CN107069734A - A kind of active filter and method with lightning protection isolation with arc-detection function - Google Patents
A kind of active filter and method with lightning protection isolation with arc-detection function Download PDFInfo
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- CN107069734A CN107069734A CN201710407647.XA CN201710407647A CN107069734A CN 107069734 A CN107069734 A CN 107069734A CN 201710407647 A CN201710407647 A CN 201710407647A CN 107069734 A CN107069734 A CN 107069734A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/01—Arrangements for reducing harmonics or ripples
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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
- G01R19/10—Measuring sum, difference or ratio
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/44—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to the rate of change of electrical quantities
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/26—Arrangements for eliminating or reducing asymmetry in polyphase networks
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/40—Arrangements for reducing harmonics
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/50—Arrangements for eliminating or reducing asymmetry in polyphase networks
Abstract
The present invention provides a kind of active filter and method with lightning protection isolation with arc-detection function, described active filter is that one kind has ground potential counterattack isolation concurrently, fault electric arc is detected, the safety utilization of electric power device of current harmonics elimination and three phase unbalance current compensation function, the current detecting of fault electric arc and current harmonics elimination and the current detecting part of compensation are shared, using same detection signal, carry out fault electric arc analysis and compensating instruction Current calculation simultaneously using common main control unit, enable devices to be sampled out before fault electric arc characteristic current is filtered, ensure the accurate detection of fault electric arc.The result of determination of described method by the use of current difference parameter is used as premise, fault electric arc is judged using relative harmonic content rate of change, the interference of nonlinear load can be effectively excluded, while being judged using four kinds of judging means, fault electric arc is accurately detected.
Description
Technical field
It is more particularly to a kind of that there is lightning protection isolation and arc-detection the present invention relates to Power Quality Detection administrative skill field
The active filter and method of function.
Background technology
In recent years, because the fire phenomena frequency that electric reason is caused has generation, a large amount of personnel are caused to injure and material damage.
The reason for causing electrical fire mainly has two：(1) electric current.Including electricity caused by the reasons such as short circuit, overload, harmonic wave and imbalance
Gas fire；(2) fault electric arc.The electricity as caused by the reasons such as electric component loose contact, earth fault produce electric arc or electric spark
Gas fire.Wherein, arc phenomenon usually occurs in supply line, and fault electric arc temperature is higher, seriously endangers fire-fighting peace
Entirely, it is to cause one of major reason of electrical fire, therefore the research detected to fault electric arc is particularly important.
And with the development of power system, more and more higher is required grid stability, a large amount of utility power quality control devices are wide
It is general to be arranged among power network.The installing of these utility power quality control devices also produces extreme influence, such as active electrical to arc-detection
Force filter (APF) although application harmonic wave and out-of-balance current are significantly improved, when fault electric arc occurs,
High frequency harmonic components in electric current, which are possible to be filtered out by APF, causes original fault electric arc detection equipment can not normally detect failure
Electric arc.
At the same time, with the industrial continuous progress of China, automatic control level also more and more higher is more and more
Distributed Control System and intelligence instrument extensive use, in order to prevent these automated productions by lightning hazards, power system
Take a large amount of lightning protection earthing measures, generally between lightning proof ground and protecting field install ground potential counterattack isolation, with it is anti-lightning strike when, by
Protecting field connection equipment is caused damage in ground potential counterattack.Ground potential counterattack isolation is generally presented low in no surge current
Impedance, occurs that high impedance is presented during surge current, buffer action is played to lightning current.But ground potential counterattack xegregating unit also has
Buffer action may be produced to the high frequency electric that fault electric arc is produced, influence the normal work of fault electric arc detection equipment.
Therefore, local potential counterattack xegregating unit, fault electric arc detection equipment, utility power quality control equipment independent operating
When, it is possible to have a negative impact mutually, cause incalculable damage.
Meanwhile, the use of the nonlinear load such as electric capacity, inductance, IGCT, IGBT can cause the current harmonics in circuit,
Also conventional fault arc detection method can be made to occur failing to judge, judge by accident.And if can be arranged using the rate of change of relative harmonic content
Except the interference of nonlinear load, in this way, emphasis compares its rate of change, if accessing nonlinear load in circuit, triggers
Relative harmonic content increase is transfinited, but its rate of change will not transfinite.Only break down electric arc when, relative harmonic content can acutely become
Change, the rate of change of adjacent two cycles m-Acetyl chlorophosphonazo containing ratio can transfinite, so as to be determined as fault electric arc.At present, also without this profit
The method judged with the rate of change of relative harmonic content fault electric arc.
