CN1033427A - Protector circuit against electric leakage - Google Patents
Protector circuit against electric leakage Download PDFInfo
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- CN1033427A CN1033427A CN 87101441 CN87101441A CN1033427A CN 1033427 A CN1033427 A CN 1033427A CN 87101441 CN87101441 CN 87101441 CN 87101441 A CN87101441 A CN 87101441A CN 1033427 A CN1033427 A CN 1033427A
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Abstract
The present invention discloses a kind of highly sensitive protector circuit against electric leakage.The present invention makes it resonance behind the mains frequency and the adjustable dc voltage source of connecting at electric capacity in parallel on the instrument transformer secondary winding, receives between controllable silicon gate pole and the negative electrode again.Because resonance effect has reduced the impedance loop of instrument transformer secondary, the voltage superposition has been raised the signal amplitude that is added on gate pole, makes instrument transformer can directly trigger common controllable silicon.Thereby the cost that makes protector reduces, volume reduces, machine sensitivity improves.
Description
Circuit disclosed by the invention is suitable for being used for constituting simple in structure, highly sensitive electric leakage protector, belongs to the protection switch by the unsymmetrical current effect.
Utilize the electric leakage protector of the characteristic formation of thyristor to have the circuit characteristic of simple.In prior art, the typical circuit of this protector all comprises these three kinds of devices of zero sequence current mutual inductor, thyristor (SCR) and relay switch.Zero sequence current mutual inductor is as the electric leakage detecting element, and controllable silicon is as control element, and relay switch is used to switch shielded electrical appliance.Wherein controllable silicon is triggered by above-mentioned zero sequence current mutual inductor secondary winding, and relay switch is controlled by silicon controlled.In prior art,, directly trigger thyristor with the output of zero sequence current mutual inductor secondary in order further to simplify circuit.
Sichuan " electronics newspaper " the 28th phase in 1987 (publication on July 12) the 4th edition has been delivered " the reliable earth leakage protector of a kind of performance simple in structure " literary composition, and the protector of being introduced just has above-mentioned whole feature.
Because zero sequence current mutual inductor can only be exported small-signal, does not often reach silicon controlled gate trigger voltage and/or electric current thresholding.In order to realize direct triggering, prior art is taked two technical measures: the one, and by adopting high permeability materials to manufacture the magnetic core of zero sequence current mutual inductor or increasing the magnetic core cross section, the sensitivity that improves zero sequence current mutual inductor increases its power output; The 2nd, select for use the thyristor of trigger sensitivity higher (trigger voltage is lower, trigger current is less) or high-sensitive particular device as control element, to adapt to the small-signal of instrument transformer output.For example above-mentioned documents adopts heavy in section magnetic core and high sensitivity controllable silicon to solve this problem, and this article requires to adopt trigger current less than 0.1 milliampere thyristor.Commercially available HG-BA series earth leakage protector (" three profits " trade mark, State-OPerated Hanguang Machinery Plant produces) then adopted the permalloy magnetic core of high permeability to manufacture zero sequence current mutual inductor, and adopted the particular device (S1 wherein and S2) of high trigger sensitivity.
The solution of prior art is because require to adopt high permeability or heavy in section magnetic core, and cooperate the controllable silicon (for example above-cited documents) of high trigger sensitivity or particular device (for example HG-BA series earth leakage protector), can cause obviously that being easy to get property of components and parts is poor, screening rate is lower and the protector volume is difficult to reduce.
Task of the present invention is: propose a kind of permission and adopt the small bore common magnetic core to manufacture zero sequence current mutual inductor, allow to adopt the protector circuit against electric leakage of general thyristor (SCR) as control element.
The present invention utilizes the method for stack and resonance to realize above-mentioned task.The protector circuit against electric leakage that is constituted can briefly be described below:
By zero sequence current mutual inductor, the protector circuit against electric leakage that thyristor (SCR) and relay switch constitute, thyristor is wherein triggered by said instrument transformer secondary, relay switch is controlled by said thyristor, feature of the present invention is: receive between the gate pole and negative electrode of thyristor behind the secondary winding of said zero sequence current mutual inductor and an adjustable dc voltage subject string connection again, on this zero sequence current mutual inductor secondary winding, also be parallel with a resonant capacitor, this capacitor with said zero sequence current mutual inductor secondary winding resonance in the frequency of the operating voltage of controlled electrical appliance.
