CN107785915A - A kind of more level active compensation devices of front-end power and control method - Google Patents
A kind of more level active compensation devices of front-end power and control method Download PDFInfo
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- CN107785915A CN107785915A CN201611031939.XA CN201611031939A CN107785915A CN 107785915 A CN107785915 A CN 107785915A CN 201611031939 A CN201611031939 A CN 201611031939A CN 107785915 A CN107785915 A CN 107785915A
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- power
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- distribution network
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Classifications
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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
- H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
- H02J3/1821—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators
- H02J3/1835—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators with stepless control
- H02J3/1842—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators with stepless control wherein at least one reactive element is actively controlled by a bridge converter, e.g. active filters
- H02J3/1857—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators with stepless control wherein at least one reactive element is actively controlled by a bridge converter, e.g. active filters wherein such bridge converter is a multilevel converter
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
- H02M5/40—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc
- H02M5/42—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters
- H02M5/44—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac
- H02M5/453—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal
- H02M5/458—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
- H02M1/007—Plural converter units in cascade
-
- 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
- Y02E40/30—Reactive power compensation
Abstract
The present invention relates to a kind of more level active compensation devices of front-end power and control method.Described device includes detection unit, control unit and compensating unit；Wherein, the detection unit connection described control unit, for obtaining residual voltage and being transferred to described control unit；Described control unit connects the compensating unit, for judging whether the power distribution network occurs singlephase earth fault and generate control signal according to the residual voltage；The compensating unit connects the power distribution network, in the presence of the control signal to the power distribution network injecting compensating electric current or zero-sequence current.The control method is based on the more level active compensation devices of above-mentioned front-end power and realized.The present invention can realize that reliable arc extinguishing during singlephase earth fault occurs for power distribution network.
Description
Technical field
The present invention relates to electric power network technique field, more particularly to a kind of more level active compensation devices of front-end power and controlling party
Method.
Background technology
China's high voltage distribution network neutral point uses small current neutral grounding mode, including isolated neutral, through arc suppression coil, height
Resistance earthing.The reactance of earth point Zero sequence synthetic is bigger than positive sequence synthesis reactance, after singlephase earth fault occurs, is not formed
Short-circuit current paths, failure phase and non-faulting mutually flow through load current, and earth fault and wire direct-to-ground capacitance form electric current and led to
Road, so that power distribution network can run the long period and search failure, it is improved power supply reliability.
, it is necessary to using arc suppression coil compensation capacitance current after current in the fault point reaches certain value, make current in the fault point control
Make in certain limit, can so avoid producing electric arc, above-mentioned way claims resonance grounding or compensation of ground.It is good in stand-by power supply
In the case of, high voltage distribution network can also use Neutral Grounding through Resistance in Electrical method, faulty line is produced larger failure electricity
Stream, rapid tripping operation, avoids arc grounding over-voltage to causing equipment to injure.
Because arc suppression coil can only compensate First Harmonic Reactive Power, and produce Leakage Current.After power distribution network reaches certain scale,
The Leakage Current of Single-phase Ground Connection Failure may make trouble point can not blow-out.Therefore need to provide a kind of device and method and make height
Press-fitting power network occurs during singlephase earth fault the electric arc of trouble point can be made reliably to extinguish.
The content of the invention
For in the prior art the defects of, the present invention provides a kind of more level active compensation devices of front-end power and controlling party
Method, what generation electric arc in the trouble point can not reliably extinguish when can solve power distribution network generation singlephase earth fault in the prior art asks
Topic.
In a first aspect, the invention provides a kind of more level active compensation devices of front-end power, including：Detection unit, control
Unit and compensating unit processed；Wherein,
The detection unit connects described control unit, for obtaining power distribution network residual voltage and being transferred to the control list
Member；
Described control unit connects the compensating unit, for judging whether the power distribution network is sent out according to the residual voltage
Raw singlephase earth fault simultaneously generates control signal；
The compensating unit connects the power distribution network, for being injected in the presence of the control signal to the power distribution network
Compensate electric current or zero-sequence current.
Alternatively, the compensating unit include corresponding to the power distribution network ABC phases power subelement, ground connection subelement and
Power supply subelement；
The input connection power distribution network bus of the power supply subelement, output end connection correspond to the power distribution network ABC phases
Power subelement power end；
The first end of the power subelement of corresponding A BC phases connects corresponding single-phase bus respectively；Second end is connected to form
Neutral point；
The first end of the ground connection subelement connects the neutral point, the second end ground connection.
