RU2352053C1 - Power unit with extended adjustment range - Google Patents

Abstract

FIELD: electrics.

SUBSTANCE: power unit includes sequence of electromagnetic device with current sensor, and adjustable reactor with control unit and control circuit, so that adjustable reactor is connected to local electric collector and is connected to generator outputs over electromagnetic device. Current sensor of electromagnetic device is connected to automatic excitation control output and to control unit input of adjustable reactor; control circuit includes setting unit, functional converter and difference unit with two inputs. Setting unit output is connected to automatic excitation control input and to '+' input of difference unit, output of which is connected to control unit input of adjustable reactor, while '-' input of difference unit is connected to current sensors of electromagnetic device over functional converter. Electromagnetic device is made in the form of stepdown transformer or current limiting reactor.

EFFECT: extended adjustment range.

4 cl, 1 dwg

Description

The invention relates to the field of electrical engineering, in particular to devices for regulating reactive power and stabilizing the voltage in the node of the electrical network.

Known controlled means of reactive power compensation (STK, STATCOM) [V.N. Ivakin, V.D. Kovalev. Prospects for power conversion technology in the electric power industry. "Electricity", 2001, No. 9]. The disadvantage of this technical solution is that these devices can only work if there is voltage in the electrical network.

Power units with an auxiliary supply circuit are known, in which voltage regulation at local power consumers can be performed by switching on-load tap-changers of auxiliary transformers [B.N. Neklepayev. The electrical part of power plants and substations. M., 1986, pp. 361-385]. The disadvantage of these power units is that with centralized automatic voltage regulation in the power system, voltage regulation on the auxiliary buses by switching the on-load tap-changer does not provide the required speed. In addition, mechanical on-load tap-changers have a limited switching resource and low operational reliability.

The closest technical solution to the proposed invention are generators of power plants with independent means of regulating reactive power and voltage in the power system.

The disadvantage of these devices is that with the existing power supply circuits of power plants, the need to maintain voltage on the tires of their own needs in strictly specified limits limits the permissible range of voltage changes at the terminals of the generators.

The aim of the invention is to expand the range of regulation of the reactive power of the power unit.

This goal is achieved by the fact that in the power unit with an extended control range, containing a series-connected transformer and a generator with an automatic excitation controller, and a local power receiver, additionally connected in series are an electromagnetic device equipped with a current sensor, a controlled reactor with a control unit and a control circuit, moreover, controlled the reactor is connected to a local power receiver and through an electromagnetic device to the generator terminals, an electric current sensor gnitnogo device through a control circuit connected to the input of automatic excitation controller and an input control unit controlled reactor; the control circuit includes a setpoint setting unit, a functional converter and a difference unit with two inputs, the output of the setpoint setting unit being connected to the input of the automatic excitation controller and to the input “+” of the difference unit, the output of which is connected to the input of the control unit of the controlled reactor, input - "the difference block through a functional converter is connected to the current sensors of the electromagnetic device; moreover, the electromagnetic device is made in the form of a step-down transformer or current-limiting reactor.

The power unit diagram is shown in the drawing.

The power unit contains a transformer 1 connected in series, a generator 2 with an automatic excitation controller 3, an electromagnetic device 4 equipped with a current sensor 5, a local power receiver 6, a controlled reactor 7 with a control unit 8 and a control circuit 9. The control circuit 9 contains a functional converter 10, a difference unit 11 with two inputs and setpoint setting block 12.

The controlled reactor 7 is connected to the local power receiver 6 and is connected to the terminals of the generator 2 through the electromagnetic device 4. The current sensor 5 of the electromagnetic device 4 is connected through the control circuit 9 to the input of the automatic excitation controller 3 and to the input of the control unit 8 of the controlled reactor 7. The output of the set point 12 is connected to the input of the automatic excitation controller 3 and to the input “+” of the difference unit 11, the output of which is connected to the input of the control unit 8 of the controlled reactor 7. The input “-” of the difference unit 11 through nktsionalny converter 10 is connected to current sensors 5 of the electromagnetic device 4.

