CN105954624A - Detection device - Google Patents
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- CN105954624A CN105954624A CN201610430657.0A CN201610430657A CN105954624A CN 105954624 A CN105954624 A CN 105954624A CN 201610430657 A CN201610430657 A CN 201610430657A CN 105954624 A CN105954624 A CN 105954624A
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- G—PHYSICS
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
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Abstract
The invention mainly relates to a detection device. A first detection module is used for detecting and extracting a first signal having a first frequency range from current information, wherein the first signal is at least used as a calculation basis for generating a compensation current that is injected into a power grid and is equal to a harmonic wave in the first signal and has an opposite phase and is at least used as a basis for determining the electric energy quality of the power grid. A second detection module is used for detecting and extracting a second signal having a second frequency range from current information, wherein the second frequency range is larger than the first frequency range; and the second signal is at least used as a basis for determining the electric energy quality of the power grid. A third detection module is used for detecting and extracting a third signal from the current information in a band-pass filtering mode, wherein the third signal is used for being compared with a preset threshold value or carrying out statistics of frequencies of exceeding the threshold value within preset time to determine whether the third signal belongs to a fault arc.
Description
Technical field
Present invention relates generally to detection equipment, exactly, be to provide a kind of detection with current sensor/transformer
Device, applies on various types of electric energy on-line monitoring equipment, as Active Power Filter-APF APF or static reacance occur
Device SVG or quality of power supply on-line computing model or other electric intelligent instruments etc., this detection equipment is humorous at detecting nonlinear load
Electric arc can also be detected while ripple and the monitoring quality of power supply, ensure the normal operation of power system with this.
Background technology
Along with the fast development of Power Electronic Technique, the electrical equipment of different loads characteristic is had to enter our life on a large scale,
Therewith together, some nonlinear loads such as inverter, commutator and various Switching Power Supply are widely used, by
The harm of power supply grid is also on the rise by this harmonic wave produced.It is filled with in a large number to electrical network during power electronic devices switch motion
Harmonic wave, make the expection standard sine electric current in electrical network and voltage waveform serious distortion.Various to the quality of power supply owing to also existing
A large amount of uses of the domestic electric appliance such as the equipment of rdativery sensitive, such as computer equipment and air-conditioning, refrigerator, TV, to electricity
The requirement of energy quality is more and more higher.All kinds of power failures caused by harmonic wave and Frequent Accidents, either to productive life also
It is that national economic development all creates the biggest negative effect.Harmonic problem includes frequency analysis, harmonic detecting and harmonics restraint
Etc. aspect, effectively suppression harmonic wave have become as and ensure one of requisite measure that power grid security, high-quality run.
In the cleanest electric power system, electric current and voltage are all sinusoidal wave.Containing only lines such as resistance, inductance and electric capacity
Property element ball bearing made in, the electric current flow through is directly proportional to the voltage of applying, and the electric current flow through is sinusoidal wave.Use Fourier
Analysis can resolve into essential part and its multiple non-sinusoidal signal.The basic reason that harmonic wave produces is due to non-thread
Property load caused.When electric current flows through load, present non-linear relation with added voltage, form non-sinusoidal current i.e.
Harmonic wave is had to produce.Switching manipulation and diode, the nonlinear characteristic of semiconductor thyristor, electric power due to semiconductor thyristor
Some equipment such as power converter of system may produce and bigger deviate from sinusoidal waveform.In supply network impedance
Under such non-sinusoidal cuve electric current cause the voltage drop of a non-sinusoidal cuve.Harmonic voltage is produced under supply network impedance
Amplitude equal to corresponding harmonic current with corresponding to the product of supply network impedance Z of this power frequency.There is the ground of harmonic source
Just there is harmonic wave side.It is also feasible that harmonic component arrives user by supply network.Such as in a supply network user producer
The harmonic wave that may be produced by adjacent another subscriber equipment of operating disturb.All of nonlinear load can produce harmonic wave
Electric current, the exemplary apparatus producing harmonic wave has: power supply under switching mode, electronics ballast of fluorescent lamp, speed-regulating actuator and
Uninterrupted power source, magnetive cord equipment and some household electrical appliance such as television set etc..In order to ensure productive life electricity consumption safety and
Being normally carried out, it is essential that the detection of the quality of power supply is analyzed.The quality of power supply includes quality of voltage, current quality, power supply quality
And power quality, including causing the deviation of the voltage of electrical equipment fault or cisco unity malfunction, electric current or frequency, its content
It is embodied in frequency departure, voltage deviation, voltage fluctuation and flicker, three-phase imbalance, temporarily or transient overvoltage, waveform are abnormal
Change, harmonic wave, voltage dip, interruption, temporarily liter and power supply continuity etc..These power quality problems can cause: relay protection
Device is jeopardized the operation of power supply safety by false triggering, various electrical equipment produces added losses and heating and causes device damage
Or burn, increase loss and cause the uneconomic operation of equipment thus cause the most smart of extra electric cost expenditure and ammeter metering outfit
Accurate, reduce the transmission quality of signal and destroy the normal delivery of signal, the resonance that may cause causes the reactive compensation cabinet cannot be just
Often operate, reduce the service life of equipment, cause computer or detection control equipment cannot normally work and even crash.Therefore,
In order to improve the quality of power supply of network system, ensure the properly functioning of electric utility, need the quality of power supply of electrical network is examined
Survey, the higher hamonic wave that especially harm on electrical network is bigger, so high performance current detecting is to controlling the quality of power supply and maintenance
Stablizing of power system is extremely important.
The conventional current sensors detecting power network current in prior art cannot detect higher hamonic wave accurately, and it is right especially to lack
The detection of transient current, transient current is usually the μ other curent change of s Microsecond grade, and commonly referred to transient current is the most negative
The phenomenons such as lotus switching action (i.e. switching device is used for realizing putting into/connecting and excise/turn off) or thunderbolt are likely to induce this
Kind of transient current phenomenon, current current sensor basically can not detect transient current, and current current sensor
When harmonic wave is serious, its error in dipping is bigger, it is impossible to high performance detection power quality parameter.
In order to improve reliability and the safety of electrical network in this external modern power systems, have been carried out huge effort to keep away
Exempting from the negative electric arc produced in network system, electric arc is a kind of not have rule and the high frequency variation phenomenon of instability, but existing
There is technology that effective monitoring of electric arc is still not carried out gratifying solution.Produce sufficiently high between two electrodes
Pressure reduction time, electric arc it may happen that, this voltage causes the gas ionization between electrode, and plasma can gradually form, and
And electric current can flow in-between the electrodes, such plasma may be heated to thousand of degrees Celsius, can cause device damage
Or catch fire.Electric arc potential in power system has a two types: parallel electric arc or serial electric arc.The parallel general electric power of electric arc
Occur between positive pole and negative pole in system, or occur between some electrode and earth terminal GND wherein.Relatively
, serial electric arc does not occurs between two circuits, but occur in the circuit of a current lead-through, in other words,
Serial arc phenomenon is likely to occur between two different piece/fragments of same circuit, serial electric arc electricity in the line
It is the most obvious that stream occurs when being interrupted (in the case of such as having connected contact switch or having destroyed plug/cable).In order to subtract
The negative effect of few electric arc, it is necessary to perform corresponding countermeasure such as breaking arc source as soon as possible, therefore electric arc is by reliably and reality
Time ground confirmation be the most important monitoring item.Another defect of existing current sensor cannot detect electrical network
Arc signal, this problem treats harshly solution.
