CN1421973A

CN1421973A - Automatic leakage circuit breaker with prevention function of malfunction

Info

Publication number: CN1421973A
Application number: CN 01140122
Authority: CN
Inventors: 堤学
Original assignee: Kawamura Electric Inc
Current assignee: Kawamura Electric Inc
Priority date: 2001-11-26
Filing date: 2001-11-26
Publication date: 2003-06-04

Abstract

The automatic high-sensitivity and high-speed current leakge breaker capable of preventing misoperation has one serial diode-capacitor circuit connected across the secondary coil of zero-sequence converter and resistor connected parallelly to the diode. The automatic breaker can be used to prevent misoperation caused by lightning surge produced between the power supply and earth and other impact voltage to make the impact current flow via the surge absorber to earth.

Description

Automatic leakage circuit breaker with prevention function of malfunction

Technical field

The present invention relates to automatic leakage circuit breaker, particularly a kind of high sensitivity, high-speed type automatic leakage circuit breaker that can prevent misoperation.This automatic leakage circuit breaker can prevent because the surge voltages such as lightning surge that produce between power supply one lateral circuit and the earth, and makes impulse current flow into the misoperation that the earth cause automatic leakage circuit breaker 1 via surge absorber 4.Surge absorber 4 is connected between the circuit 3 and the earth of automatic leakage circuit breaker 1 load 2 one sides, is used for protection load machine.

Background technology

As shown in Figure 4 and Figure 5, in the past, the circuit 3 of 1 load of automatic leakage circuit breaker, 2 one sides is input to amplifier 7 as the output of the secondary coil 6 of zero (phase) preface current transformer 5 of primary winding, when the output of secondary coil 6 surpasses detection of electrical leakage level Vs, signal SA takes place from amplifier 7 output electric leakages, under the situation more than this electric leakage generation signal SA certain time, when the delay circuit of being made up of the RC integrating circuit that produces output etc. 8 sends shutoff signal SB, make the contact 10 of tripper 9 carry out the action of opening circuit, cut off load circuit 3.

In this case, as shown in Figure 6A, if impulse current ground connection is taken place, then (shown in Fig. 6 B) is from the secondary coil 6 of zero phase current transformer 5, produce output voltage V z, direct output that the waveform of Vz is produced by impulse current and the reverse voltage when being cut off and the output that causes forms by impulse current.Surpass significantly at this output voltage V z under the state of detection of electrical leakage level Vs of amplifier 7, output time is than the delay time long (with reference to Fig. 6 C, Fig. 6 D) that is set in the delay circuit of being made up of RC integrating circuit and comparator 11 8, thereby, will produce shutoff signal SB from delay circuit 8, just there is this shortcoming of automatic leakage circuit breaker 1 misoperation in this.

And then, when impulse current under situation about flowing on the direction opposite with Fig. 6 A, the waveform that the output that reverse voltage when being cut off by the direct output of impulse current generation with by impulse current causes is formed, also shown in Fig. 6 E, become the phase anti-waveform of waveform shown in Fig. 6 B, the detection level Vs output time partly that surpasses amplifier 7 is shown in Fig. 6 E, short more a lot of than the delay time that is set in the delay circuit 8, thereby shown in Fig. 6 F, capacitor C terminal voltage is low, and automatic leakage circuit breaker 1 can misoperation.

Summary of the invention

Even thereby the object of the present invention is to provide between a kind of circuit that is in load loop and the ground wire and be connected with under the state of surge absorber, also high sensitivity, high-speed type automatic leakage circuit breaker that can misoperation when impulse current takes place.

Automatic leakage circuit breaker according to the present invention comprises: signal amplifier takes place in electric leakage, when the voltage of the zero sequence converter secondary coil of the zero-sequence current that detects load side circuit surpasses the detection of electrical leakage level, and output electric leakage generation signal; Delay circuit is used for when the output time of above-mentioned electric leakage generation signal exceeds schedule time, and the output shutoff signal is supplied with the power supply of above-mentioned load side circuit to cut off; Connect the series circuit of diode and capacitor between the secondary coil two ends of above-mentioned zero sequence converter, resistance meanwhile is connected in parallel on above-mentioned diode.

In the automatic leakage circuit breaker that constitutes like this, under the situation that impulse current ground connection is taken place, because diode current flow, the direct output from the surge current of the secondary coil of zero sequence converter produces makes the capacitor charging that is connected on this secondary coil.Meanwhile, if surge current is cut off, the charging charge that then is charged in this capacitor passes through and the diode parallel resistor, discharge into zero sequence converter in external circuit such as secondary coil parallel resistor, diode in, this discharge current removing because the output that the reverse voltage of surge current when being cut off causes, the result, the output time of part that surpasses the detection level Vs of amplifier is significantly lacked than the delay time that is set in the delay circuit, delay circuit does not produce output, and automatic leakage circuit breaker can misoperation.

