RU34818U1 - Reactive Power Compensator - Google Patents

Description

2003126066

.SCH li 3, g, and "MnKH02J3 / 18

Reactive power compensator.

The field of technology.

The utility model relates to the field of electric power industry, and in particular, to devices for regulating reactive power and voltage when controlling operating modes of electric networks. It can be used, for example, for regulating and automatically maintaining voltage on the buses of substations PO, 220, 330 and 500 kV.

The prior art.

The known reactive power compensator, adopted for the prototype 1, contains a reactor regulator, a capacitor regulator, a control unit and a control voltage driver, the output of which is connected to the control unit, and the input is designed to connect to a voltage sensor on the pins of the base.

The prototype device allows you to maintain the substation more tightly on the substation busbars by regulating reactive power (current), however, the regulation process is accompanied by an increased level of higher harmonics of the current, which requires the introduction of additional filter equipment 2.

The objective of the utility model is to reduce the level of higher harmonics of the current arising from the operation of the compensator.

Disclosure of the noble model.

The subject of the utility model is a reactive power compensator containing N reactor controllers, an N-stage capacitor controller, control units for regulators and

control voltage shaper, the output of which is connected to all control units of the reactor regulators, and the input is intended to be connected to a substation high or medium voltage sensor, while the control unit of the capacitor regulator is connected by at least one input to the control units of the first and Nth reactor regulators.

The combination of these features allows you to reduce the level of higher harmonics of the current arising from the regulation of reactive voltages (current), by ensuring the sequential operation of the regulators.

A useful model has a development, which consists in the fact that the capacitor regulator is equipped with current sensors, and the control unit of this regulator is made with an additional input designed to connect to the low voltage sensor of the substation.

This reduces the inrush current when the steps are switched on.

capacitor regulator.

The utility model has one more; it is one development that further reduces current surges and consists in the fact that the capacitor regulator is equipped with current-limiting reactors.

The utility model has two alternative developments, according to which reactor controllers can be made in the form of thyristor-reactor converters or bias-controlled reactors.

A brief description of the figures of the drawings.

The essence of the utility model is illustrated in figure 1, which shows a block diagram of the proposed device (for), taking into account its development. In FIG. 1 also shows the equipment elements of the high voltage substation on which the compensator is installed. Figure 2 shows

diagram of switching stages of a capacitor regulator in accordance with a change in control voltage.

Description of the implementation of the utility model. The circuit in figure 1 contains:

II and 2 - reactor regulators; 3 - capacitor regulator;

4, 5 and 6 - control units of regulators 1, 2 and 3, respectively;

7- substation high voltage sensor (voltage measuring transformer, connected to substation high or medium voltage buses and included in its equipment);

8- shaper control voltage.

In addition, FIGL shows the constituent part of controller 3:

9 and 10 - capacitors (or capacitor banks) of the first and second stages;

I1 and 12 - switches of the first and second stages; 13 and 14 - current-limiting reactors,

15 and 16 - capacitor current sensors (measuring current transformers);

17 - substation low voltage sensor (voltage measuring transformer as part of the substation equipment, connected to its low voltage pps).

Figure 1 also shows the power transformer (T), high, medium and low voltage busbars (HV, MV, LV), as a part of the equipment of the substation on which the compensator is installed, as well as Uycr - voltage setting (preset value).

The compensator maintains voltage on the substation buses by adjusting the reactive capacity (current) consumed

reactor regulators 1. 2 and given by the capacitor regulator 3.

The device operates as follows.

Shaper 8 outputs control voltage to inputs 18, 19 and 20 of blocks 4, 5 and 6, the level of which is proportional to the deviation of the voltage measured by sensor 7 from the set value Uycr. In the initial state, switches 11 and 12 are turned off.

Under the action of a control voltage supplied to input 18, increasing in response to characteristic I (see Fig. 2), unit 4 smoothly changes the reactive power consumed by regulator 1 from idle to rated load.

In block 5 of the control voltage supplied to the input 19, the voltage Unopora (see figure 2). The Unopora level corresponds to the exhaustion of the operating range by regulator 1 with its output in the nominal load mode. When the control voltage overcomes the voltage threshold set in block 5, it includes a regulator 2, which works similarly to regulator 1 in the range from idle to rated load. The control voltage equal to the double threshold voltage corresponds to the presence of both regulators 1 and 2 in the nominal load mode.

When the control voltage decreases according to characteristic I (see Fig. 2), the controllers 2 and 1 alternately smoothly return from the nominal load mode to the idle mode. With a further decrease in control voltage, it changes sign.

