CN107994573A - A kind of Multi-end flexible direct current transmission system multi-objective optimization design of power method - Google Patents
A kind of Multi-end flexible direct current transmission system multi-objective optimization design of power method Download PDFInfo
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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
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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
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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
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
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- 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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Abstract
The invention discloses a kind of Multi-end flexible direct current transmission system multi-objective optimization design of power method, including：Build Multi-end flexible direct current transmission system model；Start Multi-end flexible direct current transmission system model emulation；The DC capacitor voltage of detection each submodule of Multi-end flexible direct current transmission system in real time；Basis for estimation of the direction of monitoring each bridge arm current of Multi-end flexible direct current transmission system as capacitance charging and discharging in real time；Calculate the submodule quantity m opened required for j-th of bridge arm of each the i-th end of switch periods VSCij, pass through parameters revision capacitance voltage to be optimized；The input excision state of determination sub-module is simultaneously issued to control system, establishes voltage fluctuation object function and on-off times object function during stable operation；Using the optimal solution set of multi-objective genetic algorithm solving-optimizing variable.The present invention meets preferable balance of voltage effect and relatively low switching frequency at the same time, both is admirably achieved requirement, and computational efficiency higher, is particularly suitable for the occasion of Multi-end flexible direct current transmission.
Description
Technical field
The present invention relates to technical field of new energy power generation, more particularly to a kind of Multi-end flexible direct current transmission system multiple target
Optimum design method.
Background technology
Multi-end flexible direct current transmission system (Voltage Source Converter Multi-terminal HVDC,
VSC-MTDC) refer under same direct current rack, contain 3 and above voltage source converter station (voltage source
Converter, VSC) flexible direct current power transmission system.Its most significant feature is to realize multiple feed, more drop points
By electricity.As a kind of more flexible, efficiently power transmission mode, Multi-end flexible direct current transmission system the new-energy grid-connecteds such as wind-powered electricity generation,
Constructing the fields such as city DC distribution net will have broad application prospects.With the fast development of voltage source converter, it is based on
The DC transmission system of voltage source converter has become the main trend of DC transmission system development.In numerous voltage sources
In transverter topology, based on H half-bridge cascade modularization multi-level converter (MMC), because switching frequency is low, harmonic content is small,
One of the advantages that any level can be extended to, therefore become the preferred topology of following VSC-MTDC engineerings.
Each converter bridge arm has numerous submodule (SM), the equilibrium of SM capacitance voltages in MMC DC transmission engineerings
With regard to becoming unavoidable problem on MMC engineer applications.In Practical Project, SM quantity is very big, and traditional method for equalizing voltage is usual
Using the method for SM capacitance voltages sequence gating, but the sequence of pure capacitance voltage can cause higher switching loss, and work as bridge
Arm SM quantity is excessive, and the SM voltages that hundreds of even thousands of a dispersed placements are reached to quantity are ranked up undoubtedly a huge work
Journey difficult point, the energy balance between SM also become very difficult.Moreover, Multi-end flexible direct current transmission system is than traditional direct current transportation
System end number is more, the increase of submodule quantity at double, it is desirable to calculation amount it is more complicated.
Some invention equalization methods are actually that one group of voltage upper and lower limit is set near capacitance voltage rated value, will be flat
Weighing apparatus control is focused on the out-of-limit SM of capacitance voltage, so that sort again after first being handled according to out-of-limit situation, can be by directly
Stream voltage fluctuation of capacitor narrows down to minimum scope, but is bound to cause the frequent of switching frequency in SM and turns on and off, so as to increase
The big switching frequency of MMC.Add and keep the capacitor voltage equalizing algorithm of sequence to introduce state holding parameter, effectively prevent because of row
The same unnecessary switching phenomenon repeatedly of insulated gate bipolar transistor (IGBT), reduces loss caused by sequence algorithm.
It can be seen from the above that in the method that tradition is pressed, the capacitor voltage balance of SM and the switching frequency of MMC are a pair of of lances
Shield, both targets are mutually exclusive to be met at the same time, still lack effective solution regarding to the issue above in the prior art.
