CN111478204A - Protection device and distribution box with same - Google Patents

Protection device and distribution box with same Download PDF

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Publication number
CN111478204A
CN111478204A CN202010239410.7A CN202010239410A CN111478204A CN 111478204 A CN111478204 A CN 111478204A CN 202010239410 A CN202010239410 A CN 202010239410A CN 111478204 A CN111478204 A CN 111478204A
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CN
China
Prior art keywords
local ground
comparator
inverting input
ground
local
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CN202010239410.7A
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Chinese (zh)
Inventor
詹逸郎
项明诚
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shenzhen Ruihe hi tech Communication Electronics Co., Ltd
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Sanju Technology Electric Machine Shenzhen Co ltd
Sanju Electric Machine Shenzhen Co ltd
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Application filed by Sanju Technology Electric Machine Shenzhen Co ltd, Sanju Electric Machine Shenzhen Co ltd filed Critical Sanju Technology Electric Machine Shenzhen Co ltd
Priority to CN202010239410.7A priority Critical patent/CN111478204A/en
Priority to PCT/CN2020/094497 priority patent/WO2021196399A1/en
Publication of CN111478204A publication Critical patent/CN111478204A/en
Pending legal-status Critical Current

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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02BBOARDS, SUBSTATIONS OR SWITCHING ARRANGEMENTS FOR THE SUPPLY OR DISTRIBUTION OF ELECTRIC POWER
    • H02B1/00Frameworks, boards, panels, desks, casings; Details of substations or switching arrangements
    • H02B1/26Casings; Parts thereof or accessories therefor
    • H02B1/46Boxes; Parts thereof or accessories therefor
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02BBOARDS, SUBSTATIONS OR SWITCHING ARRANGEMENTS FOR THE SUPPLY OR DISTRIBUTION OF ELECTRIC POWER
    • H02B1/00Frameworks, boards, panels, desks, casings; Details of substations or switching arrangements
    • H02B1/20Bus-bar or other wiring layouts, e.g. in cubicles, in switchyards
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02HEMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/26Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents
    • H02H3/32Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

The embodiment of the invention discloses a protection device and a distribution box with the same, wherein the protection device comprises: a signal detection circuit for detecting a first voltage between a common ground contact and a local ground start point, a second voltage between the common ground contact and a local ground end point, and a third voltage between the local ground start point and the local ground end point; the controller is electrically connected with the signal detection circuit and the electric leakage protection circuit respectively; when any one of the ratio of the first difference value to the mean value of the first voltage detected and obtained in a preset time period before the current moment, the ratio of the second difference value to the mean value of the second voltage detected and obtained in the preset time period before the current moment, and the third difference value to the mean value of the third voltage detected and obtained in the preset time period before the current moment is larger than a preset ratio threshold value, the controller outputs a trigger signal to the leakage protection circuit to trigger the leakage protection circuit to be disconnected.

Description

Protection device and distribution box with same
Technical Field
The invention relates to the field of power protection, in particular to a protection device and a distribution box with the protection device.
Background
The common protection device for the electric equipment comprises an overcurrent protector, a leakage protector and the like, wherein the overcurrent protector is used for limiting current so as to prevent wires in the electric equipment from being overloaded to generate heat and be burnt, and the leakage protector is used for detecting whether leakage occurs so as to protect users. However, the current-limiting and leakage-detecting strategies only play a certain protection role.
Disclosure of Invention
In view of the above technical problems, embodiments of the present invention provide a protection device and a distribution box having the protection device.