Alternatively, the power subelement is made up of at least two power models, at least two power models series connection；
The ground connection subelement is made up of at least two power models, at least two power models series connection.
Alternatively, the power supply subelement is phase-shifting transformer；The phase-shifting transformer includes at least one primary side winding
With multiple vice-side windings, and the quantity of the multiple vice-side winding no less than the power subelement with it is described ground connection subelement in
The quantity sum of power model；
The primary side winding connects the power distribution network bus, and the vice-side winding connects power model one by one.
Alternatively, the power model includes the H bridges that 4 switching devices and electric capacity are formed, and 6 diodes are formed
Three-phase commutation bridge；
The positive pole of the negative pole connection electric capacity of first diode, positive pole connect the negative pole of the second diode and form the first power supply
End, the positive pole of second diode connect the negative pole of the electric capacity；
The negative pole of 3rd diode connects the positive pole of the electric capacity, and positive pole connects the negative pole of the 4th diode and formation second
Power end, the positive pole of the 4th diode connect the negative pole of the electric capacity；
The negative pole of 5th diode connects the positive pole of the electric capacity, and positive pole connects the negative pole of the 6th diode and formation the 3rd
Power end, the positive pole of the 6th diode connect the negative pole of the electric capacity；
First power end, the second source end and the 3rd power end are connected respectively to corresponding vice-side winding
ABC phase output terminals；
The positive pole of the first end connection electric capacity of first switch device, the second end connects the first end of the 3rd switching device, institute
The second end for stating the 3rd switching device connects the negative pole of the electric capacity；
The positive pole of the first end connection electric capacity of second switch device, the second end connects the first end of the 4th switching device, institute
The second end for stating the 4th switching device connects the negative pole of the electric capacity.
When the ground connection subelement or the power subelement are made up of at least two power models, in the H bridges
Second in first switch device single-phase bus corresponding with the first end connection of the 3rd switching device or upper level power model
Second end of switching device and the 4th switching device, second switch device is connected next stage with the 4th switching device in the H bridges
The first switch device of power model and the first end or ground of the 3rd switching device.
Alternatively, the quantity of the power model of series connection and the relation of line voltage are：
UAB,BC,CA=VH×N；
Wherein, UAB,BC,CARepresent line voltage, VHH bridge rated outputs are represented, N is represented in power subelement and ground connection subelement
The quantity of H bridges and.
Second aspect, the embodiment of the present invention additionally provide a kind of more level actives of front-end power being used for as described above and mended
The control method of device is repaid, including：
Generation injection control signal make the compensating unit to power distribution network bus inject zero-sequence current, according to residual voltage,
The direct-to-ground capacitance and bleeder resistance of power distribution network described in zero-sequence current Relation acquisition；
Obtain the residual voltage of the power distribution network, when the residual voltage exceedes residual voltage preset value if judge to occur
Singlephase earth fault；
The amplitude and phase of compensation electric current are calculated according to the residual voltage and the direct-to-ground capacitance and leak resistance, so that
The compensating unit is injected into the power distribution network of generation singlephase earth fault by electric current is compensated.
Alternatively, also include before control signal is injected in generation：
The ground connection control signal of generation first is grounded compensating unit.
Alternatively, the compensation electric current is capacity current and Leakage Current over the ground.
Alternatively, when the residual voltage is not less than residual voltage preset value, the control method also includes：
Generation second ground connection control signal make the compensating unit with disconnect；
According to the amplitude and phase relation of the voltage and current of power distribution network ABC phases, compensation electric current is obtained and by the compensation
Unit is injected into the power distribution network bus to improve its power factor.
Alternatively, the quantity of the power model of series connection is calculated using following formula：
UAB,BC,CA=VH×N；
Wherein, UAB,BC,CARepresent line voltage, VHH bridge rated outputs are represented, N is represented in power subelement and ground connection subelement
The quantity of H bridges and.