The content of the invention
In order to solve the deficiencies in the prior art, the object of the present invention is to provide a kind of Multi-end flexible direct current transmission system is more
Objective optimization design method, the present invention keep the optimization design of parameter by voltage out-of-limit and state, can meet at the same time preferably
Balance of voltage effect and relatively low switching frequency, both is admirably achieved requirement.
A kind of Multi-end flexible direct current transmission system multi-objective optimization design of power method, comprises the following steps：
Step 1：Multi-end flexible direct current transmission system mould is built in power system transient simulation software according to Practical Project
Type；
Step 2：The initial value of model running initial parameter and parameter to be optimized is set；
Step 3：Start Multi-end flexible direct current transmission system model emulation；
Step 4：The DC capacitor voltage and real-time storage of detection each submodule of Multi-end flexible direct current transmission system in real time；
Step 5：The direction of monitoring each bridge arm current of Multi-end flexible direct current transmission system is as capacitance charging and discharging in real time
Basis for estimation and real-time storage；
Step 6：J-th of bridge arm institute of each the i-th end of the switch periods VSC of adjustment method calculating is approached according to nearest level
Need the submodule quantity m openedij, VSC is voltage source current conversion station；
Step 7：Pass through parameters revision capacitance voltage to be optimized；
Step 8：State is cut off according to the input of capacitance voltage ranking results determination sub-module and is issued to control system；
Step 9：Whether judgment models operation terminates, if so, then going to step 10, otherwise, carries out next switch periods meter
Calculate, return to step four, until model running terminates；
Step 10：Establish voltage fluctuation object function and on-off times object function during stable operation；
Step 11：Using the optimal solution set of multi-objective genetic algorithm solving-optimizing variable；Judge whether to reach maximum generation
Number, if so, then obtain the optimal value of variable parameter optimal solution set and be applied to Multi-end flexible direct current transmission system Practical Project, it is no
Then, optimization algebraically adds 1 to be back to step 3 progress subsequent cycle calculating.
Further, in the step 2, model running initial parameter includes model running time, the parameter to be optimized
The state of j-th of bridge arm of initial value including the i-th end of Multi-end flexible direct current transmission system VSC keep initial parameter value, state
The initial value of running parameter initial value, the initial value of voltage attack parameter and voltage drawdown parameter.
Further, the iteration optimization algebraically of multi-objective genetic algorithm is also set up in the step 2.
Further, in the step 7, it is specially by parameters revision capacitance voltage to be optimized：
J-th of bridge arm of i-th end VSC, when current direction SM, that is, SM charges, by the SM capacitance voltages in input state
It is multiplied by state change parameter h2ij, in excision state and capacitance voltage voltage will be multiplied by less than the SM capacitance voltages of lower voltage limit
Drawdown parameter l2ij。
Further, in the step 7, j-th of bridge arm of the i-th end VSC, when electric current outflow SM, that is, SM electric discharges, will locate
State, which is multiplied by, in the capacitance voltage of the SM of discharge condition keeps parameter h1ij；Excision state will be in and capacitance voltage is higher than voltage
The SM capacitance voltages of the upper limit are multiplied by voltage attack parameter l1ij。
Further, in the step 8, by the SM of j-th of bridge arm of the i-th end VSC of Multi-end flexible direct current transmission system
It is ranked up by capacitance voltage value, if current direction SM, that is, SM charges, is put into according to the order of capacitance voltage from high to low
mijA SM, and remaining SM is cut off；If electric current outflow SM, that is, SM electric discharges, throw according to the order of capacitance voltage from low to high
Enter mijA SM, and remaining SM is cut off；
The SM on off states of each bridge arm of flexible direct current power transmission system are issued to control system, the switch of control submodule
State.
Further, in the step 10, voltage fluctuation object function and on-off times target during stable operation are established
Function：Parameter h is kept with the state of Multi-end flexible direct current transmission system1ij, state change parameter h2ij, voltage attack parameter l1ij、
Voltage drawdown parameter l2ijVariable [h as an optimization1ij h2ij l1ij l2ij]；Establish voltage fluctuation object function during stable operation
F1With on-off times object function F2。
Further, the voltage fluctuation object function F1It is defined as the electricity of all submodules in statistics parallel-adder settle-out time
Hold the maximum of magnitude of a voltage fluctuation：
F1=max (| UCijz-UC|)
Wherein, UCijkFor the z of j-th of bridge arm of the i-th end of Multi-end flexible direct current transmission system VSC in a switch periods
The capacitance voltage of a submodule；UCFor the rated capacity voltage of submodule.