A first aspect of an embodiment of the present invention provides a protection device for a distribution box, where the distribution box includes a leakage protection circuit and a local ground wire, the leakage protection circuit is used to access a live wire and a zero line of a commercial power to access a power supply, and the local ground wire is connected in series with a public ground wire; the protection device includes:
a signal detection circuit for detecting a first voltage between a common ground contact and a local ground start point, a second voltage between the common ground contact and a local ground end point, and a third voltage between the local ground start point and the local ground end point; and
the controller is electrically connected with the signal detection circuit and the electric leakage protection circuit respectively;
when any one of a ratio of the first difference value to a mean value of first voltage detected and obtained in a preset time period before the current moment, a ratio of the second difference value to a mean value of second voltage detected and obtained in a preset time period before the current moment, and a third difference value to a mean value of third voltage detected and obtained in a preset time period before the current moment is larger than a preset ratio threshold value, the controller outputs a trigger signal to the leakage protection circuit to trigger the leakage protection circuit to be disconnected;
the first difference is the difference between the first voltage obtained by detection at the current moment and the mean value of the first voltage obtained by detection in a preset time period before the current moment;
the second difference is the difference between the second voltage obtained by detection at the current moment and the mean value of the second voltage obtained by detection in a preset time period before the current moment;
the third difference is a difference between a third voltage obtained by detection at the current moment and a mean value of the third voltage obtained by detection in a preset time period before the current moment.
Optionally, the signal detection circuit comprises at least three comparators;
a non-inverting input of one of the at least three comparators is for connecting the common ground point and one of the local ground line origins and an inverting input is for connecting the common ground point and the other of the local ground line origins;
a non-inverting input of one of the at least three comparators is for connecting the common ground point and one of the local ground line terminations, and an inverting input is for connecting the common ground point and the other of the local ground line terminations;
and the non-inverting input end of one of the at least three comparators is used for connecting one of the local ground start point and the local ground end point, and the inverting input end is used for connecting the other of the local ground start point and the local ground end point.
Optionally, the number of the comparators is 6, and the comparators include a first comparator, a second comparator, a third comparator, a fourth comparator, a fifth comparator and a sixth comparator;
the non-inverting input end of the first comparator is used for being connected with the common grounding point, and the inverting input end of the first comparator is used for being connected with the starting point of the local ground wire;
the non-inverting input end of the second comparator is used for being connected with the common grounding point, and the inverting input end of the second comparator is used for being connected with the local ground wire terminal point;
the non-inverting input end of the third comparator is used for being connected with the starting point of the local ground wire, and the inverting input end of the third comparator is used for being connected with the end point of the local ground wire;
the non-inverting input end of the fourth comparator is used for being connected with the starting point of the local ground wire, and the inverting input end of the fourth comparator is used for being connected with the common ground point;
the non-inverting input end of the fifth comparator is used for being connected with the local ground wire terminal point, and the inverting input end of the fifth comparator is used for being connected with the common ground point;
and the non-inverting input end of the sixth comparator is used for connecting the local ground wire terminal, and the inverting input end of the sixth comparator is used for connecting the local ground wire starting point.
Optionally, the controller comprises a single chip microcomputer.
Optionally, the protection device further includes a test button electrically connected between the local ground start point and the local ground end point to disconnect or connect the electrical connection between the local ground start point and the local ground end point;
when the test button is disconnected, the electrical connection between the starting point of the local ground wire and the end point of the local ground wire is disconnected, and the controller is used for acquiring the state of the leakage protection circuit so as to judge whether the leakage protection circuit is conducted.
Optionally, the protection device further includes a load, and a ground line of the load is connected in series with a start point of the local ground line or an end point of the local ground line.
A second aspect of an embodiment of the present invention provides a distribution box, including:
the leakage protection circuit is used for accessing a live wire and a zero line of commercial power so as to access a power supply;
a local ground line connected in series with the common ground line; and
the protection device according to the first aspect of the embodiment of the present invention.
Optionally, the common ground wire and the local ground wire are connected in series through a water immersion contactless protector.
Optionally, the earth leakage protection circuit includes series connection's earth leakage protector and earth leakage switch, earth leakage protector is used for inserting live wire and the zero line of commercial power, earth leakage protection switch with protection device's controller electricity is connected.
Optionally, the leakage switch is a leakage air switch.
In the technical scheme provided by the embodiment of the invention, the signal detection circuit monitors the first voltage between the public ground contact and the starting point of the local ground wire, the second voltage between the public ground contact and the end point of the local ground wire and the third voltage between the starting point of the local ground wire and the end point of the local ground wire in real time, and the controller controls the leakage protection circuit to be switched off when any one of the first voltage, the second voltage and the third voltage is changed greatly, so that the power supply is cut off, and the electricity utilization safety is ensured.