As shown from the above technical solution, the present invention provides through the residual voltage for setting detection unit to obtain power distribution network bus
And it is transferred to described control unit；Judge whether power distribution network bus occurs singlephase earth fault according to residual voltage by control unit
And generate control signal；Compensating unit in the presence of the control signal to the power distribution network bus injecting compensating electric current or
Zero-sequence current.When singlephase earth fault occurs, compensating unit is to power distribution network bus injecting compensating electric current, so that current in the fault point
Control avoids trouble point that electric arc occurs in predetermined target value；When without singlephase earth fault, injection zero-sequence current is matched somebody with somebody with detecting
Power network direct-to-ground capacitance and leak resistance over the ground.The present invention can compensate electric current by harmonic into power network, make up in the prior art
Arc suppression coil can only compensate the defects of First Harmonic Reactive Power.Also, the present invention can actively inject zero-sequence current, normal work is calculated
The direct-to-ground capacitance and bleeder resistance of power distribution network when making, not only leak resistance electric current can be can also compensate for compensating electric capacity electric current, carried
The accuracy rate of height compensation.
Brief description of the drawings
The features and advantages of the present invention can be more clearly understood by reference to accompanying drawing, accompanying drawing is schematically without that should manage
Solve to carry out any restrictions to the present invention, in the accompanying drawings：
Fig. 1 is a kind of more level active compensation device structural representations of front-end power provided in an embodiment of the present invention；
Fig. 2 is the electrical block diagram of A phases compensating unit in Fig. 1；
Front-end power more level active compensation device compensation current diagrams when Fig. 3 is singlephase earth fault；
Fig. 4 is a kind of control for the more level active compensation devices of front-end power described in Fig. 1 provided in an embodiment of the present invention
Method processed.
Embodiment
To make the purpose, technical scheme and advantage of the embodiment of the present invention clearer, below in conjunction with the embodiment of the present invention
In accompanying drawing, the technical scheme in the embodiment of the present invention is clearly and completely described, it is clear that described embodiment is
Part of the embodiment of the present invention, rather than whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art
The every other embodiment obtained under the premise of creative work is not made, belongs to the scope of protection of the invention.
In a first aspect, the invention provides a kind of more level active compensation devices of front-end power, as shown in figure 1, including：Inspection
Survey unit 1, control unit 2 and compensating unit 3；Wherein,
Detection unit 1 connects control unit 2, for obtaining the residual voltage of power distribution network and being transferred to control unit 2；
Control unit 2 connects compensating unit 3, for judging whether power distribution network occurs singlephase earth fault according to residual voltage
And generate control signal；
Compensating unit 3 connects power distribution network, in the presence of control signal to power distribution network bus injecting compensating electric current or
Person's zero-sequence current.
It should be noted that detection unit 1 also includes voltage transformer in the embodiment of the present invention.The detection unit 1 is specific
For gathering the residual voltage of power distribution network bus, circuit realiration of the prior art can be used, will not be described in detail herein.The detection
Unit 1 can measure the voltage of every phase bus respectively and then synthesize residual voltage, can also measure three-phase bus synthesis simultaneously
Residual voltage, specific metering system can select according to scene, which kind of mode can obtain residual voltage regardless of, the present invention is not
It is construed as limiting.The measurement of zero-sequence current can use the current transformer that compensation device exports, and measurement phase current synthesizes zero-sequence current,
Can also the synthesis of direct measurement three-phase zero-sequence current, specific metering system can select according to scene, no matter which kind of mode is all
Zero-sequence current can be obtained, the present invention is not construed as limiting.
The effect of control unit 2 is to judge power distribution network according to the residual voltage that detection unit 1 detects in the embodiment of the present invention
Whether bus occurs singlephase earth fault, for example, singlephase earth fault or working properly, then basis occur for power distribution network bus
Control signal corresponding to demand generation.In practical application, the control unit 2 can use such as single-chip microcomputer, DSP or ARM cores
Piece etc. realizes that those skilled in the art can select suitable control chip according to concrete scene, and the present invention no longer limits.
In the embodiment of the present invention, it is single that compensating unit 2 includes the power subelement of the ABC phases corresponding to power distribution network, ground connection
Member and power supply subelement.The input connection power distribution network bus of power supply subelement, output end connection is corresponding to power distribution network ABC phases
The power end of power subelement；The first end of the power subelement of corresponding A BC phases connects corresponding single-phase bus respectively；Second end
It is connected to form neutral point；It is grounded the first end connection neutral point of subelement, the second end ground connection.
