SU538468A1 - Device for limiting the minimum excitation of a synchronous machine - Google Patents

Description

(54) COMPOSITION FOR LIMITING THE MINIMUM EXCITATION OF THE SYNCHUNG MACHINE

to a value dangerous to cars. To do this, an ARM-SD provides an OMV with a characteristic depending on the active load and the voltage value of the synchronous mouse.

In order to obtain this characteristic in an OMV containing two sensors, the outputs of which are included at the input of the element of the reference voltage at the output of the device, a phase discriminator is used, in one of the channels of which the vectors of one of the linear voltages are combined with the currents of two phases (for example in the other, the subtraction of the indicated vectors,). The signal thus obtained at the output of the phase discriminator is compared with a reference signal proportional to the voltage of the machine, and if it turns out to be greater than the reference signal, then their difference supplied to the input of the summing amplifier ARV. The disadvantage of this device is that to take into account the active load of the machine, the full phase current (in this example, 1s) is used, and not its active component, as a result of which the reactive component of this current somewhat distorts the OMV operation. Therefore, with a change in the mode of operation of the generator, the characteristic of the OMV is shifted and, so that it does not go beyond the allowable limits of the OMV, it is necessary to tune to power limitation with a margin. Thus, the ability of the machine to consume reactive power is not used.

The purpose of the invention is to increase the efficiency of the hetsrator in the modes of reactive power consumption. This is achieved by the fact that a device for limiting the minimum excitation of a synchronous machine containing two rectifiers, the outputs of the KOTvpjJx include pg. the input element of the reference voltage. is yuschegos into-; swing device provided with fazosdvigayuttsil zlemschto t, and vshr vpyulneny fazochu and void DC converter, wherein the power inputs fazoch vstvitelnyh vshr tifiers are coupled to a current one of the machine phases, and inputs one of zshravleni vshr tifiers directly, and the second - through the phase-shifting the cell is connected to the voltage of the other two phases.

A block diagram of excitation control with the proposed device is shown in the drawing.

The device for limiting the minimum excitation of the synchronous manshna contains a frequency block 1, a voltage block 2, differentiators 3, 4 and 5, intermediate current transformers 6 and 7, phase sensitive rectifiers 8 and 9 connected to the current of one of the generator phases, converters 10 and II , sinusoidal voltage in rectangular form, phase shifting element 12, through which the input of 5 etching of the sensors 9 is connected to the voltage of the generator, the element of the reference voltage 13, the inputs of which are connected to the outputs of the rectifiers 9 and 10, the adder 14, the system The exciter control theme 15, exciter 16, synchronous machine 17, current transformer 18 and voltage bus 19.

The device works as follows.

The current of one phase of the synchronous machine creates

proportional voltages on the secondary windings of intermediate transformers 6 and 7, KOTqpbie are connected to the power inputs of phase-sensitive transformers 8 and 9.

The signal is proportional to the voltage between

The two other phases of the machine, the passage through voltage converters 10 and 11, are transformed in shape from sinusoidal to rectangular and fed to the control inputs of phase-sensitive sensors 8 and 9. At the input of phase-sensitive

The signal is changed in phase from the reactive component of the current, and at the input of the fuzoc} of the actuator rectifier 8 - from its active component, which is achieved by means of a phase-shifting element 12, which turns the signal vector

voltage at 90 °.

The square-wave signals obtained using voltage converters 10 and 11 change the key state of the phase-rectifier rectifiers 8 and 9. The output signals of the phase-sensitive rectifiers 8 and 9 are summed, and the resulting signal is compared with the reference voltage proportional to the process voltage.

With increasing voltage in the ARV system,

striving to maintain a predetermined voltage level will reduce the excitation current and may transfer the synchronous map to the reactive power consumption mode. Change of reactive power of synchronous manshna results in change

signal output OMV. If the magnitude of the signal at the output of the OMV exceeds the reference voltage, their difference passes to the input of the amplifier 14 and prevents further de-excitation of the machine.

With the growth of active naruzha component

is proportional to the active current of the machine, increases the total signal of the OMV, and the limiter comes into action at a lower reactive power consumption.

The dependence of the permissible value of the consumed reactive power on the voltage at the terminals of the machine is taken into account by the magnitude of the reference voltage. If the mechanical pressure is greater, then the reference voltage in the device circuit is also larger, which means that the restriction will take effect when

greater reactive power consumption.

When the machine enters the motor mode of operation in the OMV circuit, the polarity of the primary winding of the transformer of the voltage converter 10 must be changed, which can be done automatically.

Claims (1)

Invention Formula A device for limiting the minimum excitation of a synchronous machine, containing two rectifiers, the outputs of which are connected to the input of the element of the reference voltage, which is the output of the device, characterized in that, in order to increase the efficiency of the generator in power consumption modes of the reactive power, it is equipped with a phase-shifting element, and The power supplies are phase-sensitive, the power inputs of the phase-sensitive power meters are connected to the current of one phase of the machine, and the control inputs of one of the power generators are directly connected. The second, through the phase-shifting element, is connected to the voltage of the other two phases.