Drawings
Fig. 1 is a schematic structural diagram of a protection device according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a distribution box according to an embodiment of the present invention;
FIG. 3 is a circuit diagram of a protection device according to an embodiment of the present invention;
FIG. 4A is a schematic diagram of the correct wiring of the load of the protection device according to an embodiment of the present invention;
FIG. 4B is a schematic diagram of a load miswiring of the protection device;
fig. 4C is a schematic diagram of another load miswiring of the protection device.
Reference numerals:
100: a leakage protection circuit; 110: a leakage protector; 120: a leakage switch;
200: a local ground line; 210: a local ground wire starting point; 220: a local ground wire end point;
300: a protection device; 310: a signal detection circuit; 311: a comparator; r1: a first resistor; r2: a second resistor; 320: a controller; 330: a test button; 340: a load;
400: a soaking contactless protector.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the following embodiments may be combined without conflict.
Fig. 1 is a schematic structural view of a protection device in an embodiment of the present invention, and fig. 2 is a schematic structural view of a distribution box in an embodiment of the present invention. The protection device provided by the embodiment of the invention can be used for the distribution box and can also be used for other distribution devices.
Referring to fig. 1 and fig. 2, the distribution box according to the embodiment of the present invention may include a leakage protection circuit 100 and a local ground 200, wherein the leakage protection circuit 100 is used for connecting to a live line and a neutral line of a commercial power to connect to a power supply to supply power to the distribution box. In the present embodiment, the local ground line 200 is connected in series with the common ground line. The public ground wire refers to a ground wire introduced by a power company, the local ground wire 200 refers to a ground wire additionally added in the distribution box, and the local ground wire is used for absorbing redundant electric charges when the distribution box leaks electricity. The local ground wire 200 and the common ground wire may be copper wires having a diameter of 6 mm and a length of at least 20 m, but are not limited thereto. The voltage of the commercial power of the embodiment may be 110V or 220V.
Referring to fig. 1 and fig. 2 again, the protection device 300 according to the embodiment of the invention may include a signal detection circuit 310 and a controller 320, wherein the controller 320 is electrically connected to the signal detection circuit 310 and the leakage protection circuit 100, respectively.
In the present embodiment, the signal detection circuit 310 is configured to detect a first voltage between the common ground node and the local ground start point 210, a second voltage between the common ground node and the local ground end point 220, and a third voltage between the local ground start point 210 and the local ground end point 220.
The controller 320 is configured to output a trigger signal to the leakage protection circuit 100 to trigger the leakage protection circuit 100 to turn off when any one of a ratio of the first difference to a mean value of the first voltage detected and obtained in a preset time period before the current time, a ratio of the second difference to a mean value of the second voltage detected and obtained in a preset time period before the current time, and a mean value of the third difference to a mean value of the third voltage detected and obtained in a preset time period before the current time is greater than a preset ratio threshold. The first difference value is the difference value between a first voltage obtained by detection at the current moment and the mean value of the first voltage obtained by detection in a preset time period before the current moment; the second difference is the difference between the second voltage obtained by detection at the current moment and the mean value of the second voltage obtained by detection in a preset time period before the current moment; the third difference is a difference between a third voltage obtained by detection at the current moment and a mean value of the third voltage obtained by detection in a preset time period before the current moment.
The preset ratio threshold may be set as required, for example, the preset ratio threshold may be 3%, when any ratio exceeds the preset ratio threshold, it indicates that any one of the first voltage, the second voltage and the third voltage has a large variation, the common ground contact, the local ground starting point 210 and the local ground ending point 220 may not be grounded, and the line has a risk of leakage, overcurrent, and the like, the protection apparatus 300 according to the embodiment of the present invention monitors the first voltage between the common ground contact and the local ground starting point 210, the second voltage between the common ground contact and the local ground ending point 220, and the third voltage between the local ground starting point 210 and the local ground ending point 220 in real time through the signal detection circuit 310, the controller 320 controls the leakage protection circuit 100 to be disconnected when any one of the first voltage, the second voltage and the third voltage has a large variation, so as to cut off the power supply (i.e. cut off the power supply of the distribution box), the safety of power utilization is guaranteed more.