As shown in figure 1, the compensating unit 3 includes power supply subelement 30, A phase power subelement 31, B phase power subelements
32nd, C phases power subelement 33 and ground connection subelement 34.In the embodiment of the present invention, by setting power supply subelement 30 to make
Electric energy from power distribution network is supplied to ABC phase power subelements and ground connection subelement 34 by power supply subelement 30.I.e. front end supplies
The energy of the more level active compensation device operation consumption of electricity and the energy of active compensation are all from power distribution network.How electric front-end power is
Flat active power compensator is powered using power supply unit, is increased system operation reliability, simplify control strategy, is improved and single-phase connect occurs
Compensation degree of accuracy during earth fault.
In practical application, above-mentioned power supply subelement 20 uses 6 pulse wave diode rectifications, can produce harmonic pollution power network.For
Overtone order is reduced, distribution network electric energy quality is improved, phase-shifting transformer multi-pulse rectification is used in the embodiment of the present invention.The phase shift
The phase of the vice-side winding voltage of transformer draws preceding or hysteresis primary side winding voltage phase.That is the secondary of the phase-shifting transformer
Side harmonic current can cancel each other after converting to primary side.After multi-pulse rectification, low-order harmonic cancels each other, harmonic wave in power distribution network
Content is n=mk ± 1, and wherein m is rectification pulse number, and k is positive integer.
Power supply subelement 30 uses phase-shifting transformer.The phase-shifting transformer selection mode is：The phase shift of phase shift angle=360/
The phase-shifting transformer such as transformer pulse number, the pulse wave of generally use 24,30 pulse waves, 36 pulse waves, 48 pulse waves, 60 pulse waves.As shown in Figure 2
Phase-shifting transformer has 5 secondary windings, each 12 ° of winding phase shift, is 30 pulse wave rectifiers (360 °/12 °=30), without 29 times with
Lower harmonic wave.
By using the phase-shifting transformer of multiple vice-side windings in the embodiment of the present invention, input harmonics can be made mutually to offset
Disappear, reduce percent harmonic distortion.In other words, in the present invention when using phase-shifting transformer, be free of N-1 times during N pulse wave rectifiers
Following harmonic wave, and increasing with rectification pulse number, harmonic content reduce.
As shown in FIG. 1 to 3, A phases power subelement 31, B phase power subelement 32 and C phase work(in the embodiment of the present invention
The power end of rate subelement 33 is connected to the ABC output ends of corresponding vice-side winding.A phase power subelement 31, B phase power subelements
The first end (top in Fig. 1) of 32 and C phase power subelement 33 is respectively connected to the A phase, B phase, C phase of power distribution network bus；The
Two ends (Fig. 1 lower section) are connected to the first end of ground connection subelement 34, the second end ground connection of ground connection subelement 34.Each power
Unit and ground connection subelement are connected with control unit 2, each power subelement and ground connection in the presence of control signal
Power distribution network injecting compensating electric current of the unit collective effect to generation earth fault.
As shown in figure 1, when power subelement is made up of at least two power models, at least two power model series connection
Form.The power model includes the H bridges that 4 switching devices and electric capacity are formed.The first end connection electricity of first switch device
Appearance C1 positive pole (at the points of P1 shown in Fig. 2), the first end (at the points of P2 shown in Fig. 2) of the 3rd switching device of the second end connection, the 3rd
The negative pole of the second end connection electric capacity of switching device (at the points of P3 shown in Fig. 2)；The first end connection electric capacity of second switch device
Positive pole, the second end connect the first end (at the points of P4 shown in Fig. 2) of the 4th switching device, the second end connection institute of the 4th switching device
State the negative pole of electric capacity.
When the ground connection subelement or the power subelement are made up of at least two power models, in the H bridges
Second in first switch device single-phase bus corresponding with the first end connection of the 3rd switching device or upper level power model
Second end of switching device and the 4th switching device, second switch device is connected next stage with the 4th switching device in the H bridges
The first switch device of power model and the first end or ground of the 3rd switching device.
Power subelement is in series by 5 power models in one embodiment of the invention, the circuit shown in Fig. 2 successively to
Down for first power model A1, second power model A2 ..., (A2, A3, A4, A5 are in fig. 2 by the 5th power model A5
It is not shown), wherein the input A connection A phase buses of first power subelement, output end connects second power subelement A2
Input；Second power subelement A2 output end connects the 3rd power subelement A3 input ... ..., the 5th
The input N of the output end connection ground connection subelement of power model.When power subelement is made up of 1 power model, the work(
First input and output P1 connection electric capacity C1 of rate module positive pole, the 3rd input and output P3 connection electric capacity C1 negative pole, second is defeated
Enter to export P2 connection A phase buses, the 4th input and output P4 connects the output end of the power subelement.