Further, the on-off times object function F2All submodules in statistics parallel-adder settle-out time are defined as to open
Close number：
Wherein, Xij(k) it is the on-off times of all submodules on j-th of bridge arm of k-th of the i-th end of switch periods VSC；
Sijz(k) working status of z-th of submodule of j-th of bridge arm for being k-th of the i-th end of switch periods VSC, Sijz(k+1) it is kth
The working status of z-th of submodule of j-th of bridge arm of+1 the i-th end of switch periods VSC.
Further, the step 11 is optimal using the Multi-objective Decision Model selection Pareto based on Nash equilibrium points
Solution.
Further, Multi-end flexible direct current transmission system Multipurpose Optimal Method, the Multi-end flexible direct current transmission system of application
System is made of four terminal voltage source property current conversion station VSC, and one end voltage source current conversion station VSC of Multi-end flexible direct current transmission system is used
The topological structure of modularization cascade connection multi-level MMC, per mutually upper and lower two bridge arms are included in VSC, often phase structure is identical, exchange side
Series reactance LsWith resistance Rs；L0It is connected between two bridge arms up and down；
Each bridge arm is in series by n identical submodule SM, and each submodule includes two IGBT, fly-wheel diodes
With a DC capacitor；When the top IGBT of submodule is opened, lower part IGBT is turned off, submodule is put into；The lower part of submodule
When IGBT is opened, top IGBT is turned off, submodule is removed, and passes through the switching of on off state, it is possible to achieve submodule is exported
The control of voltage.
Compared with prior art, the beneficial effects of the invention are as follows：
(1) traditional method can only meet the fluctuation for reducing capacitance voltage or reduce switching frequency, both mutually arrange at target
Reprimand cannot meet at the same time.The invention keeps parameter, state change parameter, voltage to rise ginseng by multi-objective optimization design of power state
Number, voltage drawdown parameter, can preferably correct SM capacitance voltages, optimization capacitance voltage sequence effect, while meet preferable
Balance of voltage effect and relatively low switching frequency, make both to admirably achieve requirement.
(2) traditional method once calculates the on off state that can only obtain a bridge arm submodule, and multiterminal flexible direct current is defeated
Electric system includes at least three end VSC totally nine bridge arms, and capacitor voltage equalizing optimization calculation amount is huge.The present invention with voltage fluctuation it is minimum and
The minimum target as an optimization of on-off times, using intelligent parallel algorithm, Optimal State keeps parameter, state change parameter, electricity at the same time
Attack parameter, voltage drawdown parameter are pressed, the submodule on off state on multiple VSC bridge arms, computational efficiency higher can be obtained at the same time.
(3) present invention builds Multi-end flexible direct current transmission system according to engineering is actual in power system transient simulation software
Model, detects the electrical quantity in Multi-end flexible direct current transmission system in real time, and approaching adjustment method according to nearest level calculates each
The submodule quantity opened required for bridge arm, is run, i.e. multi-objective Genetic by Multi-end flexible direct current transmission system models for several times
The successive ignition optimization of algorithm NSGA-II, continues to optimize state and keeps parameter, state change parameter, voltage attack parameter, voltage
The value of drawdown parameter, submodule capacitor voltage fluctuation is minimum during realizing stable operation and on-off times are minimum, and by more mesh
Mark Optimum Design Results are applied to actual multiterminal flexible direct current engineering.This method meet at the same time preferable balance of voltage effect and compared with
Low switching frequency, makes both to admirably achieve requirement, and computational efficiency higher, is particularly suitable for multiterminal flexible direct current
The occasion of transmission of electricity.
Brief description of the drawings
The accompanying drawings which form a part of this application are used for providing further understanding of the present application, and the application's shows
Meaning property embodiment and its explanation are used to explain the application, do not form the improper restriction to the application.
