SU253911A1 - A DEVICE FOR THE REGULATION OF THE EXCITATION AND EXTENSION OF THE FIELD OF SYNCHRONOUS ASCHIN - Google Patents

Description

The known devices for controlling the excitation and quenching of the field of synchronous machines, containing the sub-exciter, valve and transducer, made according to the bridge circuit and including the same control cells according to the number of transducer arms, the phase dilator and the automatic excitation regulator, are greatly complicated due to the need to implement special kaials communications for transmitting control signals to the gates of a rotating converter.

The proposed device eliminates the specified underrate due to the fact that the input of each of the specified control cells is connected to the power circuit of the valve in the bridge arm, and the output to the control circuit of the same valve, each cell containing an element that sets the phase position of the control pulse as a function the magnitude and frequency of the voltage of the power circuit, determined by an automatic excitation regulator connected to a phase splitter circuit connected to the excitation winding and exciter. In addition, the specified element that specifies the phase position of the control pulse, vypolpep, for example, Hier, in the form of two cores of magnetic material with a rectangular net hysteresis, the primary windings of which are connected in series

between the coax and are connected to the cathode circuit of the valve, the anode of which is connected directly to the common point of two secondary windings of the first core in series with each other and through conductances - with the beginning of the secondary winding of the second core, the end of which is connected through the oppositely connected diode to the end of the primary winding of the same of the core and through resistance to its beginning, and the beginning of one of the secondary windings of the first core is connected via a diode and resistance to the cathode circuit of the indicated ventpl and through rugoe resistance and Shockley diode - to the control circuit of the same gate, and the end - through soprotpvlenie connected to the beginning of the secondary winding of the second core.

FIG. 1 is a circuit diagram of a device for controlling the excitation and tension of the field of synchronous machines; in fig. 2, 3, 4 — versions of the control valves of the cells.

Sub-exciter (Fig. 1) feeds an increase in frequency to frequency converter 2, for example, a phase splitter, which produces a three-phase circuit of regulated voltage and frequency applied to the distributed excitation winding of the exciter 3.

At the same time, a voltage is generated at the output of the exciter, the frequency of which is equal to the algebraic sum of the frequencies of the phase dilator and the frequency corresponding to the speed vrash, enn of the shaft of the turbogenerator, and the voltage depends on the current and frequency at the output of the phase splitter.

The alternating voltage of the driver 3 through the inverter 4 is applied to the excitation winding 5 of the turbogenerator 6.

Regulation of the excitation and frequency of the output of the phase splitter occurs as a function of the signals from the automatic excitation controller 7.

Converter 4 consists of valves (thyristors) (j, connected, for example, by a bridge circuit, and a control unit consisting of six identical circuit cells 8. In the cell circuit (Fig. 2), the cathode circuit of valve B is connected in series with the winding 9 of the core 10, made of a material with a rectangular hysteresis loop, and a winding // of a core 12, also made of a material with a rectangular hysteresis loop. The beginning of the winding 9 is connected to the cathode of the veytil BI. The two windings 13, 14 of the core 10 are interconnected in series. winding and 13 through a diode 15 and a limiting resistance 16. Connect the cattle to the cattle BI and, and in parallel to the resistance, a circuit is connected from series to series resistance 17, the transistor 18 and the control electrode – cathode of the gate BI. The end of the winding 13 is connected to the beginning of the winding 14 and the anode of the valve BI. The end of the winding 14 through limiting resistance 19 is connected to the beginning of the winding 20 of the core 12, and the beginning of the winding 20 through the limiting resistance 21 is connected to the anode of the valve Si. The end of the winding 20 is connected through a meeting-on diode 22 with the end of the winding) /. Parallel to the winding 20, the discharge resistor 23 is turned on. The circuit works as follows: during iodine, the voltage on the anode of the next valve, and an example of a BI that needs to come into operation, a positive voltage appears. Through the winding 13, the diode 15 and the resistance 16 begins to flow a magnetizing current. The main voltage is applied to the winding 13, the current is limited, the voltage drop and resistance 16 is small, the dynistor 18 is locked and the valve control electrode B does not receive a signal. When the magnetic flux in the core 10 reaches a value corresponding to the saturation of the core (state "1, all, the voltage is applied to the resistance 16, the distor 18 is unlocked, and the unlocking signal is turned on the control electrode of the valve BI, which causes it to be unlocked. current non-magnetic cores 10 and 12 in the state "O. After the termination of the flow of the irm current, the reverse winding of the valve is applied to the windings 14 and 20

Si. Under the action of this voltage, the current through the winding 20 and the resistance 21 flows. At the same time, before the core 12 is re-magnetized into the state "1, the voltage across the resistance 21 is small, but therefore the current flowing through the winding 14 can be neglected practically.

After saturation of the core 12, the reverse voltage of the wind B is applied to the winding 14 n to the resistance 19. This starts the transfer of the core W from the state "O to state" 1. If the voltage is sufficient and the voltage is iriozhedeii, the core 10 k) will also be completely magnetized by the beginning of the next half period working part, and the BI electrode will receive a signal at the moment immediately following the beginning of the positive bearing on the anode.

