CN107785914A - 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 PDF

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Publication number
CN107785914A
CN107785914A CN201611026443.3A CN201611026443A CN107785914A CN 107785914 A CN107785914 A CN 107785914A CN 201611026443 A CN201611026443 A CN 201611026443A CN 107785914 A CN107785914 A CN 107785914A
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CN
China
Prior art keywords
power
end
distribution network
power distribution
subelement
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CN201611026443.3A
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Chinese (zh)
Inventor
李君�
姜俊莉
时振堂
孟凡中
钱志红
孙进
Original Assignee
中国石油化工股份有限公司
中国石油化工股份有限公司抚顺石油化工研究院
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Priority to CN201610798870 priority Critical
Priority to CN2016107988707 priority
Application filed by 中国石油化工股份有限公司, 中国石油化工股份有限公司抚顺石油化工研究院 filed Critical 中国石油化工股份有限公司
Publication of CN107785914A publication Critical patent/CN107785914A/en

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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for ac mains or ac distribution networks
    • H02J3/18Arrangements for adjusting, eliminating or compensating reactive power in networks
    • H02J3/1821Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for ac mains or ac distribution networks
    • H02J3/01Arrangements for reducing harmonics or ripples
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30Reactive 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

A kind of more level active compensation devices of front-end power and control method

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 includes the power subelement and power supply subelement corresponding to the power distribution network ABC phases;

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 power supply subelement respectively;Second end is connected to form neutrality Point, and neutral ground.

Alternatively, the power 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 be no less than the power subelement in power model quantity;

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 power subelement is made up of at least two power models, first switch device and the 3rd in the H bridges Second switch device and the 4th switch in single-phase bus or upper level power model corresponding to the first end connection of switching device Second end of device, second switch device is connected the first switch of next stage power model with the 4th switching device in the H bridges The first end or ground of device and 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 represents the quantity of H bridges in power subelement.

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 makes the compensating unit inject zero-sequence current to power distribution network bus, according to residual voltage and Zero-sequence current obtains the direct-to-ground capacitance and bleeder resistance of the power distribution network;

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, 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:

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 represents the quantity of power subelement H bridges.

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, compensating unit 2 includes the power subelement and supplied for electronic list of the ABC phases corresponding to power distribution network Member.The input connection power distribution network bus of power supply subelement, output end connection is corresponding to the power subelement of power distribution network ABC phases Power end;The first end of the power subelement of corresponding A BC phases connects corresponding single-phase bus respectively;During second end is connected to form Property point, the neutral ground.

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.In the embodiment of the present invention, by setting power supply subelement 30 to make the electric energy from power distribution network By power supply subelement 30 be supplied to ABC phase power subelements with the loop that forms.That is the more level active compensation of front-end power The energy of plant running consumption and the energy of active compensation are all from power distribution network.Compared with using DC capacitor electric supply installation, The more level active compensation devices of front-end power are powered using power supply unit, are increased system operation reliability, simplify control strategy, are carried Compensation degree of accuracy during singlephase earth fault occurs for height.

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 is advanced or lags the phase of primary side winding voltage.That is the secondary of the phase-shifting transformer Side harmonic wave electric wave can be offset after converting to primary side side.After multi-pulse rectification, low-order harmonic cancels each other, and harmonic wave contains in power distribution network It is rectification pulse number to measure as n=mk ± 1, wherein m, 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 It is 30 pulse wave rectifiers (360 °/12 °=30) that phase-shifting transformer, which has 5 secondary windings, each 12 ° of winding phase shift.Also, by being somebody's turn to do It is injected into after phase-shifting transformer by power subelement in the compensation electric current in power distribution network and is free of less than 29 times harmonic waves.

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, percent harmonic distortion is low.In other words, in the present invention when using the phase-shifting transformer of N pulse waves, rectification is being carried out to the N pulse waves N-1 following harmonic wave of Shi Buhan, and increasing with rectification pulse number, harmonic content is lower.

