CN105891705A - Detection system of a circuit breaker - Google Patents

Abstract

The invention discloses a detection system of a circuit breaker. The detection system is composed of a DSP chip, a first matching resistor, a second matching resistor, a first conditioning circuit, a second conditioning circuit, an upper computer, a first hall current sensor for detecting a current signal on an opening coil of the circuit breaker, and a second hall current sensor for detecting a current signal on a closing coil of the circuit breaker. The output terminal of the first hall current sensor is connected with one end of the first matching resistor and the input terminal of the first conditioning circuit; the output terminal of the second hall current sensor is connected with one end of the second matching resistor and the input terminal of the second conditioning circuit; the other end of the first matching resistor and the other end of the second matching resistor are grounded; and the output terminal of the first conditioning circuit and the output terminal of the second conditioning circuit are connected with the input terminal of the DSP chip. And the DSP chip is connected with the upper computer. With the detection system, a fault or a defect of a circuit breaker can be detected effectively.

Description

A kind of chopper detecting system

Technical field

The invention belongs to electronic device field of fault detection, relate to a kind of chopper detecting system.

Background technology

Primary cut-out is a kind of important electrical equipment in power system, and it is as cut-offfing and arc extinguishing Device, it bear in power system control and protection dual role, be power plant and power transformation Stand requisite equipment in power distribution equipment.Along with operation of power networks automaticity and reliability requirement Raising, the research to its fault diagnosis technology has great importance.Chopper performance reliable Property is directly connected to the reliability service of power system, and the reliability of chopper takes to a great extent Certainly in the reliability of its machinery actuating system.Therefore the mechanical breakdown to chopper carries out diagnosing right and wrong The most important, also it is to ensure that the important measures of safe operation of power system.The mechanical breakdown of chopper Diagnosis can be completed by the multiple mechanical parameter of monitoring breaker.

Present stage, chopper defect or the fault of 60%-70% cause by breaker mechanism defect, Including: mechanism's bite, oils and fats solidification, spring is aging, Slow-disconnecting and slow-connecting, link transmission axle fracture, Mechanism's tripping etc..But the state inspection of conventional circuit breaker, as infrared drawn game is put (containing superelevation Frequently, ultrasound wave, transient state ground electric wave) only for electro-contact defect and insulating element (medium) defect Diagnosis, there is no effective state-detection means to breaker mechanism.

Summary of the invention

It is an object of the invention to the shortcoming overcoming above-mentioned prior art, it is provided that a kind of chopper inspection Examining system, circuit breaker failure and defect can effectively be detected by this system.

For reaching above-mentioned purpose, chopper detecting system of the present invention include dsp chip, One build-out resistor, the second build-out resistor, the first modulate circuit, the second modulate circuit, host computer, For detecting the first Hall current sensor of the current signal on breaker open operation coil, Yi Jiyong Second Hall current sensor of the current signal on detection breaker closing coil；

Electricity is nursed one's health in the outfan of the first Hall current sensor and one end of the first build-out resistor and first The input on road is connected, the outfan of the second Hall current sensor and the one of the second build-out resistor The input of end and the second modulate circuit is connected, the other end of the first build-out resistor and the second coupling The equal ground connection of the other end of resistance, the outfan of the first modulate circuit and the outfan of the second modulate circuit All being connected with the input of dsp chip, dsp chip is connected with host computer.

Described first modulate circuit and the second modulate circuit all include the first resistance, the second resistance, Three resistance, diode, the first electric capacity, the second electric capacity and operational amplifier；

One end of first resistance is connected with one end of the positive pole of diode and the second resistance, the second electricity The other end and one end of one end of the 3rd resistance and the first electric capacity of resistance are connected, the 3rd resistance another One end is connected with one end of the second electric capacity and the inverting input of operational amplifier, the second electric capacity Other end ground connection, the outfan of operational amplifier and the in-phase input end of operational amplifier and the first electricity The other end held is connected；

The other end of the first resistance and the outfan of the first Hall current sensor in first modulate circuit Being connected, in the first modulate circuit, the outfan of operational amplifier is connected with the input of dsp chip Connecing, in the second modulate circuit, the other end of the first resistance and the outfan of the second Hall element are connected Connecing, in the second modulate circuit, the outfan of operational amplifier is connected with the input of dsp chip.