In other embodiments, the controller 320 is configured to output a trigger signal to the leakage protection circuit 100 to trigger the leakage protection circuit 100 to open when a ratio of the first difference to a mean value of the first voltage detected and obtained in a preset time period before the current time is greater than a first preset ratio threshold, and/or a ratio of the second difference to a mean value of the second voltage detected and obtained in a preset time period before the current time is greater than a second preset ratio threshold, and/or a ratio of the third difference to a mean value of the third voltage detected and obtained in a preset time period before the current time is greater than a third preset ratio threshold. In this embodiment, the first preset ratio threshold, the second preset ratio threshold and the third preset ratio threshold are not equal to each other in part. It is to be understood that the first preset ratio threshold, the second preset ratio threshold and the third preset ratio threshold may be set according to the requirement.
The size of the preset time period may also be set according to needs, for example, the size of the preset time period may be 1 second, and may also be other. Illustratively, the controller 320 samples every 1 millisecond, obtains the first voltage, the second voltage, and the third voltage, and calculates an average of the data sampled in the previous second every second.
In some embodiments, referring to fig. 3, the signal detection circuit 310 includes comparators 311, and the number of the comparators 311 is at least three.
In this embodiment, a non-inverting input of one comparator 311 of the at least three comparators 311 is used to connect one of the common ground point and the local ground line origin 210, and an inverting input is used to connect the other of the common ground point and the local ground line origin 210; a non-inverting input terminal of one comparator 311 of the at least three comparators 311 is for connecting the common ground point and one of the local ground line terminations 220 and an inverting input terminal is for connecting the common ground point and the other of the local ground line terminations 220; and a non-inverting input of one comparator 311 of the at least three comparators 311 is for connecting one of the local ground start 210 and the local ground end 220 and an inverting input is for connecting the other of the local ground start 210 and the local ground end 220.
Illustratively, referring again to fig. 3, in some embodiments, the number of comparators 311 is 6, including a first comparator, a second comparator, a third comparator, a fourth comparator, a fifth comparator, and a sixth comparator. The non-inverting input terminal of the first comparator is used for connecting a common ground point, and the inverting input terminal of the first comparator is used for connecting a local ground line starting point 210; the non-inverting input of the second comparator is used to connect to the common ground and the inverting input is used to connect to the local ground terminal 220; the non-inverting input terminal of the third comparator is used for connecting with the local ground wire starting point 210, and the inverting input terminal of the third comparator is used for connecting with the local ground wire end point 220; the non-inverting input terminal of the fourth comparator is used for connecting the local ground line starting point 210, and the inverting input terminal is used for connecting the common ground point; the non-inverting input terminal of the fifth comparator is connected to the local ground terminal 220, and the inverting input terminal is connected to the common ground point; the sixth comparator has a non-inverting input for connection to the local ground terminal 220 and an inverting input for connection to the local ground start 210. In this embodiment, the common ground contact, the local ground starting point 210 and the local ground ending point 220 are combined in pairs and input to one comparator 311, and the voltage level in the combination of the common ground contact, the local ground starting point 210 and the local ground ending point 220 is uncertain, so that the forward-reverse switching is combined again.