Causing the instrument transformer secondary can not directly trigger common silicon controlled main cause is that the controllable silicon gate resistance is less, requires triggering signal that enough trigger currents can be provided, and the trigger voltage thresholding about 0.7 volt is arranged.And the internal resistance of instrument transformer secondary is very big, can not with controllable silicon gate resistance matched well, thereby can not obtain maximum power at the controllable silicon gate pole.Take appropriate measures and reduce the internal resistance of instrument transformer secondary, and raise the signal voltage that is added on the controllable silicon gate pole, can solve the triggering problem effectively.
The present invention is resonant capacitor in parallel on instrument transformer secondary winding at first, utilizes resonance effect that the impedance of instrument transformer secondary is minimized.Insert the controllable silicon gate pole again after further making the same adjustable dc voltage subject string connection of secondary winding again, utilize this direct voltage to raise the signal voltage that is added on gate pole with the superposition of tank voltage.Owing to taked the technical measures of voltage stack and impedance matching, made the small-signal of zero sequence current mutual inductor output can trigger thyristor reliably with higher trigger voltage and trigger current thresholding.Therefore in protector circuit against electric leakage of the present invention, allow to use common magnet ring to make zero sequence current mutual inductor, allow to adopt common thyristor as control element.This can reduce manufacturing cost, reduces the volume of protector, and used being easy to get property of components and parts is relatively good, and screening rate is higher.In addition, owing to introduced the adjustable dc voltage source at the controllable silicon gate pole, it is very convenient reliable to make the protector machine sensitivity adjust.As long as regulate the voltage of gate pole direct voltage source, just can adjust machine sensitivity effectively.These characteristics also are very beneficial for production process, can reduce component parameters one Luan edge capsule toad
Label below in conjunction with accompanying drawing illustrates formation of the present invention in further detail.
The present invention has three frame accompanying drawings.
Fig. 1 is the electrical schematic diagram of protector circuit against electric leakage of the present invention.
Fig. 2 has proposed a kind of straightforward procedure that obtains said low internal resistance direct voltage source.
Fig. 3 has provided the circuit of a complete electric leakage protector, and it is a reasonable embodiment of the present invention.
The basic comprising of protector circuit against electric leakage of the present invention as shown in Figure 1.It comprises a zero sequence current mutual inductor [LH], a thyristor as control element [2], also have one is subjected to thyristor controlled relay switch [1].The secondary winding [8] of said zero sequence current mutual inductor [LH] be connected between the gate pole [4] and negative electrode [5] of said thyristor [2] after connecting in an adjustable DC voltage source [6], on this zero sequence current mutual inductor secondary winding, also be parallel with a resonant capacitor [7], this capacitor with said zero sequence current mutual inductor secondary winding [8] resonance in controlled electrical appliance operating voltage [V
In] frequency.
Because said direct voltage source [6] is connected with the output voltage of zero sequence current mutual inductor, for being dissipated, its internal resistance is sent to the signal power of controllable silicon gate pole, and this voltage source should have as far as possible little internal resistance.Utilize the described method of Fig. 2 can obtain the adjustable dc voltage of a low internal resistance.
To inserting a voltage divider of using divider resistance [14] and following divider resistance [15] formation between the negative electrode [5], the mid point of this voltage divider joins with controllable silicon gate pole [4] at controllable silicon anode [3].Capacitor [13] with a larger capacity replaces said direct voltage source [6], and the back of connecting with instrument transformer secondary [8] is inserted between controllable silicon gate pole [4] and the negative electrode [5].In this application this electric capacity is called bootstrap capacitor.By changing the voltage ratio of voltage divider, controllable silicon gate pole [4] voltage can be adjusted to desirable numerical value.This voltage should be lower than controllable silicon gate trigger voltage thresholding (about 0.7 volt) all the time.Like this, when instrument transformer secondary no-output, utilize the voltage divider mid-point voltage that bootstrap capacitor [13] is charged.When the instrument transformer secondary had signal output, the voltage on the same bootstrap capacitor of signal voltage [13] was superimposed, utilizes so-called boot strap to make the controllable silicon conducting.
