SU1339738A1 - Apparatus for protecting electric installation from phase failure - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to ensure the operability of the device in a wide frequency range. This is achieved by introducing triggers 6-8 and a second three-input element, AND-NE 5, in the device. In the absence of one of the phases, the output of the three-input element AND-NOT 5 appears logical unit arriving at the input of the executive body 9 1 Il.

Description

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The invention relates to electrical engineering and can be used in control and protection systems for three-phase electrical installations from phase loss.

The purpose of the invention ensuring the operability of the device in a wide frequency range

The drawing shows the function; aln diagram of the device.

The device contains zero-level detectors -3, forming rectangular pulses from the input voltage of alternating current, three-input elements AND-HE 4 and 5, asynchronous RS triggers 6-8, executive body 9 o

The device works as follows

If there are three phases, the detectors 1–3 of zero level form square pulses from the AC input voltage. The pulses from the outputs of the detectors 1 - 3 of the zero level are fed to the inputs S of asynchronous RS-flip-flops 6-8, switching them, and to the inputs of a three-input element AND-NOT 4 into the output of the last logical unit, is fed to the inputs R of asynchronous RS-triggers 6 - 8o From the outputs Q of asynchronous RS-flip-flops 6 to 8 logical units are fed to the inputs of a three-input element 5. The output of the latter has a logical zero arriving at the input of the actuator 9, and the device does not work

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In the absence of two phases (for example, phases B and c), the zero-level detector 1 forms square pulses from the AC input voltage. Detectors 2 and 3 of the zero level form a logical unit. The impulses from the output of the detector 1 of the zero level are fed to the input S of the asynchronous .RS trigger 6, switching it, and to the input of the three-input element AND-NOT 20 Logical units from the outputs of the detectors 2 and 3 the zero level is fed to the inputs S of asynchronous RS-flip-flops. 7 and 8 and to the inputs 4 of the three-input element AND-NOT 4 "From the output of the latter, rectangular pulses are fed to the inputs R of asynchronous RS-flip-flops 6 of them, From the output Q of an asynchronous RS-flip-flop 6, rectangular pulses are fed to the input of three-input element AND-NOT 5, From the outputs Q. asi of chronic RS-flip-flops 7 and 8, logical zeros are fed to the inputs of the three-input element AND-NOT 5c. At the output of the latter there is a logical unit, sent to the input of the actuator on 9 ,. and the device is acting

In the absence of three phases, detectors 1–3 of the zero level form a logical unit. Logical units

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In the absence of one of the phases (napri-40 - outputs of detectors 1 - 3 zero

measures of phase c) detectors 1 and 2 of the zero level form rectangular them. pulses from the AC input voltage The zero-level detector 3 forms a logical unit. The pulses from the outputs of the detectors I and 2 of the zero level are fed to the inputs S of the asynchronous RS-flip-flops 6 and 7, switching them, and to the inputs of the three-input 45

The level of the post falls on the inputs S of asynchronous RS-flip-flops 6 - 8 l to the inputs of the three-input element AND-NOT 4 From the output of the latter, a logical zero arrives at the inputs R of asynchronous RS-flip-flops switching their From the outputs of O, asynchronous RS-triggers 6-8 log zero zeros are fed to the inputs of the three input element AND-NOT 5 o To the output

Logic 50 - the last element is the logical one from the output of the detector 3 of the zero level is fed to the input S of the asynchronous RS flip-flop 8 and to the input of the three-input element AND-HE 4o From the output of the last rectangular pulses POS-gg

blunt to the inputs R of the asynchronous RS-flip-flops 6-8, switching them from the O. Asynchronous RS-flip-flops 6 and 7, the rectangular pulses are fed to the input unit, fed to the input of the spout 9 and the device is

The use of the proposed device in the control systems and the protection of three-phase plants from the phase loss allows to increase the speed and monitor the presence of phases

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3397382

The three-input element IS-NE 5, From the output O, the asynchronous RS flip-flop 8, the logical zero arrives at the input of the three-input element IS-NOT 5. At the output of the last there is a logical unit arriving at the input of the actuator 95 and the device operates

In the absence of two phases (for example, phases B and C), the zero-level detector 1 generates square pulses from the AC input voltage. Detectors 2 and 3 of the zero level form a logical unit. The pulses from the output of the detector 1 of the zero level are fed to the input S of the asynchronous .RS-trigger 6, switching it, and to the input of the three-input element AND-NOT 4. 20 Logical units from the outputs of the detectors 2 and 3 of zero The level is fed to the inputs S of asynchronous RS-flip-flops. 7 and 8 and to the inputs 4 of the three-input element AND-NOT 4 "From the output of the last, rectangular pulses are fed to the inputs R of the asynchronous RS-flip-flops 68, switching them, From the output Q of the asynchronous RS-flip-flop 6, the rectangular pulses are fed to the input of the three-input element And -NOT 5, From the outputs Q. of the asynchronous RS-flip-flops 7 and 8, logical zeros arrive at the inputs of the three-input element AND-NOT 5c. At the output of the latter there is a logical unit arriving at the input of the actuator 9 ,. and the device is acting

In the absence of three phases, detectors 1–3 of the zero level form a logical unit. Logical units.

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- detector outputs 1 - 3 zero

the level of the post fall on the inputs S of asynchronous RS-flip-flops 6 - 8 l to the inputs of the three-input element AND-NOT 4 From the last output, the logical zero goes to the inputs R of asynchronous RS-flip-flops switching their From the outputs of O, asynchronous RS-triggers 6-8 logs all zeros are fed to the inputs of the three-input element AND-NOT 5 o At the output - the last there is a logical

unit arriving at the entrance of the executive body 9 and the device is valid

The use of the proposed device in the systems for monitoring and protection of three-phase plants against phase loss allows to increase the speed and to monitor the presence of phases in

a wide range of operating frequencies in two logical states.

The performance of the device does not depend on changes in the frequency and phase skew.

Claims (1)

Invention Formula A device for protection of a three-phase electrical installation from phase loss, containing three zero-level detectors, the first AND-NOT element and an executive organ, characterized in that, in order to ensure the device's operation in a wide frequency range, it is an additional editor of N. Bobkova Compiled by VoBalashov Tehred V. Kadar Order 4236/48 Circulation 617 Subscription VNIIPI USSR State Committee : on inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab, 4/5 Production and printing company, Uzhgorod, Projecto st., 4 but equipped with three asynchronous RS-triggers and the second three-input element AND-NOT and the first element AND-NOT made three-way, with the outputs of each of the detectors zero zero vnn connection; respectively with 3 inputs of asynchronous RS-flip-flops and with the corresponding inputs of the first three-input element AND-NOT, R-inputs of asynchronous RS-flip-flops are interconnected and connected to the output of the first element AND-НЁ, the outputs of asynchronous RS-flip-flops are connected respectively to the first, second and third inputs of the second AND-NAND element, and the second element AND-NOT connected to the executive body. Proofreader H, King