SU1309166A1 - Device for checking phase alternation in three-phase network - Google Patents

Abstract

The invention relates to electrical engineering, in particular, to relay protection, and can be used to control the alternation of the phases of a three-phase network. The purpose of the invention is to simplify and increase the reliability of the device by eliminating the delay of elements for the duration of the output pulse of the third element. The device contains diodes 1-3, elements AND 4-6, threshold element 7 and executive body 10. When the correct phase alternation is violated by the moment the pulse arrives at the second input of element 6, trigger 8 is in the state "1, at the output of element 6 a reject signal is generated, which is information about a violation of proper phase rotation. The introduction of the connection between the zero input of the trigger 8 and the input terminal of the phase provides a duration that does not depend on the delay time of the elements. I il. oo o co 0 Oi

Description

The invention relates to electrical engineering and can be used in emergency protection circuits, in particular, in the control circuits for the presence and order of phase alternation in three-phase networks.

The aim of the invention is to increase the reliability of the device by eliminating the delay of elements for the duration of the output pulse of the third element And and the simplification of the device.

The drawing shows a functional diagram of the proposed device.

A device for controlling the alternation of phases of a three-phase network contains diodes 1-3, elements AND 4-6, threshold element 7, trigger 8, prohibition element 9, and actuator 10.

The output of the prohibition element 9 is connected to one output terminal 11 of the device, and the output of the actuator 10 to the second output terminal 12 of the device. The anodes of diodes 1–3, respectively, are connected to the input terminals of 13–15 phases A, B, and C, respectively, the cathodes, but to the input of the threshold element 7.

The first inputs of the elements 4 and 5 are respectively connected with the input terminals 13 and 15 of the phases A and C, respectively, the devices, the second inputs with the output of the threshold element 7 and the inputs of the executive body 10, the output of which is connected to the inverse input of the prohibition element 9.

To the single input of the trigger 8 is connected to the output element And 4, and the zero input - to the input terminal 14 of the device (phase B). The first and second inputs of the And 6 element are connected in series to the outputs of the trigger 8 and the And 5 element, and the output to the direct input of the prohibition element 9.

The device works as follows.

When the supply voltage is initially turned on, the trigger 8 is reset, in which the inhibitory signal is fed from its output to the input of the element 6. When a threshold pulse arrives from the input terminal 13 through diode 1 at the input of code element 7, an output pulse appears at its output, which simultaneously arrives at the inputs of elements 4 and 5 and the executive body.

Since the inputs of element 4 and 4 match the pulses from the output of the first element and the input pulse corresponding to phase a, a signal appears at the output that energizes trigger 8. When a second pulse appears from the input clip 14 corresponding to phase b, it arrives at zero input trigger 8 and resets it.

Upon receipt of the third pulse, co10

15

20

the course of which arrives at the second input of element 5. At its output a pulse appears, which enters the second input of element 6. It will be 3aiii-pT. i.e., with proper phase rotation, at the moment of the 5th phase C arrival, the trigger 8 will be reset and the first input of the Inhibit.

In the case of phase rotation at the output of the element 6, the signal does not work and a sequence of pulses will arrive at the actuator 10, which is perceived by it as a normal operation of the circuit.

If the phase rotation is not correct, by the moment of arrival of the pulse to the second input of element 6, trigger 8 is in the log state. "I And at the output of the element And 6 a reject impulse is formed. The executive body 10 will not work, because at its entrance, as before, the impulses arrive evenly. From the output of the AND 6 element, the signal arrives at the direct input of the prohibition element 9 and, since there is no signal at its inverse input, a signal appears at the output terminal 12. This will be the information that caused the phase interruption.

If a single phase disappears at the device input, then, since the uniform input of pulses is disturbed at the input of the actuator 10, it triggers, and at the output 12 a pulse appears, indicating a phase failure. The prohibition signal will be fed to the second input of the prohibition element 9 and there will be no pulse at the output 11.

As shown by the circuit technical analysis, in the proposed device, the introduction of a new connection between the zero trigger input and the 35 phase B input terminal ensures that the pulse duration is obtained regardless of the element delay time. This eliminates false positives due to loss of pulses.

40 In addition, the proposed device is simpler, since it does not contain a second trigger and an executive body. The executive unit is a complex device, since it must react to a change in the input pulse sequence and the use of one instead of the two executive bodies greatly simplifies the circuit.

25

thirty

50

Claims (1)

Invention Formula A device for controlling the alternation of phases of a three-phase network, containing three elements And, a trigger, an element of the prohibition, a threshold element, the input of which through diodes is connected to the input terminals of phases A, B, C corresponding to phase C, from the input terminal of the device 55 and from the first input of the first element 15 it enters the element I 5 and through diode 3 to the input of the threshold element 7, from the output of the element And, and the output of the threshold element is connected to the second inputs of the first and second the course of which arrives at the second input of element 5. At its output a pulse appears, which enters the second input of element 6. It will be 3aiii-pT. i.e., with proper phase rotation, by the time the phase C arrives, trigger 8 will be reset and the “Disable. In the case of phase rotation at the output of the element 6, the signal does not work and a sequence of pulses will arrive at the actuator 10, which is perceived by it as a normal operation of the circuit. If the phase rotation is not correct, by the moment of arrival of the pulse to the second input of element 6, trigger 8 is in the log state. "I And at the output of the element And 6 a reject impulse is formed. The executive body 10 will not work, because at its entrance, as before, the impulses arrive evenly. From the output of the AND 6 element, the signal arrives at the direct input of the prohibition element 9 and, since there is no signal at its inverse input, a signal appears at the output terminal 12. This will be the information that caused the phase interruption. If a single phase disappears at the device input, then, since the uniform input of pulses is disturbed at the input of the actuator 10, it triggers, and at the output 12 a pulse appears, indicating a phase failure. The prohibition signal will be fed to the second input of the prohibition element 9 and there will be no pulse at the output 11. As shown by the circuit technical analysis, in the proposed device, the introduction of a new connection between the zero input of the trigger and the input terminal of the phases B ensures obtaining a pulse duration independent of the element delay time. This eliminates false positives due to loss of pulses. In addition, the proposed device is simpler, since it does not contain a second trigger and the executive body. The executive unit is a complex device, since it must react to a change in the input pulse sequence and using one instead of two executive bodies of one simplifies the circuit considerably. 50 Invention Formula A device for controlling the alternation of phases of a three-phase network, containing three elements And, a trigger, an element of the prohibition, a threshold element, the input of which through diodes is connected to the input terminals of phases A, B, C  55 of the device and with the first input of the first device and with the first input of the first element I, and the output of the threshold element is connected to the second inputs of the first and second 1309166 34 elements. And the input of the executive OR element and simplify the second and third ghana, the output of which is connected to the inverse-elements And made two-input, phase the input of the prohibition element, i the output of the first V is connected to the zero input of the trigger, element And is connected to the input of which the output is connected to the first input a trigger, where the outputs of the element of the forbidden third element I, the output of which is below and of the executive body, are the output of the 5 to the direct input of the element of the prohibition, The device moves, characterized in that, the second input of the third element And the sub-key to increase the reliability of the device to the output of the second element And, the first by eliminating the delay of the elements whose input is connected to the input backwardness of the output pulse to the third-burning phase C.