The device operates as follows.

The setpoint adjusting unit 12 changes the voltage setting simultaneously at the input of the automatic excitation regulator 3 of the generator 2 and at the input “+” of the difference unit 11. At the input “-” of the difference unit 11, a correction signal from the output of the functional converter 10 is proportional to the load current of the electromagnetic device 4 Functional converter 10 is used to coordinate the driving and correcting signals at the inputs of a block of difference 11 in dimension and size. The resulting signal from the output of the difference unit 11 is fed to the input of the control unit 8 of the reactor 7 and sets the magnitude of the magnetization current in the reactor, and hence its operating current. With an increase in the voltage setting under the action of the automatic excitation controller 3, the voltage at the terminals of the generator 2 increases and the magnetization current in the reactor 7 simultaneously increases. As a result, the operating current of the reactor 7 increases, creating an additional load of the electromagnetic device 4 and an additional voltage drop across it.

When the setpoint is reduced, the process inverse to that described above occurs. In this way, counter voltage regulation is implemented at the terminals of the local power receiver 6.

In the case of an increase (for example, when starting the induction motor as part of the consumers' own needs of the power unit) or a decrease (when the engine is started) of the load of the electromagnetic device 4, the correction signal supplied to the input “-” of the difference unit 11 from the output of the functional converter 10 causes a corresponding decrease or an increase in the operating current of the reactor 7. In this way, counter correction of the voltage at the terminals of the local power receiver 6 is realized according to the magnitude of the current load.

With a simultaneous change in the load of the electromagnetic device 4 and the voltage setting, the signals from the setting unit 12 and the functional converter 10, due to the presence of the difference unit 11, turn out to be counter-compensating.

The electromagnetic device 4 can be implemented either in the form of a current-limiting reactor, or in the form of a step-down transformer. With the appropriate choice of reactance of a current-limiting reactor or step-down transformer with an increased short-circuit voltage, a reduction in short-circuit currents can be achieved at the terminals of the local power receiver 6, in particular on the auxiliary power buses of the power unit.

Connecting a controlled reactor 7 to the terminals of the generator 2 through an electromagnetic device 4 increases the reactive power generated by the generator.

The application of the proposed technical solution on all generators of a thermal power plant eliminates the need to install additional shunt reactors on high voltage buses to normalize the operation of turbine generators with reactive power loading.

The proposed technical solution allows you to fully use the available reactive power of the power unit involved in the automatic control of voltage and reactive power in the power system, to increase the speed, reliability, stability and accuracy of voltage control at the terminals of the local power receiver, for example, when starting induction motors.

In addition, connecting to the auxiliary busbars of the power unit of a controlled reactor allows the use of an auxiliary transformer with an increased short circuit voltage, which in turn will reduce the level of short circuit current on the auxiliary busbars of the power unit.

Claims (4)

1. The power unit with an extended control range, comprising a series-connected transformer and generator with an automatic excitation controller, and a local power receiver, characterized in that it is additionally introduced in series with an electromagnetic device equipped with a current sensor, a controlled reactor with a control unit and a control circuit, the controlled reactor is connected to the local power receiver and, through an electromagnetic device, to the terminals of the generator, the current sensor is electromagnetic of the device through a control circuit connected to the input of automatic excitation controller and an input control unit controlled reactor. 2. The device according to claim 1, characterized in that the control circuit comprises a setpoint setting unit, a functional converter and a difference unit with two inputs, the output of the setpoint setting unit being connected to the input of the automatic excitation controller and to the input “+” of the difference unit, the output of which connected to the input of the control unit of the controlled reactor, the input "-" of the difference unit through a functional Converter is connected to the current sensors of the electromagnetic device. 3. The device according to claim 1, characterized in that the electromagnetic device is made in the form of a step-down transformer. 4. The device according to claim 1, characterized in that the electromagnetic device is made in the form of a current-limiting reactor.