Fig. 1 is a kind of flow chart of Multi-end flexible direct current transmission system multi-objective optimization design of power method；
A kind of main electrical scheme schematic diagram of Multi-end flexible direct current transmission system engineering in Fig. 2 positions；
Fig. 3 is a kind of single-ended main circuit schematic diagram of Multi-end flexible direct current transmission system；
Fig. 4 is a kind of Pareto optimal solution set schematic diagrames of Multi-end flexible direct current transmission system Optimal Parameters.
Embodiment
It is noted that described further below is all illustrative, it is intended to provides further instruction to the application.It is unless another
Indicate, all technical and scientific terms used herein has usual with the application person of an ordinary skill in the technical field
The identical meanings of understanding.
It should be noted that term used herein above is merely to describe embodiment, and be not intended to restricted root
According to the illustrative embodiments of the application.As used herein, unless the context clearly indicates otherwise, otherwise singulative
It is also intended to include plural form, additionally, it should be understood that, when in the present specification using term "comprising" and/or " bag
Include " when, it indicates existing characteristics, step, operation, device, component and/or combinations thereof.
As background technology is introduced, the switching frequency of capacitor voltage balance and MMC that SM exists in the prior art is
Conflict, both targets mutually exclusive the problem of cannot meeting at the same time, in order to solve technical problem as above, the application proposes
A kind of Multi-end flexible direct current transmission system multi-objective optimization design of power method.
In a kind of typical embodiment of the application, there is provided attached drawing 2 show Multi-end flexible direct current transmission system work
The main electrical scheme schematic diagram of journey, the engineering are made of four terminal voltage source property current conversion stations (VSC).
One end voltage source current conversion station (VSC) main circuit schematic diagram of Multi-end flexible direct current transmission system shown in attached drawing 3, is adopted
It is identical per phase structure per mutually including upper and lower two bridge arms in VSC with the topological structure of modularization cascade connection multi-level (MMC), hand over
Flow side series reactance LsWith resistance Rs；L0It is connected between two bridge arms up and down, circulation can be suppressed to a certain extent.Each bridge
Arm is in series by n identical submodules (SM), and each submodule includes two IGBT, fly-wheel diode and a direct current
Hold.When the top IGBT of submodule is opened, lower part IGBT is turned off, submodule is put into；The lower part IGBT of submodule is opened, top
When IGBT is turned off, submodule is removed.Pass through the switching of on off state, it is possible to achieve the control to submodule output voltage.
In Practical Project, Multi-end flexible direct current transmission system includes the voltage source current conversion station (VSC) of more than 3, SM numbers
Amount is very big, and the method for traditional method for equalizing voltage generally use SM capacitance voltages sequence gating, the sequence that pure capacitance is pressed can make
Into higher switching loss, and when bridge arm SM quantity it is excessive, quantity is reached hundreds of even thousands of a dispersed placements SM voltages
Undoubtedly a huge engineering difficult point is ranked up, energy balance also becomes very difficult between SM.
As shown in Figure 1, a kind of Multi-end flexible direct current transmission system multi-objective optimization design of power method of the present invention, specific steps
It is：
(1) Multi-end flexible direct current transmission system model is actually built in power system transient simulation software according to engineering,
It is 1 second to set the model running time；The initial value of parameter to be optimized is set：The of the i-th end of Multi-end flexible direct current transmission system VSC
The state of j bridge arm keeps initial parameter value h1ij=1.02, excursion [1.0~1.05]；State change initial parameter value
h2ij=0.98, excursion [0.95~1.0]；The initial value of voltage attack parameter is l1ij=1.05, excursion [1.0~
1.1]；The initial value l of voltage drawdown parameter2ij=0.95, excursion [0.9~1.0]；Multi-objective genetic algorithm NSGA- is set
The iteration optimization algebraically Gen=50 of II；
(2) the Multi-end flexible direct current transmission system emulation in power system transient simulation software is started；
(3) each switch periods are directed to, detect the direct current of each submodule in Multi-end flexible direct current transmission system in real time
Hold voltage and real-time storage；The direction of monitoring each bridge arm current of Multi-end flexible direct current transmission system in real time, puts as capacitance charging
The basis for estimation of electricity, and real-time storage.
