CN210724190U

CN210724190U - Electric leakage circuit breaker with anti-power interference function

Info

Publication number: CN210724190U
Application number: CN201922068822.4U
Authority: CN
Inventors: 黄献国; 吴钟栅
Original assignee: Yueqing Beijiaer Electronic Technology Co ltd
Current assignee: Yueqing Beijiaer Electronic Technology Co ltd
Priority date: 2019-11-26
Filing date: 2019-11-26
Publication date: 2020-06-09
Anticipated expiration: 2029-11-26

Abstract

The utility model provides a residual current circuit breaker with anti power supply interference function belongs to the earth leakage protection field, has solved current residual current circuit breaker and has received the problem of external power source interference malfunction because of its power semiconductor switch easily. Earth leakage circuit breaker with anti power supply interference function add a power semiconductor switch and by the bleeder circuit that first divider resistance and second divider resistance constitute on current earth leakage circuit breaker's basis. The added power semiconductor switch is connected between the positive output end of the rectification circuit and the anode of the original power semiconductor switch in series in the forward direction, the voltage division circuit is connected between the positive output end and the negative output end of the rectification circuit in series, and the trigger electrode of the added power semiconductor switch is connected with the common end of the two voltage division resistors. The trip coil of the trip unit and the two power semiconductor switches are located in the same series branch.

Description

Electric leakage circuit breaker with anti-power interference function

Technical Field

The utility model relates to a residual current circuit breaker belongs to the earth leakage protection field.

Background

In recent years, with the continuous improvement of living standard of people, a large number of household appliances enter common families, people have more and more chances of electrically contacting, and accidents of electric shock and casualties of people caused by faults of electric equipment also happen occasionally. Against this background, earth leakage breakers have become widely used as an effective electrical safety device and play a very important role.

The earth leakage breaker is a switch that automatically operates when the earth leakage current in the circuit exceeds a predetermined value. The working principle is as follows: the leakage circuit breaker mainly comprises a zero sequence current transformer, a voltage detection circuit, a power semiconductor switch and a release. The zero sequence current transformer monitors the leakage current in the protected circuit in real time, converts the leakage current into an induced voltage signal and outputs the induced voltage signal to the voltage detection circuit. When the amplitude of the induced voltage signal output by the zero sequence current transformer exceeds the threshold voltage of the voltage detection circuit, the voltage detection circuit sends a trigger signal to the power semiconductor switch for controlling the opening coil to be switched on and off. After receiving the trigger signal, the power semiconductor switch is switched on, the tripping coil is electrified, the tripping contact acts, and the protected circuit is switched off.

However, the power semiconductor switch in the conventional earth leakage breaker is often turned on by mistake due to interference of an external power source, i.e., a transient spike. The consequence of the misconduction of the power semiconductor switch is the misoperation of the leakage circuit breaker, and the misoperation of the leakage circuit breaker can cause the power failure of a normal power supply circuit, thereby not only reducing the reliability of power supply, but also causing certain economic loss.

SUMMERY OF THE UTILITY MODEL

The utility model discloses a solve current earth leakage circuit breaker and receive the problem of external power source interference malfunction because of its power semiconductor switch easily, provide an earth leakage circuit breaker with anti power supply interference function.

The utility model discloses a leakage circuit breaker with anti-power interference function includes zero sequence current transformer, voltage detection circuit, trigger conduction circuit, release and rectifier circuit;

the voltage detection circuit is used for outputting a trigger signal when the amplitude of an induced voltage signal output by the zero sequence current transformer exceeds a preset action value of the residual current circuit breaker;

the trigger conduction circuit is connected with the protected circuit through the rectifying circuit and used for electrifying a tripping coil of the tripper according to the trigger signal;

the trigger conduction circuit comprises a first power semiconductor switch, a second power semiconductor switch, a first voltage-dividing resistor and a second voltage-dividing resistor;

the first power semiconductor switch and the second power semiconductor switch are sequentially and forwardly connected in series between the positive output end and the negative output end of the rectifying circuit, the first divider resistor and the second divider resistor are sequentially connected in series between the positive output end and the negative output end of the rectifying circuit, the two power semiconductor switches after being connected in series are connected in parallel with the two divider resistors after being connected in series, the trigger electrode of the first power semiconductor switch is connected with the common end of the two divider resistors, and the trigger electrode of the second power semiconductor switch is connected with the trigger signal output end of the voltage detection circuit;

the trip coil and the two power semiconductor switches are located in the same series branch.

Preferably, the rectifier circuit is a bridge rectifier circuit.

Preferably, the first power semiconductor switch and the second power semiconductor switch are both thyristors.