The each power subelement of the embodiment of the present invention is powered by phase-shifting transformer, then controls H respectively by control unit 2
The open and close of switching device are to power distribution network Injection Current in bridge.By set power supply subelement 30, power subelement 31~
33 and ground connection subelement 34, using power subelement for power subelement and ground connection subelement power supply, carried for compensation device
Energy supply amount.It can be seen that this programme can improve plant running reliability, simplify control strategy, when improving generation singlephase earth fault
The compensation degree of accuracy.
Subelement 34 is grounded in the embodiment of the present invention to be made up of at least two power models.It will be appreciated that the ground connection is sub
Unit 34 can have identical circuit structure with power subelement 31 (or power subelement 32, power subelement 33), have
Body circuit structure is referred to the circuit structure of power subelement, will not be repeated here.
It should be noted that power subelement and/or ground connection subelement use at least two power in the embodiment of the present invention
Module composition.For example, the quantity for the power model connected in the embodiment of the present invention and the relation of line voltage are：
UAB,BC,CA=VH×N；
Wherein, UAB,BC,CARepresent line voltage, VHH bridge rated outputs are represented, N is represented in power subelement and ground connection subelement
The quantity of H bridges and.
Power subelement and the quantity of ground connection subelement output-voltage levels number and power model meet：
Q=2 × N+1；
Wherein, Q represents output-voltage levels number.
In practical application, in the case where power distribution network busbar voltage is constant, the gradual step-down of partial pressure of each power model can
To improve the service life of power model；In the case where power model partial pressure is constant, it can suitably increase the number of power model
Amount, so that the more level active compensation devices of front-end power provided by the invention are applied in the power distribution network of greater degree voltage.
Those skilled in the art (when isolated neutral, or can occur singlephase earth fault, be good for according to power distribution network busbar voltage
Full phase voltage riseTimes, it is therefore desirable to configured according to line voltage) and power model pressure-resistant determination each power
The quantity of the power model of unit.
A kind of course of work of the more level active compensation devices of front-end power provided in an embodiment of the present invention includes：
During power distribution network normal work, the generation injection control signal of control unit 2 is sent to compensating unit 3.Compensating unit 3
The power subelement and ground connection subelement of ABC phases, switch letter are sent to according to injection control signal generation respective switch signal
Number be each power model in power electronic devices control terminal open and close signal, be connected to open and close signal when mend
Repay power subelement 31~33 in unit 2 to open, while be grounded subelement 34 and open, power distribution network, power subelement, ground connection are single
Loop is formed between member and ground.Then compensating unit is by controlling the open and close of power model to inject zero sequence to power distribution network
Electric current.Detection unit 1 now detects the residual voltage of power distribution network bus, according to Injection Current and the residual voltage of measurement, so that
The direct-to-ground capacitance and bleeder resistance of power distribution network can be obtained.It should be noted that in above process, ground connection subelement is kept
Opening, neutral point is set to keep ground connection.
When residual voltage exceedes residual voltage preset value, detection unit 1 judges that single-phase earthing event occurs for power distribution network bus
Barrier.As shown in figure 3, now control unit 2 calculates benefit according to the residual voltage currently measured and the direct-to-ground capacitance measured before
Repay the amplitude and phase of electric current.
Such as A, B, C phase voltage are before single-phase faultList occurs for A phases
Phase metallic short circuit, each phase voltage are changed into Power distribution network is measured before failure over the ground
Electric capacity is C and leak resistance is R, and capacitance current caused by power distribution network and Leakage Current sum are
It is I that compensation device, which produces compensation electric current,B=-I.
Control unit 2 generates compensating control signal according to above-mentioned compensation electric current and is sent to compensating unit 3.Compensating unit 3
According to above-mentioned compensating control signal to power distribution network bus (as shown in figure 3, as single phase metal earth fault, B phases and C phases occur for A phases
Produce compensation electric current, B phases compensate electric current and C phases compensate electric current and equal to the compensation electric current I calculatedB=-I) in injection mend
Electric current is repaid, so as in minimum value, avoid electric arc from occurring the current limit of single-phase fault point.In the mistake of above-mentioned injecting compensating electric current
Cheng Zhong, ground connection subelement keep ground state.