Summary of the invention
Provide a kind of detection device in the present invention, there is the current sensor of current information in detection electrical network, including first
Detection module, for detect from current information and extraction have first frequency scope (be such as generally in tens HZ to
In the band limits of tens KHZ) the first signal, it not only includes power frequency component and the most also includes that some harmonic components are believed
Number etc., and exported with the form of differential mode analog quantity, the acting body of this imitated output quantity is present: at least note in electrical network
Enter with the first signal in the middle of harmonic wave is equal in magnitude but the compensation electric current of opposite in phase provides foundation, and at least can be also used for
The information such as power frequency and the harmonic wave of electric current in monitoring electrical network, as one of foundation of the quality of power supply judging electrical network.
Detection device also includes the second detection module, and it may be used for detecting from above-mentioned current information and extraction has the second frequency
The second of rate scope (more much greater than power frequency scope, in the band limits for instance in tens KHZ to MHZ ranks)
Signal, and the form being converted into the magnitude of current exported, limits the frequency range of second frequency more than first frequency scope, its
One of effect of middle this magnitude of current of formation is embodied in: for example, whether there occurs the such high-frequency impulse of similar surge in electrical network
Thering is provided basis for estimation, therefore secondary signal is at least also used as one of foundation of the quality of power supply judging electrical network.
Detection device also includes the 3rd detection module, for detecting and extract the in the way of bandpass filtering from this current information
Three signals, the effect of the 3rd signal is mainly reflected in: screen base for monitoring on electrical network and identify that electric arc source of generation provides
Plinth, especially, as judging that whether there is electric arc in electrical network provides foundation, if in the case of electrical network has electric arc, the
Three signals are also as judging that electric arc is the foundation of normal arc or fault electric arc.Such as, exceed certain at the 3rd signal to preset
Threshold range time, one can consider that and on electrical network, create unexpected fault electric arc, and if the value of the 3rd signal is at threshold
Below value scope, then it is believed that create the conventional electric arc in tolerance on electrical network.
Or, in time period that certain is preset, (the Millisecond duration that such as specifies, second level duration, minute level duration are the least
Time level duration etc.) in judge that the 3rd signal exceedes the total degree of threshold value, if total degree is in admissible scope, electrical network
In there may be the phenomenon that switch contact is bad, it should notify management personnel patrol and examine and investigate, eliminate this bad.If otherwise
Total degree not in admissible scope, then may have occurred unacceptable arc phenomenon, it should notify administrative man in electrical network
Member takes tightened up counter-measure, such as, cut off electrical network or other operation.Therefore detection device can also include one
Processor (MCU) receive the 3rd detection module output result, be used for the 3rd signal and the comparison of threshold value or
Add up the 3rd signal within the default time period, exceed the number of times of threshold value.
Above-mentioned detection device, also includes alarm output module one submodule of processor (it can be), once its monitoring
Exceed default threshold value to the 3rd signal or within the default time period, add up the 3rd signal exceed the number of times of threshold value and do not specifying
Numerical range in time, alarm output module will externally export effective indication signal (such as high low logic level), carry out table
Levy the 3rd signal and belong to fault electric arc, when receive this indication signal prior-warning device (such as it with switching device, relay,
Communication device etc.) will be triggered to when receiving effective indication signal produce warning message, and perform various reply electric arc
Measure, warning message can be the warning of visually (warning light flicker) or acoustically (rapid police whistle sound), it is possible to
To be communication information, the e.g. circuit breaker tripping on notice electrical network turns off the communication information of electrical network.
Above-mentioned detection device, has a differential amplifier circuit in described first detection module, comprising: the first operation amplifier
Device and the second operational amplifier, the normal phase input end of each of which is respectively coupled to the pair of output of this current sensor to pick
Taking the first signal, connecting between their inverting input has the first resistance.
And connection has the second resistance between the inverting input and outfan of the first operational amplifier, and put in the second computing
Connect between inverting input and the outfan of big device and have the second resistance, thereby at the outfan and second of the first operational amplifier
Differential amplification signal is formed between the outfan of operational amplifier.First signal for example, at least includes power frequency component and harmonic wave letter
Number, differential amplifier circuit provides imitated output quantity and non-binary digital output, and the output being because it is provided to
Various current collecting devices or instrument, the most common electric instrument, quality of power supply on-line monitoring instrument, active power filtering
Device APF, reacance generator SVG etc., it is contemplated that the communication speed of the corresponding binary code element of transmission speed of analog quantity
Faster, Active Power Filter-APF can obtain and process analog quantity to produce compensation electric current to degree in time so that is formed and compensates electric current
Opportunity relative to producing any more significantly time delay the opportunity gathering harmonic source hardly.
This differential amplifier circuit also includes one or more groups preset resistance R26 being serially connected and switching device S26, each
Preset resistance R26 of group series connection and switching device S26 are both connected to inverting input and second fortune of the first operational amplifier
Calculate between the inverting input of amplifier (being also connected between node N1 and N2)；When differential amplifier circuit is set to increase
When adding the mode of operation of amplification, one or more switching device S26 are in an ON state so that this is pre-by one or more
If resistance R26 and the first resistance R25 gives parallel connection (resistance total in parallel between node N1 and N2 reduces)；Or work as institute
When stating the mode of operation that differential amplifier circuit is set to reduction amplification, one or more switching device S26 are in disconnection shape
State with preset resistance R26 that one or more and the first resistance R25 is in parallel from described differential amplifier circuit floating, lead
The resistance total in parallel caused between node N1 and N2 increases.
Above-mentioned detection device, also has an integrating circuit in the second detection module, integrating circuit includes that the 3rd computing is put
Big device, its positive and inverting input are respectively coupled to the pair of output of this current sensor to capture secondary signal, mat
An active integrator is formed by the 3rd operational amplifier.Notice that secondary signal e.g. frequency range is generally about tens
The current pulse signal of the transient changing of KHZ to MHZ megahertz of rank.
Above-mentioned detection device, described second detection module also includes voltage current adapter, and it is used for receiving described integrating circuit
Output voltage and convert this voltage to the magnitude of current and exported.Here secondary signal is converted into electric current by the second detection module
Amount mainly considers that the size of transmission line is the longest, in order to avoid the interference on extraneous circuit, advocates integrating circuit
Output voltage transmit in the form of electric current, follow-up can flow to the similar such equipment of power quality analyzer, make defeated
The current signal gone out and current sensor (such as Luo-coil) are supplied to the time integral value of the high-frequency input signal of integrating circuit
Being approximated to proportional relationship, power quality analyzer correspondence then can provide a current-to-voltage convertor to reduce this electric current
Measure into voltage signal, such as use a resistance to flow through this resistance to reduce secondary signal by current signal.
