CN108365624A - Flexible DC power transmission exchange side fault traversing and transverter energy Synergistic method - Google Patents
Flexible DC power transmission exchange side fault traversing and transverter energy Synergistic method Download PDFInfo
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- CN108365624A CN108365624A CN201710180262.4A CN201710180262A CN108365624A CN 108365624 A CN108365624 A CN 108365624A CN 201710180262 A CN201710180262 A CN 201710180262A CN 108365624 A CN108365624 A CN 108365624A
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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
- H02J3/36—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
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- 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]
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Electrical Variables (AREA)
Abstract
The shortcomings that the invention discloses for overcoming traditional imbalance fault control strategy of MMC HVDC and propose a kind of exchange side fault traversing regulation and control and transverter energy compatibility method, non-linear current control algolithm is combined together by this regulation and control method with symmetrical component method, constitute a kind of control system that can handle exchange side imbalance fault, coordinate the balance of inverter inside energy, effectively simplify inner ring current control structure, link is decoupled without PI controllers and dq, reduce the complexity of control, improve the dynamic stability of flexible direct current power transmission system, it ensure that the lasting safe and stable operation ability of system.The non-linear current control algolithm is applicable not only to MMC HVDC exchange side imbalance fault situations, is also applied for the exchange side balance of voltage and does not have the case where failure.
Description
Technical field
The present invention relates to a kind of flexible DC power transmission exchange side fault traversings and transverter energy Synergistic method, belong to electric power
Technical field.
Background technology
As the generations of electricity by new energy such as wind energy, solar energy large-scale development and large size city power load are grown rapidly, realize
Energy supply and demand wide area balances and more urgent, the flexible DC power transmission (MMC- based on modularization multi-level converter that interconnects
HVDC) it is the technology for solving extensive new energy and efficiently accessing, but complicated in moving law and operation mechanism description in it, therefore
How exchange side fault traversing regulation and control are realized with transverter energy Collaborative Control, and the failure protection capability etc. for improving transmission system is asked
Topic there is still a need in face of with solution.
At present in practical engineering application, when serious three phase short circuit fault occurs for power grid, pass through flexible alternating current
Control, makes transverter output current be reduced to zero, can reduce the short circuit current of transverter feed-in AC system, such MMC-HVDC
Other side AC system sprawling of the side fault in ac transmission system to connection can be blocked；When three-phase imbalance event occurs in AC system
When barrier, the fluctuation of power will change the Energy distribution of bridge arm submodule, and the change of energy will cause submodule capacitor voltage not
The imbalance of balance, submodule capacitor voltage will generate a large amount of harmonic circulating current in bridge arm, and the presence of harmonic current will increase
Transverter is lost, and influences output voltage/electric current quality.Unbalance control strategy common during exchange side failure is such as double at present
Dq-pi and α β-PR exist and need dynamic responding speed during the positive and negative sequence decomposition of voltage and current, control structure complexity, transient state
The shortcomings of relatively slow, needs carry out instruction current calculating according to different control targes, when network voltage is symmetrical, 2 subharmonic circulation
Three phase circulations are distributed according to negative phase-sequence to cancel out each other, may not flow into the DC side of MMC-HVDC, network voltage is not right between three-phase
When title, in addition to negative sequence component, 2 subharmonic circulation may also contain positive sequence and zero-sequence component, and positive and negative sequence component three-phase mutually supports
Disappear, do not interfere with the DC side of MMC-HVDC, and zero-sequence component will flow into DC side, leads to DC voltage, DC current and straight
It flows side power and generates fluctuation, and 2 harmonics of DC current will flow into other current conversion stations by DC power transmission line.Therefore
The present inventor proposes the regulation and control of exchange side fault traversing and the transverter energy compatibility method of a kind of MMC-HVDC, by non-linear current
Control algolithm is combined together with symmetrical component method, constitutes a kind of control system that can handle exchange side imbalance fault, association
The balance of transverter internal energy is adjusted to ensure that continuing for system to improve the dynamic stability of flexible direct current power transmission system
Safe and stable operation ability.
