SU624314A1 - Frequency differential relay - Google Patents

Description

(54) DIFFERENCE RELAY

The invention relates to semiconductor frequency difference relays, for example, in the power industry for synchronizing the operation of generators.

Known relay frequency difference, not used in the schemes of automatic self-synchronization of synchronous generators and compensators.

Also known relays frequency difference 2, containing pulse shapers connected to the isolation transformers, differential, circuit, the output of which through the pulse extender and the time delay element are connected to the executive body.

The disadvantages of such relays are the complexity of the circuit and the comparatively low maximum allowable rate of change of the frequency difference at which the relay reliably operates.

To simplify the proposed relay and increase the reliability of its operation at a high rate of change of frequencies, two logical elements AND are introduced into it

two inputs, a logical element OR, a rectifying bridge to tirnsts, otherwise the corresponding outputs of the impulse drivers are connected to each of the two inputs of logic terminals AND, whose outputs are connected to the input of the I / O logvchuysky element connected to the control electrode of the Tyrvstor, the cathode which is under the power to the swiveling body, and avod - to the straightening bridge.

FIG. 1 shows bl (described relv), frequency ranges; in fig. 2 - time diagram of his work.

Claims (2)

Variable voltage and phase voltages U and U. are supplied to the inputs of a circuit of 1 2 short pulses, respectively, and the voltage U2 (mains voltage) is indicated on the input of a forma tion; w 2 through a separation transformer 3. Formers 1 and 2 convert the supplied at their input there are sycotic voltages in the short, 1Esie impulses. Each of pulse formers 1 and 2 has two steady states and is transferred from one steady state to another by a positive or negative voltage applied to the input of these formers. During the transition from one steady state to another; short pulses occur at one or another output of the pulse formers, depending on the polarity of the input voltage. From the output of the pulse formers, short pulses are sent to logic gates And 4 and 5, output pulses from which are output only with simultaneous arrival of pulses from both the driver 1, the pulses and the driver 2 pulses. From each of the logic elements 4, 5, the pulses arrive at the logical element OR 6, the output of which is connected to the control electrode of the thyristor, Tr. Thus, the opening of the thyristor occurs only when the short pulses coincide in time. The thyristor is closed due to the fact that its circuit is powered by a full-wave rectified current from the rectifying bridge 7 at the moment when the value of the current in the circuit is equal to the holding current of the thyristor. At coincidence in phase and equality of frequencies between voltages 0 and L /. the output of the logic element 6 will occur pulses with a frequency equal to half a period. These pulses will open the thyristor, which will lead to the actuation of the actuator 8. When the frequencies are equal but the phase does not match, the pulses to the input of logic element 4 will be rewarded (not simultaneously, which will result in the absence of pulses at its output.) and not equal to the voltage frequency Ug t can be no more than one (per period) of the simultaneous arrival of pulses at the input of logic element 4 or 5. At the same time, the thyristor opens for a time close to the half-period voltage U2 I is sufficient to trigger the output organ, the trigger threshold of which is chosen so that it triggers when at least two thyristor openings follow. Delay in the actuator response time can be achieved, for example, using a resistor 1 and capacitor C included in the executive circuit Building a relay on logic elements with a thyristor simplifies its circuit, and fixing the synchronization moment with a moment of coincidence of short pulses corresponding to each of the half periods boih voltages ensures operation relay vysszhoy rate of change of the frequency difference in synchronization. In addition, by varying the pulse duration, the synchronization accuracy can be changed, which ensures the high efficiency of the use of the relay. The invention of the Relay frequency difference, containing pulse shapers, an isolation transformer, a time delay element and an executive body, characterized in that, by simplifying the relay and increasing its reliability at a high rate of change of frequencies, two I and two inputs are introduced into it, the logical element OR, the rectifying bridge and the thyristor, and the corresponding outputs of the pulse formers are connected to each of the two inputs of the logical element AND, the outputs of which are connected to the input of the logical an OR element connected by its output to the control electrode of the thyristor, one of the other two electrodes of which is connected to the executive organ, and the other is connected to the superior bridge. Sources of information taken into account in the examination: 1, Technical description and operating instructions of the relay frequency difference type ИР401А ОБК 469 017. 2. Authors certificate of the USSR N 416800, M. CL.N 02 H 3/10, 1972. 111 he G a and Yas chi ig.7