Above-mentioned detection device, described 3rd detection module has a band filter, and it includes that being respectively coupled to this electric current passes
First input node N of the pair of output of sensor4_1With the second input node N4_2: the first input node N4_1Logical with band
A the 3rd resistance R41 and one first it is in series with between the inverting input of a four-operational amplifier in wave filter
Electric capacity C41, the 3rd resistance R41 and the first electric capacity C41 the first interconnecting nodes N between the two4_3Place and the 4th operation amplifier
Connect between the outfan of device and have the second electric capacity C42, and the inverting input of four-operational amplifier and outfan connection have
4th resistance R43；And the first interconnecting nodes N4_3With the second input node N4_2Namely the positive of four-operational amplifier
It is connected with resistance R42 between input, notes the second input node N4_2It is directly coupled to the positive input of four-operational amplifier
End.It addition, the particular location of the 3rd resistance R41 and the first electric capacity C41 is: the 3rd resistance R41 is connected to first
Input node N4_1With the first interconnecting nodes N4_3Between, the first electric capacity C41 is connected to the first interconnecting nodes N4_3With the 4th
Between the inverting input of operational amplifier.
This band filter also includes one or more groups preset resistance R44 being serially connected and switching device S44, each group
Preset resistance R44 of series connection and switching device S44 be both connected to the inverting input of four-operational amplifier and outfan it
Between；When described band filter is set to increase center angular frequency ωOMode of operation time, one or more switching device S44
In an ON state so that these preset resistance R44 one or more and the 4th resistance R43 are given parallel connection (the 4th operation amplifier
In parallel total resistance between inverting input and the outfan of device reduces)；Or when described band filter is set to reduction center
Angular frequencyOMode of operation time, one or more switching device S44 are off with by one or more and the 4th
Preset resistance R44 in parallel for the resistance R43 (inverting input of four-operational amplifier and defeated floating from band filter
The in parallel total resistance gone out between end increases).In view of bandwidth BW=ωO/ Q, if quality factor Q is set to predetermined value, then
Center angular frequency ωORegulation mean that bandwidth BW also correspondence is conditioned.If or bandwidth BW is set to conversely speaking,
Predetermined value, then center angular frequency ωORegulation mean that quality factor Q also correspondence is conditioned.
Above-mentioned detection device, as option, also in the first input node N4_1With the second input node N4_2Between connect
There is over-voltage protection element, once when the first input node N4_1With the second input node N4_2Between voltage exceed protection rule
During lattice value, the over-voltage protection element connection that is just triggered carrys out voltage stabilizing, it is achieved the suppression of surge.Over-voltage protection element e.g. transient state
In the middle of voltage suppressor, varistor, discharge tube etc. one, it is also possible to be that in the middle of them, the combination of any two even will
They are applied in combination the most simultaneously, and as a example by Transient Voltage Suppressor (TVS) D41, its anode cathode direction is at joint
Point N4_1And N4_2It is arbitrary between although, but in a preferred embodiment, its anode links the second input joint
Point N4_2And negative electrode links the first input node N4_1。
Above-mentioned detection device, the first signal represents industrial frequency harmonic component, and secondary signal represents more higher wink than industrial frequency harmonic frequency
The electric current of state change, the 3rd signal represents arc signal.
Above-mentioned detection device, described current sensor is Roche hollow coil current-sensing device.
In another embodiment, present invention also offers and detect matched with devices use harmonics restraint system, including and inspection
Survey the Active Power Filter-APF APF that matched with devices uses, for producing and some harmonic waves phase place equal in magnitude in the first signal
Contrary compensation electric current injects electrical network.
Above-mentioned harmonics restraint system, this Active Power Filter-APF includes: one by the differential mode analog quantity that received (by first
Detection module is converted into this differential mode analog quantity according to the first signal) transfer the 5th operational amplifier of single-ended voltage signal to；With
And an isolation coupling module performing one-way transmission signal, (this voltage signal is by the 5th to be used for receiving this single-ended voltage signal
Operational amplifier provides), and export and follow the change of this single-ended voltage signal and the linear current I of linear changeFOLLOW；Separately
Outer also have the 6th operational amplifier, its positive input end grounding and connect at its inverting input and outlet chamber and have resistance
R54, the 6th operational amplifier is for by this linear current IFOLLOWBe converted into it outfan with this single-ended voltage signal
Linear voltage signal VOUT_F.In some optional embodiments, Active Power Filter-APF APF can be to electricity
Pressure signal VOUT_FSampling and execution ADC analog digital conversion, supporting use on-site programmable gate array FPGA or numeral
The components and parts such as signal processing DSP/instrument calculates the size of current value needing to compensate according to the data of sampling.
In another embodiment, present invention also offers and detect the power quality analyzer that matched with devices uses, it includes
One current-to-voltage convertor, secondary signal is converted into the form of the magnitude of current and is exported by the second detection module, and electric energy matter
This magnitude of current is then reduced into the voltage characterizing secondary signal by the current-to-voltage convertor of component analysis instrument.I/V transducer exists
The magnitude of current is reduced into after characterizing the voltage of secondary signal, when we need the quality of power supply analyzing electrical network, this electricity
Pressure amount provides judging basis.In addition, power quality analyzer can also utilize the first signal to analyze the electric energy of electrical network
Quality, the first signal is at least that the power frequency weighing electric current provides basis for estimation with harmonic quality, and secondary signal is the most at least
It is to provide basis for estimation for measurement transient current (Transient current).This is external judge in the quality of power supply all right
The arc information of electrical network is recorded with the output of the 3rd detection module.Weigh the master of the quality of power supply (Power Quality)
Want index such as to have voltage, frequency and waveform, generally believe it should include quality of voltage, current quality, power supply quality and
Power quality.The problem of the quality of power supply can be defined as: causes electrical equipment fault or the voltage of cisco unity malfunction, electric current
Or the abnormal variation of frequency, its content includes frequency departure, voltage deviation, voltage fluctuation and flicker, three-phase imbalance, wink
Time or transient overvoltage or wave distortion/harmonic wave, voltage dip, interruption, rise and power supply continuity etc. temporarily.
In another embodiment, present invention also offers a kind of electric arc detecting device, utilize Luo-coil sensor detection electricity
Current information in net, and also include that a wave filter, should to detect and to extract a preset signals from this current information
For comparing with default threshold value, preset signals thereby judges whether it belongs to fault electric arc.Wherein this wave filter has point
It is not coupled to first input node N of one group of outfan DSA and DSB of Luo-coil (Rogowski)4_1With second
Input node N4_2；First input node N4_1And go here and there between the inverting input of an operational amplifier A 4 in wave filter
It is associated with an a resistance R41 and electric capacity C41, the interconnecting nodes N between resistance R41 and electric capacity C414_3With this computing
Connect between the outfan of amplifier A4 and have another electric capacity C42, and the inverting input of this operational amplifier A 4 and output
End connection has another resistance R43；And this interconnecting nodes N4_3With the second input node N4_2Namely operational amplifier is just
Other a resistance R42 also it is connected with between phase input.Thus finally in the outfan generation sign of this operational amplifier A 4
The voltage signal V of this preset signalsOUT_AS。
Above-mentioned electric arc detecting device, also includes one or more groups preset resistance R44 being serially connected and switch S44, often
Preset resistance R44 of one group of series connection and switch S44 are both connected to inverting input and the outfan of this operational amplifier A 4
Between, wherein it is set to increase center angular frequency ω when this wave filterOThe first mode of operation time, one or more switch S44
In an ON state these preset resistance R44 one or more to be connected in parallel on inverting input and the outfan of operational amplifier
Between (they and R43 in parallel)；Or when wave filter is set to reduce center angular frequency ωOThe second mode of operation time, one
Individual or multiple switching device S44 be off with by one or more preset resistance R44 from this operational amplifier A 4
Inverting input and outfan between floating (they disconnect and the parallel relationship of R43).
