SU477500A1 - Device for limiting short circuit currents - Google Patents

Description

The proposed device is not suitable for the field of electrical technology, namely, devices for limiting short circuit currents.

A device for limiting short-circuit currents is known, which contains a transformer, the winding of the highest voltage with which the driver is connected to a star with a grounded main, and the winding of the lowest voltage is triangular, the three-phase double-winding reactor, doubled, connected between the transformer ipiamn lower distribution switchgear ;.

The purpose of the invention is nov. efficiently short-circuit currents to carry:, a short circuit and earth on the Ctopoiie higher voltage.

ka: la lna goal is achieved because the windings of each phase of the indicated reactor are included in the circuit of the adjacent phases of the windings of the transformer at low voltage, and the lower voltage lines / kenn are connected from the connection points of the windings of the reactor phases.

At this m it is possible to switch on induction T) 1BH (associated with a two-winding reactor, consequently, with different windings of the transformer phase, different degrees of induction and coupling between the windings; the reactor.

FIG. Tables 1 and 3 show examples of the possible inclusion of double-winding reactors; in fig. 4-6 prGvedewey vector current currents are plotted as 1I and diagrams for determining the equivalent resistance of the reactor. FIG. 1 The transformer 1 is depicted in the cutting of the corners of the winding 2 of the lower voltage, one-hour in fpevro.iijHiiK, the windings of the two-winding reactor 3 are included. Both half of the windings of the reactor 3 are turned on

0 OTHoCiiTe.ibHo B1 1 input of the transformer winding 1. In FIG. 2 the same scheme is presented, but half of the windings of 1SA -; tor ;; 3 wk,; yuchs: s according to v111B () of the two transformer 1s. For the two options listed for switching on the reactor, not sheunlx structurally different. the effect of ismo, 1b.; ovans of the reactor, the number of different nostocatelites of current will be different). Pa fng. 4a is a schematic diagram of the connection of winding 2 of transformer 1, in which the reactor1) p3 nrestap.ich is replaced by its circuit. FIG. 46 n 4c and the display. on phpg. 4d, the participating stock of the vector pattern of FIG. -in, which implies that the voltage at the voltage behind reactor 3 will correspond to DG / ;.

0

Thus, for direct current, the equivalent resistance of torus 3 is

-,,. (one)

AA, p

For reverse currents

nosledovatelstnen similarly

2- / С

(2)

-fl-- The currents of zero continuity are closed in the winding 2 of transformer 1, connected in delta, through the winding of reactor 3. The resistance of reactor 3 for currents of zero sequence will be the value (,. (3) On the phas. 5a there is a vector diagram of voltage 1n 1 at inductive The load on transformer 1 and according to the connection of the winding of the reactor 3, as shown in Fig. 2. In Fig. 56, take part 1 to indicate the vector diagram for determining the equivalent connection of the reactor 3 to the forward and backward currents . For direct currents and v) atioy posledovate.chnostey

D; G, r DA2r 2- () - / -Hr. (4) For bullet current nosledovately

 (1 + K) -Hr. (5) In the above odds: Mulah 1, 2, 3, 4, 5 is the equivalent sonorization of the reactor to 3 direct and successive currents;

 - the equivalent resistance of the reactor 3 currents reverse nosledovatelnosti;

 - Equivalent reactor resistance to 3 currents zero nose. Internal post; Хр is the resistance of the single winding of the torus 3;

K is the coupling coefficient of the windings of the reactor 3. The use of a consonant or a counter-variant of switching on the windings of the reactor 3 is determined by the specific conditions of this network.

In the proposed device is allowed

the possibility of switching on instead of each of the dual reactors 3 (see Fig. 2) of two ordinary linear reactors.

The device admits the possibility of a magnetic connection between the said reactors 3, included in the different phases of the windings of the transformer 2 within wide limits, so that the coupling coefficient can lie within O-1. For any

combinations of phases, the proposed device allows for the consonant and reciprocal inclusion of the indicated reactors. Nanri-mer, in FIG. 3 is a diagram of the incorporation of reactors 3 with magnetic coupling into various

phase windings 2 of the transformer b FIG. 6a shows the current vector range for the inductive load of the transformer 1; FIG. 66 An illustration of a vector voltage diagram corresponding to the inclusion of reactors 3 is agreed in FIG. 3, FIG. 6b shows a portion of the vector diagram of FIG. 66. For an example of the circuit shown in FIG. 3, the equivalent reactor resistance 3 currents to the direct and reverse sequence will be

equally

 (2 + X) -Hr. (6) For a sequence of currents, the equivalent resistance will be equal to (-K). (7)

NOTICE of invention

The device for limiting short-circuit currents contains a power transformer, the higher voltage windings of which are connected to the star with an earthing neutral and the low voltage windings to a triangle and a three-phase two-winding reactor, characterized in that, in order to increase the efficiency of current limiting

a short circuit of the asymmetrical ground fault on the high voltage side, the windings of each phase of the specified reactor are included in the adjacent phases of the low voltage windings of the transformer,

moreover, the lower voltage terminals are made from common points of connection of the winding of the reactor phases.

at

1

V v y p1pz

at

FIG.

BUT

1Lg

/

R