CN110474341A - A kind of mixed type MMC flexible direct-current transmission system brownout operation control method - Google Patents
A kind of mixed type MMC flexible direct-current transmission system brownout operation control method Download PDFInfo
- Publication number
- CN110474341A CN110474341A CN201910726094.3A CN201910726094A CN110474341A CN 110474341 A CN110474341 A CN 110474341A CN 201910726094 A CN201910726094 A CN 201910726094A CN 110474341 A CN110474341 A CN 110474341A
- Authority
- CN
- China
- Prior art keywords
- mmc
- mixed type
- brownout operation
- reactive power
- transmission system
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- 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
- H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
- H02J3/16—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by adjustment of reactive power
-
- 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
- H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
-
- 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
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/483—Converters with outputs that each can have more than two voltages levels
-
- 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
-
- 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
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
Abstract
The invention discloses a kind of mixed type MMC flexible direct-current transmission system brownout operation control methods, comprising the following steps: determines that the step-down coefficient η of MMC DC side exchanges with MMC the burning voltage U of side according to service requirement；The AC system voltage U of MMC exchange side when obtaining brownout operationsAnd reactive power Qv, obtain the power factor of MMC exchange sideIfIt then carries out in next step, otherwise, returns to previous step；Judge that MMC exchanges side operating condition, if Us> U then controls MMC and absorbs certain reactive power, by power factorIt adjusts to 1.45 η；If Us≤ U then controls MMC and issues certain reactive power output, by power factorIt adjusts to 1.45 η.Control method of the invention, it is realized by the original control ability of control system itself, it solves the problems, such as that bridge arm submodule can not be pressed when mixed type MMC flexible direct-current transmission system brownout operation, enhances mixed type MMC and realize brownout operation ability and improve the fault ride-through capacity in the case of the reduction of the DC voltages such as DC line insulation fault.
Description
Technical field
The present invention relates to flexible DC transmission technologies, and in particular to a kind of mixed type MMC flexible direct-current transmission system decompression
Progress control method.
Background technique
Flexible DC transmission technology rapidly develops in recent years, and extra-high voltage flexible DC transmission demonstration project also gradually open by landing
Work construction, compared to conventional high-pressure direct current transportation, extra-high voltage direct-current transmission is higher to system insulation level requirement, in severe gas
Time condition, pollution severity etc. easily occur under the environmental conditions such as Insulation Problems, if direct current overhead transmission line is still in rated direct voltage
It is run under (extra-high voltage), higher failure rate may be generated, it, need to be using drop for the reliability and availability for improving transmission line of electricity
Pressure mode is run；On the other hand, in the case where DC line fault DC voltage reduces, maintaining MMC, (modular multilevel is changed
Stream device) stably and controllable the power grid of stabilizing and increasing for maintaining network system is resisted by failures all have very great meaning
Justice.But based on the flexible HVDC transmission system of mixed type MMC, after DC voltage is reduced to a certain extent, MMC bridge arm current can go out
The case where existing permanent negative (or perseverance is just).MMC operation characteristic define half-bridge submodule be only capable of in the case where bridge arm current is positive into
Row charging, submodule carry out the Pressure and Control that periodical charge and discharge process is just able to achieve submodule in bridge arm.As bridge arm current is
Perseverance is negative, the half-bridge submodule in MMC will be caused to be chronically at the natural electric discharge under excision state, voltage will be gradually decreased, and be caused
Submodule cannot achieve Pressure and Control in MMC bridge arm, and it is other due to under-voltage fault to will appear whole half-bridge submodules under serious conditions
Road is out of service, and direct current system is caused to stop transport, and seriously threatens the stable operation of MMC.
For mixed type MMC flexible direct-current transmission of electricity brownout operation control problem, application publication number 201610865144.2
Chinese patent disclose a kind of control method, this method was proposed in the mixed type MMC flexible direct-current transmission system brownout operation phase
Between, by injecting 15~25HZ low frequency circulation to mixed type MMC bridge arm, realize that bridge arm current has just by way of increasing circulation
There is negative operating status, and then realizes that the half-bridge submodule in mixed type MMC can carry out normally in direct current system brownout operation
Charge and discharge process, solve the problems, such as that bridge arm submodule can not be pressed when mixed type MMC flexible direct-current transmission system brownout operation.
But the method, there are obvious drawback, circulation can occupy the capacity of bridge arm prototype part between increased bridge arm, cause additional loss.