Accompanying drawing explanation
Reading described further below and with reference to after the following drawings, inventive feature and advantage will be apparent to:
Fig. 1 is the schematic diagram of the exemplary applications of a quality of power supply on-line monitoring of the detection device of the present invention.
Fig. 2 is the basic module configuration diagram of the detection device with sensor.
Fig. 3 is the structural representation of differential amplifier circuit.
Fig. 4 is the circuit structure that differential signal is reduced in Active Power Filter-APF single-ended signal.
Fig. 5 is the structure of integrating circuit and voltage current adapter.
Fig. 6 is the schematic diagram of arc-detection module.
Fig. 7 is the adjustable schematic diagram of amplification of differential amplifier circuit.
Fig. 8 is the adjustable schematic diagram of center angular frequency of band filter.
Detailed description of the invention
See Fig. 1, Active Power Filter-APF APF and mainly include two large divisions: instruction current computing module and compensation are electric
There is circuit in stream, wherein compensate current occuring circuit be subdivided at least including current follow-up control module and drive circuit and
Main circuit 105.Active Power Filter-APF can be generally divided into single-phase and three-phase two kinds, and three-phase system is divided into again three-phase three-wire system
And three-phase four-wire system, the application hereinafter temporarily illustrates present invention spirit using phase three-wire three as example.
See Fig. 1, illustrate three-phase ac power supply ESAAnd ESBAnd ESC, by electrical network transmission power supply to load 110
And load 110 usually nonlinear loads are also harmonic source and target compensation.Main circuit 105 breaker in middle group S1～S2 and open
Pass group S3～S4 and switches set S5～these three groups switches of S6 are parallel with one another, any one single switches set S1～S2 in addition
Or S3～S4 or the most respectively with one DC voltage U of S5～S6DCIn parallel.Switching tube can be IGBT or MOSFET
Or BJT or GTO IGCT etc..Junction point A between two switch S1～S2 of first group and offer power supply ESA
A phase grid branch between connect and have an inductance L, injecting to the compensation electric current of this electrical network is ICA.Switch S3～S4 of second group
Between junction point B and provide ESBA phase grid branch between connect and have an inductance L, inject to the compensation electric current of this electrical network
It is ICB.And two junction point C switched between S5～S6 and offer E of the 3rd groupSCA phase grid branch between
Connecting and have inductance L, injecting to the compensation electric current of this electrical network is ICC.It should be noted that the main circuit 105 in the application
In, the factor such as the component type/quantity of switch S1～S6/concrete annexation is as just explaination/illustrate books application
One example of spirit, any main circuit/switching tube topology that can realize identical function is all applicable to the present invention and permissible
Replace it, so this is not intended that the main circuit of the present invention shall be limited only to this specific topological classification.
See Fig. 1, compensate electric current substantially by DC capacitor voltage UDCAct on exchanging the supply voltage difference surveyed
Produced by the inductance L that exchange is surveyed, DC capacitor voltage UDCCan be DC source can also be that storage capacitor carries
The DC voltage of confession, is to use as inverter when main circuit 105 produces compensation electric current, if to the electric capacity etc. of DC side
Then as commutator during energy-storage travelling wave tube charging.The operation of main circuit 105 is switches set S1～S2 or S3～S4 or S5～S6
Turn on and off decision, the most each switches set (S1～S2 or S3～S4 or S5～S6) always has one
Switch is in conducting state, and another switch is then in off state simultaneously.
See Fig. 1, assume that three phase mains sum meets E in advanceSA+ESB+ESC=0, according to Circuit theory, compensation is given
Three phase network bus respective compensation electric current sum meets ICA+ICB+ICC=0, it is assumed that Ka and Kb and Kc is according to opening
Off status switching coefficient set in advance, under the preferable and situation of rough calculation, mutually in compensate the micro-of electric current and time t
Divide and between equation and alternating current power supply, there is also following functional relationship:
For convenience of discussion, hereinafter we temporarily take phase grid branch E thereinSAAs object of study, more than other
Under a few phase grid branch ESB～ESCOperation principles the most substantially similar.See Fig. 1, the groundwork of Active Power Filter-APF
Mechanism is, at load end by Hall current sensor 101 to load current ILDetect, and by load current ILInformation
It is transferred to Active Power Filter-APF.Instruction current computing module detects that the such as harmonic and reactive currents being compensated in object divides
The information such as amount, it is assumed that load current ILHarmonic component I in informationLHBeing detected, instruction current computing module is more thereafter
By harmonic component ILHAs a command signal I* compensating electric current after reversed polarityCA.Current follow-up control module receive from
The command signal I* of instruction current computing moduleCAAfter, produce pulse width modulating signal PWM and be transferred to drive circuit, enter
One step allows the higher drive circuit of driving force to drive each switches set (S1～S2 or S3～S4 in main circuit 105
Or S5～S6) on off state, it is therefore an objective to make main circuit 105 produce real-time accurate tracking command signal I*CACompensation
Electric current ICA.If compensating electric current ICAWith load current ILHarmonic component ILHBut polarity equal in magnitude/in opposite direction, then
Both cancel out each other, and make power supply ESAThe source current I providedSAIn sinusoidal fundamental wave current component containing only intimate standard,
Reach eventually to suppress the purpose of harmonic wave in source current.
Connection node A between first group two switch S1～S2 described above and power supply E is providedSAA phase electrical network
Connecting between branch road and have inductance L, being injected to the compensation electric current of this electrical network by inductance L from node A is ICA, now with master
The A node of circuit 105 is to providing power supply ESAOne phase electrical network produce compensation electric current ICADemonstrate Active Power Filter-APF
Compensation mechanism.In the normal operation stage of Active Power Filter-APF APF, the compensation electric current I of main circuit 105 outputCA
At command signal I*CAFluctuating of value, generally can present zigzag to follow command signal I*CAThe change of value.
Its Chinese style (4) is the deformation of formula (1), it is desirable to compensate electric current ICAAccurate tracking command signal I* in real timeCA, then one
Denier compensates electric current ICAOccur any than compensating electric current ICADeviation time, it should select turn on and off in main circuit 105
Switch S1～S2 reduce this deviation, formula breaker in middle COEFFICIENT K a can take-1/3 or-2/3.Once when compensating electricity
Stream ICALess than command signal I*CA, this demonstrate compensation electric current ICAShould increase to make great efforts near command signal I*CA, now
Formula (4) the equation left side should more than 0, namely mean to switch the upper switching tube S1 in S1～S2 brachium pontis should turn off and
Lower switching tube S2 connects.When compensating electric current ICAMore than command signal I*CA, indicate compensation electric current ICAShould reduce to lean on
Nearly command signal I*CA, this up-to-date style (4) the equation left side should be less than 0, it is meant that the upper switch in switch S1～S2 brachium pontis
Pipe S1 should connect and lower switching tube S2 turns off.Namely realizing below scheme: current follow-up control module receives from finger
Make the command signal I* of current operator moduleCAAfter, the command signal I* that will receiveCAWith the actual compensation electric current I capturedCAEnter
Row compares, and produces pulse-width signal PWM and is transferred to drive circuit, allows the higher drive circuit of driving force to drive master
In circuit 105, the on off state of each switches set (S1～S2 or S3～S4 or S5～S6), makes compensation electric current ICAIn real time
Accurate tracking command signal I*CA。
It is with compensation harmonic component I aboveLHMode explain the operation of whole system.The most hereinafter content is sayed
Forming the electric current that compensates being injected into electrical network with harmonic wave opposite in phase equal in magnitude is i.e. based on compensation mechanism above.
