CN102354947B - Leakage protection device with protection function in case of live grounding wire - Google Patents
Leakage protection device with protection function in case of live grounding wire Download PDFInfo
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- CN102354947B CN102354947B CN 201110283446 CN201110283446A CN102354947B CN 102354947 B CN102354947 B CN 102354947B CN 201110283446 CN201110283446 CN 201110283446 CN 201110283446 A CN201110283446 A CN 201110283446A CN 102354947 B CN102354947 B CN 102354947B
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Abstract
The invention provides a leakage protection device with a protection function in case of a live grounding wire, and belongs to the technical field of electrical appliances. The leakage protection device comprises a residual current detector, a circuit breaker and an action test device, wherein, the residual current detector comprises a zero sequence current mutual inductor, a primary winding of the zero sequence current mutual inductor is composed of a power source phase line, a null line and the grounding wire, a secondary winding of the zero sequence current mutual inductor is connected to the circuit breaker, and the circuit breaker is connected with the power source phase line and the null line; and the action test device consists of a current-limiting resistor and a test button which are connected in series, one end of the action test device is connected to the power source phase line or null line in the front of the zero sequence current mutual inductor, and the other end of the action test device is connected to the power source null line or phase line behind the zero sequence current mutual inductor. The leakage protection device provided by the invention has the advantages of simple and reliable circuit and low cost, and can provide reliable protection against various situations such as electric leakage and electric shock and particularly can provide leakage protection in the case of the live grounding wire.
Description
Technical field
The invention belongs to the electrical appliance technical field; be specifically related to a kind of earth leakage protective device with protection function in case of live grounding wire; it also can play earth leakage protective function when the earth connection of electrical appliance power supply is charged except the defencive function that can realize common earth leakage protective device
Background technology
Current common electrical appliance earth leakage protective device roughly can be divided into two large classes by operation principle: based on the earth leakage protective device of residual current detection between phase line, zero line with based on the earth leakage protective device of electrical appliance earth strap electro-detection.
Use zero sequence current mutual inductor to detect residual current between phase line, zero line based on the earth leakage protective device of residual current detection between phase line, zero line; through amplifier amplifying signal rear drive or the mode of using senser directly to drive, drive common take electromagnet as basic circuit breaker again.Cause generation current loop between electrical appliance phase line and the earth when human electric shock's situation occurs electrical appliance; perhaps between the phase line of electrical appliance and the earth connection during because of leak current fault generation current loop; residual current will appear between the phase line of electrical appliance power circuit, the zero line; when this residual electricity flow valuve reaches the threshold value of earth leakage protective device setting; the circuit breaker of earth leakage protective device will move; disconnect the power circuit of electrical appliance, thereby the protection human body exempts from the injury of getting an electric shock.But, when the power end of electrical appliance because external cabling mistake or other reasons when causing the earth connection of power end charged, therefore the grounding system of electrical appliance will be and passive charged, if at this moment human body touch on the electrical appliance normally should ground connection position (such as shell etc.), so will through human body produce electrical appliance with electrical grounding wire to the current circuit between the earth, cause electric shock accidents.
Then from different based on the earth leakage protective device of residual current detection between phase line, the zero line, it judges with the voltage that detects between electrical appliance earth connection and zero-power line whether the earth connection of electrical appliance is charged based on the earth leakage protective device of electrical appliance earth strap electro-detection.When causing the electrical appliance earth connection charged because of leak current fault or because of the external power source problem between the phase line of electrical appliance and the earth connection; earth leakage protective device just can detect the voltage that exists between electrical appliance earth connection and the zero-power line; this voltage directly or after amplifying processing is used to the drive circuit disconnecting apparatus, avoids electrical appliance to bring the injury of getting an electric shock because of leak current fault to human body.This earth leakage protective device at the power end of electrical appliance because external cabling mistake or other reasons when causing the earth connection of power end charged, can disconnect reliably the electrical appliance power supply, but such earth leakage protective device also exist serious problem.Usually the circuit breaker of this type earth leakage protective device is not equipped with the break function of earth connection; therefore; when the problem of (leaking electricity between external cause but not the inner phase line of electrical appliance, earth connection) because power end when electrical appliance causes grounding system charged; the circuit of earth leakage protective device disconnects the outside that action can not disconnect the electrical appliance earth connection and connects, thus can't make the contact electrical appliance should earthing position the personnel of (such as shell etc.) avoid corresponding electric shock accidents.In addition; when human body touches phase line on the electrical appliance because of accidental cause; or imperfect earth but when having electric leakage situation regional with phase line on the electrical appliance; whole Circuits System the leaky that this earth leakage protective device is protected can not occur; earth leakage protective device can not move yet; at this moment, electric shock accidents still can occur in party person.
