CN201562951U

CN201562951U - Fault arc protection device

Info

Publication number: CN201562951U
Application number: CN2009201990785U
Authority: CN
Inventors: 吴为麟; 郑伟彦; 吴晶莹
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-10-26
Filing date: 2009-10-26
Publication date: 2010-08-25
Anticipated expiration: 2019-10-26

Abstract

The utility model discloses a fault arc protection device, which comprises a direct current sensor. The output end of the direct current sensor is sequentially connected with a voltage follower circuit, a signal conditioning amplifying circuit, an A/D sampling circuit, a microprocessor, a release driving circuit and a release component controlled by the release driving circuit. The voltage signals generated by the direct current sensor are transmitted to the conditioning amplifying circuit through the voltage follower circuit and are converted to the direct current signals suitable for A/D sampling; the A/D sampling circuit samples the direct current signals; and the microprocessor identifies fault arc through detecting the high-frequency characteristic in the A/D sampled signals and generates release signals to the release driving circuit and the release component controlled by the release driving circuit. By adopting the technical scheme, the fault arc protection device utilizes the direct current sensor to sample the direct current signals, and uses the high-frequency disturbance characteristics in the direct current fault arc waveform as the identification condition of the fault arc. The device can effectively detect direct current fault arc and adopt the corresponding protection measures, and expands the protection range of the conventional arc protection device.

Description

The fault electric arc protective device

Technical field

The utility model belongs to the electric circuit protection equipment field, particularly relates to a kind of protective device that is used for distribution terminal system detection failure electric arc.

Background technology

Premises electric wiring and equipment, as: the electric wire of electric wiring, socket, household electrical appliance inside or the power line of electrical equipment etc., because long running overload, perhaps there is bad situation such as be electrically connected, make the insulating barrier of electric wire occur aging, insulation effect reduces, and perhaps breakage takes place insulating barrier, and electric arc all may break down.The arc spark circuit that ignites can cause the generation of fire.Circuit protection device fuse now commonly used and ground-fault interrupter be detection failure electric arc and form open circuit protection effectively.AFCI (ArcFault Circuit Interrupter) technology is a up-to-date circuit protection technology; the fault electric arc protection can be provided; it mainly acts on is for timely branch deenergizing when breaking down electric arc, avoids load to damage, and reduces the possibility of fire.

At present; the expert has proposed some feasible AFCI detection method and protective circuits both at home and abroad; but all at 50Hz～60Hz alternating current circuit; typical home is loaded the fault electric arc current waveform as shown in Figure 6, and there are features such as amplitude reduction, asymmetric, the flat shoulder of positive-negative half-cycle and waveform are precipitous in the fault electric arc current waveform.Because, now mostly AFCI detection method and protective circuit all are whether characteristics such as derivative (di/dt, the i.e. precipitous degree of waveform) by judging current waveform or the flat shoulder of electric arc, positive and negative half-wave be asymmetric surpass and set threshold values and accumulation electric arc cycle and whether surpass threshold values and discern the fault electric arc electric current; Yet, for automobile 42v direct current supply electric arc, exceeded the traditional AFCI detection method and the failure judgement principle of protective circuit, thus arc protection device can't correct operation, can't will detect the direct current fault electric arc effectively.

Summary of the invention

In order to solve above-mentioned technical problem; the purpose of this utility model provides a kind of fault electric arc protective device; utilize direct current transducer sampling dc current signal; with the high frequency components feature that contains in the direct current fault electric arc waveform Rule of judgment, detect the direct current fault electric arc effectively and take the corresponding protection measure as identification electric arc.

To achieve the above object, the utility model has adopted following technical scheme:

A kind of fault electric arc protective device; comprise direct current transducer; the direct current transducer output is connected with voltage follower circuit in turn; the signal condition amplifying circuit; the A/D sample circuit; the trip assembley therefor of microprocessor and dropout drive circuit and control thereof; wherein; the voltage signal that direct current transducer produces is passed to the conditioning amplifying circuit by voltage follower circuit and is converted to the direct current signal that is suitable for the A/D sampling; the A/D sample circuit is sampled to this direct current signal, and microprocessor is by detecting the high-frequency characteristic identification fault electric arc in the A/D sampled signal and producing the trip assembley therefor that trip signal is given dropout drive circuit and control thereof.

Above-mentioned direct current transducer transforms chip U6 by shunt S and differential voltage and forms.

As preferably, above-mentioned direct current transducer is the Hall direct current transducer.

Owing to adopted above technical scheme; utilize direct current transducer sampling dc current signal; with the high frequency components feature that contains in the direct current fault electric arc waveform Rule of judgment as identification electric arc; can detect the direct current fault electric arc effectively and take the corresponding protection measure, enlarge the protection range of conventional arc protective device.

Description of drawings

Fig. 1 is circuit theory diagrams of the present utility model (direct currents).

Fig. 2 is a theory diagram of the present utility model.

Embodiment

Below in conjunction with accompanying drawing embodiment of the present utility model is further described in detail.

