SU1700681A1 - Method for automatic control of static source of reactive power - Google Patents

Abstract

This invention relates to the automatic regulation of the magnitude of the generated reactive power of a static reactive power source. The purpose of the invention is quality improvement. This is achieved due to the fact that in the method of controlling a static reactive power source of a plant comprising an adjustable AC-DC converter, a DC motor and a slave motor speed control system with a speed and current controller, the voltage from the outputs of the speed regulators and current is transformed into a voltage proportional to the active power consumed by the converter, summed with a voltage proportional to the active power consumed by the converter spine, and affect the source of reactive power in proportion to the amount received. 2 Il. SO with

Description

The invention relates to the automatic regulation of the magnitude of the generated reactive power - a static source of reactive power (IRM),

The purpose of the invention is to improve the quality of regulation.

Fig. 1 shows a block diagram of a device implementing the proposed method; Fig. 2 shows the error due to ignoring the effect of a change in active power.

Figure 1 shows a fragment of the slave auto-adjustment system of installation 1, including speed controller 2 and current regulator 3. The controllers are affected, respectively, by the control signals of the Speed reference Use and the current reference U $ T (the output of the speed regulator), em is the output of the current controller, proportional to the voltage of the converter.

To isolate a voltage signal proportional to reactive power, block 4 is used, having a functional converter 5 and multiplier 6. To isolate a voltage signal proportional to active power, block 7 is used, which has a block selection module 8 (is a rectifier the output of which does not change the polarity of the signal) and multiplier 9. An amplifier summing 10, a powerful reactive source 11, a TP-D 12 drive containing an AC-DC converter and a DC motor.

The method is carried out as follows.

It is known that reactive power consumed by a thyristor transducer VJ

ABOUT

about

ON 00

Lem (shear power) PC, can be determined through the active power Pa and shear coefficient Kc.

RS

Ud ld

VI - K Q Q

KV - - - y - VX (1)

C NM

where Ki is the network current distortion factor for the Larionov bridge circuit, Ki 0.955;

Ud and Id, respectively, rectified voltage and current of the converter.

The shift coefficient Kc is determined by the magnitude of the maximum rectified voltage Udo and the magnitude of the current voltage

to - Ud

Through these ratios, the reactive power can be represented as

Q -VUlo-Ua (3)

(2)

Ki where Udo const; Ki const.

Analyzing the block diagram of a direct current drive with a subordinate engine speed control system, it can be shown that in such a system

Ud Knp-U3H (4)

where QPR is the gain of the converter, and

Udo CRC iz (max), (5)

where i3n (max) is the maximum voltage of the current regulator

CP

Uai is the speed control voltage;

CT is the motor current feedback ratio. This shows that Id

Q n -vulc ui

| CHI

UST V U Zn (max) USH

(7)

(6)

The magnitude of the reactive power generated by the source of reactive power to compensate for the reactive power consumed by the converter is generally proportional to the effect (task)

Oirp-Kch-and ass (8)

From the condition of equality of the reactive power of the converter and the source Q Oirt

(9)

(9)

(max) USH

U

I

TO

etc

U3TVU23H (MaKc)

4F

sign

 ass Kt-Ki-Ko

The resulting function is implemented by the device unit 4, operating with voltages, about

proportional to a given current and voltage. The functional transducer 5 serves to obtain the square root, and then the block b multiplies the signal 3T,

 „J..2,. l ,, 2v re

ten

15

i) UZ

sign

Kt Ki Ko

As a result, the signal proportional to the signal appears at the output of this unit. The active power consumed by the thyristor converter and also causing a voltage drop in the supply network can be defined as

Pa ld Ud (10).

But the values of Ud and Id were previously recorded through the output signals of the controllers. With this in mind, Ra can be expressed through them.

CRC

Ra

Ct

life (izt |

(eleven)

20

25

thirty

35

40

50

55

Here, the absolute value of U3T is taken, since in the TP-D drive with reverse along the excitation circuit, the current of the core does not change its sign. The magnitude of the reactive power generated by the source of reactive power, in order to compensate for the reduction of the supply voltage due to the impulse of the active power of the converter, in general terms. Proportionally to the influence (task)

OIRN XGI3AD | ((12).

From the condition of equality of the active power of the converter and the magnitude of the reactive power of the source necessary to compensate for the voltage drop in the supply network D Ua from the impulse of the active power Ra Kp 0irm, where Kp is the proportionality coefficient between Pa and Oirm, necessary to compensate A Ua,

-tr-izn | izt | Kp-Ko-d

IVT

 03)

The resulting function is implemented by block 7, operating with voltages proportional to a given current and voltage of the converter. Block 8 provides the absolute value of Uar, and block 9 multiplies Kpr signals

const

u3ni | u3tj

Kt KQ Kp

As a result, a voltage signal appears at the output of this unit, which causes the source to compensate for a decrease in the grid voltage due to the impulse of the active drive power. In accordance with the foregoing, in the proposed device, a total signal is received at the input of the source 11, which is obtained by means of block 10 when signals from blocks 4 and 7 arrive at it.

i3ad U ass + UaaA

 CRC JT. vTjTg

Kt Ko L Ki iz (ex) -niz

+.

CP

UaH fUaT

Thus, the device favorably differs from the known device, since due to the possibility of compensation by means of a reactive power source of voltage fluctuations in the power supply network, due to surges of active and reactive power, the quality of electrical energy is markedly increased. The device eliminates voltage drops due to insufficient source performance, since the reference signal at the source input is formed earlier than the reactive and active power in the network, due to the presence of an inertial converter between the controllers and the network, and built on thyristors will have the same speed determined by the time delay of the converter operation.

S 15 20 25

Claims (1)

Claims of the Invention A method for automatically controlling a static reactive power source of a plant comprising an adjustable AC-DC converter, a DC motor and a slave motor speed control system with a speed and current controller, which measures the voltage at the control outputs. speed and current, transform it into a voltage proportional to the reactive power consumed by the converter, and affect the source of reactive power In order to improve the quality of regulation, the above-mentioned voltages from the outputs of the speed and current controllers are transformed into a voltage proportional to the active power consumed by the converter, summing the aforementioned voltage proportional to the reactive power consumed by the voltage proportional to the amount of active power consumed by the transducer and the above effect is proportional to the amount received. . Schig.1 and, network (%) P, Q (M8T, MBAp) # (/. sn