CN111969554A - Ground wire leakage current detection circuit of leakage protector and control mode - Google Patents

Abstract

The invention relates to the technical field of leakage protection, and discloses a ground wire leakage current detection circuit and a control mode of a leakage protector. The leakage protection chip is provided with zero sequence leakage protection and ground wire leakage protection at the same time, zero sequence leakage and ground wire leakage are completely separated, the zero sequence leakage and the ground wire leakage are not influenced mutually, the electricity safety protection is achieved, the number of components of the leakage protector is reduced, and therefore the effects of reducing production cost and reducing product volume are achieved.

Description

A ground wire leakage current detection circuit and control method of a leakage protector

technical field

The invention relates to the technical field of leakage protection, in particular to a ground wire leakage current detection circuit and a control method of a leakage protector.

Background technique

In the existing leakage protector products, one leakage protection chip cannot have both zero-sequence leakage protection and grounding leakage protection. Two or more leakage protection chips must be used to fully realize zero-sequence leakage protection and grounding leakage protection. , The increase in the number of leakage protection chips not only affects the production cost of leakage protection products, but also greatly restricts the miniaturization development of leakage protection products.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the shortcomings in the prior art, such as: one leakage protection chip in the existing leakage protector product cannot have both zero-sequence leakage protection and grounding leakage protection, and two or more must be used. The leakage protection chip can completely realize zero-sequence leakage protection and grounding leakage protection. The increase in the number of leakage protection chips affects the production cost of leakage protection products and greatly restricts the miniaturization development of leakage protection products. A detection circuit and control method of ground wire leakage current of a leakage protector are proposed.

In order to achieve the above object, the present invention adopts the following technical solutions:

A ground wire leakage current detection circuit and control method of a leakage protector, including ground wire leakage current control, wherein the ground wire leakage current control is connected with a ground wire leakage current transformer, a zero-sequence current transformer, an amplifying transistor, a triode, a disconnector Buckle drive control, leakage protection chip, trip relay, first resistor and second resistor;

The control method includes the following steps:

S1. Ground wire leakage current control is used for ground wire leakage current detection;

S2. When the ground leakage current transformer has leakage current, the ground leakage current controls the conduction and the amplifying transistor to conduct, and the low voltage of the power supply acts on the A pin of the leakage protection chip through the first resistor:

S3. The B pin of the leakage protection chip outputs a high voltage to turn on the tripping drive control;

S4. The trip relay is powered, and the leakage protector trips to form the ground wire leakage current protection;

S5. When the earth leakage current transformer detects the leakage current;

S6. Both the triode and the amplifying triode are energized, and the power supply voltage supplies power to the triode through the second resistor to realize the self-locking control of the amplifying triode and the triode;

S7. The amplifying transistor is continuously energized, and when the voltage is applied to the A pin of the leakage protection chip through the first resistor, the B pin of the leakage protection chip outputs a high voltage to turn on the tripping drive control;

S8. The trip relay is powered, and the leakage protector trips to form the ground wire leakage current protection;

S9. When there is leakage current passing through the coil of the zero-sequence current transformer, the output voltage of the zero-sequence current transformer will reach the leakage protection chip. At this time, the B pin of the leakage protection chip outputs a high voltage to turn on the tripping drive control, and the tripping relay is obtained. Electricity, the leakage protector trips to form zero-sequence leakage current protection.

Preferably, the control electrode and the cathode of the ground leakage current control are directly connected in parallel to both ends of the ground leakage current transformer.

Preferably, the output pin of the amplifying triode acts on the A terminal of the leakage protection chip through the first resistor, or the base and the emitter of the triode are connected to both ends of the ground leakage current transformer, and the amplifying triode and the triode, the second resistor A self-locking control loop is formed.

Compared with the prior art, the beneficial effects of the present invention are:

The invention adopts a leakage protection chip with both zero-sequence leakage protection and grounding leakage protection, completely separates zero-sequence leakage and grounding leakage without affecting each other, and reduces leakage protection while achieving electricity safety protection The number of components of the device is reduced, so as to achieve the effect of reducing production costs and reducing product volume.

Description of drawings

Fig. 1 is Q1 and Q2 application structure schematic diagram of the present invention;

FIG. 2 is a schematic diagram of a Q1 application structure of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inside", " The orientation or positional relationship indicated by "outside" is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, so as to The specific orientation configuration and operation are therefore not to be construed as limitations of the present invention.

1-2, a ground leakage current detection circuit and control method of a leakage protector, including a ground leakage current control SCR1, the ground leakage current control SCR1 is connected with a ground leakage current transformer ZCT1, a zero sequence current Transformer ZCT2, amplifier transistor Q1, transistor Q2, trip drive control SCR2, leakage protection chip U1, trip relay L1, first resistor R3 and second resistor R10, the ground leakage current controls the control electrode and cathode of SCR1 It is directly connected to both ends of the ground wire leakage current transformer ZCT1. The output pin of the amplifier transistor Q1 acts on the A terminal of the leakage protection chip U1 through the first resistor R3, or the base and emitter of the transistor Q2 are connected to the ground wire in parallel. At both ends of the leakage current transformer ZCT1, the amplifying transistor Q1, the transistor Q2 and the second resistor R10 form a self-locking control loop.

