RU2697856C1 - Transformer testing facility - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to electrical engineering and is used in transformer plants. With circuit breaker 1 switched on, industrial circuit voltage is converted into adjustable three-phase or three in-phase voltages in known manner in unit 2, which are transmitted via transformers 3–5 to load via switch 6–11. Such phase-shift switch connects output windings of transformers in parallel in single-phase mode (outputs B1, A1) and in three-phase circuit (outputs A1, B1, C1) – in three-phase mode. Any position of the switch is set by electric motor 14 via gear 14. Operation of engine 14 in one direction or another is provided by contactors 15, 16 connected by coils 17, 18 by commands of contacts 22, 23. Electric motor rotates to the specified side until the contact of limit switch 19 or 20 fixing contacts position 6–11 is opened. Simultaneously, the limit switch supplies current to the trigger relay winding 21, which stores the last movement direction (state) of the switch. After disconnection from circuit breaker 1 its block-contact 24 includes relay 25 of time, which electronic or mechanical (roll-over contact) method closes contact 26 for several tens of seconds, and then disconnects. At this time coil 17 or 18 of the respective contactor is switched on and the electric motor withdraw contacts 6–11 into the intermediate (third) state, when they are all open, in such condition two phases (B, C) are cut off from the output.

EFFECT: technical result consists in improvement of reliability.

1 cl, 2 dwg

Description

The invention relates to electrical engineering and is used in transformer plants. The well-known [1] circuit of a device for a similar purpose, containing a frequency converter output connected to the output three-phase transformer. The disadvantage of this device is its great complexity, due to the need to use a six-phase converter. In addition, in single-phase mode, the output power is reduced by 2/3.

The closest in technical essence and the achieved results is the installation / 2 / for testing transformers, containing a control unit, a switch with three left and three right contacts and a drive unit, a power switch and a unit for converting three-phase mains voltage into three single-phase voltages, adjustable in frequency and the amplitude connected by the outputs to the primary winding of three single-phase transformers, while the ends of the secondary windings of single-phase transformers are connected together to a common point N, and the beginning, two secondary windings are connected to common points of pairs of heterogeneous contacts, and the first two outputs of the left contacts are connected by the output of phase A, forming the output A1 of the installation, and the second output of the third left contact forms the output B1 connected to the second output of the right contact, the drive unit contains an electric motor with mechanical transmission associated with the left and right contacts of the switch, switching contactors in the power supply circuit of the motor, the coils of which are connected to the limit switches by one output, and the contacts to the contacts by the second Lok control, the left output contacts form a single-phase mode, and the right - phase. The disadvantage of this device is the relatively low reliability and complexity due to the need to install at the output of the installation of the disconnector.

The technical result of the proposal is to increase reliability and simplification. The technical result is achieved due to the fact that the second terminal of the second right contact forms terminal C1 of the device, and a bistable two-winding relay is connected to the drive unit, connected by the first heterogeneous leads of the coils to the third terminal of the limit switches, which are connected to the power pole by the middle terminal, and other terminals of the coils connected to the second power pole, the middle terminal of the switching contact of the bistable relay through the contact of the time relay is connected to the first power pole, and the extreme terminals of the contact ineny with the conclusions of the contactors. Additionally, the third pair of left and right contacts is disconnected and this right contact is connected to A and A1. In FIG. 1, 2, the diagrams are presented in the position of a three-phase test mode. The installation contains a network switch 1 and a unit 2 for converting a three-phase mains voltage to a single-phase voltage, adjustable in frequency and amplitude, the outputs are connected to the primary windings of three single-phase transformers 3, 4, 5. The ends of the secondary windings of transformers 3-5 are connected together to a common point N, and the beginning is connected with the contacts 6-11 of the switch with two stable positions. Other designations: 12 - control unit, 13 - contact drive unit 6-11. The drive 13 contains: 14 - an electric motor; 15, 16 - contactors; 17, 18 - their coils; 19, 20 - limit switches; 21 - coil double-winding bistable (trigger) relay; 22, 23 - contacts of the control unit 12; 24 - block contact switch 1; 25 - a coil of a pulse time relay; 26 - his contact; 27 - switching contact bistable relay, 28 - mechanical transmission. The outputs of transformers 3-5 are marked A, B, C, the entire installation - A1, B1, C1.

Installation works like this. When the switch 1 is turned on, the voltage of the industrial network in a known manner in block 2 is converted into an adjustable three-phase or three common-mode voltage, which is transmitted through transformers 3-5 to the load via switch 6-11. Such a phase switch connects the output windings of transformers in parallel in a single-phase mode (terminals B1, D1) and in a three-phase circuit (outputs A1, B1, C1) in a three-phase mode. One or another switch position is set by the electric motor 14 through transmission 14. The operation of the motor 14 in one direction or another is provided by contactors 15, 16, which are turned on by coils 17, 18 according to the commands of contacts 22, 23. The electric motor rotates in the specified direction until the contact of the limit switch opens 19 or 20, fixing the position of the contacts 6-11. At the same time, the limit switch supplies current to the coil 21 of the trigger relay, which remembers the last direction of movement (state) of the switch. After disconnecting the circuit breaker 1, its block contact 24 turns on the time relay 25, which electronically or mechanically (rolling contact) closes contact 26 for several tens of seconds, and then disconnects it. At this time, the coil 17 or 18 of the corresponding contactor is turned on and the electric motor moves the contacts 6-11 to the intermediate (third) state, when all of them are open, in this state, see FIG. 1, two phases (B, C) are cut off from the outlet, and in FIG. 2 all three. Those. in this state, voltage cannot be supplied from the outside (from the load). Those. You can not put an additional disconnector on the output. This is very important in the distribution test systems of plants, where there are usually several such plants (including electric machines).

Thus, the device very easily provides a transition from one mode to another, providing high reliability.

Information sources

1. Patent for utility model of the Russian Federation No. 142928, cl. G01R 31/12, June 17, 2013

2. Patent for utility model of the Russian Federation No. 119544, class. Н02М 5/451, Н02М 5, December 4, 2012

Claims (1)

Installation for testing transformers, comprising a control unit, a switch with three left and three right contacts and a drive unit, a network switch and a unit for converting a three-phase mains voltage into three single-phase voltages, adjustable in frequency and amplitude, connected by outputs to the primary winding of three single-phase transformers, the ends of the secondary windings of single-phase transformers are connected together to a common point N, and the beginnings B, C of two secondary windings are connected to the common points of pairs of heterogeneous contacts tov and the first two outputs of the left contacts are connected by the output of phase A, forming the output A1 of the installation, and the second output of the third left contact forms the output B1 connected to the second output of the right contact, the drive unit contains an electric motor with a mechanical transmission associated with the left and right contacts of the switch, switching contactors in the power supply circuit of the electric motor, the coils of which are connected to the limit switches by one pin and the second to the contacts of the control unit, while the left contacts form the single-phase output, and the right ones are three-phase, characterized in that the second terminal of the second right contact forms the terminal C1 of the device, and a bistable two-winding relay is connected to the drive unit, connected by the first heterogeneous leads of the coils to the third terminal of the limit switches, which are connected to the power pole by the middle terminal, and other terminals coils are connected to the second power pole, the middle terminal of the bistable relay switching contact is connected to the first power pole via the time relay contact, and the terminal's extreme terminals are connected to contactor leads.

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