Except above two kinds of common earth leakage protective devices; also there is mechanism's earth wire Issues on Static Electrification to carry out some researchs; such as Chinese patent CN01129867.7 and Chinese patent CN201020662937.2, these two patents disclose a kind of all-purpose leakage protection plug that the ground wire electrified detection ability is monitored that has.This earth leakage protective device can detect because the power supply residual current that human body contact electrical appliance phase line is got an electric shock and caused also can detect because of the charged situation of power end earth connection, can avoid polytype electric leakage, electric shock accidents.But; such earth leakage protective device has used two current transformers; and need to test or monitoring arrangement be set respectively to common earth leakage protective and the charged situation of earth connection; cause the cost of earth leakage protective device to increase; and owing to having been had more a current transformer and a test circuit by conventional earth leakage protective device based on residual current detection; make whole earth leakage protective device become more complicated, brought certain impact also for the reliability of earth leakage protective device.
In view of above-mentioned prior art, be necessary existing electrical appliance earth leakage protective device is improved, for this reason, the applicant has carried out good try, has found the way that solves the problems of the technologies described above, and technical scheme described below produces under this background
Summary of the invention
Task of the present invention is that a kind of earth leakage protective device with protection function in case of live grounding wire will be provided; it can protect human body to avoid causing electric shock accidents because touching the electric leakage of electrical appliance phase line or electrical appliance; also can the power end earth connection because of external error or other reason avoid when charged human body because of touch on the electrical appliance should ground connection the position electric shock accidents occurs, various electric leakages, electric shock situation are all made reliably protecting.
Task of the present invention is finished like this, a kind of earth leakage protective device with protection function in case of live grounding wire, be characterized in: comprise residual current detection device, circuit breaker and motion test device, described residual current detection device is realized by a zero sequence current mutual inductor, its armature winding is made of jointly power supply phase line, zero line and earth connection, wherein power supply phase line, zero line be with identical direction and identical number of turns coiling, and earth connection is then with the direction opposite with power supply phase line, zero line and identical or close number of turns coiling; The secondary winding of described zero sequence current mutual inductor is connected to circuit breaker as its action triggers signal, described circuit breaker is connected to obtain working power with the power supply phase line with zero line, the all phase line of deenergization, zero line and earth connection during action remain open function when having simultaneously outage; Described motion test device is connected in series by a current-limiting resistance and a testing button and forms, and the one end is connected to power supply phase line or the zero line before the zero sequence current mutual inductor, and the other end is connected to zero-power line or the phase line after the zero sequence current mutual inductor.
In a specific embodiment of the present invention, the secondary winding of described zero sequence current mutual inductor has been connected respectively resistance R 1 and parallel connection before being connected to circuit breaker resistance R 2, wherein an end of resistance R 1 is connected with an end of zero sequence current mutual inductor secondary winding, the other end of resistance R 1 is connected with circuit breaker, one end of resistance R 2 is connected with the tie point that circuit breaker is connected with resistance R, and the other end of resistance R 2 and circuit breaker are connected the tie point of the other end and are connected with the zero sequence current mutual inductor secondary winding.
Technical scheme of the present invention has just realized the required various possible electric leakage that possesses of earth leakage protective device, electrical shock protection function and complete motion test function owing to only using a current sensing means and a motion test device, and circuit is simple and reliable.
Description of drawings
Fig. 1 is the schematic diagram of one embodiment of the invention.
Fig. 2 is the schematic diagram of another embodiment of the present invention.
Embodiment
The below specifically describes the course of action of electrical appliance earth leakage protective device in the various electric leakages that may damage human body, contact situation; suppose that the elementary earth connection winding turns of zero sequence current mutual inductor is identical with the winding turns of phase line, zero line, the elementary residual electricity flow valuve of instrument transformer that the action of circuit for electric leakage protector disconnecting apparatus sets is I
Δ
, the permeance of this residual electricity flow valuve and the elementary number of turns, instrument transformer permeability magnetic material and the trigger characteristic of circuit breaker are determined the secondary winding turns of zero sequence current mutual inductor jointly.
The first situation, the electrical appliance power end connects normal, power supply phase line, zero line normal power supply, the normal ground connection of power ground line.When there are the electric leakage situation in phase line, the earth connection of electrical appliance; if this leakage current is I; because the elementary phase line of the zero sequence current mutual inductor of earth leakage protective device is opposite with the number of turns equidirectional of earth connection; its elementary equivalent residual current will reach 2I, reach the residual operating current I of circuit breaker regulation when the 2I value
Δ
, this circuit breaker will move, and uses phase line, zero line, the earth connection of appliances power source all to disconnect.
