RU2273909C1 - Electroinductive device - Google Patents

Abstract

FIELD: electrical engineering; high-voltage supply mains.

SUBSTANCE: proposed device that can be used as variable inductive reactance apparatus designed to control reactive power and voltage and to limit surge voltages has shell-core magnetic circuit with core or cores split in two equal parts, each part mounting control winding coils wound on each part of core and supply mains winding placed as a whole on core; novelty is that cross-sectional area of supply mains winding is larger by two to five times than that of control winding and total height of mains and control windings is 1.1 to 1.9 times greater than that of core carrying them. In this way overload capacity of device is raised by 1.5-3 times while nonlinear distortions in supply current are maintained within desired level throughout entire control range.

EFFECT: enhanced overload capacity of device and operating stability of power system.

2 cl, 3 dwg

Description

The present invention relates to the field of electrical engineering and can be used in high-voltage electrical networks as a magnitude-controlled inductance for regulating reactive power, voltage, limiting overvoltage, increasing the stability of power systems.

Known electrical induction device, the so-called controlled shunt reactor of transformer type, which is an analogue of the present invention [1]. The analog inductance is controlled by shorting the sections of its control winding with a key device (a semiconductor key or a mechanical switch). The permissible level of nonlinear distortion of the current consumed by the network winding during power control and its sinusoidality in the nominal mode is achieved in the analogue by the fact that with completely shorted sections of the control winding, the reactor power consumption is equal to its rated power, i.e. the nominal inductance of the analog is equal to the mutual inductance of the network and control windings . The disadvantage of the analogue is that it does not have overload capacity in terms of power consumption, while the ability of an electro-induction device to 2-3 times overload during operation increases its efficiency, in terms of ensuring the stability of the electrical network in normal and emergency conditions, and in parts of surge protection at the connection point.

Partially, the disadvantages of the analogue [1] are eliminated in the known electro-induction device [2], the so-called magnetization-controlled shunt reactor, which is the prototype of the present invention. The regulation of the inductance of the prototype is carried out by magnetizing the magnetic circuit with a constant current control winding. The permissible level of nonlinear distortion in the current of the network winding is achieved by the fact that in the nominal mode the magnetic circuit is saturated to half-period (half-limit) saturation. Due to the even greater saturation of the magnetic circuit, up to a full-period (limit), in the prototype it is possible to achieve a power consumption exceeding the nominal [3]. The disadvantage of the prototype is that its technically feasible level of overload, achieved through bias, does not exceed 30-40% of the rated power of the device.

The aim of the invention is to increase the overload capacity of the electric induction device in power up to 1.5-3 times while maintaining an acceptable level of non-linear distortion of the mains current in the entire control range.

This goal is achieved in that in an electro-induction device containing an armored rod magnetic circuit with a rod (s) split into two identical parts, on each part of which (which) are located sections of the control winding, covering each part of the rod, and sections of the network winding, covering the entire rod , the cross section of the network winding is 2 to 5 times greater than the cross section of the control winding, and the total height of the network and control windings is 1.1 to 1.9 times the height of the covered about them the core. In the proposed electro-induction device, the mutual inductance of the network and control windings can be from 1/3 to 2/3 of its rated inductance.

The essence of the proposed device is illustrated by the circuit (Figure 1), characteristic waveforms of current and voltage (Figure 2) and design (Figure 3). The proposed electric induction device comprises an armored rod magnetic circuit with a rod 1 split into two parts, on which sections of the control winding 2 are located, covering each of the parts of the rod 1 and the network winding 3, covering the entire rod 1.

Armored core can be performed both in single-phase and in three-phase versions (see Figure 1). By outputs A, B, C, O, the network winding 3 is connected to a high-voltage network U _c . To the conclusions a, b, from the control winding 2 is connected a synchronized key element _KE (semiconductor key or mechanical switch). To the conclusions of the midpoints of the control winding +, - a source of variable control voltage U _y is connected.

The proposed electric induction device operates as follows. When connecting the network winding 3 to the high-voltage network U _c and the zero value of the control voltage U _y , alternating magnetic fluxes appear in the magnetic circuit, similar to magnetic fluxes, for example, double-winding transformers in idle mode [2]. In this case, the rod 1 and the remaining sections of the magnetic circuit are in an unsaturated state (the maximum value of the magnetic flux induction does not exceed the saturation induction of electrical steel). As a result, the inductance of the network winding is maximum in magnitude, and the mains current consumed by it is I _c ≈0. This mode, which is commonly called the idle mode, is shown in FIG. 2 in the time interval 0-t ₁ .

