SU1417103A1 - Reactive power compensator - Google Patents

Abstract

The invention relates to power engineering and can be used to stabilize the voltage and compensate for reactive power in electric networks. The purpose of the invention is to improve the quality of electricity and reduce the loss of electricity in the network by reducing the level of higher harmonics in the network current, as well as reducing the specific power ycTaiioii.ionnoii and increasing the resource due to the reduction of overvoltages and supercurrent in transients. The compensator contains a voltage converter connected to the mains through a switch. Between the findings of the alternating current G1reobrazovat.-1 VK. These are consecutively connected reactors and valve switches, which provides compensation for higher harmonics of the generator as a result of a phase shift of 180 e.h. hail, between them and the high harmonics of the mentioned reactors and vents. k.ioche The compensator is equipped with a chain of switchgear-type P1) 1x cable and a switch to turn on the switch and a chain of priority VC, 1N1O1P1Ya.iocha. 1I in relation to the inclusion of converter valves, which provides a reduction in overvoltage. 3 hp ff, 2 and. 1. C (L

Description

four

And: i.) The bather is designed to power industry and can be used in electrical grids to stabilize the voltage and compensate for reactive power.

The purpose of the invention is to improve the quality of electricity and reduce electricity losses in the network by reducing the level of higher harmonics in the network current, as well as reducing the specific installed capacity and increasing the life of the compressor by reducing the overload in transients.

FIG. 1 and 2 is a diagram of the compensator.

The capacitor (Fig. 1) contains a voltage converter 1, including a valve bridge 2, each arm of which is formed by counter-parallel-connected valves, for example, thyristor valves 3 and diode valves 4 (check valves). Between the poles of bridge 2 there is a capacitor 5 simulating a source of constant radiation. In the phases of the converter 1, the reactors 6 are switched on with the aim of detecting the higher harmonics of the mains current. Between the pins of the time and time, the current of the converter 1 of the controller is connected in series with the Hi and Ie reactors 7 and valve switches 8. The compensator can be used with the alternating current network through switch 9. The compensator can be used in the compensator. This is accomplished with the help of the regulator 11, from the output of which the control pulses arrive at the control inputs of the compensator valves. For commissioning of the compensator, a start-up unit 12 is used, pa example of a control unit, the output of which is connected to the controller 11 and the first input of the logical element I 13, another input. which is connected with the control channel of the valve wrench 8. The output of the element And 13 is included in the control circuit of the circuit breaker 9.

According to FIG. 2 return valves 4 are polished in the form of 1x valves. The output of the start-up unit 12 is connected to the control input of the switch 9 via pe; i.e. 14 times, and B the control channel of the controllers of the 1 voltage is turned on by the time relay 15.

The fixed-capacitor in the stationary mode works as follows.

G1 reformed. 1 in a compensator mode (control angle is zero) generates cosine components of the odd-numbered harmonics of the phase current, except for multiples of three, into the network. Valve switches 8 and reactors 7 form phases of the compensator, which are connected in delta. The phase current of such a compensator contains the same spectrum of high harmonics, but in addition there are also harmonics that are multiples of three. The connection of phases in trego, 1iike excludes from the mains current of the harmonic is ViTHiiie three, comes to shift in the phase of the mains current, in. relation to the phase, which is caused by a change in the phase of higher harmonics (5, 7, 17, 19, etc.) by 180 e. hail. Thus, in the total mains current, these harmonics are partially compensated for. As a result, the total content of higher harmonics decreases, which leads to an improvement in the quality of electricity and a decrease in its losses in the network. Full of mutual compensation

Q specified higher harmonics do not occur, since the amplitudes of these harmonics in the compensator based on the voltage converter and the compressor in the form of sequentially connected reactor and valve switches have a different character5 not depending on the mode of operation.