Seeing Fig. 2, air core coil sensor 102 is used for replacing the Hall current sensor 101 of Fig. 1, and this air core coil passes
Sensor 102 is used for detecting load current ILThe various components of information, air core coil 102 does not the most use and is similar to suddenly
Containing the magnetic core of ferrimagnet as your current sensor 101, its coil is wrapped in and plays the soft of physical support effect
Property or rigid backbone on constitute Circular Winding, its skeleton be not magnetic core so air core coil 102 is without hysteresis effect, do not have yet
Phase error and magnetic saturation phenomenon, the bandwidth of response is from 0.1HZ to several MHZ.The reason of air core coil sensor 102
Opinion foundation is Faraday law of electromagnetic induction and Ampere circuit law, the load current I of electrical networkLTubular wire is passed through along axis
During the hub of a spool of coil sensor 102, can produce strain in the volume range that the Circular Winding structure of its coil is surrounded
The magnetic field changed, the induced voltage U produced at the two ends of coil1(t)=M × (di/dt), it and the change of t in time that need to measure
The differential equation of alternating current i be directly proportional, M is the mutual inductance of coil windings.The advantage of air core coil sensor 102
One of be that the voltage that it exports belongs to the category of light current, compare Hall current sensor 101 output forceful electric power, or
Produced electric arc when comparing any one-level APF of unloading, air core coil sensor 102 has more preferably safety effect.When
When air core coil sensor 102 provides load current information for other equipment, Active Power Filter-APF can utilize similar family
The crystal connector being connected with telephone set with telephone wire achieves a butt joint air core coil sensor 102.Hall current sensor cannot be protected
The similar high-frequency harmonic with spike composition of card is accurately detected, and the alternating current detection bandwidth of air core coil sensor
Non-constant width, conventional spike harmonic wave can catch in the way of not loss of accuracy.
Shown in Figure 2, the detection device of the present invention, except the current sensor 102 of current information in detection electrical network, also wraps
Include first detection module 211, for detecting and extract first signal with first frequency scope from current information, and with
The form of differential mode analog quantity is exported, and the acting body of this imitated output quantity is present: for injecting in electrical network and in the first signal
Some harmonic components are equal in magnitude but the compensation electric current of opposite in phase provides foundation.In view of the first signal at least includes that power frequency is believed
Breath and harmonic component information, it also serves as the foundation of the quality of power supply judging electrical network.
Detection device also include the second detection module 311, it for detect from above-mentioned current information and extraction have second frequency
The secondary signal of rate scope, and it is converted into magnitude of current ISETForm exported.Limit second frequency scope and compare first frequency
The frequency of scope wants height, it is understood that: the smallest limit value in this band limits of second frequency scope should be more than first
Maximum upper limit in this band limits of frequency range.Form this magnitude of current ISETActing body present: be used as learn electrical network
The approach of the middle quality of power supply, can be whether to there occurs in electrical network that the such high-frequency impulse of similar surge provides basis for estimation, the
Binary signal at least includes transient current information more higher than work frequency, and it also serves as the foundation judging the quality of power supply.
Detection device also includes the 3rd detection module 411, is used in the way of bandpass filtering (Band-pass) from this electric current
Detecting and extract the 3rd signal in information, the effect of the 3rd signal is mainly reflected in: as judging whether there is electricity in electrical network
Arc provides foundation, if in the case of having electric arc in electrical network, the 3rd signal is also as judging that electric arc is normal arc or event
The foundation of barrier electric arc.Such as, when the sizes values at the 3rd signal exceedes certain threshold range preset, one can consider that
Unexpected fault electric arc is created, if the value of the 3rd signal is below threshold range, then it is believed that at electrical network on electrical network
Do not produce electric arc or the conventional electric arc (non-faulting electric arc) creating in tolerance.Detection device can also possess
One processor 412 (MCU) receives result V of the 3rd detection module 411 outputOUT_AS, because this result VOUT_AS
Characterize the sizes values of the 3rd signal, thus processor can utilize this result complete the 3rd signal and the comparison of threshold value or
It is to add up the 3rd signal within the default time period, exceed the number of times of threshold value.
Seeing Fig. 3, first detection module 211 the most at least includes the differential amplification electricity that can detect current signal
Road 211, based on present invention spirit, the amplification of differential amplifier circuit 211 can utilize amplification to control mould
Block is controlled, and additionally can pass to Active Power Filter-APF in time to avoid in view of the signal detected by air core coil
Cause any unnecessary delay, signal analog quantity that differential amplifier circuit 211 detects (and unconventional 1/0 2 enter
Code element digital quantity processed) flow to Active Power Filter-APF, in order to achieve a butt joint with differential amplifier circuit 211, active electric power
Wave filter realizes the reception of differential analog signal to one the 5th operational amplifier A 5 of application.
Seeing Fig. 3, amplifying circuit 211 includes the first operational amplifier A 1 and the second operational amplifier A 2, wherein Roche
Two ends DSA, DSB correspondence of air core coil is respectively coupled to the normal phase input end V of the first operational amplifierIN1With the second fortune
Calculate the normal phase input end V of amplifier A2IN2.The DSA end of Fig. 3 coil and normal phase input end VIN1Between connect have electricity
Resistance R21, and the DSB end of coil and normal phase input end VIN2Between connect have resistance R22, the most also in the first computing
The normal phase input end V of amplifier A1IN1Normal phase input end V with the second operational amplifier A 2IN2Between connect have an electricity
Holding C21, when the signal frequency of input is relatively low, the capacitive reactance of electric capacity C21 makes the most greatly the input impedance of differential amplifier circuit very
High.See Fig. 3, in the inverting input (node N1) of the first operational amplifier A 1 and the second operational amplifier A 2
Connect between inverting input (node N2) and have the first resistance R25, and anti-phase defeated in the first operational amplifier A 1
Enter end and its outfan VOUT1Between connect have the second resistance R23, and the anti-phase input in the second operational amplifier A 2
End and its outfan VOUT2Between connect have the second resistance R24, the resistance value size of resistance R23 and R24 can phase
With, but the resistance of they and R25 can be the same or different.
See Fig. 3, under the most rough calculated case, outfan VOUT1～VOUT2Between differential voltage VOUT2-VOUT1
Generally more equal to (VIN2-VIN1) × (1+2 × R23/R25), wherein VIN2-VIN1Equal to Roche air core coil two
Faradism pressure reduction between end DSA and DSB two ends, thus we can be implemented in the first operational amplifier A 1 and second
Operational amplifier A 2 respective outfan VOUT1～VOUT2Between, capture air core coil two ends DSA～DSB easily
The differential amplification signal of the induced voltage sensed.Fig. 7 is the improvement structure of difference channel in Fig. 3.