Electric leakage circuit breaker have anti power supply interference function's theory of operation as follows:

when the protected circuit works normally and the trigger conduction circuit is interfered by an external power supply, the instantaneous spike signal firstly reaches the first power semiconductor switch. At this time, the first power semiconductor switch may be turned on by the high voltage across it. However, due to the presence of the first power semiconductor switch, the transient spike hardly affects the second power semiconductor switch. Even if the first power semiconductor switch is turned on, the second power semiconductor switch is always in the off state because the trigger signal is not received. In this case, the trip coil is not energized, and the trip contact of the trip unit does not malfunction.

When the leakage current in the protected circuit exceeds a preset value, the voltage detection circuit sends a trigger signal to the second power semiconductor switch, and the second power semiconductor switch is conducted. When the second power semiconductor switch is conducted, the cathode potential of the first power semiconductor switch is reduced, and the voltage division circuit formed by the first voltage division resistor and the second voltage division resistor triggers the first power semiconductor switch to conduct the first power semiconductor switch. As a result, when the leakage current in the protected circuit is too large, both the power semiconductor switches are turned on, and accordingly, the trip coil is turned on, the trip contact of the trip unit operates, and the protected circuit is turned off.

Compare with current electric leakage circuit breaker, electric leakage circuit breaker with anti power supply interference function add a power semiconductor switch (first power semiconductor switch) and by the bleeder circuit that first divider resistance and second divider resistance constitute. In operation, the leakage circuit breaker isolates the external power supply interference through the first power semiconductor switch, so that the second power semiconductor switch is not or less interfered by the external power supply, and the purpose of the anti-power supply interference function is achieved. From this, under the interference of external power source, electric leakage circuit breaker with anti power source interference function be difficult for taking place the malfunction accident.

Drawings

The electrical leakage breaker with anti-power interference function of the present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, in which:

fig. 1 is a schematic circuit diagram of an electrical leakage breaker with a power interference immunity function according to an embodiment, where L is a live wire, N is a neutral wire, and a trip coil and a trip contact are both denoted by KA.

Detailed Description

The following will further explain the leakage breaker with anti-power interference function according to the present invention with reference to the attached drawings.

Example (b): the present embodiment is described in detail below with reference to fig. 1.

The leakage circuit breaker with the power supply interference resistance function comprises a zero sequence current transformer, a voltage detection circuit, a trigger conduction circuit, a release and a rectification circuit;

the trigger conduction circuit is connected with the protected circuit through the rectifying circuit and used for electrifying a tripping coil KA of the tripper according to the trigger signal;

the trigger conducting circuit comprises a thyristor SCR1, a thyristor SCR2, a voltage division resistor R1 and a voltage division resistor R2;

the anode of the thyristor SCR1 and the first end of the voltage-dividing resistor R1 are both connected with the positive polarity output end of the rectifying circuit, the cathode of the thyristor SCR1 is connected with the anode of the thyristor SCR2 through the trip coil KA, the second end of the voltage-dividing resistor R1 is connected with the gate of the thyristor SCR1 and the first end of the voltage-dividing resistor R2, the cathode of the thyristor SCR2 and the second end of the voltage-dividing resistor R2 are both connected with the negative polarity output end of the rectifying circuit, and the gate of the thyristor SCR2 is connected with the trigger signal output end of the voltage detection circuit.

The rectifying circuit of the embodiment is realized by a bridge rectifying circuit.

In practical applications, the resistances of the voltage dividing resistor R1 and the voltage dividing resistor R2 need to be designed according to the voltage of the circuit to be protected and the trigger voltage of the thyristor SCR 1. In addition, if the external power supply interference is too strong, the number of thyristors used for isolating the external power supply interference can be increased according to actual conditions, and accordingly, the voltage division circuit needs to be adjusted.

Owing to set up two thyristors, electric leakage circuit breaker with anti power supply interference function compare with current single crystal brake pipe formula electric leakage circuit breaker, its withstand voltage has increased one time, can easily pass through 4000V voltage impact test.

Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that features described in different dependent claims and herein may be combined in ways different from those described in the original claims. It is also to be understood that features described in connection with individual embodiments may be used in other described embodiments.

Claims

1. A leakage circuit breaker with power interference resistance function comprises a zero sequence current transformer, a voltage detection circuit, a trigger conduction circuit, a release and a rectification circuit;

the trigger conduction circuit is characterized by comprising a first power semiconductor switch, a second power semiconductor switch, a first voltage dividing resistor and a second voltage dividing resistor;

2. A residual current circuit breaker with a function of resisting power supply interference according to claim 1, characterized in that the rectifying circuit is a bridge rectifying circuit.

3. A residual current circuit breaker with mains interference immunity as claimed in claim 1, characterized in that the first power semiconductor switch and the second power semiconductor switch are thyristors.