The capacitor [7] in parallel with instrument transformer secondary [8] also plays the effect that absorbs interference signal with instrument transformer secondary winding except that playing resonance effect.All signals that is not equal to 50 hertz are all absorbed by the resonant tank of this electric capacity and instrument transformer secondary winding formation, cause the controllable silicon false triggering and be unlikely.That is to say that the shunt-resonant circuit that is made of instrument transformer secondary winding [8] and resonant capacitance [7] is had the frequency-selecting effect, also can make circuit of the present invention have good antijamming capability.In addition, in the controllable silicon triggering loop of protector circuit against electric leakage of the present invention, do not add any link that may cause long delay, therefore, instantaneous operation when electric leakage protector of the present invention reaches the protection value at leakage current.
It is very easy implementing the present invention, utilizes electric principle shown in Figure 2, increases power supply circuits and after simple improvement, just can constitute complete protector circuit against electric leakage as shown in Figure 3.
In Fig. 3 circuit, line voltage [V
In] after decompression capacitor [16] step-down, rectifier bridge [12] rectification, resistance [17] and filter capacitor [18] filtering, be the protector circuit power supply.After connecting with light-emitting diode [20] and thyristor [2], closed type relay switch [1] inserts the rectifier power source two ends.On said relay switch, be parallel with fly-wheel diode [19], be used for the back-emf of lead coil.Be connected to a parallel resistance [21] on light-emitting diode [20], its effect is just in case light-emitting diode [20] is burnt, and still can guarantee the reliable adhesive of relay switch [1].The voltage divider that is made of last divider resistance [14] and trimmer potentiometer [23] is connected on controllable silicon [2] two ends.This voltage divider mid point is connected to voltage-stabiliser tube [22] to (controllable silicon negative electrode [5]) between the ground, and it plays stable and controllable silicon gate pole current potential, helps to reduce the influence of voltage fluctuation to protector machine sensitivity, stability and protective current.The centre cap of trimmer potentiometer joins with controllable silicon gate pole [4] through an isolation resistance [24] as the output of voltage divider, and this can prevent the influence of voltage divider [14 and 23] to resonant tank.In the present embodiment, resonant capacitance [7] directly is connected on the controllable silicon gate pole [4], be connected between controllable silicon gate pole [4] and the negative electrode [5] after the same bootstrap capacitor of instrument transformer secondary winding [8] [13] series connection, this connection can make resonant tank that the required precision of electric capacity and inductance parameters is reduced, beneficial to production process, anti-interference effect is strengthened.But the resonance frequency that should be noted that resonant tank this moment when the designing and calculating circuit parameter is relevant with the series value of two electric capacity.Make two capacitance values equate than the effect that is easier to obtain.Line voltage [V
In] export [V through two normally-closed contacts [10] and the former limit of the zero sequence current mutual inductor winding [9] of relay switch [1] from output
Out].Do not taking place under the electric leakage situation, the magnetic flux that two former limit windings produce at any time should be cancelled out each other, and two normally-closed contacts keep on-states.At input voltage [V
In] and output voltage [V
Out] between be connected to the series loop of a test-run a machine switch [25] and current-limiting resistance [26].When depressing test-run a machine switch [25], produce a simulation leakage current by resistance [26].This electric current makes instrument transformer pair [8] limit that signal output be arranged, and triggers controllable silicon [2] and makes relay switch [1] adhesive, normally-closed contact [10] disjunction.Be parallel with a reset switch [11] at said controllable silicon [2] two ends, depress this switch, thereby make it to turn-off, relay switch [1] is resetted controllable silicon anode and cathode [5 and 3] short circuit.
Above-mentioned components and parts are pressed routine selection of parameter, can obtain desirable protection effect.