Invention content
The shortcomings that it is an object of the invention to overcome traditional imbalance fault control strategy and propose a kind of flexible direct current
Transmission of electricity exchange side fault traversing and transverter energy Synergistic method, this method use non-linear current control algolithm, effectively simplify
Inner ring current control structure decouples link without PI controllers and dq, reduces the complexity of control, and according to exchange side failure
Collaborative Control inverter inside energy, improves the ability of flexible direct current power transmission system safe and stable operation.
The technical characteristic of the present invention is as follows：
A kind of flexible DC power transmission exchange side fault traversing and transverter energy Synergistic method, this method is using outer shroud
Voltage controls, the double -loop control mode of inner ring non-linear current control.Non-linear current control algolithm is a kind of according to three-phase electricity
Flow reference valueIt come the simple algorithm controlled, is controlled compared to conventional voltage, simplifies inner ring PI controls and dq decouples link.It is logical
Cross the voltage v of selection MMC outputs0, allow the electric current i of each phaseg(g=a, b, c) is in reference valueRange
It is interior.
In the exchange side balance of voltage and when do not have failure, non-linear current control algolithm controls active-power P*And nothing
Work(power Q*, dq shaft current components can be found out by formula (1) (2)WithReference value, by dq/ α β and α β/abc coordinate systems
Transformation finds out three-phase currentReference value, upper and lower bridge arm submodule in the conduction state is obtained by modulation strategy
Number of blocks nupiAnd nlowi, submodule capacitor voltage is balanced finally by sort algorithm, inverter inside energy hole is made to reach
Most preferably.
When exchange side breaks down, either singlephase earth fault or phase-to phase fault all can cause voltage not
Non-linear current control algolithm is combined together by balance, the present invention with symmetrical component method, and exchange side can be handled by constituting one kind
The control system of imbalance fault completes the Collaborative Control of exchange side fault traversing and inverter inside energy.The system can be with
The independent reference value for calculating forward-order current and negative-sequence current, and linear combination can be carried out to forward-order current and negative-sequence current
To obtain the reference value of combination current.Active-power P and reactive power Q can be expressed as the letter of positive-negative sequence voltage and current
Number.
Description of the drawings
Fig. 1 is the structure diagram of non-linear current control algolithm.
Fig. 2 is structure diagram of the non-linear current control system under imbalance fault.
Specific implementation mode
Below with reference to figure, invention is further described in detail with specific implementation process：
When the MMC exchange side balance of voltage and when there is no failure, the output voltage u of MMC0It only takes and network voltage ugMost
Similar value, upper and lower bridge arm voltage are respectivelyWith Wherein k=nlow, led for lower bridge arm
Logical submodule number, UDCFor MMC DC voltages, uCFor submodule capacitor voltage, Fig. 1, which gives, calculates MMC upper and lower bridge arms
The submodule number purpose algorithm of conducting,Floor is downward bracket function.
In the system that inner ring as shown in Figure 2 control is non-linear current control, when imbalance fault occurs for MMC exchange side
When, the symmetrical component method eliminated first by using postpones signal is by network voltage uabcIt is decomposed into positive-sequence component upWith negative phase-sequence point
Measure un, the PI controllers of top to power grid by injecting positive sequence reactive powerTo make positive sequence voltageStablize in rated value, but
It isValue limited by MMC rated current, in order to ensure positive sequence active power be 0, by the reference value of d axis forward-order currents
It is set as 0, by the forward-order current reference value of dq axisWithThe reference value of three-phase forward-order current can be found out with positive sequence phase angle thetaIn the PI controllers of lower section, by the reference value of negative sequence voltageIt is set as 0, PI controller output currents
Since negative phase-sequence reactive power can change negative sequence voltage un,Value again limited by MMC rated current, in order to ensure negative phase-sequence
Active power is 0, by d axis negative-sequence current reference valuesAlso it is set as 0, by negative-sequence current reference valueWithWith negative phase-sequence phase angle theta
The reference value of three-phase negative/positive electric current can be found out Finally by the normal of positive-negative sequence current reference value and PI controllers
Number finds out the reference value of three-phase current Finally show that upper and lower bridge arm is on shape according to novel coordination control strategy
The submodule quantity n of stateupiAnd nlowi, realize the Collaborative Control of exchange side fault traversing and transverter energy.
