Electric leakage test circuit, electric leakage protection circuit and electric leakage circuit breaker

Abstract

The utility model discloses an electric leakage test circuit, an electric leakage protection circuit and an electric leakage circuit breaker, which can safely and effectively simulate electric leakage conditions through the electric leakage test circuit, accurately sense electric leakage signals through a residual current transformer, prevent current backflow through a diode D15 and guarantee test accuracy. Meanwhile, the electric leakage signal processing circuit, the anti-surge circuit, the rectifying circuit and other modules are integrated to form an electric leakage protection system with complete functions, and stable operation of the circuit is ensured. The system not only improves the electric leakage detection precision and safety, but also optimizes the circuit structure and functions, provides powerful guarantee for safe and stable operation of an electric power system, and has remarkable beneficial effects.

Description

TECHNICAL FIELD

[0001] The utility model relates to an electric leakage signal processing circuit technical field, concretely relates to an electric leakage test circuit, an electric leakage protection circuit and an electric leakage circuit breaker. BACKGROUND

[0002] In the previous design, the test button loop is one phase of the power supply through the test resistance and the test button to another phase (such as shown in the drawings), and the test loop detection winding TA2 always has a high voltage, which causes the test loop detection winding TA2 to generate a leakage current to the residual current detection winding TA1, affecting the detection accuracy of the residual current detection winding TA1 to the leakage current. Figure 5 、 Figure 6

[0003] In the existing design, insulation is added between the winding TA1 and the winding TA2 of the residual current transformer, which increases the volume of the transformer and the difficulty of the transformer production process. INVENTION CONTENTS

[0004] (I) Technical problem to be solved

[0005] To solve the above problems, the utility model provides an electric leakage test circuit, an electric leakage protection circuit and an electric leakage circuit breaker, aiming to solve the problem that the high voltage causes the test loop detection winding TA2 to generate a leakage current to the residual current detection winding TA1, affecting the detection accuracy of the residual current detection winding TA1 to the leakage current.

[0006] (II) Technical scheme

[0007] The electric leakage test circuit of the utility model, the electric leakage test circuit includes:

[0008] A residual current transformer is used to be sleeved on the external power supply main line;

[0009] A test loop is partially wound on the residual current transformer to form a winding TA1, the test loop includes an a end and a b end, the b end is connected to the power supply rectifier, and the a end is used to be connected to the external power supply main line;

[0010] The test loop also has a diode D15 for preventing current from flowing back to the test circuit through the power supply rectifier to generate a leakage current.

[0011] In the utility model, the power supply main line is a three-phase power supply main line, including A phase, B phase and C phase, wherein the a end is connected to one of the three phases A, B and C.

[0012] ​In the utility model, the power main circuit is three-phase power main circuit, including A phase, B phase, C phase, N phase, wherein, the a end is connected with one of the four phases of A phase, B phase, C phase, N phase.

[0013] In the utility model, the diode D15 is located between the winding TA1 and the b end.

[0014] The test circuit further includes a test button.

[0015] Another leakage protection circuit of the utility model, including the leakage test circuit of the above technical scheme, still include:

[0016] Leakage signal processing circuit, with the power main circuit is connected, the leakage signal processing circuit is partly wound on the residual current transformer and forms the winding TA2;

[0017] Surge protection circuit and rectifier circuit, wherein the rectifier circuit is connected with the power main circuit, and the surge protection circuit is connected with the power main circuit.

[0018] The leakage signal processing circuit and the rectifier circuit are further provided with a driving circuit.

[0019] In the utility model, the residual current transformer and the winding TA1, the winding TA2 constitute leakage detection circuit.

[0020] Another leakage circuit breaker of the utility model has the leakage protection circuit of the above technical scheme.

[0021] (Three) beneficial effects

[0022] Compared with the prior art, the utility model has the beneficial effects that:

[0023] (1) the leakage test circuit designed in the utility model can safely and effectively simulate the leakage condition without being directly exposed to the actual leakage risk.