Illustratively, in some embodiments, the number of comparators 311 is 3, including a seventh comparator, an eighth comparator, and a ninth comparator. The non-inverting input of the seventh comparator is used to connect to a common ground and the inverting input is used to connect to the local ground starting point 210, or the non-inverting input of the seventh comparator is used to connect to the local ground starting point 210 and the inverting input is used to connect to a common ground. The non-inverting input of the eighth comparator is used to connect to a common ground and the inverting input is used to connect to the local ground termination 220, or the non-inverting input of the eighth comparator is used to connect to the local ground termination 220 and the inverting input is used to connect to a common ground. The non-inverting input of the ninth comparator is used to connect to the local ground start 210 and the inverting input is used to connect to the local ground end 220. Optionally, the non-inverting input of one of the comparators 311 and the other comparator 311, or the ninth comparator, is connected to the local ground terminal 220, and the inverting input is connected to the local ground start 210. The present embodiment is applicable to the case where the voltage level of the combination of the common ground contact point, the local ground line starting point 210 and the local ground line ending point 220 is known, specifically, the non-inverting input terminal of the seventh comparator is used for connecting the larger voltage of the common ground point and the local ground line starting point 210, and the inverting input terminal is used for connecting the smaller voltage of the common ground point and the local ground line starting point 210. The non-inverting input of the eighth comparator is used to connect the greater of the voltages at common ground and local ground termination 220 and the inverting input is used to connect the lesser of the voltages at common ground and local ground termination 220. The non-inverting input of the ninth comparator is used to connect the larger of the voltages at the local ground start 210 and local ground end 220, and the inverting input is used to connect the smaller of the voltages at the local ground start 210 and local ground end 220.
It is understood that the number of comparators 311 can be other values greater than 3. In addition, in the embodiment of the present application, the type of the comparator 311 is not particularly limited, and optionally, the comparator 311 is a differential amplifier.
Alternatively, referring again to fig. 3, the non-inverting input terminal of one comparator 311 of the at least three comparators 311 is connected to one of the common ground point and the local ground line origin 210 via a first resistor R1, and the inverting input terminal is connected to the other of the common ground point and the local ground line origin 210 via a first resistor R1; a non-inverting input terminal of one comparator 311 of the at least three comparators 311 is connected to one of the common ground point and the local ground terminal 220 via a first resistor R1, and an inverting input terminal is connected to the other of the common ground point and the local ground terminal 220 via a first resistor R1; and the non-inverting input terminal of one comparator 311 of the at least three comparators 311 is connected to one of the local ground start 210 and the local ground end 220 via a first resistor R1, and the inverting input terminal is connected to the other of the local ground start 210 and the local ground end 220 via a first resistor R1.
Further, referring to fig. 3 again, a second resistor R2 is connected in series between the non-inverting input terminal and the inverting input terminal of each comparator 311.
The resistance values of the first resistor R1 and the second resistor R2 can be selected according to requirements, for example, the first resistor R1 is 100 megaohms, and the second resistor R2 is 1 megaohm.
Optionally, the controller 320 includes a single chip, such as an ARM (Advanced RISC Machines, RISC microprocessors), an AVR (reduced instruction set high speed 8-bit single chip), and the like, and of course, the controller 320 may also include a special chip and other devices capable of processing and transmitting data, such as an ASIC (Application Specific integrated circuit) chip, and may also be a Programmable Device such as an FPGA (Field Programmable Gate Array), a CP L D (Complex Programmable logic Device), and the like.
Referring to fig. 2, the earth leakage protection circuit 100 may include an earth leakage protector 110 and an earth leakage switch 120 connected in series, where the earth leakage protector 110 is used for connecting to the live line and the neutral line of the commercial power, and the earth leakage switch is electrically connected to the controller 320 of the protection device 300.
Referring again to fig. 2, the protection device 300 may further include a test button 330, where the test button 330 is electrically connected between the local ground start point 210 and the local ground end point 220 to disconnect or connect the electrical connection between the local ground start point 210 and the local ground end point 220; also, the test button 330 is electrically connected to the earth leakage switch 120. When the test button 330 is turned off, the electrical connection between the local ground starting point 210 and the local ground ending point 220 is disconnected, and the controller 320 is configured to obtain the state of the earth leakage protection circuit 100 (i.e. the state of the earth leakage switch 120) to determine whether the earth leakage protection circuit 100 is turned on. The test button 330 can check whether the test button 330 triggers the earth leakage protection circuit 100 to shut down when the local ground starting point 210 is electrically disconnected from the local ground ending point 220, as a normal check.
Referring to fig. 2 and 4A, the protection device 300 may further include a load 340, and the ground of the load 340 is connected in series with the start point 210 of the local ground or the end point of the local ground 200, so that the ground of any load 340 can be found immediately when it is disconnected. I.e. in series with the ground of each load 340 from the local ground origin 210. While fig. 4B (T-connection) and fig. 4C (split-line connection) are wrong connections, in fig. 4A-4C, the open connection is an open circuit. The load 340 of the embodiments of the present application may include any load, and may also include a connector, such as a socket, capable of connecting any load.