The content of the invention
In order to solve problem described in background technology, the present invention provides a kind of with lightning protection isolation and arc-detection function
Active filter and method, the current detecting of fault electric arc and current harmonics elimination and the current detecting part of compensation are total to
Enjoy, using same detection signal, carry out fault electric arc analysis and compensating instruction galvanometer simultaneously using common main control unit
Calculate, enable devices to be sampled out before fault electric arc characteristic current is filtered, it is ensured that the accurate detection of fault electric arc.Wherein
Fault arc detection method by the use of the result of determination of current difference parameter as premise, using relative harmonic content rate of change pair therefore
Barrier electric arc is judged, can effectively exclude the interference of nonlinear load, while judged using four kinds of judging means, can
Accurately fault electric arc is detected in the case of complex device.
In order to achieve the above object, the present invention is realized using following technical scheme：
A kind of active filter with lightning protection isolation and arc-detection function, be one kind have concurrently ground potential counterattack isolation,
The safety utilization of electric power device of fault electric arc detection, current harmonics elimination and three phase unbalance current compensation function, including voltage sensor
Device, current sensor, sample circuit, signal processing circuit, main control MCU, arc fault warning circuit, switching value isolation and amplifier electricity
Road, IGBT drive circuit, current harmonics elimination and main compensation circuit and ground potential counterattack isolation module.
Described main control MCU connects voltage sensor and current sensor by signal processing circuit and sample circuit, main
After control MCU calculates same voltage and current sample signal respectively through fault electric arc analysis and instruction current, event is carried out respectively
Hinder electric arc warning output and the output of IGBT triggering commands；Enable devices to be sampled out before fault electric arc characteristic current is filtered
Come, it is ensured that the accurate detection of fault electric arc.
The ground potential counterattack isolation module is made up of a lightning current frequency impedance device, is installed in series in lightning proof ground with protecting
Formation thunder and lightning insulation blocking between ground is protected, Low ESR is presented under normal circumstances, it is ensured that the normal safety ground of equipment；Work as thunder and lightning
Stream from lightning protection ground terminal strike back when, under lightning current frequency, the element shows high impedance, the counterattack of isolation thunder and lightning, forces thunder and lightning
Stream can only be released to earth mat so that protection ground terminal exempt from back flashover harm, after the completion of lightning current is released, the lightning protection every
Low impedance state is returned to again from element.
Described main control MCU also controls power supply while fault electric arc alarm is exported by switching value spacing output circuit
The disconnection of breaker, cuts off the electricity supply during failure.
Described current harmonics elimination and main compensation circuit are electronic power convertor, including multigroup IGBT units, composition
Two level or three-level three-phase voltage source converter topology, can also constitute split-phase H bridge structural topologies, described main control MCU
IGBT trigger pulse, real-Time Compensation load harmonic and out-of-balance current are exported by IGBT drive circuit.
A kind of control method with lightning protection isolation with the active filter of arc-detection function, it is characterised in that including
Following steps：
Step 1: electric on system initialization, device；
Step 2: acquisition system three-phase voltage and three-phase current, and signal is delivered into signal modulation process circuit；
Step 3: signal modulation process circuit is modulated processing to voltage and current signal respectively, and will be modulated after
Signal deliver to main control MCU unit；
Step 4: main control MCU unit calculates the command current value for needing to compensate by sample rate current, voltage parameter；Meanwhile,
To current signal processing, arc current characteristic value is extracted；
Step 5: instruction current of the main control MCU unit according to the compensation of calculating, passes through instruction current tracking module, generation
Trigger pulse, controls IGBT, real-Time Compensation load harmonic and out-of-balance current；
Meanwhile, main control MCU unit carries out analysis judgement, such as according to logical calculated is passed through to extracting arc current characteristic value
Meet fault electric arc signal, then send instruction to fault electric arc warning module, and cut off the electricity supply breaker by output signal, cut
Disconnected fault electric arc；As do not met, instruction, and return to step two are not sent.