Like this, even in high sensitivity, high-speed type automatic leakage circuit breaker, the present invention also has can use simple circuit, and obtain easily not can be because of the effect of the automatic leakage circuit breaker of impulse current ground connection misoperation.

The accompanying drawing summary

Fig. 1 is the circuit diagram of one embodiment of the present of invention.

Fig. 2 is the oscillogram of showing its operating characteristics.

Fig. 3 is the electrical circuit diagram of the common surge absorber connection status of displaying the present invention and prior art embodiment.

Fig. 4 is the circuit diagram of prior art embodiment.

Fig. 5 and Fig. 6 are the oscillograms of showing the operating characteristics of prior art embodiment.

Embodiment

Below, the formation of one embodiment of the present of invention is described with Fig. 1 and Fig. 2.Among the figure, represent with prosign with the part that circuit was identical in the past.

As shown in Figure 1, the lead-out terminal of load circuit 3, be connected on the amplifier 7 as the secondary coil 6 of the zero sequence converter 5 of primary winding.When the output voltage of this secondary coil 6 surpassed detection of electrical leakage level Vs, signal SA took place in amplifier 7 output electric leakages.Between the lead-out terminal of the secondary coil 6 of zero sequence converter 5, connect sensitivity and set and use resistance R1, between the input terminal of amplifier 7, be used to prevent that excessive input from causing that amplifier 7 impaired diode D1, D2 are connected to two rightabouts.In addition, between the lead-out terminal of the secondary coil 6 of zero sequence converter 5, be connected with the series circuit of forming by capacitor C1 and diode D3, be used for absorbing the output of the secondary coil 6 of the zero sequence converter 5 that produces owing to the impulse current that flows to ground wire, this impulse current is because in the surge voltage of the lightning surge of power supply one side of automatic leakage circuit breaker 1 generation etc., and flows in the ground wire via surge absorber 4.And and this diode D3 is connected with discharge resistance R2 in parallel, by resistance R 2 charging charge of capacitor C1 discharged in the external circuit of resistance R 1 grade.Between the secondary coil 6 of zero sequence converter 5 and amplifier 7, also be connected with electric current brownout resistance R3 and be used to give the above-mentioned capacitor C1 resistance R 4 of sufficient charging voltage.

In addition, on amplifier 7, be connected with delay circuit 8.Delay circuit 8 is made up of RC integrating circuit and comparator 11.When the output time from the electric leakage generation signal SA of this amplifier 7 surpassed delay time, delay circuit 8 produced detection of electrical leakage signal SB.In this case, delay circuit 8 is connected with known shearing device 9 on this delay circuit 8, when this shearing device 9 produces electrical leakage breaking signal SB at this delay circuit 8, makes contact 10 cut off action to cut off load circuit 3.

Below, the effect of present embodiment is described.In the automatic leakage circuit breaker 1 that constitutes like this, if impulse current ground connection (with reference to Fig. 2 A) is taken place, because diode D3 conducting, the direct output that causes from the impulse current (with reference to Fig. 2 B) of the secondary coil 6 of zero sequence converter 5, make the capacitor C1 charging that is connected on this two coil 6, simultaneously, if impulse current is cut off, the charging charge that then is charged among this capacitor C1 discharges into resistance R 1 by the discharge resistance R2 with diode D3 parallel connection, produces the voltage waveform shown in Fig. 2 C between capacitor C1 two ends.On the other hand, because the effect of the discharging current corresponding with this Fig. 2 C, the output voltage V z of the waveform shown in Fig. 2 B that is caused by reverse voltage when impulse current is cut off is eliminated, the voltage waveform shown in input Fig. 2 D on amplifier 7, its result, the output time of part that surpasses the detection of electrical leakage level Vs of amplifier 7 is significantly lacked than the delay time that is set in the delay circuit 8, does not produce output (with reference to Fig. 2 E) from delay circuit 8, and automatic leakage circuit breaker 1 can misoperation.

That is, by connect surge absorber 4 between the circuit/the earth of the load circuit 3 that uses high sensitivity, high-speed type automatic leakage circuit breaker 1 ON/OFF control load 2, even impulse current ground connection is taken place, automatic leakage circuit breaker 1 can misoperation yet.

Claims

1. automatic leakage circuit breaker, it is characterized in that, this automatic leakage circuit breaker comprises: signal amplifier takes place in electric leakage, when the voltage of the zero sequence converter secondary coil of the zero-sequence current that detects load side circuit surpasses the detection of electrical leakage level, and output electric leakage generation signal; Delay circuit is used for when the output time of above-mentioned electric leakage generation signal exceeds schedule time, and the output shutoff signal is supplied with the power supply of above-mentioned load side circuit to cut off; Connect in the series circuit of diode and capacitor between the two ends of the secondary coil of above-mentioned zero sequence converter, resistance is connected in parallel on above-mentioned diode.