In the embodiment of the present invention, please refer to fig. 2, one end of the test button 330 is connected to one end of the ground wire of the load 340, so as to realize the connection between the test button 330 and the local ground wire starting point 210; the other end of the test button 330 is connected to the other end of the ground of the load 340 to enable connection of the test button 330 to the local ground terminal 220.
Referring to fig. 2, the distribution box of the present invention further includes an earth leakage protection circuit 100, a local ground 200, and the protection device 300 of the above embodiment. The leakage protection circuit 100 is used for connecting to a live wire and a zero wire of a commercial power to connect to a power supply. The local ground line 200 is connected in series with the common ground line.
Alternatively, the common ground wire is connected in series with the local ground wire 200 through the submersion contactless protector 400. Referring again to fig. 2, the common ground is connected to one end of the submersion contactless protector 400, and the local ground starting point 210 is connected to the other end of the submersion contactless protector 400, so that the series connection between the common ground and the local ground 200 is realized.
Referring to fig. 2 again, the earth leakage protection circuit 100 includes an earth leakage protector 110 and an earth leakage switch 120 connected in series, the earth leakage protector 110 is used for connecting the live wire and the neutral wire of the commercial power, and the earth leakage switch is electrically connected to the controller 320 of the protection device 300. The leakage switch 120 may be a leakage air switch, or may be another type of leakage switch.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (10)

1. A protection device is used for a distribution box, the distribution box comprises an electric leakage protection circuit (100) and a local ground wire (200), the electric leakage protection circuit (100) is used for being connected into a live wire and a zero wire of commercial power so as to be connected into a power supply, and the local ground wire (200) is connected with a public ground wire in series; characterized in that said protection device (300) comprises:
a signal detection circuit (310) for detecting a first voltage between a common ground contact and a local ground origin (210), a second voltage between the common ground contact and a local ground destination (220), and a third voltage between the local ground origin and the local ground destination (220); and
a controller (320) electrically connected to the signal detection circuit (310) and the leakage protection circuit (100), respectively;
when any one of a ratio of the first difference value to a mean value of a first voltage detected and obtained in a preset time period before the current time, a ratio of the second difference value to a mean value of a second voltage detected and obtained in a preset time period before the current time, and a third difference value to a mean value of a third voltage detected and obtained in a preset time period before the current time is greater than a preset ratio threshold value, the controller (320) outputs a trigger signal to the leakage protection circuit (100) to trigger the leakage protection circuit (100) to be switched off;
the first difference is the difference between the first voltage obtained by detection at the current moment and the mean value of the first voltage obtained by detection in a preset time period before the current moment;
the second difference is the difference between the second voltage obtained by detection at the current moment and the mean value of the second voltage obtained by detection in a preset time period before the current moment;
the third difference is a difference between a third voltage obtained by detection at the current moment and a mean value of the third voltage obtained by detection in a preset time period before the current moment.
2. The protection device according to claim 1, wherein the signal detection circuit (310) comprises at least three comparators (311);
-a non-inverting input of one comparator (311) of at least three of said comparators (311) is for connecting said common ground point and one of said local ground line origins (210), and an inverting input is for connecting said common ground point and the other of said local ground line origins (210);
a non-inverting input of one (311) of at least three of said comparators (311) for connecting said common ground point and one of said local ground line terminations (220), and an inverting input for connecting said common ground point and the other of said local ground line terminations (220);
and a non-inverting input of one (311) of at least three of said comparators (311) is for connecting one of said local ground start (210) and said local ground end (220) and an inverting input is for connecting the other of said local ground start (210) and said local ground end (220).