[0024] (2) the cooperation of the leakage signal processing circuit and the residual current transformer in the utility model enables the system to accurately sense and process the leakage signal. Especially in the test process, through the ingenious design of the test circuit, when the test button SB is pressed, a clear leakage current can be simulated, so that the leakage signal on the winding TA2 is easy to detect. When the test button SB is not pressed, the winding TA2 is in a suspended state, avoiding the interference of high voltage leakage on the residual current detection winding TA1, and ensuring the accuracy of leakage detection. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the circuit structure for the leakage current test circuit;

[0027] Figure 2 This is a schematic diagram of the module structure of the leakage current protection circuit;

[0028] Figure 3 This is a schematic diagram of the circuit structure of a leakage current protection circuit (three-phase three-wire).

[0029] Figure 4 This is a schematic diagram of the circuit structure of a leakage current protection circuit (three-phase four-wire).

[0030] Figure 5 The circuit structure diagram of the leakage current test circuit in the background art is shown below. Figure 1 ;

[0031] Figure 6 The circuit structure diagram of the leakage current test circuit in the background art is shown below. Figure 2 .

[0032] 10. Test circuit; 11. Terminal a; 12. Terminal b; 20. Rectifier circuit; 30. Surge protection circuit; 40. Residual current transformer; 50. Leakage signal processing circuit; 60. Leakage detection circuit; 70. Drive circuit. Detailed Implementation

[0033] The technical solution of this utility model will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0034] Example 1

[0035] like Figures 1-3 The leakage current test circuit, leakage current protection circuit, and leakage current circuit breaker shown are intended to provide a system that can safely and effectively conduct leakage current tests and protect circuits from leakage current hazards. The following is a detailed description of this embodiment:

[0036] In the embodiment, the leakage test circuit comprises a test loop 10 and a residual current transformer 40, when the leakage circuit breaker is working or in use, the external power supply main line passes through the residual current transformer 40. Wherein the test loop 10 has a terminal a 11 and a terminal b 12, and a part of the test loop 10 is wound on the residual current transformer 40 to form a winding TA1.

[0037] The external power supply main line is a three-phase power line, including A phase, B phase and C phase, the terminal a 11 of the test loop 10 is electrically connected with one of the three phases, and a test resistor RS and a test button SB are further connected in series between the terminal a 11 and the winding TA1. In particular, the test button is a normally open button. It should be noted that the positions of the test resistor RS and the test button SB are not particularly limited, that is, as long as the two components are connected in series in the test circuit. It should be noted that the positions of the test button SB and the diode D15 are not particularly limited, as long as the test button SB and the diode D15 are connected in series at the terminal a and the terminal b respectively, that is, the test button SB and the diode D15 must be at the terminal a and the terminal b respectively.

[0038] Further, the terminal b 12 of the test loop 10 is connected to the power supply rectifier, and the test loop 10 further has a diode D15 connected between the winding TA1 and the power supply rectifier. In the test loop 10, the introduction of the diode D15 is an important safety feature. It is placed between the winding TA1 and the terminal b 12, and the purpose is to prevent the current from flowing back to the test circuit through the power supply rectifier during the test, which may cause unnecessary leakage current, affect the accuracy of the test result, and even cause damage to the circuit. The one-way conductivity of the diode D15 ensures that the current can only flow in the predetermined direction, that is, from the terminal a 11 to the terminal b 12, effectively avoiding the backflow problem.

[0039] Specifically, the utility model discloses a leakage protection circuit, not only contains above-mentioned leakage test circuit, still increased leakage signal processing circuit 50, anti surge circuit 30 and rectifier circuit 20 etc. Circuit module. Leakage signal processing circuit 50 part also winds on residual current transformer 40, forms winding TA2.