When the control voltage U _y appears, in the rod 1 split into two parts, magnetization fluxes of the same magnitude and directed in opposite directions arise and begin to increase [2]. The saturation of the rod 1 with these flows reduces the inductance of the network winding 3 and, as a result, the network current I _c increases (see the graphs of Figure 2 in the interval (t ₁ -t ₂ ). In the nominal mode (interval t ₂ -t ₃ in FIG. 2) when

where I _c is the effective current of the network winding;

I _n - rated current of the device,

a half-period saturation mode occurs in the device [2]. Half-period saturation provides the sinusoidality of the mains current I _c in the nominal mode and the permissible level of distortion of its shape in the intermediate modes of power consumption (interval t ₁ -t ₂ in Fig. 2). With further magnetization of the rod 1 by the control voltage U _{y, the} network current I _c begins to exceed the rated value of the device current (see interval t ₃ -t ₄ in figure 2) up to the full-cycle saturation current:

where I _P - current full-time saturation of the device.

When half-period saturation (see interval t ₄ -t ₅ in figure 2), the current of the network winding I _c , as in the nominal mode, has a sinusoidal shape.

With full-period saturation, both parts of the rod 1 are in a saturated state all the time (the induction in them exceeds the saturation induction value of electrical steel) and their further magnetization no longer affects the value of the consumed mains current I _c [3]. Therefore, a subsequent increase in the mains current I _s is performed by shorting the terminals a, b, c of the control winding of the key device _KE . With the complete shorting of the conclusions a, b, c, the mains current I _s becomes the maximum possible (interval (t ₅ -t ₆ in figure 2):

where I _max is the maximum possible current of the network winding.

As can be seen from the graphs in Fig. 2, explaining the operation of the device, the regulation of the mains current I _c from idle to 1.33 nominal (I _n ) is carried out by magnetizing the rod 1. Subsequent adjustment of the mains current up to 2 times from the nominal (I _max ) is carried out shorting the terminals of the control winding 2.

The degree of overload of the device due to magnetization depends on the ratio of the cross section of the network winding S _co to the cross section of the control winding S _oy (Figure 3). The degree of congestion due to shorting terminals a, b, c control windings 2, except for the relationship of cross-sections of the windings also affects the ratio of the total height H of the coils _with + H _ou rod to the height H _o (sm.Fig.3). To obtain the required operating efficiency of the device, depending on the connection point and the requirements for it, it is technically feasible to provide 1.2 ÷ 1.5 times the current overload due to magnetization and 1.5 ÷ 3.0 times the overload due to shorting the winding management.

The range of 1.5 ÷ 3 times the overload of the device in terms of power, of which 1.2 ÷ 1.5 times the overload is carried out due to magnetization, is provided with the following ratios of design parameters:

where S _co is the cross section of the network winding,

S _oy is the cross section of the control winding.

An integral criterion for fulfilling the above ratios of a device already manufactured is the ratio of the mutual inductance of the network and control windings to its nominal inductance. When conditions (4) and (5) are fulfilled, the mutual inductance of the network and control windings is from 1/3 to 2/3 of the rated inductance of the device.

Compared with the analogue and prototype, the present invention has the advantage of expanding the range of power consumption up to 1.5-3 times in relation to the nominal. Moreover, the distortion of the mains current in the entire control range does not exceed the distortions of the mains current of the prototype. In addition, there are special points on the control characteristic of the device where the current of the mains winding is almost sinusoidal: in nominal mode, full-period saturation mode, maximum power consumption mode.

The performance of the proposed electro-induction device is confirmed by calculations, physical modeling and testing of the layout.

Literature

1. Alexandrov G.N. On the methodology for calculating controlled transformer-type shunt reactors. Electricity. 1998. No. 4. Page 15-20.

2. Bryantsev A.M. Magnetization controlled electric reactors - as an element of the electric power system. Electrical Engineering 2003. No1. Page 2-4.

3. Bryantsev A.M. Magnetizable ferromagnetic devices with extreme saturation of sections of the magnetic system. Electricity. 1986. No. 2. Page 23-29.

Claims (2)

1. An electro-induction device comprising an armored rod magnetic core with a rod (s) split into two identical parts, on each part of which (which) are located sections of the control winding, covering each part of the rod, and sections of the network winding, covering the entire rod, the cross section of the network winding 2–5 times the cross-section of the control winding, and the total height of the network and control windings is 1.1–1.9 times the height of the rod covered by them. 2. The electro-induction device according to claim 1, characterized in that the mutual inductance of the network and control windings is from 1/3 to 2/3 of its rated inductance.

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