Fault arc detection method in a kind of active filter with lightning protection isolation and arc-detection function, using four
The condition of kind judges jointly, and one of which decision condition is by the use of the result of determination of current difference parameter as premise, using humorous
Ripple containing ratio rate of change judged fault electric arc, effective detection can be out of order electric arc in complex situations, including as follows
Step：
Step 1：Persistently electric current is sampled (according to actual hardware situation, each cycle adopts 64 or 128 points)；
Step 2：The sampled value of electric current is 128 each cycles or 64 each cycles.Exemplified by 64 points, current sampling data is remembered
For I0、I1、……、I63, normal cycle electric current is designated as In0、In1、……、In63(sampled value and normal value are perunit value).Calculate
The difference parameter of current sampling period electric current and normal cycle electric current：
By IperWith threshold value S1Compare, if Iper≤S1, then normal cycle current value is given by sampled current value width, updates normal
Periodic current value；If Iper＞ S1, then calculating is further analyzed to judge whether to be occurred by fault electric arc；
Step 3：The average value of calculating current：
Judge whether the positive-negative half-cycle of electric current is symmetrical with the average value of electric current.If IaveMore than given threshold value S2, then it is assumed that
Waveform symmetry is unsatisfactory for requiring, is that waveform symmetry indicates parameter m1 assignment 1, is otherwise m1 assignment 0；
Step 4：Calculate the difference of the two neighboring sampled value of sample rate current：
ΔIk=Ik+1-Ik(k=0,1,2 ... 62) (3)
With the maximum K of the differencev=max [Δ I0, Δ I1..., Δ I62] represent the maximum rate of change of electric current.If Kv
It is current changing rate parameter m2 assignment 1 more than threshold value S3, then it is assumed that current changing rate is excessive, otherwise m2 is entered as zero；
Step 5：The wave mode parameter of calculating current：
Wherein, α is configured according to actual current, typically takes normal current peak value.Can be with table with the wave mode parameter of electric current
Show whether electric current contains flat shoulder.If KpMore than threshold value S4, then it is assumed that electric current contains flat shoulder, parameter m3 is indicated for flat shoulder
Assignment 1, otherwise m3 be entered as zero；
Step 6：Detect sample rate current harmonic wave with FFT, calculate sample rate current electric current higher hamonic wave (calculate the 3rd herein, 5,7,
9 subharmonic) containing ratio rate of change Δ PnIf, Δ PnIt is harmonic wave more than threshold value S4, then it is assumed that sample rate current harmonic content is abnormal
Indicate that parameter m4 is entered as 1, be otherwise entered as 0；
Step 7：Calculate the sum of four instruction parameters in 3~step 6 of above-mentioned steps, i.e. m=m1+m2+m3+m4；If m>=
2, fault electric arc cycle indicates parameter sum=sum+1, if sum>=6, then trigger alarm signal；If sum<6, then return to step
Rapid 2 continue to differentiate；If m<2, then it is assumed that there is no fault electric arc, it is sum assignment 0, and normal current is updated to now
Sample rate current.
Step 6 is comprised the following steps that：
Step 601. calculates sampling period odd harmonic containing ratio rate of change Δ PnWith given threshold Δ PthCompare；Harmonic wave
Containing ratio is defined asWherein I1For fundamental current, IhFor the root-mean-square value of h subharmonic currents,Xh1For h subharmonic current sampled values, M be take 3 in sampling number, this example, 5,7,9 times it is humorous
Ripple, calculating odd harmonic containing ratio is
Step 602. is based on the 1st normal power frequency sampling period electric current odd harmonic containing ratio P that step 2 is judged
Value, calculates two neighboring power frequency sampling period electric current odd harmonic containing ratio rate of change Δ Pn, Δ Pn=Pn- P, double sampling week
The difference of electric current odd harmonic containing ratio is sampling period odd harmonic containing ratio rate of change Δ P between phasen。
Compared with prior art, the beneficial effects of the invention are as follows：
1st, a kind of active filter with lightning protection isolation and arc-detection function of the invention, by the electric current of fault electric arc
Detection is shared with current harmonics elimination and the current detecting part of compensation, using same detection signal, enables devices to
Fault electric arc characteristic current is sampled out before being filtered, it is ensured that the accurate detection of fault electric arc.
2nd, a kind of active filter and its control method with lightning protection isolation and arc-detection function of the invention, are utilized
Same main control MCU is handled same current data, fault electric arc characteristic value and compensating instruction current value is calculated respectively, respectively
IGBT drive circuit to fault electric arc warning circuit and filtering is controlled, and perfectly realizes and two kinds are realized with individual equipment
Take into account and use while function, effectively solve to cause fault electric arc to be failed to judge, judged by accident due to the use of Active Power Filter-APF
The problem of.
3rd, the fault electric arc detection side of a kind of active filter with lightning protection isolation and arc-detection function of the invention
Method, by the use of the result of determination of current difference parameter as premise, is judged fault electric arc using relative harmonic content rate of change,
The interference of nonlinear load can be effectively excluded, while being judged using four kinds of judging means, fault electric arc is accurately detected.