(4) required for j-th of bridge arm that adjustment method calculates each the i-th end of switch periods VSC being approached according to nearest level
The submodule quantity m openedij；
J-th of bridge arm of (5) i-th end VSC, when current direction SM, that is, SM charges, by the SM capacitances in input state
Voltage is multiplied by state change parameter h2ij, will be multiplied by excision state and capacitance voltage less than the SM capacitance voltages of lower voltage limit
Voltage drawdown parameter l2ij；When electric current outflow SM, that is, SM electric discharges, the capacitance voltage of the SM in discharge condition is multiplied by state and is protected
Hold parameter h1ij；In excision state and capacitance voltage voltage attack parameter l is multiplied by higher than the SM capacitance voltages of upper voltage limit1ij；
(6) in the switch periods, the SM of j-th of bridge arm of the i-th end VSC of Multi-end flexible direct current transmission system is pressed into capacitance
Magnitude of voltage is ranked up, if current direction SM, that is, SM charges, m is put into according to the order of capacitance voltage from high to lowijA SM,
And remaining SM is cut off；If electric current outflow SM, that is, SM electric discharges, m is put into according to the order of capacitance voltage from low to highijIt is a
SM, and remaining SM is cut off；
(7) in the switch periods, the SM on off states of each bridge arm of flexible direct current power transmission system are issued to control system,
The on off state of control submodule.
(8) next switch periods repeat step (2) arrives step (7), until model running terminates；
(9) parameter h is kept with the state of Multi-end flexible direct current transmission system1ij, state change parameter h2ij, voltage rise ginseng
Number l1ij, voltage drawdown parameter l2ijVariable [h as an optimization1ij h2ij l1ij l2ij]；Parallel-adder settle-out time generally takes 0.5 second extremely
Period between 0.7 second；Establish voltage fluctuation object function F during stable operation1With on-off times object function F2；
Voltage fluctuation object function F1It is defined as the voltage fluctuation of capacitor amount of all submodules in statistics parallel-adder settle-out time
Maximum：
F1=max (| UCijz-UC|)
Wherein, UCijkFor the z of j-th of bridge arm of the i-th end of Multi-end flexible direct current transmission system VSC in a switch periods
The capacitance voltage of a submodule；UCFor the rated capacity voltage of submodule；
On-off times object function F2It is defined as the on-off times of all submodules in statistics parallel-adder settle-out time：
Wherein, Xij(k) it is the on-off times of all submodules on j-th of bridge arm of k-th of the i-th end of switch periods VSC；
Sijz(k) working status of z-th of submodule of j-th of bridge arm for being k-th of the i-th end of switch periods VSC, Sijz(k+1) it is kth
The working status of z-th of submodule of j-th of bridge arm of+1 the i-th end of switch periods VSC；
(10) multi-objective genetic algorithm NSGA-II solving-optimizing variables [h is used1ij h2ij l1ij l2ij] Pareto most
Excellent disaggregation, iteration optimization algebraically Gen add 1；
(11) if iteration optimization algebraically Gen is less than or equal to 50, repeat step (2) to (10)；
(12) Pareto optimal solutions [h is chosen using the Multi-objective Decision Model based on Nash equilibrium points1ij h2ij l1ij
l2ij], as shown in figure 4, being applied to Multi-end flexible direct current transmission system Practical Project.
Fluctuation or the reduction switching frequency that the present invention can only meet to reduce capacitance voltage for traditional method, both targets
Mutually exclusive the problem of cannot meeting at the same time.Three bridge arms of flexible direct current power transmission system that the present invention is obtained by the above method
Optimal working status S*, submodule and switching frequency can be reduced at the same time, solve flexible direct current power transmission system capacitor voltage equalizing control
The basic problem of system.
In addition, traditional method once calculates the on off state that can only obtain a bridge arm submodule, tradition sorts equal
Pressure control method its computation complexity isThe computation complexity of the present invention is n × ngen, ngenFor intelligent algorithm
Evolutionary generation.Since bridge arm SM quantity is very more, quantity reaches hundreds of or even thousands of, so ngen＜ n.Flexible DC power transmission
It is three bridge arms that system, which includes, if multiterminal flexible direct current system bridge arm is more, efficiency of algorithm of the invention is brighter
Aobvious, computation complexity is lower.