The second situation, the electrical appliance power end connects normal, power supply phase line, zero line normal power supply, the normal ground connection of power ground line or unearthed.There are not the electric leakage situation in the phase line of electrical appliance, earth connection, the electrical appliance normal operation.When zero line and earth connection, human body can not produce influential reaction on touching electrical appliance.On touching electrical appliance during phase line, will consist of current circuit (do not have electric current in the power ground line this moment) through human body between power supply phase line and the earth, if this electric current is I, then the elementary residual current of zero sequence current mutual inductor will be similarly I, reach the residual operating current I of circuit breaker regulation when this current value I
Δ
The time, this circuit breaker will move, and uses phase line, zero line and the earth connection of appliances power source all to disconnect.
The third situation, the electrical appliance power end connects unusual, power supply phase line, zero line normal power supply, the power ground line is unusually charged because of outside connection error or other reasons.When having the electric leakage situation between phase line on the electrical appliance and the earth connection or between zero line and the earth connection, with top the first situation analysis.When between phase line on the electrical appliance and the earth connection, when not having the electric leakage situation between zero line and the earth connection, electrical appliance can work.Touch electrical appliance on phase line such as human body this moment, with top the second situation analysis; When touching earth connection, because earth connection is charged on the electrical appliance at this moment, will consist of current circuit through human body between this earth connection and the earth, if this electric current is I, then the elementary residual current of zero sequence current mutual inductor will be similarly I, reach the residual operating current I of circuit breaker regulation when this current value I
Δ
, this circuit breaker will move, and uses phase line, zero line and the earth connection of appliances power source all to disconnect.
In the general situation, except the phase line that directly is connected to power supply and the special circumstances between the zero line, human body touches on the electrical appliance live part to be caused getting an electric shock and all consists of the shock current loop between this alive circuit and the earth because human body is in, because elementary power ground line and the phase line zero line of zero sequence current mutual inductor oppositely winds the line, electric current in this electric shock circuit always can at the elementary formation residual current of zero sequence current mutual inductor (see second and the analysis of the third situation), reach the residual operating current I of circuit operation device regulation when this electric current
Δ
, this circuit breaker will move, and uses phase line, zero line and the earth connection of appliances power source all to disconnect, thereby from avoiding to the full extent the generation of electric shock accidents.
The motion test device is for use in testing for the Reliability of Microprocessor of specifying circuit breaker under the residual current condition, and the current-limiting resistance in the motion test device circuit calculates according to the residual electricity flow valuve of the voltage between power supply phase line, zero line and regulation and obtains.When pressing testing button; the electric current that will occur expected design in the motion test device circuit; consist of according to previously described circuit; obviously this electric current is detectable residual current fully concerning zero sequence current mutual inductor; this moment can action message such as circuit breaker; corresponding electric leakage, electric shock situation when occuring in earth leakage protective device so, and certainty also can action message.
In order more clearly to describe technical spirit of the present invention and effect, the below provides two kinds of embodiments of the present invention.
Embodiment 1:
See also Fig. 1, the phase line L of power supply, zero line N and earth connection G on the zero sequence current mutual inductor 1 as armature winding, wherein the direction of winding of phase line L and zero line N is all identical with winding turns, the direction of winding of the direction of winding of earth connection G and phase line L and zero line N is opposite and winding turns is identical, and power supply phase line L, zero line N and earth connection G are connected to electrical appliance 4 behind zero sequence current mutual inductor 1 armature winding.The secondary winding lead-out wire of zero sequence current mutual inductor 1 is connected to circuit breaker 3 as its triggering signal, whole being connected of deenergization phase line L, zero line N and earth connection G and electrical appliance 4 during circuit breaker 3 action.Circuit breaker 3 is connected to power supply phase line L and zero line N simultaneously, to obtain the power supply of circuit breaker.When various electric shocks or electric leakage situation appear in electrical appliance 4, according to top analysis, corresponding residual current will appear in the armature winding of zero sequence current mutual inductor 1, by the number of turns of design zero sequence current mutual inductor 1 secondary winding and the adjusting of circuit breaker, in the time of can making zero sequence current mutual inductor 1 armature winding the residual current of regulation occur, the signal that its secondary winding occurs just can the action of circuits for triggering disconnecting apparatus, thereby all cuts off the electricity supply and being connected of electrical appliance.The motion test device is connected in series by a current-limiting resistance R and a testing button PB and forms, and the one end is connected to power supply phase line or the zero line before the zero sequence current mutual inductor 1, and the other end is connected to zero-power line or the phase line after the zero sequence current mutual inductor 1.