See Fig. 7, it is known that the inverting input of node N1 and the first operational amplifier A 1 is connected, node N2 and second
The inverting input of operational amplifier A 2 is connected, and the first resistance R25 is connected between node N1 and N2.Can learn
Differential amplifier circuit 211 also includes one or more groups resistance R26 being serially connected and switching device S26, and each group
It is respective anti-phase defeated that the resistance R26 and switching device S26 of series connection is both connected to the first and second operational amplifier A 1～A2
Enter between end (i.e. between node N1～N2), it is therefore intended that, it is intended that entire gain or the title of amplifying circuit 211 are put
Big multiple is adjustable.Between node N1～N2 in addition to the first resistance R25 originally existed, when each group is mutually gone here and there
The resistance R26 of connection is when connecting with the S26 in switching device S26, just allows the resistance R26 in this group and the first resistance R25
It is connected in parallel between node N1～N2.So the resistance R26 of effective status introduced between node N1～N2 (S26 connects
Logical) the most, the in parallel total resistance between node N1～N2 is the least, and vice versa, casts out between node N1～N2
Resistance R26 (S26 disconnection) the most, the resistance in parallel total between node N1～N2 is the biggest.Switch S26 connects
The low and high level that logical or shutoff can be exported by the processor 412 in Fig. 7 drives switch S26 to switch over.When needs increase
When adding the amplification of differential amplifier circuit 211, connect one or more switching device S26 to realize one or more
This resistance R26 and the first resistance R25 gives parallel connection.Or when needing the amplification reducing amplifying circuit 211, disconnect
One or more switching device S26 are to realize resistance R26 in parallel to one or more scripts and the first resistance R25 from putting
In big circuit floating (floating), floating resistance R26 is high-impedance state.
See Fig. 4, active filter APF has a differential mode analog quantity exported by first detection module 211 and transfers to
5th operational amplifier A 5 of single-ended voltage signal, two amplifier each outfans in the differential amplifier circuit 211 in Fig. 3
Between output differential amplification signal (VOUT2-VOUT1) be coupled to the 5th operational amplifier A 5 normal phase input end and
Inverting input.The outfan V of such as the second operational amplifier A 2 in Fig. 3OUT2It is coupled to the 5th by resistance R52
The normal phase input end V of operational amplifier A 5INB, the outfan V of the first operational amplifier A 1 in Fig. 3OUT1By electricity
Resistance R51 is coupled to the inverting input V of the 5th operational amplifier A 5INA, and anti-phase defeated in the 5th operational amplifier A 5
Enter to connect between end and outfan and have feedback resistance R53, be equivalent to the 5th operational amplifier A 5 and be configured to an active ratio
Example amplifier.Therefore the 5th operational amplifier A 5 is by this differential amplification signal (VOUT2-VOUT1) transfer self outfan to
One single-ended voltage signal of output.The differential data that 5th operational amplifier A 5 of active filter APF receives is
High Speed Analog amount, the resistance of R31 and R32 can be identical or different, rough calculation differential voltage VOUT2-VOUT1Conversion
The single-ended voltage signal becoming the 5th operational amplifier A 5 approximates (VOUT2-VOUT1)×R33/R31.At other can
Select embodiment, a reference voltage VREF can be loaded into the normal phase input end V of the 5th operational amplifier A 5INB, come
Make difference value VOUT2-VOUT1Slightly upward lifting and be easier to sensed.
See the isolation that Fig. 4, active filter APF also include making front stage circuits and late-class circuit realize electrical isolation
Coupling module 515, as example, isolation coupling module 515 can be with light emitting diode and sensitive device (as photosensitive
Transistor) cooperate to provide output electric current, isolation coupling module 515 completes the signal of telecommunication optical signal signal of telecommunication
Conversion, play the buffer action of input signal and output signal.Due to mutual between the input and output of isolation coupling module 515
Being isolated, signal of telecommunication transmission has unidirectional feature, thus has good electrical isolation capabilities and capacity of resisting disturbance.So
Isolation coupling module 515 can be greatly improved signal to noise ratio as terminal isolation element in transmission information.In the present invention every
Receive the single-ended voltage signal of the 5th operational amplifier A 5 output from coupling module 515, and generate and the 5th operation amplifier
The single-ended voltage signal of device A5 output remains the linear current I of linear relationshipFOLLOW.5th operational amplifier A 5 acts on
At least two, first is the electrical isolation realizing front stage, and second is to form that to followed by the 5th operational amplifier A 5 defeated
The single-ended voltage signal gone out changes and the linear current of linear change.
Seeing Fig. 4, active filter APF and also include the 6th operational amplifier A 6, it is by linear current IFOLLOWConversion
It is reduced into final desired magnitude of voltage.The current output terminal of isolation coupling module 515 output is coupled to and the 6th computing
The node N3 that the inverting input of amplifier A6 is connected, the positive input end grounding of the 6th operational amplifier A 6 and also
Connect at its inverting input and outlet chamber and have resistance R54, although being not expressly shown in figure, resistance R54 can set
It is set to adjustable resistance or direct and its one adjustable resistance of series connection.6th operational amplifier A 6 will be by resistance R54
The linear current I that this node N3 is absorbedFOLLOWIt is converted into the voltage signal V of its outputOUT-F.Owing to defining before
Linear current IFOLLOWLinear relationship, then the 6th computing is kept with the single-ended voltage signal of the 5th operational amplifier A 5 output
The voltage signal V of amplifier A6 outputOUT-FAlso the single-ended voltage signal with the 5th operational amplifier A 5 output keeps linear
Relation.As preference, it is also possible to connect a benefit between inverting input and the outfan of the 6th operational amplifier A 6
Repaying electric capacity C51, it is in parallel with resistance R54, compensates electric capacity C51 and is used for improving circuit stability and reducing circuit output making an uproar
The bandwidth of operation of sound and limiting circuit is within about about 10kHz.
Seeing Fig. 5, in the second detection module 311, it is detected from above-mentioned current information and extraction has second frequency model
The secondary signal enclosed, and it is converted into magnitude of current ISETForm exported, figure not illustrating, power quality analyzer can
With the current-to-voltage convertor that is configured with for by this magnitude of current ISETIt is reduced into the voltage characterizing secondary signal.Such as electricity
Stream electric pressure converter is a resistance, magnitude of current ISETFlow through this resistance and will be reduced into voltage, the electric energy on electrical network
Quality (Power Quality) can emerge from out completely from the voltage waveform that this is reduced.Wherein the second inspection
The integrating circuit 311A surveying module 311 includes the 3rd operational amplifier A 3, its normal phase input end VINDLogical
Cross the one that a resistance R32 is coupled in two-terminal DSA of this air core coil and DSB, its inverting input VINC
It is coupled to the another one in two-terminal DSA of this air core coil and DSB by a resistance R31.Thus the 3rd computing
Amplifier A3 the most also can be put in the 3rd computing from the pair of output of current sensor 102 to capture to secondary signal
Being connected between inverting input and the outfan of big device A3 has electric capacity C31 and connection to have resistance R33, resistance R33 and electricity
Hold C31 in parallel, and the 3rd operational amplifier A 3 is configured one integrator of formation.See Fig. 2 and Fig. 5, the second detection
Module 311 also includes voltage current adapter (V/I converter) 311B, transducer 311B for receiving the 3rd fortune
Calculate the output voltage of amplifier A3, and this voltage that voltage current adapter 311B exports is converted into magnitude of current ISETGive
With output.The current-to-voltage convertor (I/V converter) 611 of power quality analyzer configuration is responsible for voltage x current
The magnitude of current I of transducer 311B outputSETIt is reduced into magnitude of voltage.Power quality analyzer can also be to the magnitude of voltage being reduced into
Sampling and execution ADC analog digital conversion, support the use on-site programmable gate array FPGA or Digital Signal Processing DSP etc.