The foregoing is merely the preferred embodiment of the application, the application is not limited to, for the skill of this area
For art personnel, the application can have various modifications and variations.It is all within spirit herein and principle, made any repair
Change, equivalent substitution, improvement etc., should be included within the protection domain of the application.
Claims (10)
1. a kind of Multi-end flexible direct current transmission system multi-objective optimization design of power method, it is characterized in that, comprise the following steps：
Step 1：Multi-end flexible direct current transmission system model is built in power system transient simulation software according to Practical Project；
Step 2：The initial value of model running initial parameter and parameter to be optimized is set；
Step 3：Start Multi-end flexible direct current transmission system model emulation；
Step 4：The DC capacitor voltage and real-time storage of detection each submodule of Multi-end flexible direct current transmission system in real time；
Step 5：Judgement of the direction of monitoring each bridge arm current of Multi-end flexible direct current transmission system as capacitance charging and discharging in real time
According to simultaneously real-time storage；
Step 6：Required for j-th of bridge arm that adjustment method calculates each the i-th end of switch periods VSC is approached according to nearest level
The submodule quantity m openedij, VSC is voltage source current conversion station；
Step 7：Pass through parameters revision capacitance voltage to be optimized；
Step 8：State is cut off according to the input of capacitance voltage ranking results determination sub-module and is issued to control system；
Step 9：Whether judgment models operation terminates, if so, then going to step 10, otherwise, carries out next switch periods calculating,
Return to step four, until model running terminates；
Step 10：Establish voltage fluctuation object function and on-off times object function during stable operation；
Step 11：Using the optimal solution set of multi-objective genetic algorithm solving-optimizing variable；Judge whether to reach maximum algebraically, if
It is then to obtain the optimal value of variable parameter optimal solution set and be applied to Multi-end flexible direct current transmission system Practical Project, it is otherwise, excellent
Changing algebraically adds 1 to be back to step 3 progress subsequent cycle calculating.
2. a kind of Multi-end flexible direct current transmission system multi-objective optimization design of power method as claimed in claim 1, it is characterized in that, institute
State in step 2, model running initial parameter includes the model running time, and the initial value of the parameter to be optimized is soft including multiterminal
Property the i-th end of DC transmission system VSC j-th of bridge arm state keep initial parameter value, state change initial parameter value, voltage
The initial value of attack parameter and the initial value of voltage drawdown parameter.
3. a kind of Multi-end flexible direct current transmission system multi-objective optimization design of power method as claimed in claim 2, it is characterized in that, institute
State the iteration optimization algebraically that multi-objective genetic algorithm is also set up in step 2.
4. a kind of Multi-end flexible direct current transmission system multi-objective optimization design of power method as claimed in claim 1, it is characterized in that, institute
State in step 7, be specially by parameters revision capacitance voltage to be optimized：
J-th of bridge arm of i-th end VSC, when current direction SM, that is, SM charges, the SM capacitance voltages in input state are multiplied by
State change parameter h2ij, will be multiplied by voltage in excision state and capacitance voltage less than the SM capacitance voltages of lower voltage limit and decline
Parameter l2ij。
5. a kind of Multi-end flexible direct current transmission system multi-objective optimization design of power method as claimed in claim 4, it is characterized in that, institute
State in step 7, j-th of bridge arm of the i-th end VSC, when electric current outflow SM, that is, SM electric discharges, by the electricity of the SM in discharge condition
Hold voltage and be multiplied by state holding parameter h1ij；It will multiply in excision state and capacitance voltage higher than the SM capacitance voltages of upper voltage limit
With voltage attack parameter l1ij。
6. a kind of Multi-end flexible direct current transmission system multi-objective optimization design of power method as claimed in claim 1, it is characterized in that, institute
State in step 8, the SM of j-th of bridge arm of the i-th end VSC of Multi-end flexible direct current transmission system is arranged by capacitance voltage value
Sequence, if current direction SM, that is, SM charges, m is put into according to the order of capacitance voltage from high to lowijA SM, and by remaining SM
Excision；If electric current outflow SM, that is, SM electric discharges, m is put into according to the order of capacitance voltage from low to highijA SM, and by remaining
SM is cut off；
The SM on off states of each bridge arm of flexible direct current power transmission system are issued to control system, the switch shape of control submodule
State.