Common practice be control system take certain measure by loop current suppression between bridge arm be 0, therefore this method by increase circulation
Control method disagreed with existing control mode.
Summary of the invention
The object of the present invention is to provide a kind of mixed type MMC flexible direct-current transmission system brownout operation control methods, with solution
The problem of certainly bridge arm submodule can not be pressed when mixed type MMC flexible direct-current transmission system brownout operation.
In order to achieve the above object, the technical solution adopted by the present invention is that:
A kind of mixed type MMC flexible direct-current transmission system brownout operation control method, it is characterised in that: including following step
It is rapid:
Determine that the step-down coefficient η of MMC DC side exchanges with MMC the burning voltage U of side according to service requirement；
The AC system voltage U of MMC exchange side when obtaining brownout operationsAnd reactive power Qv, obtain the function of MMC exchange side
Rate factor
IfIt then carries out in next step, otherwise, returns to previous step；
Judge that MMC exchanges side operating condition, if Us> U then controls MMC and absorbs certain reactive power, by power because
NumberIt adjusts to 1.45 η；If Us≤ U then controls MMC and issues certain reactive power output, by power factorIt adjusts
It is whole to 1.45 η.
Compared with the prior art, the advantages of the present invention are as follows:
1, control method of the invention, asking of can not pressing of half-bridge submodule in bridge arm when can effectively solve brownout operation
Topic, greatly strengthen mixed type MMC brownout operation ability, improve the DC voltages such as DC line insulation fault reduce in the case of
Fault ride-through capacity.
2, control method of the invention realizes system brownout operation based on own reactive control performance, does not generate new fortune
Row drawback only relies on the original control performance of control system itself and realizes, be not required to the new controller of additional designs, realizes simple.
3, control method of the invention, by suitably adjusting the idle interaction of MMC, bridge arm current can be realized having just has
It is negative, it is ensured that all submodules well presses in MMC bridge arm.
4, control method of the invention, the idle interactive adjustment amount of MMC fully consider exchange side system operating condition, realize
Mixed type MMC provides Reactive-power control support to AC system while promoting brownout operation ability, and it is steady to be conducive to AC system
Fixed operation.
Detailed description of the invention
Fig. 1 is the topological structure of mixed type MMC；
Fig. 2 is the flow chart of control method of the invention.
Specific embodiment
In order to make the foregoing objectives, features and advantages of the present invention clearer and more comprehensible, with reference to the accompanying drawing and specific real
Applying mode, the present invention is described in further detail.
Mixed type MMC is made of 6 bridge arms, and each bridge arm is by N number of submodule and bridge arm reactor L0It constitutes, bridge arm submodule
Block includes a certain number of full-bridge submodules and half-bridge submodule, and topological structure and electrical quantity mark are as shown in Figure 1.
According to MMC basic functional principle, three bridge arms are in the case where full symmetric: working direct current IdcIt is mutually single at 3
Mean allocation in member, i.e., the DC current in each phase element areAlternating current in each phase element is then divided equally in upper and lower
Bridge arm, wherein a, b, c represent A, B, C phase, accordingly, the available following relationship (1) by taking A phase phase element as an example:
In above formula, ipaFor bridge arm current on A phase phase element, inaFor A phase phase element lower bridge arm electric current, IdcFor MMC DC side
Electric current, ivaSide A phase, which is exchanged, for MMC exports electric current, IvmSide A phase, which is exchanged, for MMC exports current amplitude,It is defeated that side A phase is exchanged for MMC
Current phase out.
It is smaller to consider that inverter loss accounts for compared with transimission power simultaneously, there are following relationship (2) for approximation:
That is:
In above formula, PvSide active power, P are exchanged for MMCdcFor MMC DC side power, UdcFor MMC DC voltage, UvFor
MMC exchanges output line voltage virtual value, IvOutput line current effective value is exchanged for MMC,For MMC exchange side power because
Number, value interval be (0,1], the above-mentioned available relational expression of two formulas (3) of simultaneous:
Under determining operating condition, power factorValue be it is determining, for company, flexible HVDC transmission system institute
The AC system connect is strong AC system, alternating voltage UvSubstantially constant can be maintained, so with DC voltage UdcDecline,
It will appear following relational expression (4):
Wherein,For the step-down coefficient of MMC DC side, U 'dcMMC DC side when for direct current system brownout operation
Virtual voltage inverter side (I will occur for relational expression (3) when operating condition meets relational expression (4)dcIt is positive) bridge arm current
Perseverance is positive, rectification side (IdcIt is negative) bridge arm current perseverance the case where being negative.In MMC operation characteristic half-bridge submodule be only capable of be in electric current
Timing is charged, and the case where bridge arm current is persistently negative such as occurs, then half-bridge submodule will be continuously maintained in excision state,
Into nature discharge condition, half-bridge submodule voltage will be reduced persistently, and submodule cannot achieve Pressure and Control in MMC bridge arm, sternly
Ghost image rings the control performance of MMC and threatens system stable operation.
