CN2817167Y - Residual current protection circuit - Google Patents
Residual current protection circuit Download PDFInfo
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- CN2817167Y CN2817167Y CN 200520043046 CN200520043046U CN2817167Y CN 2817167 Y CN2817167 Y CN 2817167Y CN 200520043046 CN200520043046 CN 200520043046 CN 200520043046 U CN200520043046 U CN 200520043046U CN 2817167 Y CN2817167 Y CN 2817167Y
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- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
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Abstract
The utility model provides a residual current protection circuit which comprises a circuit breaker, a zero sequence current transformer, a fault detection circuit, a final control relay, a latch circuit and a testing circuit. When the situation of ground fault or neutral grounding appears on a conducting wire, the fault detection circuit can detect residual current, lock up the latch circuit in a second double stable state, maintain the final control relay in a powerdown state and disconnect the connection between a load and a power supply, so that the purpose of safety protection is achieved. Simulated residual current can be produced in the circuits by a testing button (TA) so as to detect the normal operation of an electric leakage protective plug, and the testing button (TA) can also be used as a breaking button of the electric leakage protective plug.
Description
Technical Field
The utility model belongs to the technical field of electron, electrical equipment's power consumption safety protection, in particular to residual current safety arrangement.
Background
A typical power supply for conventional electrical devices is an ac power source, which is received by an electrical device or a load through a socket of a pair of wires. The electronic and electric equipment is directly connected with the power supply through a pair of wires, a series of dangerous conditions are formed, particularly, the risks of ground faults and grounded neutral conditions of the phase lines are higher, and when the currents of the phase lines and the neutral lines are unbalanced, the ground faults can occur; a grounded neutral condition occurs when the neutral conductor is grounded at the load. Both of these situations are extremely dangerous and can result in serious personal injury and other property damage.
Disclosure of Invention
An object of the utility model is to provide a residual current protection circuit, it can discover earth fault or neutral ground fault, avoids conventional electronic equipment or load and therefore the loss that causes.
In order to achieve the purpose, the utility model adopts the following technical proposal,
a residual current protection circuit comprises a circuit breaker, a zero sequence current transformer, a fault detection circuit, a rectification circuit, an execution relay circuit, a latch circuit and a test circuit, wherein,
the zero sequence current transformer comprises an induction coil, wherein the primary of the induction coil is connected to a power supply, and the secondary of the induction coil is respectively connected with a fault detection circuit and a test circuit; the zero sequence current transformer senses a ground fault or a grounded neutral fault in a power supply and generates a sensing signal at the secondary level;
the circuit breaker comprises a switch, the switch is connected to any one of two phase lines of a power supply, the circuit breaker is connected with an execution relay circuit and is controlled by the execution relay circuit, when the switch is switched off, a load on the phase line is powered off, and when the switch is switched off, the load on the phase line is powered on;
the rectifying circuit is connected with a power supply and provides a direct-current stabilized voltage supply for the line relay circuit and the fault detection circuit;
the execution relay circuit comprises a relay, two ends of a primary side of the relay are respectively connected with the fault detection circuit and the latch circuit and used for receiving a trigger signal of the latch circuit, and a secondary side of the relay is connected with the switch; the execution relay circuit can work in the power-on state and the power-off state, and the execution relay circuit respectively puts the switch in the closed state and the open state when the power is on or off;
the latch circuit is connected with the fault detection circuit and the execution relay circuit; the latch circuit is operable in both bistable states, and when the latch circuit is in an open bistable state, the relay circuit is switched from a de-energized state to a maintained energized state; the relay circuit transitions from an energized state to a sustained de-energized state when the latch line is in a conductive bi-stable state. The latch circuit can adopt silicon controlled rectifier or rectifier diode circuit, the utility model discloses well preferred rectifier diode circuit, rectifier diode circuit's positive pole links to each other with execution relay circuit, negative pole ground connection.
The fault detection circuit comprises a control circuit, wherein the control circuit amplifies and compares a secondary induction signal of the zero-sequence current transformer, and once a ground fault or a grounded neutral fault is found, a control signal is output to the latch circuit, so that the latch circuit is locked in a conducted bistable state, and the relay is maintained in a power-off state.
As an improvement of the utility model, still include test circuit, test circuit is including the test switch and the current-limiting resistor of establishing ties, test circuit links to each other with the power, when test switch closed, produced a simulation earth fault current, make circuit breaker's switch disconnection to make the load outage.
As a further improvement of the present invention, the door latch further comprises a reset switch connected to the actuating relay circuit and the latch circuit, the reset switch being configured to restore the bi-stable state in which the latch circuit is disconnected, thereby restoring the normal power supply state of the circuit.
The design adopts a single-voltage structure and a zero-current blocking unidirectional silicon controlled rectifier reset circuit, the structure is simple, the function is superior, in order to realize the function that the plug can be automatically closed and disconnected when the power supply is changed, the contact switching mechanism of the plug adopts the traditional electromagnetic relay structural mode, the contact is connected with the circuit when the plug is held, and the contact is disconnected with the circuit when the plug is released.
