the entire spectrum of odd harmonics and increased losses.

Also known is the design of an electric magnetization reactor containing coils of the main winding, coils of the control winding and a magnetic system with rods and yokes, the rods of the magnetic system being made as separate armored cores with central rods and side yokes located orthogonally to the axes of the coils of the main winding, on the central the rods of the armored cores are placed control coil coils, and the cores themselves are separated from the yokes by non-magnetic gaps [2]
This design in its essence and the achieved result is closest to the invention.

 Its disadvantages are the presence of odd harmonics in the operating current of the reactor in the entire control range and increased added losses.

 The aim of the invention is to reduce harmonics in the operating current of the reactor over the entire control range and to reduce additional losses.

 For this, an electric magnetization reactor containing the main winding coils, control winding coils and a magnetic system with rods and yokes, the magnetic system rods being made as separate armored cores with central rods and side yokes located orthogonally to the axes of the main winding coils, on the central rods armored cores placed control winding coils, and the cores themselves are separated from the yokes by non-magnetic gaps, equipped with additional cores with correcting windings and magnetic shunts, the yokes of the magnetic system in the area of the scattering channel are provided with protrusions of electrical steel, and the shunts are placed in the scattering channel of the reactor, on both sides of the frontal parts of the control winding coils, with additional cores with correcting windings located between the magnetic shunts and the yoke protrusions and corrective windings are connected in series with the coils of the control winding; magnetic shunts are separated from additional cores by non-magnetic gaps.

 In FIG. 1 shows a General view of one rod of an electric reactor with magnetization; in FIG. 2 same, top view; figure 3 General view of the additional core with a correcting winding; figure 4 graph of changes n. from. reactor when magnetizing.

 An electric magnetization reactor contains coils of the main winding 1, coils of the control winding 2 and a magnetic system with rods and yokes 3, the rods of the magnetic system being made as separate armored cores 4 with central rods and side yokes located orthogonally to the axes of the coils of the main winding, on the central control rod coils are placed on the rods of the armored core cores, and the cores themselves are separated from the yokes by non-magnetic gaps, the reactor is equipped with additional cores 5 with correcting windings 6 and magnetic shunts 7, the yokes 3 of the magnetic system in the area of the scattering channel are provided with protrusions 8 of electrical steel, and the shunts 7 are placed in the scattering channel of the reactor, on both sides of the frontal parts of the coils of the control winding 2, with additional cores 5 with corrective windings 6 are located between the magnetic shunts and the protrusions of the yoke, and corrective windings 6 are connected in series with the coils of the control winding 2; magnetic shunts 7 are separated from additional cores 5 by non-magnetic gaps.

 The described reactor operates as follows.

The coils of the main winding 1 are connected to an AC voltage source. The control winding 2 with the correction winding 6 is connected to a constant current source, the value of which can be changed from zero to the nominal value. When the current in the control winding 2 changes, the current in the main winding 1 changes, thereby controlling the reactive power of the reactor within Q _o ≅ ≅ Q _reg ≅ Q _n , where Q _{o is the} minimum reactive power determined by the magnitude of the non-magnetic gaps in the magnetic system of the reactor. The rated power of the reactor corresponds to the rated current in the main winding.

 Considering the operation of the reactor according to the prototype, if there is an alternating voltage U const on the main winding, the total alternating magnetic flux in the lateral sections of the armored core and adjacent channels will also be a constant value.

.With increasing current in the control winding from zero to a value when B _o will be greater than B _S (Fig. 4), and then, to a value of B _o ', the angle α will increase from zero, at B _o B _S, to a certain value at B _o >> B _S and further, when B _o '> B _o > B _S , i.e. in the range 0≅ α ≅

.

A similar picture of the change in the angle α can be obtained by fixing the current in the control winding at some intermediate value, at which, for example, the induction in the core would be equal to B _o , but the variable induction in the lateral sections of the armored core would change. In this case, with B _o const, with an increase in B _{m, o} , the angle α will decrease, and with a decrease in B _{m, o} increase.

The invention boils down to the fact that with increasing current in the control winding, and hence the induction B _o , an increase in the variable induction in the lateral sections of the armored core occurs at the same time. The angle α remains constant over the entire range of current changes in the control winding and variable induction in the side sections of the core to the nominal value.

The implementation of the described technical solution is ensured by the presence of two parallel-connected magnetic resistances along the alternating magnetic flux path: one, which is the side sections of the armored core with non-magnetic gaps between the core and yokes, which in the idle mode of the reactor, mainly due to relatively large non-magnetic gaps, represent a sufficiently large magnetic resistance, and another, which is a magnetic shunt with relatively no large, compared with the first, non-magnetic gaps, which have significantly less than the first, magnetic resistance. Therefore, in a mode close to B _o B _S , mainly the entire magnetic flux will pass through the magnetic shunts and only a small part of it along the side sections of the cores. In this case, the angle α will have the maximum possible value selected in advance.

