RU1798824C - Three-phase reactor of zero sequence - Google Patents

Abstract

Usage: electrical engineering, limiting the currents of single-phase earth faults in electric networks to a fire-safe value. SUMMARY OF THE INVENTION: the device comprises parts of windings 1-6 located on the rods 7, 8 of the magnetic wire. Parts of the windings are connected to a three-phase winding. The winding of each phase is formed by two semi-windings of 1.5, 2.4, 3, b. The semi-windings are connected in series and are located on different terminals of the magnetic circuit. The indicated connection of the windings makes it possible to reduce the non-asymmetry of the inductive resistances of the scattering, and hence the distortion of the three-phase voltage introduced by the reactor. 2 ill.

Description

The invention relates to electrical engineering, in particular to three-phase zero sequence reactors. Zero-sequence reactors serve to limit the currents of single-phase earth faults in electrical networks to a fireproof value.

The aim of the invention is to improve the quality of the voltage at the outlet of the reactor by reducing the asymmetry of the inductive resistance of the scattering of its windings.

Figure 1 shows a schematic representation of a reactor for a double-core magnetic wire; Figure 2 shows the connection of parts of the reactor phase windings.

The reactor contains six parts (semi-windings) of phases 1-6 located on the rods x of the two-core magnetic wire. Half-windings 1,2,3 are concentrically placed on the first core 7 of the magnetic circuit, half-windings 4, 5, 6 are on the second core 8.

V «r W All half-windings have turns, the radial size (width) of each half-winding is L, the size of the Channels between the half-windings is C, and the average diameter of the windings is D, the height of the windings is h. The winding of each phase is formed by two semi-windings connected in series and placed on different rods of the magnetic circuit,

In this case, the inner half-winding 1 of one rod 7 and the middle half-winding 5 of the other rod 8 form the winding of one phase (for example, phase A), the middle half-winding 2 of the rod 7 and the outer half-winding 4 of the rod 8 form the winding of the second phase (for example, phase B), and the outer the semi-winding 3 of the rod 7 and the inner half-winding 6 of the rod 8 form the winding of the third phase (for example, phase C).

The present invention extends to a reactor with a three-rod (multi-rod) magnetic circuit, in which all of the foregoing is true for any pair of adjacent rods arranged on each rod of which parts of the windings of three phases are concentrically placed.

From the expression (2) for this reactor follows

and cw

Oo6p. - - s --fj- X

x (D + b + c) d + D (2d + b / 3) + + aD (+ b / 3) + a (D - b - c) 5 -f

+ a (D - b - + a2 (D + b + o w Ddu O + -f

33

, / a «h b + с -i + (a - 1) - ry- J,

where O) is the corner frequency,

W-number of turns of the phase winding, HQ 4 l, 1СГ7 Гн / м - magnetic constant,

h is the height of the windings,

D is the average diameter of the windings,

6 s + 2b / 3 - reduced channel width of the scattering channel of a pair of adjacent parts of the phase windings,

b is the radial size (width) of each part of the winding,

c is the channel between the parts of the windings. Collected .. due to the inductive voltage drop on this reactor is theoretically almost two times less than in the known.

Reverse voltage drop in the reactor at real

the size of the first option will be

0.5-0.7% of rated voltage instead

1-1.5% in a known reactor, with usually

permissible value of 2%, such a decrease is significant.

The reactor operates as follows.

The reactor is included in the dissection of all three phases of the line supplying the protected section of the network. In normal operation on

undesired small voltage drops and voltage distortions occur in the reactor. When one of the network phases closes behind the reactor to the ground, i.e. with the most frequent damage, usually requiring the disconnection of the damaged part of the network, in this case the entire network continues to work normally, because the reactor reduces the fault current to a safe value .. Since the resistance of the reactor to current

the zero sequence is very large, the closing current is very small. A short circuit not energized by a significant current may disappear by itself. If it does not disappear on its own, the reactor provides a long

operation of the network without fire and the ability to prepare for the elimination of short circuits by personnel at a convenient time.

. Thus, when applying this proposal, at no additional cost, a voltage distortion reduction of more than half is achieved.

Claims (1)

SUMMARY OF THE INVENTION A three-phase zero sequence reactor comprising a three-phase winding, divided into parts in each phase, a core magnetic circuit. on each of the two rods of which are concentrically the inner, middle and outer parts of the windings of three phases are placed, connected in each phase in series, characterized in that, in order to improve the quality of the voltage at the outlet of the reactor by reducing the asymmetry of the inductive resistances of the scattering of the windings, the inner part of the winding of the first phase of one rod is connected to the middle part of the winding of another rod of the same phase, the middle part of the winding of the second phase of the first rod is connected to the outer part of the winding of the second rod of the same phase, the outer part of the winding of the third phase of the first rod connected to the secondary winding of the second rod part of the same phase. FIG. 2