[0040] The rectifier circuit 20 is directly connected to the power supply main line, and the anti surge circuit 30 is also directly connected to the power supply main line, responsible for converting alternating current into direct current for subsequent circuit use. The anti surge circuit 30 is directly connected to the power supply main line, and its function is to protect the entire leakage protection circuit from the damage of transient overvoltage (such as lightning strike or power grid fluctuation) from the power line. The driving circuit 70 and the leakage signal processing circuit 50 are further connected in series behind the rectifier circuit 20.

[0041] To enhance the driving capability of the leakage current signal processing circuit 50, a driving circuit 70 is also provided between the leakage current signal processing circuit 50 and the rectifier circuit 20. This design ensures that the leakage current signal processing circuit 50 can reliably trigger protection actions and maintain efficient operation even under extreme conditions.

[0042] like Figure 1 , Figure 2 When the test button SB is pressed, the circuit flows from phase A through the test resistor RS, the test button SB, the test winding TA2, and the diode D15 to the ground of the rectifier circuit 20, and then back to phase B or phase C through the rectifier circuit 20. A simulated leakage current is formed on the test winding TA2. The residual current detection winding TA1 senses the leakage signal, which is then processed by the leakage signal processing circuit 50 and output to the drive circuit 70. The drive circuit 70 drives the trip coil KM to operate and disconnect the circuit breaker.

[0043] When the test button SB is not pressed, there is no voltage at terminal a1 because the two ends of the test button are not connected. Terminal b12 is blocked by the reverse cutoff of the diode, so the voltage of the other two phases cannot be applied to terminal b12. Therefore, winding TA2 is essentially suspended and there is no high voltage. This does not affect the high voltage leakage of winding TA1, thus ensuring the accuracy of residual current detection winding TA1 in detecting leakage current.

[0044] Specifically, refer to Figure 4 The external power supply main circuit is a three-phase four-wire circuit, which includes phase A, phase B, phase C, and phase N. The connection between the surge protection circuit 30, rectifier circuit 20, leakage current signal processing circuit 50, and drive circuit 70 and the external power supply main circuit is the same as that of a three-phase three-wire circuit. The difference is that the a terminal 11 of the test circuit 10 can be connected to one of the four phases: phase A, phase B, phase C, and phase N.

[0045] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the concept and scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the design concept of the present invention should fall within the protection scope of the present invention. The technical content for which protection is sought in the present invention has been fully described in the claims.

Claims

1. An electric leakage test circuit, characterized by comprising: The leakage test circuit comprises: A residual current transformer for being sleeved on an external power supply main line; A test loop, a part of which is wound on the residual current transformer to form a winding TA1, the test loop comprising an a terminal and a b terminal, the b terminal being connected to a power supply rectifier, and the a terminal being used for connecting to the external power supply main line; The test loop further comprises a diode D15 for preventing current from flowing back to the test circuit through the power supply rectifier to generate leakage current.

2. The leakage test circuit according to claim 1, wherein The power supply main line is a three-phase power supply main line comprising A phase, B phase and C phase, wherein the a terminal is connected to one of the three phases.

3. The leakage test circuit according to claim 1, wherein The power supply main line is a three-phase power supply main line comprising A phase, B phase, C phase and N phase, wherein the a terminal is connected to one of the four phases.

4. The leakage test circuit according to claim 2 or 3, characterized in that, The diode D15 is located between the winding TA1 and the b terminal. The test circuit further comprises a test button.

5. A leakage current protection circuit, characterized in that, The leakage test circuit according to any one of claims 1-4 further comprises: A leakage signal processing circuit connected to the power supply main line, a part of the leakage signal processing circuit being wound on the residual current transformer to form a winding TA2; A surge resistance circuit and a rectifier circuit, wherein the rectifier circuit is connected to the power supply main line, and the surge resistance circuit is connected to the power supply main line; A driving circuit is further arranged between the leakage signal processing circuit and the rectifier circuit.

6. The ground-fault circuit of claim 5, wherein, The residual current transformer, the winding TA1 and the winding TA2 constitute a leakage detection circuit.

7. An arc fault circuit interrupter, comprising: The leakage protection circuit according to claim 5 or 6.

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