Embodiment 1:

As Fig. 1; a kind of fault electric arc protective device shown in Figure 2; comprise power circuit 7 and direct current transducer 8; direct current transducer 8 is connected with signal load resistance R 11; direct current transducer 8 outputs are connected with voltage follower circuit 4 in turn; signal condition amplifying circuit 6; A/D sample circuit 5; the trip assembley therefor 3 of microprocessor 2 and dropout drive circuit 1 and control thereof; wherein; the direct current transducer 8 generation voltage signals of sense current in direct electricity are passed to conditioning amplifying circuit 6 by voltage follower circuit 4 and are converted to the direct current signal that is suitable for the A/D sampling; 5 pairs of these direct current signals of A/D sample circuit are sampled, and the signal of 2 pairs of A/D samplings of microprocessor carries out the trip assembley therefor 3 that arc characteristic is differentiated and the generation trip signal is given dropout drive circuit 1 and controlled.Microprocessor 2 is with the high frequency components feature that contains in the direct current fault electric arc waveform Rule of judgment as identification electric arc, thereby can detect the direct current fault electric arc effectively and take the corresponding protection measure, enlarged the protection range of conventional arc protective device.

In the present embodiment, above-mentioned direct current transducer 8 transforms chip U6 by shunt S and differential voltage and forms; Certainly, described direct current transducer 8 can also be the Hall direct current transducer.Above-mentioned voltage follower circuit 4 is made up of resistance R 2, resistance R 3 and amplifier U5A, the in-phase input end connecting resistance R2 of amplifier U5A, resistance R 2 connects signal load resistance R 11, and connecting resistance R3 between the reverse input end of amplifier U5A and the output is passed to signal condition amplifying circuit 6 with the voltage signal isolation.Above-mentioned signal condition amplifying circuit 6 is made up of rheostat VR2, resistance R 12 and amplifier U5B, the in-phase input end of amplifier U5B connects the output of voltage follower circuit 4, the reverse phase input connecting resistance R12 of amplifier U5B, meet rheostat VR2 between the reverse input end of amplifier U5B and the output, amplifier U5B output connects the pull-up circuit of being made up of resistance R 4 and resistance R 10, and the end that picks out of pull-up circuit connects A/D sample circuit 5.Above-mentioned A/D sample circuit 5 can independently separate with microprocessor 2, also can select the microprocessor that carries the A/D sample circuit for use.Carry out transfer of data by data/address bus P0.0-P0.7 between microprocessor 2 chips U1 and A/D chip U2, every a set time, U1 enters regularly and interrupts, obtain current signal replication from U2, the address wire of U1 produces control signal by control chip X2A and X2B (X2A and X2B are that model is two passages of the control chip of SN74HCO2N), and U2 is carried out synchronously, reads and writes control.Above-mentioned dropout drive circuit 1 is made up of resistance R 1 that is in series and optocoupler O1; Trip assembley therefor 3 is for connecting the release K1 of optocoupler O1.The I/O mouth P1.7 of microprocessor chips U1 connects the input of optocoupler O1 by resistance R 1, work back U1 is if detect fault electric arc, then this I/O mouth is put high level, optocoupler O1 work, the output triode short circuit of optocoupler O1, the coil electricity of release K1, the adhesive contact disconnects the switch of receiving on the load.Above-mentioned power circuit 7 comprises: capacitor C 4 and C5 are connected across the AC power two ends, and diode D2, D3, D4, D5 form rectification circuit, and the AC power on the capacitor C 5 is rectified into direct current, by voltage stabilizing chip U4 output DC source; Capacitor C 2, C3 are connected in parallel between the input and earth terminal of voltage stabilizing chip U4, play the effect of filtering; Diode D6, D7 are connected across the end of incoming cables, prevent overvoltage.Power circuit 7 provides galvanic current for each circuit module.

The utility model is not limited to above embodiment; the utility model both can be used as an independently system; also can combine, form multi-functional circuit protection device with other existing circuit-breaker such as ground-fault interrupter or current protector or overcurrent protective device.

Claims

1. fault electric arc protective device; it is characterized in that; comprise direct current transducer (8); direct current transducer (8) output is connected with voltage follower circuit (4) in turn; signal condition amplifying circuit (6); A/D sample circuit (5); the trip assembley therefor (3) of microprocessor (2) and dropout drive circuit (1) and control thereof; wherein; the voltage signal that direct current transducer (8) produces is passed to conditioning amplifying circuit (6) by voltage follower circuit (4) and is converted to the direct current signal that is suitable for the A/D sampling; A/D sample circuit (5) is sampled to this direct current signal, and microprocessor (2) is by detecting the high-frequency characteristic identification fault electric arc in the A/D sampled signal and producing the trip assembley therefor (3) that trip signal is given dropout drive circuit (1) and control thereof.

2. fault electric arc protective device according to claim 1 is characterized in that, described direct current transducer (8) transforms chip U6 by shunt S and differential voltage and forms.

3. fault electric arc protective device according to claim 1 is characterized in that, described direct current transducer (8) is the Hall direct current transducer.