4th, a kind of active filter with lightning protection isolation and arc-detection function of the invention, ground potential is strikeed back and isolated
Integration of equipments makes integral device have ground potential counterattack isolation work(into the active filter with isolation fire prevention warning function
Can, and the detection of fault electric arc is not influenceed, than each, progress fault electric arc Detection results are good during independently installed situation.
Brief description of the drawings
Fig. 1 has lightning protection isolation and the structural representation of the active filter of arc-detection function for a kind of of the present invention；
Fig. 2 has lightning protection isolation and the main control MCU function of the active filter of arc-detection function for a kind of of the present invention
Structural representation；
Fig. 3 controls for a kind of of the present invention with lightning protection isolation and the main control MCU of the active filter of arc-detection function
Structural representation；
Fig. 4 for a kind of active filter with lightning protection isolation and arc-detection function of the present invention ground potential counterattack every
From modular structure schematic diagram；
Fig. 5 is a kind of two level harmonics of the embodiment of active filter that function is detected with fault electric arc of the present invention
Electric current suppresses and main compensation circuit structure chart；
Fig. 6 is a kind of three level harmonics of the embodiment of active filter that function is detected with fault electric arc of the present invention
Electric current suppresses and main compensation circuit structure chart；
Fig. 7 is a kind of split-phase H bridge knots of the embodiment of active filter that function is detected with fault electric arc of the present invention
Structure current harmonics elimination and main compensation circuit structure chart；
Fig. 8 has lightning protection isolation and the compensation of the embodiment of the active filter of arc-detection function for a kind of of the present invention
Instruction current computational methods；
Fig. 9 examines for a kind of of the present invention with lightning protection isolation with the fault electric arc in the active filter of arc-detection function
Survey method flow diagram.
Embodiment
The embodiment provided below in conjunction with accompanying drawing the present invention is described in detail.
As shown in Figure 1, 2, a kind of active filter with lightning protection isolation with arc-detection function, is that one kind has ground electricity concurrently
Strike back the safety utilization of electric power device of isolation, fault electric arc detection, current harmonics elimination and three phase unbalance current compensation function, bag in position
Include voltage sensor, current sensor, sample circuit, signal processing circuit, main control MCU, arc fault warning circuit, switching value
Spacing output circuit, IGBT drive circuit, current harmonics elimination and main compensation circuit and ground potential counterattack isolation module.
As shown in figure 3, described main control MCU connects voltage sensor and electric current by signal processing circuit and sample circuit
Sensor, after main control MCU calculates same voltage and current sample signal respectively through fault electric arc analysis and instruction current, point
Carry out not fault electric arc warning output and the output of IGBT triggering commands；Enable devices to before fault electric arc characteristic current is filtered
It is sampled out, it is ensured that the accurate detection of fault electric arc.
As shown in figure 4, the ground potential counterattack isolation module is made up of a lightning current frequency impedance device, it is installed in series
Thunder and lightning insulation blocking is formed between lightning proof ground and protecting field, Low ESR is presented under normal circumstances, it is ensured that the normal safety of equipment
Ground connection；When lightning current is strikeed back from lightning protection ground terminal, under lightning current frequency, the element shows high impedance, isolates the anti-of thunder and lightning
Hit, force lightning current to be released to earth mat so that protection ground terminal exempts from back flashover harm, when lightning current is released completion
Afterwards, the lightning protection isolation element returns to low impedance state again.
Described lightning current frequency impedance device is a kind of reactor, and its core material can be FERRITE CORE such as MnZn system
Material, Ni-Zn series material, magnesium zinc system material etc. or alloy type magnetic core such as silicon (silicon) steel, ferrocart core, sendust, iron nickel
Alloy, molybdenum permalloy, amorphous, microcrystallizing alloy etc..Wire rod can be polyurethanes enamel-covered wire, polyester enamelled wire from adhesive aggregation
Carbamate enamel-covered wire, silk-covered wire, twisted wire, plating copper cash, three layer insulation wire, PVC lines etc..Its equivalent model is represented by reason
Think inductance series equivalent resistance parallel parasitic capacitance again, high resistant now is presented for the frequency range of lightning current energy-intensive to external characteristic table
Anti-, other frequency ranges show as Low ESR.Conducting state is shown as under normal circumstances, impedance is low, it is ensured that the normal peace of equipment
Full ground connection；When earthed system have lightning current by when, under lightning current frequency, the element be high impedance, block thunder and lightning counterattack,
So that lightning current can only be released to earth mat.After the completion of lightning current is released, ground potential counterattack isolation element is returned to again
Low impedance state.