With increasing current in the control winding and the correcting winding connected in series, the magnetic resistance of the section with magnetic shunts increases due to an increase in the magnetic resistance of the magnetized additional core along the passage of part of the alternating magnetic flux. Thus, with an increase in magnetization, the magnetic flux of the main winding is simultaneously redistributed, which is gradually displaced from the shunts to the side sections of the armored core, and therefore, the amplitude of the magnetic induction also increases in these areas. In this case, with an increase in the difference (B _o B _S ) (Fig. 4), the amplitude of the inductions B ₁ and B ₂ in the lateral sections of the core also increases, while the angle α remains constant over the entire control range.

для формы кривой рабочего тока, приближающейся к трапецеидальной, может быть произведен по формуле

0, где ν= 3,5,7, номера нечетных гармоник, на основании необходимости исключения из рабочего тока реактора на всем диапазоне регулирования любой нечетной гармоники либо минимизации группы нечетных гармоник.The choice of the angle α enclosed in the range 0 <α <

for the shape of the curve of the working current, approaching the trapezoidal, can be produced by the formula

0, where ν = 3,5,7, the numbers of odd harmonics, based on the need to exclude from the operating current of the reactor in the entire control range any odd harmonics or minimize the group of odd harmonics.

So, for example, asking whether it is necessary to exclude from the operating current of the reactor over the entire range of third harmonic regulation, ν 3, the angle α under the sum sign should be 60 ^о , to exclude the fifth harmonic, ν 5, α 36 ^о , etc. To minimize current harmonics in the working groups, for example the third and fifth, ν 3,5, angle α under the summation sign will be ^about 62.6 respectively, for minimizing the fifth and seventh harmonics, ν 5,7, angle α will be respectively equal to 35, 3 ^o etc. Solving the above expression of the sum by numerical methods, one can set any number of harmonics in the reactor current and their combination: with the presence of harmonics that are multiples of three, or without them, taking into account the possibility of using the described reactor in a three-phase group with the main windings connected to a triangle and corresponding compensation of harmonics that are multiple three in a triangle.

, а затем величину электромагнитной индукции холостого хода
B_m,o a(K_уJ_у)/(0,36-0,44)sinα где Q_н задаваемое номинальное значение мощности реактора;
К_р задаваемая глубина регулирования реактора;
ω угловая частота;
К_с коэффициент заполнения сталью геометрического сечения бронестержневого сердечника;
(К_уJ_у) произведение задаваемого коэффициента заполнения окна бронестержневого сердечника обмоткой управления на задаваемую плотность тока в обмотке управления.Having determined the choice of angle α, it is possible to determine the geometric size of the side of the armored core by the formula
a (3.73 ÷ 4.50) 10

and then the magnitude of the electromagnetic induction idle
B _{m, o} a (K _y J _y ) / (0.36-0.44) sinα where Q _{n is the} set nominal value of the reactor power;
K _p set depth regulation of the reactor;
ω angular frequency;
K _with coefficient of filling with steel of the geometric cross section of the armored core;
(K _y J _y ) the product of the specified fill factor of the window of the armored core of the control winding by the specified current density in the control winding.

 The numerical coefficients in both formulas characterize the range of the choice of the ratio of the cross sections of the central rods to the lateral yokes (side sections) of the armored core.

 In addition to the foregoing, it should be noted that in order to avoid short circuit of the yoke electrical steel plates with the additional core cores between the latter, it is also necessary to provide for a small technological gap, which can be formed by, for example, applying a thin layer of epoxy compound on the surface of the plates in the areas of their mutual contact or other insulating material.

Claims (2)

 1. ELECTRIC REACTOR WITH MAGNETIZATION, comprising coils of the main winding, coils of the control winding and a magnetic system with rods and yokes, the rods of the magnetic system made in the form of separate armored cores with central rods and side yokes located orthogonally to the axes of the coils of the main winding, on the central rods armored cores placed control winding coils, and the cores themselves are separated from the yokes by non-magnetic gaps, characterized in that the reactor is equipped with with cores with correcting windings and magnetic shunts located on them, the yokes of the magnetic system from the outer frontal part of the control winding are provided with protrusions of electrical steel on both sides, additional cores with correcting windings are located between the yoke protrusions and magnetic shunts located along the entire height of the reactor and combining opposite protrusions, and the correcting windings are connected in series with the coils of the control winding.  2. The reactor according to claim 1, characterized in that the magnetic shunts are separated from additional cores by non-magnetic gaps.