3. The protection device according to claim 2, wherein the number of comparators (311) is 6, including a first comparator, a second comparator, a third comparator, a fourth comparator, a fifth comparator and a sixth comparator;
wherein the non-inverting input of the first comparator is adapted to be connected to the common ground and the inverting input is adapted to be connected to the local ground start (210);
the non-inverting input of the second comparator is used for connecting the common ground point, and the inverting input of the second comparator is used for connecting the local ground terminal (220);
the non-inverting input end of the third comparator is used for being connected with the local ground wire starting point (210), and the inverting input end of the third comparator is used for being connected with the local ground wire end point (220);
the non-inverting input end of the fourth comparator is used for connecting the local ground wire starting point (210), and the inverting input end of the fourth comparator is used for connecting the common ground point;
the non-inverting input terminal of the fifth comparator is used for connecting the local ground terminal (220), and the inverting input terminal of the fifth comparator is used for connecting the common ground point;
the non-inverting input of the sixth comparator is used for connecting the local ground terminal (220), and the inverting input of the sixth comparator is used for connecting the local ground starting point (210).
4. The protection device of claim 1, wherein the controller (320) comprises a single-chip microcomputer.
5. The protection device according to claim 1, characterized in that the protection device (300) further comprises a test button (330) electrically connected between the local ground start (210) and the local ground end (220) to break or make the electrical connection of the local ground start (210) and the local ground end (220);
when the test button (330) is turned off, the electrical connection between the local ground starting point (210) and the local ground ending point (220) is disconnected, and the controller (320) is used for acquiring the state of the earth leakage protection circuit (100) to judge whether the earth leakage protection circuit (100) is conducted or not.
6. The protection device according to claim 1, characterized in that the protection device (300) further comprises a load (340), the load (340) having its ground line connected in series with the local ground line starting point (210) or the local ground line ending point.
7. An electrical box, characterized in that the electrical box comprises:
the leakage protection circuit (100) is used for accessing a live wire and a zero line of commercial power so as to access a power supply;
a local ground line (200) connected in series with the common ground line; and
the protection device (300) of any one of claims 1 to 6.
8. The electrical box according to claim 7, characterized in that said common ground and said local ground (200) are connected in series by means of a submersion contactless protector (400).
9. The electrical box according to claim 7, wherein the earth leakage protection circuit (100) comprises an earth leakage protector (110) and an earth leakage switch (120) connected in series, the earth leakage protector (110) is used for accessing the live wire and the neutral wire of the commercial power, and the earth leakage switch is electrically connected with the controller (320) of the protection device (300).
10. The electrical box of claim 9, wherein the electrical leakage switch (120) is an electrical leakage air switch.
CN202010239410.7A 2020-03-30 2020-03-30 Protection device and distribution box with same Pending CN111478204A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111934221A (en) * 2020-08-12 2020-11-13 国网江苏省电力有限公司南通供电分公司 Marine power distribution alarm device and control system thereof
CN112421314A (en) * 2020-11-20 2021-02-26 深圳市瑞禾高科通讯电子有限公司 Plug-and-play power consumption protection device and socket electric appliance

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Publication number Priority date Publication date Assignee Title
CN101060243A (en) * 2006-04-18 2007-10-24 万家盛 Zero line broken protective method and its control circuit
KR100608116B1 (en) * 2006-05-22 2006-08-08 (주)한림종합건축사사무소 Earth apparatus for door of distributing board a common housing
CN101661072A (en) * 2009-09-23 2010-03-03 河南省电力公司商丘供电公司 Online monitoring device and monitoring method of multipoint earthing of iron core of transformer
CN102214910B (en) * 2010-04-03 2015-10-14 樱花卫厨(中国)股份有限公司 Intelligent electric leakage detection protecting
CN102324717B (en) * 2011-10-05 2013-04-03 刘睿刚 Leakage protection device
CN105207062B (en) * 2015-10-20 2018-05-18 宁波市锦达电器设备制造有限公司 Self-test power distribution cabinet

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111934221A (en) * 2020-08-12 2020-11-13 国网江苏省电力有限公司南通供电分公司 Marine power distribution alarm device and control system thereof
CN112421314A (en) * 2020-11-20 2021-02-26 深圳市瑞禾高科通讯电子有限公司 Plug-and-play power consumption protection device and socket electric appliance

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