Components and parts/instrument is according to the size of the data reproduction secondary signal of sampling.
Seeing Fig. 6, the 3rd detection module 411 has a band filter, and it includes being coupled to this current sensor 102
First input node N of a lead-out terminal DSA4_1, also include being coupled to the second of another lead-out terminal DSB
Input node N4_2, the first input node N4_1Anti-phase input with a four-operational amplifier A4 in band filter
A the 3rd resistance R41 and a first electric capacity C41, the 3rd resistance R41 and the first electric capacity C41 it is in series with between end
Both are provided with a first interconnecting nodes N in the position of interconnection4_3, the first interconnecting nodes N4_3With four-operational amplifier A4
Outfan between connect and have the second electric capacity C42, and the inverting input of four-operational amplifier A4 and outfan connect and have
4th resistance R43.Thus four-operational amplifier A4 is configured to band filter.
Note at the first interconnecting nodes N4_3With the second input node N4_2(this second input node N4_2Put with the 4th computing
The normal phase input end of big device A4 is directly coupled together) between be connected with resistance R42, other 3rd resistance R41 and the first electricity
The particular location holding both C41 is: the 3rd resistance R41 is connected to the first input node N4_1With the first interconnecting nodes N4_3
Between, the first electric capacity C41 is connected to the first interconnecting nodes N4_3And between the inverting input of four-operational amplifier A4.
See Fig. 6, as option, also in the first input node N4_1With the second input node N4_2Between connect have class
Like Transient Voltage Suppressor or discharge tube or the such over-voltage protection element of varistor, with Transient Voltage Suppressor D41 it is
Example, its anode cathode direction is at node N4_1With node N4_2It is arbitrary between although, namely anode links first
Input node N4_1Time negative electrode link the second input node N4_2, or anode links the second input node N4_2Negative electrode is linked
First input node N4_1, but in a preferred embodiment, we select the latter.
In order to understand the band filter examination for electric arc intuitively, its several parameters such as center angular frequency ωOWith
Bandwidth BW and quality factor Q should sufficiently be explained.Be merely for convenience of analysis and not to present disclosure
Do any restriction, it is assumed that the capacitance of electric capacity C42 and the electric capacity C41 the most relatively (capacitance of such as C41
It is fluctuate again on the basis of the capacitance of electric capacity C42 the 50% of C42, i.e. C42±C42× 50%), more
Under rough design conditions, the center angular frequency ω of band filterOSubstantially meet following functional relation:
Seeing Fig. 8, band filter also includes one or more groups preset resistance R44 being serially connected and switch S44, often
One group series connection preset resistance R44 and switching device S44 be both connected to four-operational amplifier A4 inverting input and
Between outfan (in parallel with resistance R43 again after they concatenations).When band filter is set to increase center angular frequency ωO's
During mode of operation, one or more switching device S44 in an ON state with by these preset resistance R44 one or more and
4th resistance R43 gives parallel connection (the in parallel total resistance between inverting input and the outfan of four-operational amplifier A4
Reduce).Or when band filter is set to reduce center angular frequency ωOMode of operation time, the most one or more switches
Device S44 is off with preset resistance R44 that one or more and the 4th resistance R43 is in parallel from bandpass filtering
In device floating (resistance in parallel total between inverting input and the outfan of four-operational amplifier A4 increases).Switch S44
Turn on and off the low and high level that can be exported by the processor 412 in Fig. 8 drive switch S44 switch over.Consider
To bandwidth BW=ωO/ Q, if quality factor Q is set to predetermined value, then center angular frequency ωORegulation mean bandwidth BW
Also correspondence is conditioned.If or bandwidth BW is set to predetermined value conversely speaking, then center angular frequency ωORegulation meaning
Quality factor Q also correspondence to be conditioned.It addition, another critically important parameter of wave filter is bandpass center center angular frequency
Rate ωOVoltage amplification factor A at placeUO=-R43/ (2R41).If the inverting input of four-operational amplifier A4 and
Be parallel with R44 between outfan, then resistance R43 in above formula should be by the anti-phase input of four-operational amplifier A4
In parallel total resistance between end and outfan is replaced.
6th operational amplifier A 6 produce output result V in band filterOUT_AS, detect the process that device possesses
Device 412 is also used for receiving this result V of the 3rd detection module 411 outputOUT_AS, because result VOUT_ASCharacterize and detect
The sizes values of the 3rd signal measured, thus processor 412 can utilize this characterize the output result of the 3rd signal and
Threshold value compares, or statistics the 3rd signal exceedes the number of times of threshold value within the default time period.Such as, at the 3rd signal
When exceeding certain threshold range preset, one can consider that and on electrical network, create unexpected fault electric arc, if the and the 3rd
The value of signal is below threshold range, then it is believed that create the conventional electric arc in tolerance on electrical network.Such that it is able to
We utilize the 3rd signal as judging that whether there is electric arc in electrical network provides foundation.If it addition, having electric arc in electrical network
In the case of, the 3rd signal is also as judging that electric arc is the foundation of normal arc or fault electric arc.If it is said that in general,
Three signals allow bias to be then defined as normal arc, otherwise relative to ginseng relative to the bias of reference spectrum less than threshold value
The bias examining frequency spectrum allows bias to be then defined as improper fault electric arc more than threshold value.In order to avoid or reduce electric arc
Negative effect, it should start the countermeasure in breaking arc source as soon as possible, the arc-detection mechanism that therefore present invention provides is permissible
Determining electric arc the soonest and reliably, maintenance or supervision staff for power system are provided convenience.
Above, by explanation and accompanying drawing, giving the exemplary embodiments of the ad hoc structure of detailed description of the invention, foregoing invention carries
Go out existing preferred embodiment, but these contents have been not intended as limitation.For a person skilled in the art, in reading
State bright after, various changes and modifications will be apparent to undoubtedly.Therefore, appending claims should be regarded as and contains this
Bright true intention and whole variations and modifications of scope.In Claims scope, the scope of any and all equivalence is with interior
Hold, be all considered as still belonging to the intent and scope of the invention.
Claims (17)
1. a detection device, it is characterised in that there is the current sensor of current information in detection electrical network, also include:
First detection module, for detecting and extract first signal with first frequency scope from this current information, first
Signal is at least used as forming the calculating compensating electric current being injected into electrical network with its central harmonic wave opposite in phase equal in magnitude and depends on
According to, and the first signal at least also serves as the foundation of the quality of power supply judging electrical network；
Second detection module, for detecting and extract the secondary signal with second frequency scope from this current information, second
Frequency range is higher than the frequency of first frequency scope, and secondary signal is at least used as judging the foundation of the quality of power supply of electrical network；
3rd detection module, for detecting and extract the 3rd signal in the way of bandpass filtering from this current information, the 3rd letter
Number it is used for comparing or to add up it with default threshold value within the default time period, to exceed the number of times of threshold value thereby judge
Whether it belongs to fault electric arc.