7. a kind of Multi-end flexible direct current transmission system multi-objective optimization design of power method as claimed in claim 1, it is characterized in that, institute
State in step 10, establish voltage fluctuation object function and on-off times object function during stable operation：With multiterminal flexible direct current
The state of transmission system keeps parameter h1ij, state change parameter h2ij, voltage attack parameter l1ij, voltage drawdown parameter l2ijAs
Optimized variable [h1ij h2ij l1ij l2ij]；Establish voltage fluctuation object function F during stable operation1With on-off times target letter
Number F2。
8. a kind of Multi-end flexible direct current transmission system multi-objective optimization design of power method as claimed in claim 7, it is characterized in that, institute
State voltage fluctuation object function F1It is defined as the maximum of the voltage fluctuation of capacitor amount of all submodules in statistics parallel-adder settle-out time
Value：
F1=max (| UCijz-UC|)
Wherein, UCijkFor z-th of son of j-th of bridge arm of the i-th end of Multi-end flexible direct current transmission system VSC in a switch periods
The capacitance voltage of module；UCFor the rated capacity voltage of submodule.
9. a kind of Multi-end flexible direct current transmission system multi-objective optimization design of power method as claimed in claim 7, it is characterized in that, institute
State on-off times object function F2It is defined as the on-off times of all submodules in statistics parallel-adder settle-out time：
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Wherein, Xij(k) it is the on-off times of all submodules on j-th of bridge arm of k-th of the i-th end of switch periods VSC；Sijz(k)
For the working status of z-th of submodule of j-th of bridge arm of k-th of the i-th end of switch periods VSC, Sijz(k+1) opened for kth+1
Close the working status of z-th of submodule of j-th of bridge arm in cycle the i-th end VSC.
10. a kind of Multi-end flexible direct current transmission system multi-objective optimization design of power method as claimed in claim 1, it is characterized in that,
The step 11 chooses Pareto optimal solutions using the Multi-objective Decision Model based on Nash equilibrium points.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109149981A (en) * | 2018-08-20 | 2019-01-04 | 华中科技大学 | A kind of Multipurpose Optimal Method based on genetic algorithm suitable for MMC |
| CN111368489A (en) * | 2020-02-11 | 2020-07-03 | 南方电网科学研究院有限责任公司 | Test sequence modeling method and device for multi-terminal direct-current power transmission system |
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|---|---|---|---|---|
| US20160006365A1 (en) * | 2014-07-03 | 2016-01-07 | Massachusetts Institute Of Technology | High-Frequency, High Density Power Factor Correction Conversion For Universal Input Grid Interface |
| CN105281356A (en) * | 2015-11-10 | 2016-01-27 | 中国科学院电工研究所 | Coordination control method of multi-terminal flexible direct-current power transmission system |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160006365A1 (en) * | 2014-07-03 | 2016-01-07 | Massachusetts Institute Of Technology | High-Frequency, High Density Power Factor Correction Conversion For Universal Input Grid Interface |
| CN105281356A (en) * | 2015-11-10 | 2016-01-27 | 中国科学院电工研究所 | Coordination control method of multi-terminal flexible direct-current power transmission system |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109149981A (en) * | 2018-08-20 | 2019-01-04 | 华中科技大学 | A kind of Multipurpose Optimal Method based on genetic algorithm suitable for MMC |
| CN109149981B (en) * | 2018-08-20 | 2019-10-25 | 华中科技大学 | A kind of Multipurpose Optimal Method based on genetic algorithm suitable for MMC |
| CN111368489A (en) * | 2020-02-11 | 2020-07-03 | 南方电网科学研究院有限责任公司 | Test sequence modeling method and device for multi-terminal direct-current power transmission system |
| CN111368489B (en) * | 2020-02-11 | 2023-05-16 | 南方电网科学研究院有限责任公司 | Test sequence modeling method and device for multi-terminal direct current transmission system |
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