Described main control MCU also controls power supply while fault electric arc alarm is exported by switching value spacing output circuit
The disconnection of breaker, cuts off the electricity supply during failure.
Described current harmonics elimination and main compensation circuit are electronic power convertor, including multigroup IGBT units, composition
Two level or three-level three-phase voltage source converter topology, can also constitute split-phase H bridge structural topologies, described main control MCU
IGBT trigger pulse, real-Time Compensation load harmonic and out-of-balance current are exported by IGBT drive circuit.
As shown in figure 5, to use two level three-phase voltage source type transverters topology in embodiment.Six groups are included in topology
IGBT units.
As shown in fig. 6, to use three-level three-phase voltage source converter topology in embodiment.12 groups are included in topology
IGBT units.
As shown in fig. 7, to use split-phase H bridge structure three-phase voltage source types transverter topology in embodiment.Included in topology
Three groups of IGBT units.
A kind of control method with lightning protection isolation with the active filter of arc-detection function, it is characterised in that including
Following steps：
Step 1: electric on system initialization, device；
Step 2: acquisition system three-phase voltage and three-phase current, and signal is delivered into signal modulation process circuit；
Step 3: signal modulation process circuit is modulated processing to voltage and current signal respectively, and will be modulated after
Signal deliver to main control MCU unit；
Step 4: main control MCU unit calculates the command current value for needing to compensate by sample rate current, voltage parameter；Meanwhile,
To current signal processing, arc current characteristic value is extracted；
Step 5: instruction current of the main control MCU unit according to the compensation of calculating, passes through instruction current tracking module, generation
Trigger pulse, controls IGBT, real-Time Compensation load harmonic and out-of-balance current；
Meanwhile, main control MCU unit carries out analysis judgement, such as according to logical calculated is passed through to extracting arc current characteristic value
Meet fault electric arc signal, then send instruction to fault electric arc warning module, and cut off the electricity supply breaker by output signal, cut
Disconnected fault electric arc；As do not met, instruction, and return to step two are not sent.
As shown in Figure 8, it is preferable that the instruction current computational methods of compensation, in the present embodiment using based on instantaneous reactive
The i of Power Theoryp-iqMethod detection compensates electric current to illustrate, and the protection domain of this patent includes but is not limited to this detection side
Method.Comprise the following steps：
1st, detection load current ia, ib, ic；
2nd, ABC three-phase currents are changed into by electric current ip, iq under rest frame by rotation transformation；
3rd, by low pass filter LPF, the fundamental positive sequence of load current is obtained
4th, by rotating electric current iaf, ibf, icf for changing under ABC coordinate systems；
5th, load harmonic current and out-of-balance current iah, ibh, ich, i.e. compensation device can be obtained by being supported electric current and subtracting
Instruction current；
6th, by instruction current tracking module, tactile pulse is generated, IGBT, real-Time Compensation load harmonic and imbalance is controlled
Electric current.
As shown in figure 9, a kind of detect with lightning protection isolation with the fault electric arc in the active filter of arc-detection function
Method, is judged jointly using four kinds of conditions, and one of which decision condition by the use of current difference parameter result of determination as
Premise, is judged fault electric arc using relative harmonic content rate of change, effective detection can be out of order electricity in complex situations
Arc, comprises the following steps：
Step 1：Persistently electric current is sampled (according to actual hardware situation, each cycle adopts 64 or 128 points)；
Step 2：The sampled value of electric current is 128 each cycles or 64 each cycles.Exemplified by 64 points, current sampling data is remembered
For I0、I1、……、I63, normal cycle electric current is designated as In0、In1、……、In63(sampled value and normal value are perunit value).Calculate
The difference parameter of current sampling period electric current and normal cycle electric current：
By IperWith threshold value S1Compare, if Iper≤S1, then normal cycle current value is given by sampled current value width, updates normal
Periodic current value；If Iper＞ S1, then calculating is further analyzed to judge whether to be occurred by fault electric arc；
Step 3：The average value of calculating current：
Judge whether the positive-negative half-cycle of electric current is symmetrical with the average value of electric current.If IaveMore than given threshold value S2, then it is assumed that