First Hall current sensor and the second Hall element are compensation Hall element.

Also include that alarm module, alarm module are connected with the outfan of dsp chip.

The model of described operational amplifier is LM324N.

The method have the advantages that

Chopper detecting system of the present invention in use, by the first Hall current sensor And second current signal that obtains in chopper on closing coil of Hall current sensor and switching winding On current signal, then the current signal of described switching winding and the current signal of closing coil are turned It is changed to voltage signal, enters in dsp chip after described voltage signal is conditioned, and at DSP core Sheet carries out analog digital conversion, and the voltage signal after analog digital conversion is shown in host computer, user It is right to be carried out by the voltage signal after analog digital conversion and the voltage signal collected when normally working Ratio judges that chopper the most normally works, simple in construction, easy to operate.

Accompanying drawing explanation

Fig. 1 is the test philosophy figure of switching winding in the present invention；

Fig. 2 is the first modulate circuit 3 and circuit theory diagrams of the second modulate circuit in the present invention；

Fig. 3 is switching winding loop and the equivalent circuit diagram in closing coil loop；

Fig. 4 is the current characteristics oscillogram of switching winding and closing coil.

Wherein, 1 it is the first Hall current sensor, 2 is the first build-out resistor, 3 is the first conditioning Circuit, 4 be dsp chip, 5 for host computer.

Detailed description of the invention

Below in conjunction with the accompanying drawings the present invention is described in further detail:

With reference to Fig. 1 and Fig. 2, chopper detecting system of the present invention include dsp chip 4, First build-out resistor the 2, second build-out resistor, first modulate circuit the 3, second modulate circuit, upper Machine 5, for detect current signal on breaker open operation coil the first Hall current sensor 1, And for detecting the second Hall current sensor of the current signal on breaker closing coil；The The outfan of one Hall current sensor 1 and one end of the first build-out resistor 2 and the first modulate circuit The input of 3 is connected, the outfan of the second Hall current sensor and the one of the second build-out resistor The input of end and the second modulate circuit is connected, the other end of the first build-out resistor 2 and second The equal ground connection of the other end of distribution resistance, the outfan of the first modulate circuit 3 and the second modulate circuit defeated Going out the end input all with dsp chip 4 to be connected, dsp chip 4 is connected with host computer 5.

Described first modulate circuit 3 and the second modulate circuit all include the first resistance R1, the second resistance R2, the 3rd resistance R3, diode D, the first electric capacity C1, the second electric capacity C2 and operation amplifier Device W；One end of first resistance R1 and the positive pole of diode D and one end phase of the second resistance R2 Connect, the other end of the second resistance R2 and one end of the 3rd resistance R3 and the one of the first electric capacity C1 End is connected, the other end of the 3rd resistance R3 and one end of the second electric capacity C2 and operational amplifier W Inverting input be connected, the other end ground connection of the second electric capacity C2, operational amplifier W's is defeated Go out end to be connected with the in-phase input end of operational amplifier W and the other end of the first electric capacity C1；The The other end of the first resistance R1 and the output of the first Hall current sensor 1 in one modulate circuit 3 End is connected, the outfan of operational amplifier W and dsp chip 4 in the first modulate circuit 3 Input is connected, the other end of the first resistance R1 and the second hall sensing in the second modulate circuit The outfan of device is connected, the outfan of operational amplifier W and DSP core in the second modulate circuit The input of sheet 4 is connected.

It should be noted that the first Hall current sensor 1 and the second Hall element are compensation Formula Hall element.Present invention additionally comprises the output of alarm module, alarm module and dsp chip 4 End is connected；The model of operational amplifier W is LM324N.