If the pressure and the frequency at the input of the valve converter 4 (Fig. 1) due to a change in voltage and frequency at the output of the phase splitter will change the proportionionio (for example, increase with force of the excitation), the opening angle of the BI-Hz converter is rectified. The mode is practically unmeasured, since the impact on the 10 and 12 bits (Fig. 2), expressed in volt-seconds, is retained. If, for example, the input frequency of the converter is increased more than the voltage, or the voltage is reduced more than the frequency so that during the application of the return voltage the valve (the change in the magnetic state of the core 10 will not be completely completed) , the control signal is delayed by the time required to complete the non-magnetic core of the direct voltage to the winding 13. Due to the fact that as the angle of the valve increases (the continuous flow condition direct current in the circuit), the duration of the application of the reverse naught contraction, the initial increase in the angle will continue to increase. The presence of such a kind of positive feedback makes the system in the sense range of sensory to relatively small changes in the parameters of the supply and injection. An increase in the deceleration angle of the unlocking of the wind will go down until the slowing down volt-seconds of the reverse voltage applied to the valve after the operating current has stopped flowing to it, will not be sufficient to transfer the core 12 from the state "O to state I." At the same time, the winding 14 will practically no longer affect the magnitude of the opening angle of the time of the heart 10 of the state “O to state” 1 and the exit angle will depend on the volt-seconds of the positive voltage on the valve. Corresponding to yu 1, it selects the required value of the lag angle by unlocking the valve by selecting the parameters of the winding 13 and the core 10. In this case, the converter will operate in the inverter mode. A return to rectification mode can be realized by a corresponding increase in voltage or a decrease in frequency at its input. The required rate of conversion from mode to mode is provided by an appropriate selection of the parameters of the circuit elements and the ratio of voltage and frequency at the input. A circuit cell for controlling the converter valves can be made as shown in FIG. 3, and contain a diode 15, limiting resistances 16, 17, dynistor 18 and one saturating core 10, the inclusion of which is characterized in that the end of the winding 14 is connected to the end of the winding 9 through the limiting resistance 19, the zener diode 24 and the on-opposite diode 25.

In addition, the circuit cell can be made as shown in FIG. 4, contain diodes 15, 22, limiting resistances 16, 17, dynistor 18, discharge resistance 23 and two cores 10 and 12, and differ in that the secondary winding 13 of core 10 is connected to the diagonal current of the bridge through the limiting resistance 21, made on diodes 26-29, and limiting resistance 30 is included in the diagonal of the alternating current of the bridge, and in addition, the diagonal is connected on one side to the anode of valve B, and the other to diode 15 and the beginning of winding 20 of core 12.

With regard to the excitation of powerful synchronous masin, the proposed device allows:

1) Normal mode of operation with excitation control by changing the voltage at the output of the phase splitter at a certain frequency at the same frequency or by simultaneously changing the frequency and voltage at the output of the phase splitter, as well as the sequence of phase alternation. The parameters of the converter control circuit elements are chosen such that changes in the supply voltage and frequency when regulating the generator excitation in the normal mode practically do not lead to a change in the valve unlocking angle. This provides stable control without changing the modes of self-oscillations and small ripple currents in the load circuit of the converter.

2) Excitation boost mode. This increases the voltage and frequency at the output of the phase splitter with the condition that the nominal current is maintained

in the excitation winding of the exciter.

This leads to the fact that the voltage and frequency at the input of the valve converter increase proportionally. Valve release angles remain constant and close to the minimum value. In connection with an increase in the voltage at the output of the valve converter, the current in the excitation winding of the synchronous machine increases, which results in a forcing of the field. The speed is high, since the impact on the process occurs with a delay time corresponding to the impregnation of the driver.

3) Quench Nol. At the same time, the frequency at the input of the converter increases when the voltage is saved (in the normal mode) or the voltage drops while the frequency remains high (in the boost mode). At the same time, the registration angle is rapidly increased and the converter goes into the inverter mode. The transition to the normal mode of the exciter after the field is quenched occurs automatically after the frequency of the nanometer is reduced.

The advantages of the proposed device include:

1) A clear unlocking of the converter valves, powering the field winding, has a high inductance both in the rectifier and in the diverter mode of operation with a relatively simple control circuit.

2) Fast, practically efficiently regulated excitation in the normal mode and small current pulsations in the excitation winding, as the converter valves operate at low angles.

3) Fast, inertia-free forcing of the excitation with the power of the exciter selected by the nominal excitation mode, due to the simultaneous modified voltage and frequency in the winding of the exciter and the exciter.

4) Fast-scale 1H1 floor by switching the valve driver to the inverter mode and transition to the normal excitation mode when the converter goes to the rectifier and it goes.

Subject invention

Claims (2)

1. A device for controlling the excitation and damping of the field of synchronous machines, comprising a node exciter, a valve converter made according to a bridge circuit and including the same control unit 1e by the number of converter arms, a phase splitter and an automatic excitation regulator, characterized in that, in order to simplify and raise the nostp, the input of each of these control cells is connected to the ventpl's power circuit in the shoulder of the bridge, and the output to the control of the same valve, irichem, each cell contains an element that the phase position of the control pulse in magnitude and frequency funktsin voltage power Exalt defined by automatic excitation regulator included in fazorasschepntel circuit connected to the winding vozbuzhdsnn nodvozbuditel. 2. The device according to claim 1, iklichayu (ces by the fact that the specified element, setting the phase position of the control pulse, is made, for example, in the form of two cores of magnetic material with a rectangular loop nestration, the primary windings of which are connected in series with each other and included in the cathode circuit of the valve, the anode of which is connected to the midpoint of the two secondary windings of the first core connected in series with each other and through the satellite (Ш (Ш i. .  v: H-l-P I .J Lenn - with the beginning of the secondary winding of the second core, the end of which is connected through an oppositely connected diode to the end of the primary winding of the same core and through resistances - to its beginning, first one of the secondary windings of the first core is connected through the diode and, accordingly, the resistance connected to the resistor connected and a dynistor to the cathode of the valve and to the control electrode of the same valve. b; fe f% i / i