The control method includes the following steps:

S1, ground wire leakage current control SCR1 is used for ground wire leakage current detection;

S2. When the ground leakage current transformer ZCT1 has leakage current, the ground leakage current controls the conduction of SCR1 and the conduction of the amplifying transistor Q1, and the low voltage of the power supply acts on the A pin of the leakage protection chip U1 through the first resistor R3;

S3. The B pin of the leakage protection chip U1 outputs a high voltage to turn on the trip drive control SCR2;

S4. The tripping relay L1 is powered, and the leakage protector trips to form ground leakage current protection;

S5. When the ground wire leakage current transformer ZCT1 detects the leakage current;

S6, the transistor Q2 and the amplifying transistor Q1 are both powered on, and the power supply voltage supplies power to the transistor Q2 through the second resistor R10 to realize the self-locking control of the amplifying transistor Q1 and the transistor Q2;

S7. The amplifying transistor Q1 is continuously energized, and when the voltage is applied to the A pin of the leakage protection chip U1 through the first resistor R3, the B pin of the leakage protection chip U1 outputs a high voltage to turn on the trip drive control SCR2;

S8. The trip relay L1 is powered, and the leakage protector trips to form the ground wire leakage current protection;

S9. When there is leakage current passing through the coil of the zero-sequence current transformer ZCT2, the zero-sequence current transformer ZCT2 outputs the voltage to the leakage protection chip U1. At this time, the B pin of the leakage protection chip U1 outputs a high voltage to turn on the trip drive control SCR2. , the tripping relay L1 is powered, and the leakage protector trips, forming zero-sequence leakage current protection.

In the present invention, a leakage protection chip U1 is used to have both zero-sequence leakage protection and grounding leakage protection, and the zero-sequence leakage and grounding leakage are completely separated without affecting each other. The number of components of the leakage protector is reduced, so as to achieve the effect of reducing production costs and reducing product volume.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. The equivalent replacement or change of the inventive concept thereof shall be included within the protection scope of the present invention.

It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any relationship between these entities or operations. any such actual relationship or sequence exists. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus.

Claims (3)

1. A ground wire leakage current detection circuit and a control method of a leakage protector, comprising a ground wire leakage current control (SCR1), characterized in that the ground wire leakage current control (SCR1) is connected with a ground wire leakage current transformer ( ZCT1), zero sequence current transformer (ZCT2), amplifier transistor (Q1), transistor (Q2), trip drive control (SCR2), leakage protection chip (U1), trip relay (L1), first resistor (R3) ) and the second resistor (R10); The control method includes the following steps: S1. Ground wire leakage current control (SCR1) is used for ground wire leakage current detection; S2. When the ground leakage current transformer (ZCT1) has leakage current, the ground leakage current control (SCR1) is turned on and the amplifying transistor (Q1) is turned on, and the low voltage of the power supply acts on the leakage protection chip ( A foot of U1); S3. The B pin of the leakage protection chip (U1) outputs a high voltage to turn on the trip drive control (SCR2); S4. The trip relay (L1) receives electricity, and the leakage protector trips to form the ground wire leakage current protection; S5. When the earth leakage current transformer (ZCT1) detects the leakage current; S6, both the triode (Q2) and the amplifying triode (Q1) are energized, and the power supply voltage supplies power to the triode (Q2) through the second resistor (R10) to realize the self-locking control of the amplifying triode (Q1) and the triode (Q2); S7. When the amplifying transistor (Q1) is continuously energized, and the voltage is applied to the A pin of the leakage protection chip (U1) through the first resistor (R3), the B pin of the leakage protection chip (U1) outputs a high voltage to make the trip drive control (SCR2) ) is turned on; S8. The trip relay (L1) receives electricity, and the leakage protector trips to form the ground wire leakage current protection; S9. When there is leakage current passing through the coil of the zero-sequence current transformer (ZCT2), the zero-sequence current transformer (ZCT2) outputs the voltage to the leakage protection chip (U1), at this time, the B pin of the leakage protection chip (U1) outputs a high voltage The tripping drive control (SCR2) is turned on, the tripping relay (L1) is energized, and the leakage protector is tripped to form zero-sequence leakage current protection. 2 . The ground leakage current detection circuit and control method of a leakage protector according to claim 1 , wherein the control electrode and the cathode of the ground leakage current control (SCR1) are directly connected in parallel to the ground leakage current. 3 . Both ends of the current transformer (ZCT1). 3. The earth leakage current detection circuit and control method of a leakage protector according to claim 1, wherein the output pin of the amplifying transistor (Q1) acts on the leakage protection chip ( The A terminal of U1), or the base and emitter of the triode (Q2) are connected to both ends of the ground leakage current transformer (ZCT1), and the amplifying triode (Q1) is composed of the triode (Q2) and the second resistor (R10). Self-locking control loop.

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