The operation principle of the present invention is:

Electric magnet is one of important original paper of breaker operation mechanism, when in coil by electric current, Producing magnetic flux in electric magnet, iron core, by electromagnetic force adhesive, makes breaker open operation or combined floodgate, Therefore chopper all produces switching winding current waveform and closing coil current waveform, the separating brake of correspondence Coil current waveform and closing coil current waveform reflect electric magnet itself and the lock bolt controlled Or valve and chain contact working condition in operation, wherein sub-gate circuit and closing a floodgate back The solenoid circuit equivalent circuit diagram on road is as shown in Figure 3.

Its differential equation is represented by

$U=Ri\left(t\right)+\frac{d\mathrm{\ψ}}{dt}---\left(1\right)$

Wherein, ψ is magnetic linkage, it is assumed that electric magnet is unsaturated, then magnetic linkage ψ=Li, inductance L is not Change with i, but inductance L changes with the air gap delta of electric magnet and changes, i.e.

$U=Ri+\frac{d\left(Li\right)}{dt}=Ri+L\frac{di}{dt}+i\frac{dL}{dt}=Ri+L\frac{di}{dt}+i\frac{dL}{d\mathrm{\δ}}\·\frac{d\mathrm{\δ}}{dt}=Ri+L\frac{di}{dt}+i\frac{dL}{d\mathrm{\δ}}\·\mathrm{\υ}---\left(2\right)$

When solenoid is just switched on power supply, owing to coil has certain inductance, electric current can not reach at once To stabling current, but being progressively gradually increased by 0, meanwhile, captivation unshakable in one's determination is the most gradually Increasing, the captivation at electric magnet is not enough so that during action unshakable in one's determination, δ=δ max is constant, i.e. ferrum The movement velocity of the heart is v=0, then formula (2) becomes:

$U=Ri+L_1\frac{di}{dt}---\left(3\right)$

Wherein, L₁During for δ=δ max, the inductance of electromagnet coil, the general solution of the differential equation is:

$i={\mathrm{Ce}}^{-\frac{R}{t_1}t}+\frac{U}{R}---\left(4\right)$

Wherein, C is general solution constant, the initial condition of t=0 and i=0 obtain of the differential equation Particular solution is

$i=\frac{U}{R}(1-e^{-\frac{R}{t_1}t})---\left(5\right)$

Therefore, before iron core moves, coil current i exponentially rises, at time t₁Electric current increases Big to action current I_d, the suction of electric magnet exceedes counteracting force, setting in motion unshakable in one's determination, v > 0；Deng Value loop increases a counter electromotive force increased overGenerally, coil current I is than electric current I during firm setting in motion unshakable in one's determination_dNumerical value little, therefore, on electric current i deviation index Rising curve, constantly decline, this process is until adhesive unshakable in one's determination, and stop motion unshakable in one's determination, v=0, by formula (2), the differential equation of electric current becomes:

$U=Ri+L_2\frac{di}{dt}---\left(6\right)$

Wherein L₂During for δ=δ min, the inductance of electromagnet coil, therefore electric current stops with iron core T=t₂Time electric current I₂For initial value, exponentially rise, finally reach stationary valueOn Stating change procedure can be with the typical divide-shut brake coil current characteristic waveforms explanation in Fig. 4, this waveform 5 stages can be divided into according to motion unshakable in one's determination:

L) stage t=t₀-t₁, coil is at t₀Moment is energized to t₁Moment iron core setting in motion；

2) stage t=t₁-t₂, motion unshakable in one's determination, electric current declines, t₂For controlling the valley point of electric current, generation The load of table actuating procedure unshakable in one's determination machinery thus noticeable deceleration or stop motion；

3) stage t=t₂-t₃, stop motion unshakable in one's determination, electric current the most exponentially rises；

4) stage t=t₃-t₄, this stage is the continuity in stage 3, and electric current reaches the stable state of approximation；

5) stage t=t₄-t₅, electric current cut-offs the stage, and auxiliary switch K disjunction is at auxiliary switch contact Between produce electric arc being elongated, arc voltage quickly raises and forces electric current to decrease up to rapidly extinguishing.