This residual current protection circuit not only can prevent the electric shock accident because of the electrical apparatus trouble arouses, but also can prevent the electric shock accident because of the power failure outside the electrical apparatus leads to, the utility model provides a residual current protection circuit it can detect earth fault and the neutral condition of ground connection on the wire, contains the relay that can cut off an at least wire between power and the load, the relay can be circular telegram and maintain on the on-state with minimum power consumption and minimum calorific capacity, its component quantity is minimum, the equipment is simple.
The present invention will be further described with reference to the accompanying drawings and examples.
Drawings
Fig. 1 is a schematic diagram of a residual current protection circuit according to an embodiment of the present invention;
fig. 2 is a circuit diagram of the residual current protection circuit according to an embodiment of the present invention.
Detailed Description
As shown in fig. 1 and 2, a residual current protection circuit includes: the circuit breaker, zero sequence current transformer, fault detection circuit, rectifier circuit, execution relay circuit, latch circuit, reset switch RA 1. Wherein,
the zero sequence current transformer comprises induction coils LM1 and LM2, the primary sides of the two induction coils are connected to a power supply, and the secondary sides of the induction coils are respectively connected with a fault detection circuit and a test circuit; the zero sequence current transformer senses a ground fault or a grounded neutral fault in a power supply and generates a sensing signal at the secondary level;
the circuit breaker comprises a switch, the switch is connected to any one of two phase lines of a power supply, the circuit breaker is connected with an execution relay circuit and is controlled by the execution relay circuit, when the switch is switched off, a load on the phase line is powered off, and when the switch is switched off, the load on the phase line is powered on;
the rectification circuit is connected with a power supply and provides a direct-current stabilized voltage supply for the execution relay circuit and the fault detection circuit; the rectifier circuit adopts a bridge rectifier circuit consisting of diodes V1, V2, V3 and V4, a voltage dependent resistor RN1 is connected in series to two phase lines of a power supply, and a resistor R1 and a capacitor C5 are used for reducing circuit noise.
The relay circuit includes a relay FL1, a transistor V7, current limiting resistors R2 and R4, a filter circuit including a voltage dividing resistor R7 and a noise reduction capacitor C7, and a rectifier diode V5 for preventing reverse high-voltage interference during relay operation. The two ends of the primary side of the relay are respectively connected with the fault detection circuit and the latch circuit and used for receiving a trigger signal of the latch circuit, and the secondary side of the relay is connected with the switch; the divider resistor R4 is connected with the reset switch RA and the base of the triode V7. The relay circuit selectively moves or maintains the switch in an open or closed position, the relay operable in both the energized and de-energized states, the relay setting the switch to the closed position when energized and the switch to the open position when de-energized, the circuit detection circuit selectively supplying a primary voltage to the relay through the switch when the switch is in the open position such that the relay transitions from the de-energized state to the energized state. The power supply line supplies a secondary voltage to the relay, the secondary voltage being lower than the primary voltage when the relay is energized by the primary voltage sufficient to maintain the relay in an energized state but insufficient to cause it to change from an de-energized state to an energized state.
The latch circuit consists of a rectifier diode V6, a current-limiting resistor R3 and a filter capacitor C6, and is connected with the fault detection circuit and the execution relay circuit; the positive pole of the rectifier diode V6 is connected with the execution relay circuit through the resistor R3, the negative pole is grounded, one end of the filter capacitor C6 is connected with the output control signal pin of the control chip of the fault detection circuit, and the other end is grounded; when the latch circuit is in a conductive bistable state, the latch circuit enables the relay to be changed from a power-on state to a power-off maintaining state;
the fault detection circuit comprises a control circuit, wherein the control circuit comprises filter capacitors C2 and C4, a coupling capacitor C3, a feedback resistor R5, a capacitor C1, a current-limiting resistor R6 and a control chip, pins VCC and GND of the control chip are respectively connected with the positive electrode and the negative electrode of a direct-current power supply output by a rectifying circuit, coupling signals output from induction coils LM1 and LM2 respectively enter input signal pins of the control chip after being filtered and rectified, and output signal pins of the control chip are connected with a gate latch circuit. The control circuit amplifies and compares the induction signals of the secondary stage of the zero-sequence current transformer, and once a ground fault or a grounded neutral fault is found, the control circuit outputs a control signal to the latch circuit to lock the latch circuit in a conducted bistable state and maintain the relay in a power-off state. The power supply to the fault circuit is disconnected.
The test circuit comprises a test switch TA1, current-limiting resistors RT1 and R8 and rectifier diodes V8 and V9 which are connected in series. The test circuit is connected with the power supply, and when the test switch is closed, a simulated earth fault current is generated to disconnect the switch of the circuit breaker, so that the power supply of the fault circuit is disconnected.
The reset switch RA1 is connected to the implement relay circuit and the latch circuit and is used to restore the bi-stable state of the latch circuit open, thereby restoring normal power to the circuit.