Detection device the most according to claim 1, it is characterised in that there is in described first detection module a difference
Divide amplifying circuit, comprising:
First, second operational amplifier, the normal phase input end of each of which is respectively coupled to a pair output of this current sensor
End, to capture the first signal, connects between their inverting input and has the first resistance；And
Connect between the first and second respective inverting inputs of operational amplifier and respective outfan and have the second resistance, mat
This forms differential amplification signal between the outfan of first, second operational amplifier.
Detection device the most according to claim 2, it is characterised in that this differential amplifier circuit also includes one group or many
Preset resistance that group is serially connected and switching device, the preset resistance of each group of series connection and switching device be both connected to first, the
Between the inverting input of two operational amplifiers；
When described differential amplifier circuit is set to the mode of operation increasing amplification, one or more switching devices are in connection
State is to give parallel connection by these preset resistance one or more and the first resistance；Or
When described differential amplifier circuit is set to the mode of operation reducing amplification, one or more switching devices are in disconnection
State with by the preset resistance of one or more and the first resistor coupled in parallel from described differential amplifier circuit floating.
Detection device the most according to claim 1, it is characterised in that described second detection module has an integration
Circuit, comprising:
3rd operational amplifier, its positive and inverting input are respectively coupled to the pair of output of this current sensor to pick
Take secondary signal, form an integrator by the 3rd operational amplifier.
Detection device the most according to claim 4, it is characterised in that described second detection module also includes voltage electricity
Stream transformer, it is used for receiving the output voltage of described integrating circuit and converting this voltage to the magnitude of current being exported.
Detection device the most according to claim 1, it is characterised in that it is logical that described 3rd detection module has a band
Wave filter, it includes the first and second input nodes being respectively coupled to the pair of output of this current sensor:
It is in series with the 3rd between the inverting input of a four-operational amplifier in the first input node and band filter
Resistance and the first electric capacity, at the first interconnecting nodes of the 3rd resistance and the first electric capacity and between the outfan of four-operational amplifier
Connect and have the second electric capacity, and the inverting input of four-operational amplifier and outfan connection have the 4th resistance；And
It is connected with another resistance between the normal phase input end of the first interconnecting nodes and the second input node namely four-operational amplifier.
Detection device the most according to claim 6, it is characterised in that this band filter also includes one or more groups
The preset resistance being serially connected and switching device, preset resistance and the switching device of each group of series connection are both connected to the 4th computing and put
Between inverting input and the outfan of big device；
When described band filter is set to the mode of operation increasing center angular frequency, one or more switching devices are in connection
State is to give parallel connection by these preset resistance one or more and the 4th resistance；Or
When described band filter is set to the mode of operation reducing center angular frequency, one or more switching devices are in disconnection
State with by the preset resistance of one or more and the 4th resistor coupled in parallel from described band filter floating.
Detection device the most according to claim 6, it is characterised in that connect between the first and second input nodes and have
Over-voltage protection element, over-voltage protection element is one of Transient Voltage Suppressor, discharge tube, varistor or combinations thereof.
Detection device the most according to claim 1, it is characterised in that the first signal at least includes that power frequency information is harmonious
Wave component information, secondary signal at least includes transient current information more higher than work frequency.
Detection device the most according to claim 1, it is characterised in that described current sensor is Roche tubular wire
Loop current sensor.
11. detection devices according to claim 1, it is characterised in that also include alarm output module, once report
Alert output module monitor the 3rd signal exceed default threshold value or within the default time period the 3rd signal exceed threshold value time
When number is not in the numerical range specified, causes this alarm output module output indication signal to characterize the 3rd signal and belong to fault
Electric arc, and trigger the prior-warning device generation warning message receiving this indication signal further.
12. 1 kinds and the Active Power Filter-APF of detection matched with devices use as claimed in claim 1, it is characterised in that
Electrical network is injected with the compensation electric current of harmonic wave opposite in phase equal in magnitude in the first signal for producing.
13. Active Power Filter-APFs according to claim 12, it is characterised in that including:
One the 5th operational amplifier that the differential mode analog quantity that first detection module exports is transferred to single-ended voltage signal；
One isolation coupling module performing one-way transmission signal, is used for receiving this single-ended voltage signal, and this list is followed in output
The change of terminal voltage signal and the linear current of linear change；
One the 6th operational amplifier, its positive input end grounding and connect in its inverting input and outlet chamber and have resistance, use
In the voltage signal linear with this single-ended voltage signal that this linear current is converted into its outfan.
14. 1 kinds and the power quality analyzer of detection matched with devices use as claimed in claim 1, it is characterised in that
Including a current-to-voltage convertor, secondary signal is converted into the form of the magnitude of current and is exported by the second detection module, electric energy
This magnitude of current is reduced into the voltage characterizing secondary signal by the current-to-voltage convertor of mass-synchrometer；And
The power frequency that first signal passes judgment on electric current for power quality analyzer provides basis for estimation with harmonic quality, and secondary signal is electricity
Transient current information offer basis for estimation can be weighed by mass-synchrometer.
15. 1 kinds of electric arc detecting devices, it is characterised in that utilize the current information in Luo-coil sensor detection electrical network,
And also include a wave filter to detect and to extract a preset signals from this current information, this preset signals for in advance
If threshold value compare or add up this preset signals and within the default time period, exceed the number of times of threshold value thereby judge that it is
No belong to fault electric arc；Wherein
This wave filter has the first and second input nodes of the one group of outfan being respectively coupled to Luo-coil sensor；
A resistance and one it is in series with between the inverting input of an operational amplifier in the first input node and wave filter
Individual electric capacity, is connected between interconnecting nodes and the outfan of this operational amplifier between this resistance and electric capacity and has another electric capacity, and should
The inverting input of operational amplifier and outfan connect another resistance；And
A resistance also it is connected with between the normal phase input end of this interconnecting nodes and the second input node namely operational amplifier；
Thus produce at the outfan of this operational amplifier and characterize the voltage signal of this preset signals.
16. electric arc detecting devices according to claim 15, it is characterised in that this wave filter also includes one group or many
Preset resistance that group is serially connected and switching device, preset resistance and the switching device of each group of series connection are both connected to this computing and put
Between inverting input and the outfan of big device；
When described wave filter is set to the mode of operation increasing center angular frequency, one or more switching devices are in connection shape
State is to be connected in parallel on these preset resistance one or more between the inverting input of operational amplifier and outfan；Or
When described wave filter is set to the mode of operation reducing center angular frequency, one or more switching devices are in disconnection shape
State with by one or more preset resistance from floating between the inverting input and outfan of this operational amplifier.
17. electric arc detecting devices according to claim 15, it is characterised in that also include alarm output module, one
Denier alarm output module monitor the 3rd signal exceed default threshold value or within the default time period the 3rd signal exceed threshold value
Number of times not in the numerical range specified time, cause this alarm output module export effective indication signal characterize the 3rd letter
Number belong to fault electric arc, and trigger further and receive the prior-warning device of this indication signal and produce warning message.
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