RU2559024C1 - Device intended for power take-off from power transmission line - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention suggests device intended for power take-off from power transmission line, wherein current is not changed practically in the middle part. The device comprises transformer, which primary winding is connected in-series to the line open at the connection point and secondary winding is connected to load. Automatically controlled reactive impedance is connected in parallel to load.

EFFECT: providing voltage for the load independent of its value.

1 dwg

Description

The invention relates to electrical engineering and can be used for power selection in half-wave power lines through series-connected transformers.

The known selection of power from the power line through a transformer, the primary windings of which are connected to the phases of the power line either by a star or a triangle. The load is connected to the secondary windings of this transformer also by a star or a triangle (Handbook of Designing Electric Power Systems / Edited by S.S. Rokotyan and I.M. Shapiro, 2nd ed., Revised and additional - M .: Energy, 1977 .-- 288 p.).

This power take-off is called parallel and is used in modern electrical networks in which the voltage varies within the range that allows its regulation to be applied (as a rule, up to 10 ... 15% of the nominal).

A feature of half-wave power transmission is a change in voltage in the middle of the line from almost zero to maximum. This does not allow the use of parallel power take-off in this part of the line. At the same time, the current in the middle part of the line varies within 5 ... 10% of the natural value regardless of the transmitted power. Therefore, for this part of the line a sequential power take-off is proposed. In sequential selection, the primary windings of the phases of the transformer are connected in series to the power line, the load is connected to the secondary windings connected either by a star or a triangle (Prototype. Shcherbakov V.K., Lukashev E.S., Olshevsky O.V., Putilova A.T. Customized power lines // Novosibirsk: Publishing House of the SB RAS of the USSR, 1963. - 274 p.).

A common feature with the claimed device is the presence of an intermediate power take-off in the middle part of a half-wave or half-wave power transmission line connected by transformers in series to an open line at the point of connection.

The disadvantage of sequential power take-off is an unacceptable rupture in the load circuit of the secondary winding due to a violation, while the equality of the magnetomotive forces between the secondary and primary windings of the transformer connected in series and, for this reason, extra-high voltage inducing, are dangerous for the staff and insulation of the transformer itself.

The aim of the invention is to stabilize the voltage at the load when changing its power from zero to maximum, while the voltage mode in the intermediate power take-off system and the load current in the primary circuit of a series transformer must be adequately stable and not affect the transmission mode of natural power through half-wave lines.

This goal is achieved by the fact that in the known device for power selection in the middle part of the main half-wave line containing the transformer, the primary winding of which is connected in series to the open, at the connection point, the secondary winding is connected in parallel to the load of the intermediate system, parallel to the load in the middle part intermediate line connected reactance automatically controlled by the control system, changed so that the intermediate load current in the primary winding of the transformer does not change in magnitude. Thus, the voltage at the load remains stable.

The device (Fig. 1) for power selection in the middle part of the main half-wave line 1 consists of a transformer 2, the primary winding of which is connected in series to the open, at the connection point, line 1. The secondary winding of the transformer 2 is connected to the load 3, in parallel through which current transformers 5 and 6, a phase shift angle measuring device 7, a control system 8 and a power thyristor unit 9 are connected with an adjustable reactance 4 (inductance-capacitive in FIG. 1).

Since the load 3 varies in time, its resistance also changes. With a decrease in load 3, its resistance increases. With a constant current line 1 and a simultaneous increase in the resistance of the load 3 increases proportionally to the voltage on the load 3, which can lead to unacceptable modes. To eliminate this drawback, an automatically controlled reactance 4 is connected in parallel with the load 3, which is reduced through current transformers 5 and 6, a phase shift angle measuring device 7, a control system 8, and a power thyristor unit 9 so that the load resistance 3 and reactive modules connected in parallel resistance 4 remained constant; in this case, the voltage at the load remains stable.

Claims (1)

A device for power take-off from a half-wave power line containing a transformer, the primary winding of which is sequentially connected to an open line at the point of connection, and the secondary winding is connected to a load, characterized in that in order to stabilize the voltage at the load, an automatically adjustable reactance is connected in parallel with it .