Waveform symmetry is unsatisfactory for requiring, is that waveform symmetry indicates parameter m1 assignment 1, is otherwise m1 assignment 0；
Step 4：Calculate the difference of the two neighboring sampled value of sample rate current：
ΔIk=Ik+1-Ik(k=0,1,2 ... 62) (3)
With the maximum K of the differencev=max [Δ I0, Δ I1..., Δ I62] represent the maximum rate of change of electric current.If Kv
It is current changing rate parameter m2 assignment 1 more than threshold value S3, then it is assumed that current changing rate is excessive, otherwise m2 is entered as zero；
Step 5：The wave mode parameter of calculating current：
Wherein, α is configured according to actual current, typically takes normal current peak value.Can be with table with the wave mode parameter of electric current
Show whether electric current contains flat shoulder.If KpMore than threshold value S4, then it is assumed that electric current contains flat shoulder, parameter m3 is indicated for flat shoulder
Assignment 1, otherwise m3 be entered as zero；
Step 6：Detect sample rate current harmonic wave with FFT, calculate sample rate current higher hamonic wave (calculate the 3rd herein, 5,7,9 times
Harmonic wave) containing ratio rate of change Δ PnIf, Δ PnIt is that harmonic wave is indicated more than threshold value S4, then it is assumed that sample rate current harmonic content is abnormal
Parameter m4 is entered as 1, is otherwise entered as 0；
Step 7：Calculate the sum of four instruction parameters in 3~step 6 of above-mentioned steps, i.e. m=m1+m2+m3+m4；If m>=
2, fault electric arc cycle indicates parameter sum=sum+1, if sum>=6, then trigger alarm signal；If sum<6, then return to step
Rapid 2 continue to differentiate；If m<2, then it is assumed that there is no fault electric arc, it is sum assignment 0, and normal current is updated to now
Sample rate current.
Step 6 is comprised the following steps that：
Step 601. calculates sampling period odd harmonic containing ratio rate of change Δ PnWith given threshold Δ PthCompare；Harmonic wave
Containing ratio is defined asWherein I1For fundamental current, IhFor the root-mean-square value of h subharmonic currents,Xh1For h subharmonic current sampled values, M be take 3 in sampling number, this example, 5,7,9 times it is humorous
Ripple, calculating odd harmonic containing ratio is
Step 602. is based on the 1st normal power frequency sampling period electric current odd harmonic containing ratio P that step 2 is judged
Value, calculates two neighboring power frequency sampling period electric current odd harmonic containing ratio rate of change Δ Pn, Δ Pn=Pn- P, double sampling week
The difference of electric current odd harmonic containing ratio is sampling period odd harmonic containing ratio rate of change Δ P between phasen。
A kind of active filter with lightning protection isolation with arc-detection function of the present invention, the electric current of fault electric arc is examined
Survey and shared with current harmonics elimination and the current detecting part of compensation, using same detection signal, enabled devices in event
Barrier arc characteristic electric current is sampled out before being filtered, it is ensured that the accurate detection of fault electric arc.
A kind of active filter and its control method with lightning protection isolation and arc-detection function of the present invention, using same
One main control MCU is handled same current data, and fault electric arc characteristic value and compensating instruction current value are calculated respectively, right respectively
Fault electric arc warning circuit and the IGBT drive circuit of filtering are controlled, and perfectly realize and two kinds of work(are realized with individual equipment
Can while take into account and use, effectively solve to cause fault electric arc to be failed to judge due to the use of Active Power Filter-APF, judge by accident
Problem.
A kind of fault arc detection method with lightning protection isolation with the active filter of arc-detection function of the present invention,
By the use of the result of determination of current difference parameter as premise, fault electric arc is judged using relative harmonic content rate of change, can
Effectively to exclude the interference of nonlinear load, while being judged using four kinds of judging means, fault electric arc is accurately detected.
A kind of active filter with lightning protection isolation with arc-detection function of the present invention, ground potential counterattack isolation is set
It is standby to be integrated into the active filter with isolation fire prevention warning function, make integral device that there is ground potential counterattack isolation work(
Can, and the detection of fault electric arc is not influenceed, than each, progress fault electric arc Detection results are good during independently installed situation.
Above example is implemented lower premised on technical solution of the present invention, gives detailed embodiment and tool
The operating process of body, but protection scope of the present invention is not limited to the above embodiments.Method therefor is such as without spy in above-described embodiment
It is conventional method not mentionlet alone bright.
