RU2774916C1 - Device for protecting consumers from asymmetry of supply voltages and/or breakage of the zero-wire - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to the field of electrical engineering. According to the invention, at the beginning of a four-wire line, a three-phase circuit breaker is switched on, to the outputs of which a receiving-controlling body is connected, having a connection with an independent release of the three-phase circuit breaker. A mixed three-phase load is connected after the receiving-controlling body. At the end of the four-wire line, a zero-sequence current filter is switched on, the output of which is connected via a current-limiting resistor to the power input of the current sensor. The power output of the current sensor is connected to a common point with the zero conductor and the input of the zero-wire breakage sensor. The power output of the zero-wire breakage sensor is connected via another current-limiting resistor to the grounding device. The information outputs of the two sensors are connected to a transmitting device that has a connection with the receiving-controlling body.

EFFECT: protecting consumers from the breakage of the zero-wire and/or the asymmetry of the supply voltages.

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Description

The present invention relates to the field of electrical engineering and can be used to protect consumers from supply voltage unbalance and (or) neutral wire breakage.

A known invention is a device for monitoring the continuity of neutral conductors in lines of 0.38 kV [1], the technical task of which is to ensure the control of the continuity of neutral conductors. The problem is solved by the fact that in the device for monitoring the continuity of neutral conductors in 0.38 kV lines, containing a three-phase power transformer connected by phase wires to single-phase and three-phase consumers, the dead-earthed neutral of the transformer is connected to zero protective and zero working conductors, according to the invention, a single-phase two-winding transformer, the primary winding of which is included in the cut of the zero working conductor and is connected by means of a resistor and a button to the phase wire, and the secondary winding of the transformer is connected in series with the reacting element acting on the signal element and is included in the cut of the zero protective conductor, the output of which is connected to the grounding device .

The disadvantage of the considered analog is the need to lay an additional wire, the performance of the device depends on the difference in resistance between the zero point of the transformer and the grounding device of the electrical equipment, which can change under the influence of external factors, it is required to introduce additional resistance into the neutral wire in the form of a signal transformer winding.

The closest in technical essence to the proposed invention is a protection device for electric energy meters and consumers from unbalance of supply voltages [2], containing a three-phase circuit breaker with an executive body that is connected to an amplifier, a mixed three-phase load is connected to the power line, while three phase the wires pass through a three-phase circuit breaker and with a neutral conductor enter the magnetic circuit window of the zero-sequence current transformer, the secondary winding of which is connected through the mentioned amplifier to the executive body, and the outgoing wires from the magnetic circuit window of the zero-sequence current transformer are connected to a three-phase electricity meter, after which they are connected to power lines with taps mixed three-phase loads, and at the end of each three-phase tap of the line, zero-sequence voltage filters are connected to the phase conductors, with connected by their zero points through threshold elements with additionally introduced grounding devices.

The disadvantage of the presented prototype is a decrease in the accuracy of detecting asymmetric modes of operation of the electrical network with an increase in the length of the line, the impossibility of adjusting the response threshold by the amount of asymmetry without interfering with the electrical circuit.

The technical objective of the invention is to protect consumers of electrical energy from asymmetry of supply voltages and (or) breakage of the neutral wire.

The technical result is achieved by the fact that the device for protecting consumers of electrical energy from asymmetry of supply voltages and (or) a break in the neutral wire, containing a four-wire power line, a mixed three-phase load and a three-phase circuit breaker, at the beginning of the four-wire line, a three-phase circuit breaker is switched on, to the outputs of which the sensing-controlling body, having a connection with the independent release of the three-phase circuit breaker, after the sensing-controlling body, a mixed three-phase load is connected, at the end of the four-wire line, a zero-sequence current filter is connected, the output of which is connected through a current-limiting resistor to the power input of the current sensor, the power output of the current sensor connected to a common point with a neutral conductor and an input of a sensor for detecting a break in the neutral wire, the power output of which is connected through another current-limiting resistor to a grounding device, information The outputs of the two sensors are connected to a transmitter that is in communication with the receiving-controlling body.