Embodiment 2:
See also Fig. 2, this embodiment consists of as the basis take the first embodiment.This embodiment compares with the first embodiment, before the secondary winding of zero sequence current mutual inductor 1 is connected to circuit breaker 3, the resistance R of having connected respectively 1 and resistance R 2 in parallel, wherein an end of resistance R 1 is connected with an end of zero sequence current mutual inductor 1, the other end of resistance R 1 is connected with circuit breaker 3, the two ends of resistance R 2 all are connected with circuit breaker 3, are used for the susceptibility of 3 pairs of zero sequence circuit of regulating circuit disconnecting apparatus instrument transformer, 1 secondary winding output signal.Wherein the resistance of R1 may diminish to zero, and is namely straight-through; The resistance of R2 can be very large, until disconnect (being equivalent to infinity).In actual production, because the needed signal strength signal intensity of action of circuit breaker has certain dispersion, the corresponding selection by R1, R2 can make the performance of earth leakage protective device substantially reach consistent.
The above has listed the use-case of the present invention at single phase circuit, but the present invention is not subjected to the restriction of single phase circuit, and the present invention is applicable too for three-phase circuit.When the phase line indication in each embodiment was whole triple line of three phase mains, all discussed same the establishment front of the present invention.Simultaneously, when three-phase electric appliance used phase three-wire three connected mode and earth connection, all discussed equally establishment after using the three-phase phase line to substitute phase line and zero line front of the present invention.These all should be considered as equivalent transformation of the present invention.
In sum, technical scheme provided by the invention has remedied the shortcoming in the prior art, has reached goal of the invention, has embodied non-obvious technique effect
Claims (1)
1.
A kind of earth leakage protective device with protection function in case of live grounding wire, it is characterized in that: comprise residual current detection device, circuit breaker and motion test device, described residual current detection device is realized by a zero sequence current mutual inductor, its armature winding is made of jointly power supply phase line, zero line and earth connection, wherein power supply phase line, zero line be with identical direction and identical number of turns coiling, and earth connection is then with the direction opposite with power supply phase line, zero line and identical or close number of turns coiling; The secondary winding of described zero sequence current mutual inductor is connected to circuit breaker as its action triggers signal, described circuit breaker is connected to obtain working power with the power supply phase line with zero line, the all phase line of deenergization, zero line and earth connection during action remain open function when having simultaneously outage; Described motion test device is connected in series by a current-limiting resistance and a testing button and forms, the one end is connected to power supply phase line or the zero line before the zero sequence current mutual inductor, the other end is connected to zero-power line or the phase line after the zero sequence current mutual inductor, the secondary winding of described zero sequence current mutual inductor has been connected respectively resistance R 1 and parallel connection before being connected to circuit breaker resistance R 2, wherein an end of resistance R 1 is connected with an end of zero sequence current mutual inductor secondary winding, the other end of resistance R 1 is connected with circuit breaker, one end of resistance R 2 is connected with the tie point that circuit breaker is connected with resistance R, and the other end of resistance R 2 and circuit breaker are connected the tie point of the other end and are connected with the zero sequence current mutual inductor secondary winding
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| CN 201110283446 CN102354947B (en) | 2011-09-22 | 2011-09-22 | Leakage protection device with protection function in case of live grounding wire |
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| CN 201110283446 CN102354947B (en) | 2011-09-22 | 2011-09-22 | Leakage protection device with protection function in case of live grounding wire |
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| CN102354947A CN102354947A (en) | 2012-02-15 |
| CN102354947B true CN102354947B (en) | 2013-01-23 |
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| CN105988057B (en) * | 2015-02-09 | 2019-04-02 | 苏州益而益电器制造有限公司 | Use power detection circuit |
| DE102017202959A1 (en) * | 2017-02-23 | 2018-08-23 | Siemens Aktiengesellschaft | Apparatus and method for determining a ground conductor resistance for a charging device |
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| CN201142467Y (en) * | 2007-12-30 | 2008-10-29 | 邵宝平 | Creepage protecting plug |
| CN101478099B (en) * | 2008-01-04 | 2013-04-17 | 创奇科技有限公司 | Neutral grounding fault creepage protecting plug |
| CN201230077Y (en) * | 2008-06-21 | 2009-04-29 | 邵宝平 | Leakage protection plug |
| CN202231406U (en) * | 2011-09-22 | 2012-05-23 | 常熟市天银机电股份有限公司 | Earth leakage protection device with earth wire electrified protection function |
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