Claims (6)
1. a kind of active filter with lightning protection isolation with arc-detection function, is that one kind has ground potential counterattack isolation, event concurrently
The safety utilization of electric power device of barrier arc-detection, current harmonics elimination and three phase unbalance current compensation function, including voltage sensor,
Current sensor, sample circuit, signal processing circuit, main control MCU, arc fault warning circuit, switching value spacing output circuit,
IGBT drive circuit, current harmonics elimination and main compensation circuit and ground potential counterattack isolation module；
Characterized in that, described main control MCU connects voltage sensor by signal processing circuit and sample circuit and electric current is passed
Sensor, after main control MCU calculates same voltage and current sample signal respectively through fault electric arc analysis and instruction current, respectively
Carry out fault electric arc warning output and the output of IGBT triggering commands；Enable devices to the quilt before fault electric arc characteristic current is filtered
Sampling comes out, it is ensured that the accurate detection of fault electric arc；
The ground potential counterattack isolation module is made up of a lightning current frequency impedance device, is installed in series in lightning proof ground and protecting field
Between formed thunder and lightning insulation blocking, Low ESR is presented under normal circumstances, it is ensured that the normal safety ground of equipment；When lightning current from
When lightning protection ground terminal is strikeed back, under lightning current frequency, the element shows high impedance, isolates the counterattack of thunder and lightning, forces lightning current only
It can be released to earth mat so that protection ground terminal exempts from back flashover harm, after the completion of lightning current is released, lightning protection isolation member
Part returns to low impedance state again.
2. a kind of active filter with lightning protection isolation with arc-detection function according to claim 1, its feature exists
In described main control MCU also controls electric power disconnection while fault electric arc alarm is exported by switching value spacing output circuit
The disconnection of device, cuts off the electricity supply during failure.
3. a kind of active filter with lightning protection isolation with arc-detection function according to claim 1, its feature exists
It is electronic power convertor in, described current harmonics elimination and main compensation circuit, including multigroup IGBT units constitute two level
Or three-level three-phase voltage source converter topology, split-phase H bridge structural topologies can also be constituted, described main control MCU passes through
IGBT drive circuit exports IGBT trigger pulse, real-Time Compensation load harmonic and out-of-balance current.
4. a kind of control method of the active filter with lightning protection isolation and arc-detection function, it is characterised in that including with
Lower step：
Step 1: electric on system initialization, device；
Step 2: acquisition system three-phase voltage and three-phase current, and signal is delivered into signal modulation process circuit；
Step 3: signal modulation process circuit is modulated processing to voltage and current signal respectively, and will be modulated after letter
Number deliver to main control MCU unit；
Step 4: main control MCU unit calculates the command current value for needing to compensate by sample rate current, voltage parameter；Meanwhile, to electricity
Signal transacting is flowed, arc current characteristic value is extracted；
Step 5: instruction current of the main control MCU unit according to the compensation of calculating, passes through instruction current tracking module, generation triggering
Pulse, controls IGBT, real-Time Compensation load harmonic and out-of-balance current；
Meanwhile, main control MCU unit carries out analysis judgement to extracting arc current characteristic value, such as met according to logical calculated is passed through
Fault electric arc signal, then send instruction to fault electric arc warning module, and breaker, cut-out cut off the electricity supply by output signal therefore
Hinder electric arc；As do not met, instruction, and return to step two are not sent.
5. a kind of with lightning protection isolation and the fault arc detection method in the active filter of arc-detection function, its feature exists
In, judged jointly using four kinds of conditions, and one of which decision condition by the use of current difference parameter result of determination as preceding
Carry, fault electric arc judged using relative harmonic content rate of change, effective detection can be out of order electric arc in complex situations,
Comprise the following steps：
Step 1：Persistently electric current is sampled, according to actual hardware situation, each cycle adopts 64 or 128 points；