(the magnetic core specification is the LH-zero sequence current mutual inductor: 31 * 17 * 7MXD-2000)
1-relay switch (JOX-13F, 110 volts of direct currents)
2-thyristor (2N6565,700 volts of 1 peaces)
7-resonant capacitance (10 microfarads/16 volt)
8-instrument transformer secondary winding (0.12 millimeter 1000 circle, inductance value about 2 is enjoyed)
The former limit of 9-instrument transformer winding (1.5 millimeters two-wire and around 10 circles)
13-bootstrap capacitor (10 microfarads/16 volt)
16-decompression capacitor (0.22 microfarad/400 volt)
17-current-limiting resistance (110 Europe/1 watt)
18-filter capacitor (1 microfarad/400 volt)
21-parallel resistance (1 kilo-ohm)
22-voltage-stabiliser tube (replacing to obtain the voltage stabilizing value about 2 volts) with light-emitting diode
23-trimmer potentiometer (2.2 kilo-ohms of resistances)
24-isolation resistance (2.4 kilo-ohms)
26-artifical resistance (20 kilo-ohms/2 watts)
Other elements all can be chosen according to rule, and all elements all can adopt other close model elements of performance and parameter to replace.Because protector circuit against electric leakage power consumption of the present invention is very little, so except that clearly marking, all the power of resistive element is 1/8.
The course of work of present embodiment is:
The energising back does not have electric leakage and does not depress test-run a machine switch [25], then not adhesive of relay switch [1], line voltage [V yet as electrical appliance
In] export [V through two normally-closed contacts [10] and two former limit windings [9] of this relay switch
Out].While line voltage [V
In] be added between the controllable silicon anode and cathode [3 and 5] through decompression capacitor [16], rectifier bridge [12], current-limiting resistance [17], relay switch [1].The voltage at controllable silicon two ends is through last divider resistance [14] and trimmer potentiometer [23] dividing potential drop, and with after voltage-stabiliser tube [22] voltage stabilizing, be added to controllable silicon gate pole [4] through isolation resistance [24], give the charging of bootstrap capacitor [13] and resonant capacitance [7], charging voltage equals the output voltage of voltage divider.By regulator potentiometer [23], can make the voltage (being the voltage divider output voltage) that is added on gate pole [4] a little less than the gate trigger voltage thresholding.Because this moment, gate pole [4] no current flow through, thus not conducting of controllable silicon [2], not adhesive of relay switch [1], contact [10] keep on-state, and electrical network passes through two normally-closed contacts [10] of relay switch to the electrical appliance normal power supply.
If electrical appliance electric leakage has taken place or depressed test-run a machine switch [25], the magnetic flux imbalance that instrument transformer [LH] former limit winding [9] produces will generate a voltage signal in the secondary winding [8].After foregoing resonance and stack, this voltage is added on the controllable silicon gate pole [4].If leakage current has reached the protective current value of setting up, the signal voltage peak value that is added on gate pole will be higher than the trigger voltage thresholding of gate pole.When first was higher than the signal peak arrival that triggers thresholding, controllable silicon [2] made relay switch [1] adhesive with conducting, normally-closed contact [10] disjunction, the current supply circuit of cut-out electrical appliance.Change the gate pole bias voltage by regulating trimmer potentiometer [23], just can easily and reliably change the opportunity of protector action, i.e. the size of protective current.This direct voltage triggers thresholding (about 0.7 volt) near gate pole more, and the sensitivity of protector is high more, and protective current is more little.Vice versa.But this voltage must not be greater than or equal to silicon controlled gate trigger voltage thresholding.
Leakage current will disappear because two normally-closed contact branches are had no progeny, and the leak current fault of electrical appliance might not be removed at this moment, so protector should have the self-sustaining ability.The present embodiment protector circuit adopts electricity to keep, and realizes self-sustaining if promptly utilize after the controllable silicon conducting electric current not reduce to keep the characteristic that can not turn-off voluntarily below the electric current.For this reason, must be added with filter capacitor [18] in the protector current supply circuit, to eliminate the zero crossing in the supply power voltage.Press reset switch [11] with controllable silicon anode and cathode [3 and 5] short circuit, controllable silicon is turn-offed again, protector will restore electricity.
The method of adjustment of protector circuit against electric leakage of the present invention is as follows:
At first choose suitable electric leakage and simulate resistor [26], be as the criterion so that can in being suitable for voltage range, produce the leakage current of regulation according to the protective current of product standard regulation and suitable voltage range.Following divider resistance in the voltage divider (trimmer potentiometer [23]) is transferred to extreme lower position, depresses test-run a machine switch [25] again, make the former limit of instrument transformer produce a leakage current that simulates.At this moment observing the voltage waveform of controllable silicon gate pole [4] with oscilloscope, should be the overlaid waveforms of the same complete sine voltage of direct voltage.As not being, should change the capacitor [7 and 13] of resonant tank earlier, make the gate voltage waveform become the overlaid waveforms of direct current and sinusoidal voltage.This explanation resonant tank can operate as normal.Slowly adjust trimmer potentiometer [23] then, improve the gate pole bias voltage, till making relay switch [1] adhesive just.