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 ground.Each power subelement is connected with control unit 2, every in the presence of control signal Power distribution network injecting compensating electric current of the individual power subelement 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 power subelement is made up of at least two power models, first switch device and the 3rd in the H bridges Second switch device and the 4th switch in single-phase bus or upper level power model corresponding to the first end connection of switching device Second end of device, second switch device is connected the first switch of next stage power model with the 4th switching device in the H bridges The first end or ground of device and 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 output end connection ground connection of power model.When power subelement is made up of 1 power model, the first input of the power model Export P1 connection electric capacity C1 positive pole, the 3rd input and output P3 connection electric capacity C1 negative pole, the second input and output P2 connection A phases mother Line, the 4th input and output P4 connect 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.

One end is directly grounded at the neutral point of power subelement in the embodiment of the present invention, can so simplify circuit, is saved Investment.

When power subelement is formed using at least two power models in the embodiment of the present invention, with the increasing of power model Add, in the case where power distribution network busbar voltage is constant, the gradual step-down of partial pressure of each power model, so as to apply higher In voltage gradation.

The quantity of power model, the quantity and line of the power model connected in the embodiment of the present invention are rationally set for convenience The relation of voltage is:

UAB,BC,CA=VH×N;

Wherein, UAB,BC,CARepresent line voltage, VHH bridge rated outputs are represented, N represents the quantity of H bridges in power subelement.

The quantity of power subelement output-voltage levels number and power model meets:

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 of ABC phases is sent to according to injection control signal generation respective switch signal, the switching signal is each power The open and close signal of switching device control terminal in module, power in compensating unit 2 when being connected to open and close signal Unit 31~33 is opened and (when setting ground connection subelement, opened simultaneously), is formed back between power distribution network, power subelement and ground Road.Then compensating unit is by controlling the open and close of power model to inject zero-sequence current to power distribution network.Detection unit 1 is now The residual voltage of power distribution network bus is detected, according to Injection Current and the residual voltage of measurement, so as to obtain pair of power distribution network Ground electric capacity and bleeder resistance.It should be noted that in above process, if ground connection subelement is set, the ground connection subelement Need to keep it turned on, neutral point is kept 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 fault A phases occur Single phase metal short circuit, each phase voltage are changed into Power distribution network pair is measured before failure Ground electric capacity is C and leak resistance is R, and capacitance current caused by power distribution network and Leakage Current sum areIt 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 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.

The more level active compensation devices of front-end power provided in an embodiment of the present invention, which are also used as reactive power compensator, to be made With,.The detection unit 1 of control unit 2 obtain residual voltage so as to obtain the power factor of power distribution network bus, then according to power because The control signal that number generation control compensating unit 3 acts, the idle and harmonic wave of control power subelement compensation power distribution network, so as to reach To 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, according to zero sequence electricity Pressure and zero-sequence current obtain the direct-to-ground capacitance and bleeder resistance of the 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, 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:

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 represents the quantity of H bridges in power subelement.

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 (10)

  1. 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. 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 and power supply subelement corresponding to the power distribution network ABC phases;
    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 and the neutral-point solid ground.
  3. 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.
  4. 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 The quantity of winding is no less than the quantity of power model in the power subelement;
    The primary side winding connects the power distribution network bus, and the vice-side winding connects power model one by one.
  5. 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 power subelement is made up of at least two power models, first switch device and the 3rd switch in the H bridges Second switch device and the 4th switching device in single-phase bus or upper level power model corresponding to the first end connection of device The second end, second switch device is connected the first switch device of next stage power model with the 4th switching device in the H bridges With the first end or ground of the 3rd switching device.
  6. 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 the quantity of power subelement H bridges.
  7. 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 and zero sequence Electric current obtains the direct-to-ground capacitance and bleeder resistance of the power distribution network;
    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. 8. control method according to claim 7, it is characterised in that the compensation electric current is capacity current and leakage over the ground Electric current.
  9. 9. the control method according to claim 7 or 8, it is characterised in that when the residual voltage is not less than residual voltage During preset value, the control method also includes:
    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.
  10. 10. 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 the quantity of power subelement H bridges.
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