SU389605A1 - DEVICE FOR CONTROLLING THE PACIFIC TIRISTORS - Google Patents

Description

one

The invention relates to the field of excitation control of generators.

Devices are known for controlling suction thyristors in a power phase compounding circuit of a synchronous generator, connected by cathodes to a common point and connected in parallel to a power rectifier supplying the excitation winding of a synchronous generator, containing a measuring voltage generator with a voltage divider at the input, threshold element, a Zener diode. connected to the output of the measuring unit, a semiconductor switch, the control circuit of which is connected to the output of the threshold element, and the output By connecting the winding of the three-phase voltage for power control electrodes of the thyristors suction.

The basis for the operation of such a device is the principle of adjusting the opening angle of thyristors.

When using the open angle control, each suction thyristor has its own control channel, with the result that the control circuits are cumbersome and difficult to set up and operate, and therefore unreliable.

The purpose of the invention is to simplify the suction thyristor control circuit and increase the reliability in the specified compounding systems.

This is achieved by the fact that the measuring device of the device is designed as a frequency multiplier. FIG. 1 is presented in principle

diagram of the automatic voltage regulation system of the synchronous generator based on power phase compounding using the proposed suction thyristor control device; in fig. 2 a,

b, c, d are given the curves explaining the operation of the device of one of the phases.

The excitation winding of the synchronous generator 1 is powered via a power rectifier 2 from the secondary winding 3 of a magnetic shunt power transformer 4 with a magnetic shunt that separates the secondary 3 and serial 5 windings from the primary winding 6 and the low-power winding 7 used to power the thyristor control electrodes of the recovery system 8 connected in parallel to the secondary winding 3.

A device for controlling the thyristors of the suction 8 contains a voltage divider from the resistance of the set point 9 and the resistance 10;

a measuring unit // consisting of a linear 12 and a nonlinear 13 transformers and a resonant circuit 14; the voltage source of the comparison is zener diode 15, the semiconductor switch 16, which uses a trigger, the output transistor of which is connected by an emitter to common cathodes

suction thyristors 8, and a collector to a common point of the low-power winding 7, supplying suction thyristors control electrodes through diodes 17.

The device for controlling the thyristors of the scoca operates as follows.

The line voltage from the buses of the synchronous generator 1 through the voltage divider 9, 10 is fed to the input of the measuring element 11, which is a frequency tripler. Parameters and switching on the windings of linear 12 and nonlinear 13 transformers are chosen so that the amplitude of the output voltage of the measuring element 11 varies in proportion to the amplitude of the voltage, and the frequency of the output voltage is three times higher than the frequency of the input voltage, harmonic components having a frequency different from triple, shunted by resonant circuit 14.

When the voltage across the synchronous generator / above the set value is exceeded, the Zener diode 15 is punctured, the output transistor of the semiconductor switch 16 is unlocked and held in an open state until the polarity of the voltage at the input of the measuring body changes. During the open state of the output transistor of the semiconductor switch 16, the voltage from the winding 7 of the corresponding phase of the compounding transformer 4 through the diode 17 is applied to the control electrode of the corresponding suction thyristor 8 and turns it on. When one of the suction thyristors 8 is turned on, the secondary winding 3 of the corresponding phase is shunted, and the current in the winding of the synchronous generator / is reduced, which causes a decrease in the voltage on the generator buses. If the inclusion of a single suction thyristor is insufficient to reduce the voltage to a set value, the next suction thyristor turns on in the same way and will turn on until the voltage on the buses of the synchronous generator 1 drops to a predetermined value.

Thus, the control of suction thyristors of any phase is carried out through the same semiconductor switch 16, the time

the open state of which generates a thyristor control signal of the corresponding phase from the sinusoidal voltage of the winding 7 of the power compounding transformer 4.

FIG. 2a shows the voltage curve f / B of the phase B of the synchronous generator /; in fig. 26 —the voltage curve t / u on the thyristor of the suction of phase B is shifted with respect to the f / B curve due to the high inductance of the compounding transformer 4 due to the presence of a magnetic shunt; in fig. 28 - voltage curves bv at the input and voltage f / meas at the output of the measuring device 11 of the device and voltage f / st, equal to the stabilization voltage of the Zener diode 15. Time ti, t, t correspond to the time of switching on the output transistor of the semi-conductor key 16, moments of time / 2, U, 5 - the moment of its shutdown; in fig. 2 g is the voltage curve t / A on the winding 7 of the compounding transformer 4 connected to the suction thyristor 8 of phase B, the shaded part corresponds to the signal supplied to the control electrode of this thyristor.

Subject invention

A device for controlling the suction thyristors in the circuit of the oil phase compounding of a synchronous generator, connected by cathodes to a common point and connected in parallel to a power rectifier supplying the excitation winding of the synchronous generator, containing a measuring voltage generator with a voltage divider at the input, a threshold element, for example, a zener diode, connected to the output of the measuring unit, a semiconductor switch, the control circuit of which is connected to the output of the normal element, and the output is connected to a three-phase voltage winding for supplying control electrodes of suction thyristors, characterized in that, in order to simplify the device and increase its reliability, the measuring device of the device is designed as a frequency tripler.

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