In FIG. 1 shows a block diagram of a device for protecting consumers from asymmetry of supply voltages and (or) a break in the neutral wire.

At the beginning of the four-wire line 1, 2, 3, 4, a three-phase circuit breaker 5 is turned on, a sensing-controlling body 6 is connected to the outputs of the three-phase circuit breaker 5, which is connected to the independent release of the three-phase circuit breaker 5. After the sensing-controlling body 6, a mixed three-phase load is connected 7, at the end of the line, a zero-sequence current filter 8 is connected through a current-limiting resistor 9 to the power input of the current sensor 10, and the power output is connected to the common connection point of the neutral conductor 4 and to the power input of the neutral wire break detection sensor 11, the power output of which is connected through current-limiting resistor 12 to the grounding device 13. The information outputs of the sensors 10, 11 are connected to the transmitting device 14, which is in communication with the receiving-controlling body 6.

A device for protecting consumers from asymmetry of supply voltages and (or) a break in the neutral wire works as follows.

In normal operation, when three-phase sales 1, 2, 3 flow alternating current, through a three-phase circuit breaker 5 and a sensing-control body 6, to a mixed three-phase load 7, the geometric sum of the three phase currents flowing through the neutral wire 4 tends to zero value. On the zero-sequence current filter 8, there is not enough of the resulting current of the sum of the three phases to fix the current sensor 10, and with the sensor for fixing a break in the neutral wire 11, there is no signal for a break in the neutral wire 4, the transmission element 14 sends signals about the normal operation of the electrical network to the perceiving - control body 6, as a result, there is no signal from the perceiving-controlling 6 to open the independent release of the three-phase circuit breaker 5.

In the event of a break in the neutral wire 4, according to the information outputs of the sensor for fixing a break in the neutral wire 11, information is transmitted to the transmitting body 14, which sends a signal to the receiving-controlling body 6 to open the power contacts of the circuit breaker release 5.

If the level of unbalance in the protected line is exceeded, which is expressed in exceeding the permissible level on the zero-sequence current filter 8, using the current sensor 10 transmits, via information outputs, to the transmitting device 14, which transmits the values of the resulting current to the sensing-controlling body 6, for comparisons with the set allowed value. In the event that the set permissible value of the resulting current is exceeded, the sensing-controlling body 6 sends a signal to open the power contacts of the independent release of the three-phase circuit breaker 5.

When one of the phase conductors breaks, similar device response processes occur, as well as when the established permissible level of unbalance is exceeded.

Used sources

1. Patent for invention RU 2 348 094 C2, IPC H02N 5/10, G01R 31/08, Device for monitoring the continuity of zero conductors in 0.38 kV lines [text] / Olin D.M., Popov N.M., FGOU VPO "Kostroma State Agricultural Academy" - No.: 2007114502/09; dec. 04/17/2007; publ. 27.02.2009

2. Patent for invention RU 2 716 151 C1, IPC H02N 5/10, Protection device for electric energy meters and consumers from supply voltage unbalance [text] / Popov D.S., Popov N.M., Kostroma State Agricultural Academy » - No.: 2716151; dec. 10/14/2019; publ. 06.03.2020

Claims (1)

A device for protecting consumers from asymmetry of supply voltages and / or a break in the neutral wire, containing a four-wire power line, a mixed three-phase load and a three-phase circuit breaker, characterized in that at the beginning of the four-wire line a three-phase circuit breaker is switched on, to the outputs of which a sensing-controlling body is connected, having connection with an independent release of a three-phase circuit breaker, a mixed three-phase load is connected after the sensing-controlling body, a zero-sequence current filter is connected at the end of the four-wire line, the output of which is connected through a current-limiting resistor to the power input of the current sensor, the power output of the current sensor is connected to a common point with zero conductor and the input of the sensor for fixing a break in the neutral wire, the power output of which is connected through another current-limiting resistor to the grounding device, the information outputs of the two sensors are connected to the transmission communication device that has a connection with the perceiving-controlling body.

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