In practical application, according to the demand of different power distribution networks, the more level of front-end power provided in an embodiment of the present invention have
Source compensation device can have different compensation ways.For example, when power distribution network bus needs band singlephase earth fault operation, now
Electric current is compensated as capacity current and Leakage Current over the ground.When power distribution network needs quick excision singlephase earth fault, the compensation
Electric current is overcompensation electric current, can so start zero-sequenceprotection fast trip, so as to cut off faulty line and singlephase earth fault
Point.
In practical application, the bleeder resistance that the embodiment of the present invention measures can conveniently detect the insulation situation of power distribution network, carry
High security of distribution network energy.
In practical application, the more level active compensation devices of front-end power provided in an embodiment of the present invention are also used as idle
Compensation device uses, and now breaker disconnection is that power subelement is earth-free.According to the power factor of power distribution network bus, Ran Hougen
The control signal of the control action of compensating unit 3 is generated according to power factor, control power subelement compensates the idle and humorous of power distribution network
Ripple, so as to reach the purpose of regulation distribution network voltage quality.
Second aspect, the embodiment of the present invention additionally provide a kind of more level actives of front-end power being used for as described above and mended
The control method of device is repaid, as shown in figure 4, including：
S1, generation injection control signal make the compensating unit inject zero-sequence current to power distribution network bus, with described in acquisition
The direct-to-ground capacitance and bleeder resistance of power distribution network；
S2, the residual voltage for obtaining the power distribution network, when the residual voltage exceedes residual voltage preset value if judge
Generation singlephase earth fault；
S3, the amplitude and phase for compensating electric current are calculated according to the residual voltage and the direct-to-ground capacitance and leak resistance,
So that compensation electric current is injected into the power distribution network that singlephase earth fault occurs by the compensating unit.
Alternatively, also include before control signal is injected in generation：
The ground connection control signal of generation first is grounded compensating unit.
Alternatively, the compensation electric current is capacity current and Leakage Current over the ground.
Alternatively, when the residual voltage is not less than residual voltage preset value, the control method also includes：
Generation second ground connection control signal make the compensating unit with disconnect；
According to the amplitude and phase relation of the voltage and current of power distribution network ABC phases, compensation electric current is obtained and by the compensation
Unit is injected into the power distribution network bus to improve its power factor.
Alternatively, the quantity of the power model of series connection is calculated using following formula：
UAB,BC,CA=VH×N；
Wherein, UAB,BC,CARepresent line voltage, VHH bridge rated outputs are represented, N is represented in power subelement and ground connection subelement
The quantity of H bridges and.
As seen from the above, control method provided in an embodiment of the present invention is had based on the more level of front-end power described above
Source compensation device is realized, thus can solve same technical problem, and obtains identical technique effect, is no longer gone to live in the household of one's in-laws on getting married one by one herein
State.
In the present invention, term " first ", " second ", " the 3rd " are only used for describing purpose, and it is not intended that instruction or
Imply relative importance.Term " multiple " refers to two or more, is limited unless otherwise clear and definite.
Although being described in conjunction with the accompanying embodiments of the present invention, those skilled in the art can not depart from this hair
Various modifications and variations are made in the case of bright spirit and scope, such modifications and variations are each fallen within by appended claims
Within limited range.
Claims (11)
- A kind of 1. more level active compensation devices of front-end power, it is characterised in that including：Detection unit, control unit and compensation Unit；Wherein,The detection unit connects described control unit, for obtaining power distribution network residual voltage and being transferred to described control unit；Described control unit connects the compensating unit, for judging whether the power distribution network occurs list according to the residual voltage Phase earth fault simultaneously generates control signal；The compensating unit connects the power distribution network, in the presence of the control signal to the power distribution network injecting compensating Electric current or zero-sequence current.
- 2. the more level active compensation devices of front-end power according to claim 1, it is characterised in that the compensating unit bag Include the power subelement corresponding to the power distribution network ABC phases, ground connection subelement and power supply subelement；The input connection power distribution network bus of the power supply subelement, work(of the output end connection corresponding to the power distribution network ABC phases The power end of rate subelement；The first end of the power subelement of corresponding A BC phases connects corresponding single-phase bus respectively；Second end is connected to form neutrality Point；The first end of the ground connection subelement connects the neutral point, the second end ground connection.
- 3. the more level active compensation devices of front-end power according to claim 2, it is characterised in that the power subelement It is made up of at least two power models, at least two power models series connection；The ground connection subelement is by least two power Module composition, at least two power models series connection.
