SU443440A1 - Device for automatic control of voltage in distribution networks - Google Patents

Description

one

The invention can find wide application in radial and conditionally closed electrical networks.

A device for automatic voltage regulation in distribution grids is known, comprising a booster transformer included in a distribution line, a power supply unit and an automatic switch-on unit for excitation winding of a booster transformer, consisting of a voltage control angle with control units of the minimum and maximum voltage deviation limits from the nominal, to the outputs of which a time delay block, a circuit switching block and a shorting node connected to it are connected excitation winding of booster transformer with contactor at the output.

In order to increase the voltage control accuracy when the power flow direction in the proposed device is changed, the automatic excitation winding unit includes a power flow direction control unit in the line, the inputs of which, respectively, are connected to the excitation winding of the booster transformer and shorting node of this winding, and the output - with one of the outputs of the circuit switching unit. The excitation winding of booster transformer is made in the form of two sections with a common neutral point, connected in a star.

The shorting node contactor is latched, and the shorting node contains a rectifying and charging unit, the input of which is connected to the power supply unit, and the output is connected to the contactor, which makes it possible to increase the reliability of the device during instantaneous disappearance of the line voltage.

The drawing is a block diagram of the described device.

The device contains a three-phase two-step voltage transformer

1 included in the distribution line, power supply unit 2 and automatic transformer excitation unit 3. The transformer consists of a series winding included in the line break,

and an excitation winding made in the form of two sections with a common neutral point connected in a star. Power supply 2 is either a separate power transformer or a 380V line. Block 3

automatically turning on the excitation winding of the transformer 1 includes a voltage monitoring unit 4 containing a control mode setting unit 5 connected by its input with a power supply unit 2, and

the outputs through blocks b and 7 of the voltage control at the minimum and maximum permissible deviation limits from the nominal with the time delay unit 8, the output of which is connected to the execution unit 9. The output of unit 9 is connected to one of the inputs of the circuit switching unit 10, the remaining inputs of which are connected respectively, with the outputs of the power supply unit 2 directly and through the voltage regulator 11, the power direction control unit 12 in the line, as well as with one of the outputs of the control unit 13 of the short circuit winding unit 14 1. The outputs of the unit 10 are connected to the excitation winding of the transformer 1 and the input of the control unit 13, connected to one of the inputs of the shorting unit 15, to the other input of which the output of the rectifying-charging unit 16 connected with its input to the stabilizer is connected. wives One of the outputs of the shorting unit 15 is connected to the excitation winding of the transformer 1, and the other to one of the inputs of the power flow direction control unit 12, the other input of which is connected to the excitation winding of the transformer 1. The adjustment mode setting unit 5 is, for example , transformers with taps and switches. The voltage control units 6 and 7 are made, for example, on transistors operating in the normal mode and cut-off mode, and the time delay unit 8 is based on the charge-discharge capacitor principle. Executive unit 9 contains the executive relay. Circuit switching unit 10 includes two contactors and six intermediate relays. The power flow direction control unit 12 consists of a current transformer 17 included in a short-circuited field winding, a voltage transformer 18 and a power relay 19. The shorting winding unit 15 is made in the form of one latch contactor, the control coil of which is located in the control unit 13.

At the rated voltage in the distribution line at the output of the voltage control unit 4, there is no signal. The excitation winding of transformer 1 is shorted. From the output of the power control unit 12, the signal flows into the circuit switching unit 10 and prepares it to work, i.e., to switch the excitation winding of the transformer 1 in the desired direction. As the mains voltage increases or decreases, the voltage at the output of the power supply unit 2 changes accordingly. Depending on the voltage regulation mode set by block 5 and on the voltage level at the output of power supply unit 2, either unit 6 or voltage control unit 7 is triggered, respectively, at the minimum or maximum allowable limit of the voltage deviation from the nominal value. Timed signal generated

enters through the Executive unit 9 in the unit 10 circuit switching. Since unit 2 is already prepared for operation in the desired direction, the signal from one of its outputs goes to switching on the corresponding sections of the excitation winding of the transformer 1, and from the other to the controlled roller (block 13) of the latching contactor. In block 15, the latch is removed from the contactor, while

the corresponding section of the exciter excitation of the transformer 1 is turned on. With a significant decrease in the voltage in the line, for example during a short circuit at a remote point of the line, and instantaneous disappearance

the voltage signal from the output of the rectifying block 16 enters the block, 15 and the excitation winding of the transformer is short-circuited. The stabilizer And voltage serves to power the automatic block

switching on the excitation winding of the transformer 1 with stabilized voltage and thus ensures sufficient accuracy and reliability of the contactors and relays with significant voltage deviations from the nominal (up to 30-50%).

Subject invention

Claims (2)

1.A device for automatic voltage regulation in distribution networks, containing a booster transformer included in the distribution line, a power supply unit and an automatic switch-on unit for the booster transformer excitation winding, consisting of a voltage monitoring unit with control units of the minimum and maximum allowable voltage deviation limits nominal value, to the outputs of which a temporary block is connected delay, a circuit switching unit and a shorting node of the excitation winding of the booster transformer connected to it with an output contactor, characterized in that, in order to increase control accuracy when changing the direction of power flow in a line, the automatic switching unit of the excitation winding contains a node controlling the direction of power flow in the line, the inputs of which, respectively, are connected to the excitation winding of booster transformer and shorting node of this winding, and the output .. from the outputs of the circuit switching unit, where the excitation winding of the booster transformer is made in the form of two sections with a common neutral point connected in a star. 2. The device according to claim 1, characterized in that, in order to increase the reliability of the initial disappearance of the voltage in the line, the contactor of the shorting unit is made with a latch, and the shorting unit contains a rectifying and charging unit, the input of which is connected to the unit food, and the output - with a coitactor .. - -ne