Under the normal working condition, the sum of current vectors in the circuit is zero, no signal is output from the zero sequence current transformer, the rectifier diode V6 is blocked, the rectifier diode V7 is conducted, the relay FL1 is attracted, the iron core pushes the contact to be closed, the power indicator lamp is on, and the circuit is indicated to be normally electrified.
When the earth fault current in the protected circuit exceeds a preset value, a signal detected by the zero sequence current transformer is amplified by the electronic amplification circuit and then triggers the rectifier diode V6 to be conducted, so that the rectifier diode V7 is blocked, the relay FL1 is de-energized, and the iron core drives the contact to be disconnected under the action of the spring, thereby playing a role in protection. When the ground fault is removed, the reset button RA1 is pressed, so that the rectifier diode V6 blocks the rectifier diode V7 from conducting, and the circuit recovers to a normal power supply state. The test button TA1 can generate a simulated residual current in the circuit to detect the normal operation of the earth leakage protection plug, and can also be used as a breaking button of the earth leakage protection plug.
Claims (3)
1. A residual current protection circuit, comprising: a circuit breaker, a zero sequence current transformer, a fault detection circuit, an execution relay, a latch circuit and a test circuit, wherein,
the zero sequence current transformer comprises two induction coils, one end of each induction coil is connected to a power supply, and the other end of each induction coil is respectively connected with a fault detection circuit and a latch circuit; the zero sequence current transformer can induce a ground fault or a grounded neutral fault in a power supply and generate an induction signal on a secondary side;
the circuit breaker comprises a switch, a latch circuit and a control circuit, wherein the switch is connected to any one of two phase lines of a power supply and is controlled by the latch circuit;
the execution relay comprises a relay, the primary relay is connected with the fault detection circuit and powered by the fault detection circuit, and is also connected with the latch circuit and receives a trigger signal of the latch circuit, and the secondary relay is connected with the switch; when the power is on, the execution relay puts the switch into a closed state, and when the power is off, the execution relay puts the switch into an open state;
the latch circuit is connected with the fault detection circuit and the execution relay; when the latch circuit is in an off bistable state, the execution relay is switched from a power-off state to a power-on maintaining state; when the latch circuit is in a conducting bistable state, the execution relay is switched from a power-on state to a power-off maintaining state;
the fault detection circuit comprises a rectification circuit and a control circuit, wherein the rectification circuit provides a direct-current stabilized voltage power supply for the circuit, the control circuit can amplify and compare a secondary induction signal of the zero-sequence current transformer, and once a fault is found, the control circuit outputs a control signal to enable the latch circuit to be locked in a conduction bistable state;
the test circuit includes a test switch TA1 connected directly in series with two phase lines of the power supply for generating a simulated ground fault current.
2. The residual current protection circuit of claim 1, wherein: a reset switch RA1 is included and is connected to the actuator relay and latch circuit for restoring the circuit to a normal power state.
3. The residual current protection circuit of claim 1, wherein: the latch circuit includes a rectifier diode V6 having an anode connected to the actuator relay and a cathode connected to ground.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200520043046 CN2817167Y (en) | 2005-06-30 | 2005-06-30 | Residual current protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200520043046 CN2817167Y (en) | 2005-06-30 | 2005-06-30 | Residual current protection circuit |
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| Publication Number | Publication Date |
|---|---|
| CN2817167Y true CN2817167Y (en) | 2006-09-13 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200520043046 Expired - Fee Related CN2817167Y (en) | 2005-06-30 | 2005-06-30 | Residual current protection circuit |
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| CN (1) | CN2817167Y (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103269057A (en) * | 2013-05-20 | 2013-08-28 | 益而益(集团)有限公司 | Ground fault protection device |
| CN101789580B (en) * | 2009-01-25 | 2014-07-09 | 张佩佩 | Fault detection and protection method of power-supply system and device for realizing same |
| CN104597353A (en) * | 2015-01-23 | 2015-05-06 | 深圳供电局有限公司 | Detection device and method for three-remote-point zero-sequence protection state |
| CN107526010A (en) * | 2017-09-30 | 2017-12-29 | 南京国电南自电网自动化有限公司 | A kind of distributed small current earthing wire-selecting method based on double CT samplings |
-
2005
- 2005-06-30 CN CN 200520043046 patent/CN2817167Y/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101789580B (en) * | 2009-01-25 | 2014-07-09 | 张佩佩 | Fault detection and protection method of power-supply system and device for realizing same |
| CN103269057A (en) * | 2013-05-20 | 2013-08-28 | 益而益(集团)有限公司 | Ground fault protection device |
| CN103269057B (en) * | 2013-05-20 | 2016-03-30 | 益而益(集团)有限公司 | A kind of earth-fault protection |
| CN104597353A (en) * | 2015-01-23 | 2015-05-06 | 深圳供电局有限公司 | Detection device and method for three-remote-point zero-sequence protection state |
| CN107526010A (en) * | 2017-09-30 | 2017-12-29 | 南京国电南自电网自动化有限公司 | A kind of distributed small current earthing wire-selecting method based on double CT samplings |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20060913 Termination date: 20110630 |