The controllable silicon triggering method that the present invention proposes also can be widely used in the occasion that other must trigger thyristor with small-signal.
Claims (7)
1, by zero sequence current mutual inductor [LH], the protector circuit against electric leakage that thyristor [2] and relay switch [1] constitute, thyristor wherein [2] is triggered by said instrument transformer secondary [8], relay switch [1] is subjected to said thyristor [2] control, feature of the present invention is: the secondary winding [8] of said zero sequence current mutual inductor be connected between the gate pole [4] and negative electrode [5] of said thyristor [2] after connecting in an adjustable DC voltage source [6], on this zero sequence current mutual inductor secondary winding [8], also be parallel with a resonant capacitor [7], this capacitor with said zero sequence current mutual inductor secondary winding [8] resonance in the frequency of controlled electrical appliance operating voltage.
2, circuit as claimed in claim 1, it is characterized in that said adjustable dc voltage source provides with following method: between controllable silicon anode and cathode [5 and 3], insert a voltage divider that constitutes by last divider resistance [14] and following divider resistance [15], the mid point of this voltage divider joins with controllable silicon gate pole [4], replace said direct voltage source [6] with a capacitor [13] and receive between controllable silicon gate pole [4] and the negative electrode [5] with after instrument transformer secondary winding [8] serial connection, the voltage ratio by the change voltage divider is adjusted to the gate pole direct voltage and is lower than controllable silicon gate trigger voltage thresholding slightly.
3, circuit as claimed in claim 2 is characterized in that: insert an isolation resistance [24] between said voltage divider mid point and controllable silicon gate pole [4].
4, as claim 2 and 3 described circuit, it is characterized in that: the following divider resistance of voltage divider replaces with a trimmer potentiometer [23], the centre tap of this trimmer potentiometer is the voltage divider output, joins with controllable silicon gate pole [4] through said isolation resistance [24].
5, circuit as claimed in claim 4 is characterized in that: said voltage divider mid-point voltage promptly is connected to a voltage-stabiliser tube [22] at the voltage divider mid point through voltage stabilizing between ground (controllable silicon negative electrode [4]).
6, as claim 2,3 and 5 described circuit, it is characterized in that: said resonant capacitance [7] directly is connected between controllable silicon gate pole [4] and the negative electrode [5].
7, circuit as claimed in claim 4 is characterized in that: said resonant capacitance [7] directly is connected between controllable silicon gate pole [4] and the negative electrode [5].
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 87101441 CN1033427A (en) | 1987-12-03 | 1987-12-03 | Protector circuit against electric leakage |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 87101441 CN1033427A (en) | 1987-12-03 | 1987-12-03 | Protector circuit against electric leakage |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1033427A true CN1033427A (en) | 1989-06-14 |
Family
ID=4813428
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 87101441 Pending CN1033427A (en) | 1987-12-03 | 1987-12-03 | Protector circuit against electric leakage |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1033427A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101345407B (en) * | 2008-07-29 | 2011-05-25 | 人民电器集团有限公司 | Creepage breaker |
| CN104124874A (en) * | 2014-07-16 | 2014-10-29 | 广州金升阳科技有限公司 | Ultrahigh-frequency isolating resonant converter |
| CN104868906A (en) * | 2015-05-26 | 2015-08-26 | 施文斌 | Integrated circuit and voltage selection circuit |
-
1987
- 1987-12-03 CN CN 87101441 patent/CN1033427A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101345407B (en) * | 2008-07-29 | 2011-05-25 | 人民电器集团有限公司 | Creepage breaker |
| CN104124874A (en) * | 2014-07-16 | 2014-10-29 | 广州金升阳科技有限公司 | Ultrahigh-frequency isolating resonant converter |
| CN104124874B (en) * | 2014-07-16 | 2017-02-15 | 广州金升阳科技有限公司 | Ultrahigh-frequency isolating resonant converter |
| CN104868906A (en) * | 2015-05-26 | 2015-08-26 | 施文斌 | Integrated circuit and voltage selection circuit |
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