In this regard, proposing the HVDC transmission system of mixed type MMC a kind of the present invention is based on the feature of relational expression (4)
Brownout operation control method, core concept be by MMC reactive power can independent control characteristic, it is appropriate increase MMC without
Function power production (absorption) is measured to adjust and reduce power factorAvoid the occurrence of the operating condition of relational expression (4), it is ensured that relational expression
(3) bridge arm current have just have it is negative, as shown in Fig. 2, it mainly realizes that steps are as follows:
(1) determine that the step-down coefficient η of MMC DC side exchanges with MMC the burning voltage U of side according to service requirement；
(2) the AC system voltage U of MMC exchange side when obtaining brownout operationsAnd reactive power Qv, obtain MMC exchange side
Power factor
(3) ifIt then carries out in next step, otherwise, returns to previous step, system operates normally；
(4) judge that MMC exchanges side operating condition；
If Us> U illustrates then to control MMC absorption compared to AC network reactive power is sufficient at this time under normal conditions
Certain reactive power, by power factorIt adjusts to 1.45 η；
If Us≤ U illustrates then to control MMC sending compared to AC network reactive power lacks at this time under normal conditions
Certain reactive power, by power factorIt adjusts to 1.45 η；
Wherein, the reactive power Δ Q that MMC is absorbed or issuedvxCalculation formula it is as follows:
In formula, PvSide active power, Q are exchanged for MMCvSide reactive power is exchanged to adjust preceding MMC, η is step-down coefficient；It needs
It should be noted that the reactive power after adjusting cannot be greater than the maximum value that MMC allows.
Control method of the invention is realized by the original control ability of control system itself, is not needed additional designs again
New controller realizes simply, while not generating new operation drawback solve mixed type MMC flexible direct-current transmission system drop
The problem of bridge arm submodule can not be pressed when pressure operation enhances mixed type MMC and realizes brownout operation ability and improve direct current
Fault ride-through capacity in the case of the reduction of the DC voltages such as line insulation failure.
Above-listed detailed description is illustrating for possible embodiments of the present invention, and the embodiment is not to limit this hair
Bright the scope of the patents, all equivalence enforcements or change without departing from carried out by the present invention, is intended to be limited solely by the scope of the patents of this case.
Claims (2)
1. a kind of mixed type MMC flexible direct-current transmission system brownout operation control method, it is characterised in that: the following steps are included:
Determine that the step-down coefficient η of MMC DC side exchanges with MMC the burning voltage U of side according to service requirement；
The AC system voltage U of MMC exchange side when obtaining brownout operationsAnd reactive power Qv, obtain MMC exchange side power because
Number
IfIt then carries out in next step, otherwise, returns to previous step；
Judge that MMC exchanges side operating condition, if Us> U then controls MMC and absorbs certain reactive power, by power factorIt adjusts to 1.45 η；If Us≤ U then controls MMC and issues certain reactive power output, by power factorAdjustment
To 1.45 η.