Step 2：The sampled value of electric current is 128 each cycles or 64 each cycles；Exemplified by 64 points, current sampling data is designated as I0、
I1、……、I63, normal cycle electric current is designated as In0、In1、……、In63, sampled value and normal value are perunit value；Calculate current
Sampling period electric current and normal cycle electric current difference parameter：
<mrow>
<msub>
<mi>I</mi>
<mrow>
<mi>p</mi>
<mi>e</mi>
<mi>r</mi>
</mrow>
</msub>
<mo>=</mo>
<msubsup>
<mi>&Sigma;</mi>
<mrow>
<mi>i</mi>
<mo>=</mo>
<mn>0</mn>
</mrow>
<mn>63</mn>
</msubsup>
<mo>|</mo>
<msub>
<mi>I</mi>
<mrow>
<mi>n</mi>
<mi>i</mi>
</mrow>
</msub>
<mo>-</mo>
<msub>
<mi>I</mi>
<mi>i</mi>
</msub>
<mo>|</mo>
</mrow>
By IperWith threshold value S1Compare, if Iper≤S1, then normal cycle current value is given by sampled current value width, updates normal cycle
Current value；If Iper＞ S1, then calculating is further analyzed to judge whether to be occurred by fault electric arc；
Step 3：The average value of calculating current：
<mrow>
<msub>
<mi>I</mi>
<mrow>
<mi>a</mi>
<mi>v</mi>
<mi>e</mi>
</mrow>
</msub>
<mo>=</mo>
<mfrac>
<mn>1</mn>
<mn>64</mn>
</mfrac>
<msubsup>
<mi>&Sigma;</mi>
<mrow>
<mi>k</mi>
<mo>=</mo>
<mn>0</mn>
</mrow>
<mn>63</mn>
</msubsup>
<msub>
<mi>I</mi>
<mi>k</mi>
</msub>
</mrow>
Judge whether the positive-negative half-cycle of electric current is symmetrical with the average value of electric current；If IaveMore than given threshold value S2, then it is assumed that waveform
Symmetry is unsatisfactory for requiring, is that waveform symmetry indicates parameter m1 assignment 1, is otherwise m1 assignment 0；
Step 4：Calculate the difference of the two neighboring sampled value of sample rate current：
ΔIk=Ik+1-Ik(k=0,1,2 ... 62) (3)
With the maximum K of the differencev=max [Δ I0, Δ I1..., Δ I62] represent the maximum rate of change of electric current；If KvIt is more than
Threshold value S3, then it is assumed that current changing rate is excessive, is current changing rate parameter m2 assignment 1, and otherwise m2 is entered as zero；
Step 5：The wave mode parameter of calculating current：
<mrow>
<msub>
<mi>K</mi>
<mi>p</mi>
</msub>
<mo>=</mo>
<msubsup>
<mi>&Sigma;</mi>
<mrow>
<mi>k</mi>
<mo>=</mo>
<mn>0</mn>
</mrow>
<mn>63</mn>
</msubsup>
<msub>
<mi>d</mi>
<mi>k</mi>
</msub>
<mo>-</mo>
<mo>-</mo>
<mo>-</mo>
<mrow>
<mo>(</mo>
<mn>4</mn>
<mo>)</mo>
</mrow>
</mrow>
Wherein, α is configured according to actual current, typically takes normal current peak value；It can be represented with the wave mode parameter of electric current
Whether electric current contains flat shoulder；If KpMore than threshold value S4, then it is assumed that electric current contains flat shoulder, parameter m3 assignment is indicated for flat shoulder
1, otherwise m3 be entered as zero；
Step 6：Sample rate current harmonic wave is detected with FFT, sample rate current higher hamonic wave containing ratio rate of change is calculated, calculating the 3rd herein,
5th, 7,9 subharmonic containing ratio rate of change Δ PnIf, Δ PnIt is humorous more than threshold value S4, then it is assumed that sample rate current harmonic content is abnormal
Ripple indicates that parameter m4 is entered as 1, is otherwise entered as 0；
Step 7：Calculate the sum of four instruction parameters in 3~step 6 of above-mentioned steps, i.e. m=m1+m2+m3+m4；If m>=2, therefore
Hinder electric arc cycle and indicate parameter sum=sum+1, if sum>=6, then trigger alarm signal；If sum<6, then return to step 2 after
It is continuous to differentiate；If m<2, then it is assumed that there is no fault electric arc, be sum assignment 0, and by normal current be updated to now sampling electricity
Stream.
6. it is according to claim 5 a kind of with lightning protection isolation and the failure electricity in the active filter of arc-detection function
Arc detection method, it is characterised in that step 6 is comprised the following steps that：
Step 601. calculates sampling period odd harmonic containing ratio rate of change Δ PnWith given threshold Δ PthCompare；Harmonic wave contains
Rate is defined asWherein I1For fundamental current, IhFor the root-mean-square value of h subharmonic currents,Xh1For h subharmonic current sampled values, M be take 3 in sampling number, this example, 5,7,9 times it is humorous
Ripple, calculating odd harmonic containing ratio is
Step 602. value based on the 1st normal power frequency sampling period electric current odd harmonic containing ratio P that step 2 is judged,
Calculate two neighboring power frequency sampling period electric current odd harmonic containing ratio rate of change Δ Pn, Δ Pn=Pn- P, the double sampling cycle it
Between electric current odd harmonic containing ratio difference be sampling period odd harmonic containing ratio rate of change Δ Pn。
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| CN113702755A (en) * | 2021-08-10 | 2021-11-26 | 国网江苏省电力有限公司盐城供电分公司 | Method for detecting grounding arc fault of power distribution system |
| CN117239941A (en) * | 2023-11-16 | 2023-12-15 | 交通运输部东海航海保障中心上海航标处 | New energy lighthouse current detection device, power distribution control system and method |
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