In transition processes, the compensator works as follows. During start-up, which is carried out by switching on the switch 9 on a command from the start-up unit 11, overloads (overvoltages and overcurrents) may occur in the voltage converter circuit 1. This is because the capacitor 5 and the reactors 6 form an oscillating circuit connected to the AC network. Overloading is limited by the inclusion of reactor converter 7 between the phases, the presence of which leads to a change in the nature of the transient process. If the transition process in the compensator circuit causes

0 with emergency mode, in this case, the keys 8 are in operation and the reactors 7 contribute to the limitation of overloads in the converter 1 of the module. When starting the compensator for this purpose, it is necessary to ensure VC,: 1 key of key 8 before switching off switch 9 is performed. To do this, provide logic element P 13. The command from start block 12 is fed to the input of element 13 and input regulator 11 of the torus. , which begins to produce impu.IAA control valves of the compensator. Through the element And 13 command to turn on the switch 9 passes only when a signal arrives at the second input element And 13. i.e., in the presence of control pulses, .eni on the valve switches 8. This provides

5 is switched on 8 switches switching power switch 9. Thus, when starting, the controller 11, the start block 12 and the logical element AND 13 (J will activate the priority switch on valve switches 8 i-: io depending on the switch on the switch H.

0 The compensator of FIG. 2 works with.-H-any way.

 1st ritual vk. respect to: the ratio of the inclusion to the switch-on.m 9 | csst. 1 e1c by using pe.ie 14 npevieiu-i, which delays the insertion 1

5 cniiia.ia for the inclusion of off. readers 9 on m. until 6yjiyT is included for 1UCH1 8. IIi H 11: i) from the compensator in the form of transform-,. iH pa; 1 | 1nzhsni non-current (; iiec -;: pi-; cP;

0

the start has a shorter duration, if the start is carried out with the valves closed, t, e, the switch 9 must be turned on before the control pulses go to the gates of the bridge 2. To this end, the time relay 15 is inserted into the control channel of the gates 2, the shutter speed whose time is longer than the total delay time of the relay 14 and the switching time of the switch 9.

The check valves 4 can be made controlled in order to reduce the effect of the capacitor 5 on the transient at start-up, since in this case it does not enter the current loop when the switch 9 is turned on, which is the case when using diode gates.

The invention improves the quality of electricity and leads to a decrease in its losses. In addition, the invention allows to reduce overloads of the elements of the compensator in transients, this provides a reduction in the stock of the voltage and current of the elements of the comprexitor and, consequently, a decrease in its unit cost and increased resource.

Claims (4)

1. A reactive power compensator in the form of a voltage converter connected to the network through a switch, characterized in that, in order to improve the quality of electric power and reduce electric power losses in the network by reducing the level of higher harmonics in the network current, as well as reducing the specific current five 0 five 0 Capacity and increased resource life by limiting overvoltages and overcurrents in transients, it is additionally equipped with series-connected reactors and valve switches connected between the AC terminals of the converter. 2. The compensator according to claim 1, characterized in that it is equipped with a priority circuit for switching the valve keys to turn the switch on, the nieii consists of the start unit, the regulator and / or the element H, and the output of the start unit is connected to the first the input of the circuit 11 and the regulator controller, the controller output is connected to the control inputs of the valve key and the converter gate and the second input of the element I, the output of which (.) V () is connected to the input of the inclusion of the switch; 1. 3. The compensator according to claim 2, distinguished by the fact that it is equipped with a npnopnTCTHort circuit to turn on the switch by otpon1nik) to turn on the converter valves, 1 paratrete, consisting of two relays in one circuit, and the input lepBOro pe.ie connection time with the output of the start-up unit and the controller input, the first output of which is connected to the inputs of the valve terminals, and the second output is connected to the input of the second relay time- {. the output of which is connected to the control: 1ЯK) - П1ПМИ valve inputs will be converted, h par pa rning. and the output of the first time relay is connected to the power input. 1yuchaty, ::. 4. Compensator but Mon. 1-3, characterized in that the non-return valves convert. H. Voltage control with. We. 9fO  13-CHK 72 (cg.2 / 7.5