Wherein, t₀-t₁Relevant with control power supply and coil resistance；t₁-t₂Change characterize electric magnet ferrum Heart travelling mechanism is with or without bite, dropout and mechanical load change conditions；t₂-t₃Can reflect that operation passes The situation of dynamic system motion；The most diagnosable chopper of analysis by above several different characteristic times Some mechanical fault trend, including refusing point, refusing the faults such as conjunction.

The DC simulation signal of breaker open operation coil and closing coil is that I1 becomes through Hall element Transformation becomes the current signal I2, I2 of 0～6mA to be converted into dsp chip 4 through build-out resistor The voltage signal U that can accept₀。U₀Dsp chip 4 simulation input is passed to after modulate circuit Passage, is carried out analog digital conversion by the A/D converter within dsp chip 4, then at host computer 5 On show.

Being current-limiting resistance with reference to Fig. 2, R1, the electric current preventing sensor output is excessive and damages electricity Source unit.First electric capacity C1, the second electric capacity C2, the second resistance R2, the 3rd resistance R3 and fortune Calculate amplifier W and constitute second order active low-pass filter circuit together, as the second resistance R2=4.7k Ω, 3rd resistance R3=5.1k Ω, the first electric capacity C1=22nF, the second electric capacity C2=47nF, filter The cut-off frequency of wave circuitThe present invention is to switching winding and combined floodgate Coil current during coil charged moment carries out high-speed data acquisition, through dsp chip 4 with upper Serial data communication between machine 5, is depicted switching winding current curve and combined floodgate by host computer 5 Coil current curve.

Claims (5)

1. a chopper detecting system, it is characterised in that include dsp chip (4), first Distribution resistance (2), the second build-out resistor, the first modulate circuit (3), the second modulate circuit, host computer (5), for detect current signal on breaker open operation coil the first Hall current sensor (1), And for detecting the second Hall current sensor of the current signal on breaker closing coil；

The outfan of the first Hall current sensor (1) and one end of the first build-out resistor (2) and The input of one modulate circuit (3) is connected, the outfan of the second Hall current sensor and second One end of build-out resistor and the input of the second modulate circuit are connected, the first build-out resistor (2) The equal ground connection of the other end of the other end and the second build-out resistor, the outfan of the first modulate circuit (3) and The outfan of the second modulate circuit all inputs with dsp chip (4) are connected, dsp chip (4) It is connected with host computer (5).

Chopper detecting system the most according to claim 1, it is characterised in that described first Modulate circuit (3) and the second modulate circuit all include the first resistance (R1), the second resistance (R2), 3rd resistance (R3), diode (D), the first electric capacity (C1), the second electric capacity (C2) and computing Amplifier (W)；

One end of first resistance (R1) and the positive pole and the one of the second resistance (R2) of diode (D) End is connected, the other end of the second resistance (R2) and one end of the 3rd resistance (R3) and the first electricity The one end holding (C1) is connected, the other end of the 3rd resistance (R3) and the second electric capacity (C2) The inverting input of one end and operational amplifier (W) is connected, the other end of the second electric capacity (C2) Ground connection, the in-phase input end of the outfan of operational amplifier (W) and operational amplifier (W) and the The other end of one electric capacity (C1) is connected；

In first modulate circuit (3), the other end and first Hall current of the first resistance (R1) sense The outfan of device (1) is connected, the output of operational amplifier (W) in the first modulate circuit (3) End is connected with the input of dsp chip (4), the first resistance (R1) in the second modulate circuit The outfan of the other end and the second Hall element is connected, operational amplifier in the second modulate circuit (W) outfan is connected with the input of dsp chip (4).

Chopper detecting system the most according to claim 1, it is characterised in that the first Hall Current sensor (1) and the second Hall element are compensation Hall element.

Chopper detecting system the most according to claim 1, it is characterised in that also include report Alert module, alarm module is connected with the outfan of dsp chip (4).

Chopper detecting system the most according to claim 1, it is characterised in that described computing The model of amplifier (W) is LM324N.