Claims (2)
1. the regulation and control of exchange side fault traversing and the transverter energy compatibility method of a kind of MMC-HVDC, it is characterised in that：It uses
It is outer loop voltag control, the double -loop control mode of inner ring non-linear current control, non-linear current control is a kind of according to three-phase
Current reference valueIt come the simple algorithm controlled, is controlled compared to conventional voltage, it decouples link without PI controllers and dq, has
Effect simplifies inner ring current control structure.When exchange side breaks down, by non-linear current control algolithm and symmetrical point
Amount method is combined together, and constitutes a kind of control system that can handle exchange side imbalance fault, coordinates inverter inside energy
Balance ensure that the lasting safe and stable operation ability of system to improve the dynamic stability of flexible direct current power transmission system.
2. according to claim 1, the regulation and control of exchange side fault traversing and the transverter energy compatibility method of the MMC-HVDC are answered
MMC-HVDC is used to be characterized in that：1. the reference input of the non-linear current control is three-phase current2. the exchange
Side fault traversing regulates and controls method and uses non-linear current control algolithm when exchanging lateral balance, and being used in imbalance fault will be non-
The method that linear current control algolithm is combined with symmetrical component method.3. the control system of the processing exchange side imbalance fault can
With the independent reference value for calculating forward-order current and negative-sequence current.4. the control system of the processing exchange side imbalance fault exists
When fault traversing with inverter inside energy Collaborative Control.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201710180262.4A CN108365624A (en) | 2017-03-23 | 2017-03-23 | Flexible DC power transmission exchange side fault traversing and transverter energy Synergistic method |
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| CN201710180262.4A CN108365624A (en) | 2017-03-23 | 2017-03-23 | Flexible DC power transmission exchange side fault traversing and transverter energy Synergistic method |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110350571A (en) * | 2019-07-15 | 2019-10-18 | 贵州电网有限责任公司 | A kind of control method promoting flexible DC transmission exchange side fault ride-through capacity |
| CN110994660A (en) * | 2019-11-07 | 2020-04-10 | 长沙理工大学 | MMC power operation interval optimization method based on energy flow law |
| CN112952855A (en) * | 2021-03-31 | 2021-06-11 | 中国电建集团华东勘测设计研究院有限公司 | MMC fault ride-through method based on smooth switching of current instruction |
| CN114256854A (en) * | 2020-09-21 | 2022-03-29 | 南京南瑞继保电气有限公司 | Fault ride-through method and control system for flexible direct current transmission system |
| CN114336723A (en) * | 2020-09-29 | 2022-04-12 | 南京南瑞继保电气有限公司 | Island fault ride-through control method and device for converter of flexible direct current transmission system |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110350571A (en) * | 2019-07-15 | 2019-10-18 | 贵州电网有限责任公司 | A kind of control method promoting flexible DC transmission exchange side fault ride-through capacity |
| CN110994660A (en) * | 2019-11-07 | 2020-04-10 | 长沙理工大学 | MMC power operation interval optimization method based on energy flow law |
| CN114256854A (en) * | 2020-09-21 | 2022-03-29 | 南京南瑞继保电气有限公司 | Fault ride-through method and control system for flexible direct current transmission system |
| CN114336723A (en) * | 2020-09-29 | 2022-04-12 | 南京南瑞继保电气有限公司 | Island fault ride-through control method and device for converter of flexible direct current transmission system |
| CN114336723B (en) * | 2020-09-29 | 2024-02-02 | 南京南瑞继保电气有限公司 | Island fault ride-through control method and device for converter of flexible direct current transmission system |
| CN112952855A (en) * | 2021-03-31 | 2021-06-11 | 中国电建集团华东勘测设计研究院有限公司 | MMC fault ride-through method based on smooth switching of current instruction |
| CN112952855B (en) * | 2021-03-31 | 2022-06-10 | 中国电建集团华东勘测设计研究院有限公司 | MMC fault ride-through method based on smooth switching of current instruction |
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