- 4. the more level active compensation devices of front-end power according to claim 3, it is characterised in that the power supply subelement For phase-shifting transformer；The phase-shifting transformer includes at least one primary side winding and multiple vice-side windings, and the multiple secondary Quantity sum of the quantity of winding no less than the power subelement and power model in the ground connection subelement；The primary side winding connects the power distribution network bus, and the vice-side winding connects power model one by one.
- 5. the more level active compensation devices of front-end power according to claim 3 or 4, it is characterised in that the power mould Block includes the H bridges that 4 switching devices and electric capacity are formed, and the three-phase commutation bridge that 6 diodes are formed；The positive pole of the negative pole connection electric capacity of first diode, positive pole connect the negative pole of the second diode and form the first power end, The positive pole of second diode connects the negative pole of the electric capacity；The negative pole of 3rd diode connects the positive pole of the electric capacity, and positive pole connects the negative pole of the 4th diode and forms second source End, the positive pole of the 4th diode connect the negative pole of the electric capacity；The negative pole of 5th diode connects the positive pole of the electric capacity, and positive pole connects the negative pole of the 6th diode and forms the 3rd power supply End, the positive pole of the 6th diode connect the negative pole of the electric capacity；First power end, the second source end and the 3rd power end are connected respectively to the ABC of corresponding vice-side winding Phase output terminal；The positive pole of the first end connection electric capacity of first switch device, the second end connect the first end of the 3rd switching device, and described the Second end of three switching devices connects the negative pole of the electric capacity；The positive pole of the first end connection electric capacity of second switch device, the second end connect the first end of the 4th switching device, and described the Second end of four switching devices connects the negative pole of the electric capacity.When the ground connection subelement or the power subelement are made up of at least two power models, first in the H bridges Second switch in switching device single-phase bus corresponding with the first end connection of the 3rd switching device or upper level power model Second end of device and the 4th switching device, second switch device is connected next stage power with the 4th switching device in the H bridges The first switch device of module and the first end or ground of the 3rd switching device.
- 6. the more level active compensation devices of front-end power according to claim 5, it is characterised in that the power model of series connection Quantity and the relation of line voltage be：UAB,BC,CA=VH×N；Wherein, UAB,BC,CARepresent line voltage, VHH bridge rated outputs are represented, N represents power subelement and H bridges in ground connection subelement Quantity and.
- 7. a kind of control method for being used for the more level active compensation devices of front-end power as described in any one of claim 1~6, It is characterised in that it includes：Generation injection control signal makes the compensating unit inject zero-sequence current to power distribution network bus, according to residual voltage, zero sequence Electric current is to obtain the direct-to-ground capacitance of the power distribution network and bleeder resistance；Obtain the residual voltage of the power distribution network, when the residual voltage exceedes residual voltage preset value if judge to occur it is single-phase Earth fault；The amplitude and phase of compensation electric current are calculated according to the residual voltage and the direct-to-ground capacitance and leak resistance, so that described Compensating unit is injected into the power distribution network of generation singlephase earth fault by electric current is compensated.
- 8. control method according to claim 7, it is characterised in that also include before control signal is injected in generation：The ground connection control signal of generation first is grounded compensating unit.
- 9. control method according to claim 8, it is characterised in that the compensation electric current is capacity current and leakage over the ground Electric current.
- 10. according to the control method described in any one of claim 7~9, it is characterised in that when the residual voltage is not less than zero During sequence voltage preset value, the control method also includes：Generation second ground connection control signal make the compensating unit with disconnect；According to the amplitude and phase relation of the voltage and current of power distribution network ABC phases, compensation electric current is obtained and by the compensating unit It is injected into the power distribution network bus to improve its power factor.
- 11. control method according to claim 7, it is characterised in that the quantity of the power model of series connection utilizes following table It is calculated up to formula：UAB,BC,CA=VH×N；Wherein, UAB,BC,CARepresent line voltage, VHH bridge rated outputs are represented, N represents power subelement and H bridges in ground connection subelement Quantity and.
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| CN107783010A (en) * | 2016-08-31 | 2018-03-09 | 中国石油化工股份有限公司 | A kind of more level active compensation devices of front-end power and control method |
| CN109782117A (en) * | 2019-03-29 | 2019-05-21 | 云南电网有限责任公司电力科学研究院 | A kind of ground fault disappearance method of discrimination based on controllable voltage source range-adjusting |
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