The control voltage of the opposite sign at the inputs 18 and 19 of blocks 4 and 5 holds the regulators 1 and 2 in idle mode. Under the influence of this voltage at input 20, block 6 connects

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capacitors 9 of the first stage to the busbars of the LV substation switch 11.

As a result of connecting the capacitors 10, the voltage on the substation tires increases sharply. Accordingly, the increased control voltage is shifted to the positive range of values by the characteristic P (see figure 2). At the same time, the regulators 1 and 2 are again included in the above described operation. When the control voltage is again reduced with its transition to the negative region, the next stage of the regulator 3 (by switch 12) is likewise turned on and the control voltage is shifted to the characteristic Ш (see Fig. 2), and Knobs 1 and 2 go into their respective states.

With a further increase in the tracing voltage to a double threshold value, block 6 turns off one stage of regulator 3 (for example, by switch 12) and, thereby, returns the control voltage to characteristic P. Repeated achievement of a double threshold value by the control voltage causes the remaining stage of regulator 3 to turn off by switch 11 and transition of control voltage to characteristic I.

The described operation process is characterized by the fact that the total range of reactive power regulation required to maintain the voltage at the substation’s pins within the specified limits is divided between the regulators operating in sequence, which ensures a corresponding decrease in the level of higher current harmonics.

To increase the accuracy of switching controller 3, when regulators 1 and 2 exhaust the range of smooth regulation, block 6 can be connected to blocks 4 and 5 via inputs 21 and 22. The corresponding outputs of blocks 4 and 5 signal that controller 1 is in idle mode and finding knob 2 in 6

rated load mode. In this case, the input 20 of block 6 may not be used.

To increase the reliability of sequential sequential operation of reactor reactive current regulators, to prevent overlapping of their control ranges, blocks 4 and 5 can be connected by circuits 23, allowing the operation of the corresponding reactor regulator upon receipt of a signal from a neighboring reactive regulator about the exhaustion of the control range.

Depending on the control regimes typical for a given substation, the sensor 8 can be connected to the HV buses (as shown in Fig. 1) or to the CH millet.

In the process of operation of the regulator 3, the capacitors 9 and 10 are switched by switches 11 and 12. When disconnected from the buses, the capacitors remain charged, the sign of which depends on the phase of the voltage on the capacitor at the time of shutdown. The inclusion of switches 11, 12 not synchronized with the voltage on the tires can lead to large inrush currents or require large delays before switching on to discharge capacitors. To eliminate this drawback, the controller 3 can be equipped with current sensors 15 and 16, and the control unit 6 is made with an additional input designed to connect to the low voltage sensor 17 of the substation.

An analysis of the tripping process of the three phases of the battery shows that the signs of the charges on the disconnected capacitors are determined by the direction of transition of the current of the disconnected capacitor through zero (from plus to zero or from minus to zero).

Block 6, controlling with the help of sensors 15 and 16 the direction of the transition through zero currents, disconnected capacitors, and the phase or sign of the voltage coming from the sensor 17, provides for

subsequently turning on the corresponding switch 11 or 12, applying voltage of the desired polarity to the capacitors 9 or 10, thereby reducing the inrush current when the capacitor is connected.

Controller 3 can be equipped with current-limiting reactors 13 and 14, which additionally reduces current surges during switching of switches 11, 12. Turning on reactors 13 and 14 in front of switches 11, 12 and capacitors 9, 10 allows reducing currents through the elements of capacitor controller 3 during short circuits in it chains.

Reactor regulators can be made in two alternative versions: in the form of thyristor-reactor converters or in the form of reactors controlled by magnetization.

Sources of information

1. Certificate of invention “Reactive power compensator No. 1467668, H02J 3 / 18.1988.

2.Zrazhevskaya Z.S., Ilinichnin V.V., Kochkin V.I., Lavrent'ev V.M., Mipgga V.V., Peshekhonov B.C., Skorobogatov A.N. Research thyristor compensator. Power Stations, 1988, JSfoll, pp. 57-60.

Claims (5)

1. A reactive power compensator comprising N reactor controllers, an N-stage capacitor controller, controller control units and a control voltage driver, the output of which is connected to all reactor control unit control units, and the input is designed to connect a substation high or medium voltage sensor, while the capacitor regulator control unit is connected by at least one of its input to the control units of the first and Nth reactor regulators. 2. The compensator according to claim 1, in which the capacitor regulator is equipped with current sensors, and the control unit of this regulator is made with an additional input for connecting to a low voltage sensor of the substation. 3. The compensator according to claim 1, in which the capacitor regulator is equipped with current-limiting reactors. 4. The compensator according to claim 1, in which the reactor controllers are made in the form of thyristor-reactor converters. 5. The compensator according to claim 1, in which the reactor controllers are made in the form of reactors controlled by magnetization.