2. a kind of mixed type MMC flexible direct-current transmission system brownout operation control method according to claim 1, feature
Be: the reactive power after adjusting cannot be greater than the maximum value that MMC allows.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910726094.3A CN110474341B (en) | 2019-08-07 | 2019-08-07 | Voltage reduction operation control method for hybrid MMC flexible direct current power transmission system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910726094.3A CN110474341B (en) | 2019-08-07 | 2019-08-07 | Voltage reduction operation control method for hybrid MMC flexible direct current power transmission system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110474341A true CN110474341A (en) | 2019-11-19 |
| CN110474341B CN110474341B (en) | 2020-09-22 |
Family
ID=68510348
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910726094.3A Active CN110474341B (en) | 2019-08-07 | 2019-08-07 | Voltage reduction operation control method for hybrid MMC flexible direct current power transmission system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110474341B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111509712A (en) * | 2020-05-15 | 2020-08-07 | 南方电网科学研究院有限责任公司 | Multi-terminal main loop transformation method of direct current transmission system |
| CN111725832A (en) * | 2020-06-05 | 2020-09-29 | 西安交通大学 | Direct-current side voltage indirect control method of multi-terminal flexible power transmission system based on simplified offline algorithm |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011065253A1 (en) * | 2009-11-26 | 2011-06-03 | 株式会社日立製作所 | Power conversion device |
| CN106357141A (en) * | 2016-09-29 | 2017-01-25 | 国网青海省电力公司经济技术研究院 | Reduced voltage operation method for hybrid MMC-HVDC (modular multilevel converter based high voltage direct current) system |
-
2019
- 2019-08-07 CN CN201910726094.3A patent/CN110474341B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011065253A1 (en) * | 2009-11-26 | 2011-06-03 | 株式会社日立製作所 | Power conversion device |
| CN106357141A (en) * | 2016-09-29 | 2017-01-25 | 国网青海省电力公司经济技术研究院 | Reduced voltage operation method for hybrid MMC-HVDC (modular multilevel converter based high voltage direct current) system |
Non-Patent Citations (1)
| Title |
|---|
| 王坤等: "交流侧故障时MMC-HVDC换流单元的控制策略探讨", 《广西电力》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111509712A (en) * | 2020-05-15 | 2020-08-07 | 南方电网科学研究院有限责任公司 | Multi-terminal main loop transformation method of direct current transmission system |
| CN111725832A (en) * | 2020-06-05 | 2020-09-29 | 西安交通大学 | Direct-current side voltage indirect control method of multi-terminal flexible power transmission system based on simplified offline algorithm |
| CN111725832B (en) * | 2020-06-05 | 2022-02-22 | 西安交通大学 | Direct-current side voltage indirect control method of multi-terminal flexible power transmission system based on simplified offline algorithm |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110474341B (en) | 2020-09-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107947221B (en) | Power electronic transformer direct-current fault ride-through method | |
| CN108964097B (en) | Pumped storage and renewable energy power generation cooperative operation system and method | |
| TWI774142B (en) | Ac load power supply system and method | |
| CN110212565A (en) | A kind of dc power control strategy inhibiting continuous commutation failure | |
| CN105656067B (en) | Multistage online mobile energy storage power supply system and control method thereof | |
| CN102222937A (en) | Photovoltaic grid-connected inverter and grid-connected control method thereof | |
| CN106026142B (en) | three-phase load unbalance compensation method and system | |
| CN106026122B (en) | A kind of method that asynchronous excitation integrates phase modifier and its reactive-load compensation and active balance | |
| CN102593832A (en) | Three-wire DC microgrid system suitable for modern buildings and control method thereof. | |
| CN112018785B (en) | Receiving-end power grid flywheel energy storage frequency modulation method and system based on frequency disturbance complementation | |
| CN110474341A (en) | A kind of mixed type MMC flexible direct-current transmission system brownout operation control method | |
| CN202488205U (en) | Novel serial-parallel conversion-type UPS | |
| CN104993520A (en) | Frequency converter low-voltage ride-through (LVRT) supporting apparatus based on super capacitor | |
| CN109217379A (en) | It is a kind of with from the cascade connection type energy-storage system black-start method of the ability of equalization and application | |
| CN108631293B (en) | DC/DC converter operation mode for DC distribution network and control method | |
| CN110165685B (en) | Storage battery energy storage inverter and control method thereof | |
| CN204515032U (en) | A kind of proving installation of energy feedback unit | |
| CN103606924A (en) | Dynamic voltage compensation apparatus and method | |
| CN113725848A (en) | Off-grid type light storage diesel power supply system and method for avoiding frequent switching of operation modes | |
| WO2017132802A1 (en) | Inverter control device and method for energy interconnection and energy storage of ac bus | |
| CN105449662A (en) | Method for determining direct current isolated island operation control measures | |
| CN210838950U (en) | Device for active demand power flow transfer between double-circuit power supply systems | |
| CN111864762B (en) | Reactive power coordination control method for hybrid multi-feed-in direct current system for reducing switching of filter | |
| CN111969627A (en) | Electric energy quality optimization system and island microgrid | |
| Wong et al. | Simplified benchtop model of a distributed energy resource management system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |