CN110504691A - It is a kind of meter and VSC control mode alternating current-direct current power distribution network optimal load flow calculation method - Google Patents
It is a kind of meter and VSC control mode alternating current-direct current power distribution network optimal load flow calculation method Download PDFInfo
- Publication number
- CN110504691A CN110504691A CN201910753366.9A CN201910753366A CN110504691A CN 110504691 A CN110504691 A CN 110504691A CN 201910753366 A CN201910753366 A CN 201910753366A CN 110504691 A CN110504691 A CN 110504691A
- Authority
- CN
- China
- Prior art keywords
- direct current
- vsc
- active
- alternating current
- converter station
- 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.)
- Pending
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
- H02J3/04—Circuit arrangements for ac mains or ac distribution networks for connecting networks of the same frequency but supplied from different sources
- H02J3/06—Controlling transfer of power between connected networks; Controlling sharing of load between connected networks
Abstract
The invention discloses a kind of meter and the alternating current-direct current power distribution network optimal load flow calculation methods of VSC control mode, on the basis of control AC distribution host moves management equipment, based on VSC converter station steady-state operation model, by VSC operational parameter control and active management equipment collectively as decision variable, using meter and the alternating current-direct current network loss of the accurate active loss of converter station as objective function, in the case where meeting alternating current-direct current power distribution network and converter station safe operation constraint condition, construct the AC distribution net optimal load flow mathematical model of the interconnection of flexible direct current containing multiterminal, and foundation solution is carried out to model using alternating current-direct current alternating iteration tidal current computing method and dual particle swarm algorithm.Present invention alternating current-direct current network loss after considering VSC Optimization about control parameter is effectively cut down, and has good practicability and preferable convergence.
Description
Technical field
The invention belongs to alternating current-direct current power distribution network optimal load flow calculating field more particularly to a kind of meter and VSC control modes
Alternating current-direct current power distribution network optimal load flow calculation method.
Background technique
DC techniques based on voltage source converter (VSC) are applied to power distribution network for electrical domain, helps to alleviate and work as
The pressure that preceding city electric distribution system faces, alternating current-direct current mixing power distribution network are more suitable for the development trend of future city distribution, can subtract
The intermediate link of few distributed generation system and DC load access power grid, reduces cost of access, improves transformation efficiency and electric energy
Quality, alleviates that urban distribution network website corridor is limited with the high contradiction of load density, while can play the work of dynamic reactive support
With to improve system global voltage level and reduce network loss.
It is calculated for the alternating current-direct current optimal load flow of the net of DC distribution containing VSC, existing research achievement: using Forward and backward substitution method
The power distribution network of radial feature is handled, but the algorithm is in processing ring network structure, other distributed generation resources and more distributed generation resources
Situations such as have certain limitation；It is carried out using multiterminal flexible interconnection alternating current-direct current power distribution network of the Zbus algorithm for sagging control is improved
Processing, but the algorithm need to sagging curve carry out step-by-step processing, and Algorithm Convergence have it is to be strengthened.
For the optimal load flow calculation method of the AC distribution net interconnected with flexible direct current, existing research achievement: Yi Zhongfen
The OLTC exact linearization method modeling method of section linearisation, based on second order cone method of relaxation and Branch Power Flow model construction containing OLTC's
Important participation element each in active distribution network has been carried out corresponding linearisation and modeled, built by active distribution network optimal load flow model
Be based on the Dynamic Optimal Power Flow Problem model of Second-order cone programming；Comprehensive a variety of controllable devices are to voltage, the capacity problem in power distribution network
Multi-source coordination control strategy is carried out, which includes the interconnections of middle pressure flexible direct current, establish positive semidefinite relaxation optimal load flow model；But
Its only consider using DC line as interconnection come using, be not directed to VSC converter station control and modeling.
Existing research achievement, which is not directed to VSC converter station in the soft AC distribution net optimal load flow directly interconnected, to be had
Effect is accurately controlled modeling, generally only simplifies direct current interconnection portion.The optimization operation of alternating current-direct current power distribution network is substantially one
A includes continuous, discrete decision variable optimal power flow problems, and distribution network line resistance be can not ignore, and optimal load flow must be same
When meet AC and DC trend constraint and the factors such as system voltage, reactive power could be taken into account.Therefore, alternating current-direct current distribution
The problem of net optimal load flow is non-convex difficult MIXED INTEGER of solution, nonlinear optimization.
Summary of the invention
Goal of the invention: in view of the above problems, the present invention propose it is a kind of meter and VSC control mode alternating current-direct current power distribution network it is optimal
Tidal current computing method considers VSC Optimization about control parameter, and alternating current-direct current network loss effectively cut down, have good practicability and compared with
Good convergence.
Technical solution: to achieve the purpose of the present invention, the technical scheme adopted by the invention is that: it is a kind of meter and VSC control
The alternating current-direct current power distribution network optimal load flow calculation method of mode, comprising steps of
(1) VSC converter station steady-state model is established, the active loss of VSC converter station is calculated；
(2) alternating current-direct current power distribution network optimal load flow model is established, objective function is that the friendship comprising VSC converter station active loss is straight
The active via net loss of power distribution network is flowed, decision variable is active management element and the specific control of VSC converter station of AC distribution net
Control variable under mode；
(3) model is solved based on alternating current-direct current alternating iteration power flow algorithm and dual particle swarm algorithm.
Further, in the step 1, VSC converter station steady-state model are as follows:
Pc,dci=-Pci-Pc,lossi
Wherein, Pc,lossiFor VSC power loss, PciThe active power of side gusset, P are exchanged for VSCc,dciIt is straight for VSC flow direction
Flow the direct current injecting power of node.
The active loss of VSC converter station are as follows:
Wherein, ai、biAnd ciFor loss characteristic parameter；IciFor the alternating current per unit value that VSC flows through, coefficient aiSimulation with
IciSquare directly proportional loss, coefficient biSimulation and IciDirectly proportional loss, coefficient ciSimulate fixed loss.
Further, in the step 2, objective function are as follows:
Wherein,For the active via net loss of direct current,To exchange active via net loss,For VSC converter station
Active loss.
The active management element of AC distribution net includes on-load regulator transformer, reactive power compensator, active regulating device.
VSC converter station control mode includes active component control and reactive component control, and active component control includes fixed straight
Active power controller and the sagging control of active-voltage are determined in galvanic electricity control, and reactive component control includes determining Reactive Power Control and determining
Alternating voltage control.
The constraint condition for meeting active management element and the specific control mode of VSC converter station includes:
Equality constraint includes:
The trend equilibrium equation of AC system and the active balance equation of DC grid:
Wherein, Δ Pi、ΔQiRespectively exchange active power deviation, the reactive power deviation of node i；Pgi、QgiRespectively
The active power output of i-th generator, idle power output；Pdi、QdiThe respectively active power, idle of converter station injection exchange node i
Power；θijPhase angle difference between node i and j；Gij+jBijAdmittance between node i and j；
Inequality constraints condition includes:
AC system inequality constraints:
Wherein, PGimax、PGiminFor generated power power output bound；QGimax、QGiminUp and down for generator reactive power output
Limit；Uimax、UiminFor node voltage bound；PijmaxFor the branch ij trend upper limit；
DC grid runs inequality constraints:
Wherein, Udcimax、UdciminThe permitted voltage bound of respectively DC node i；IdcimaxIt can for DC line ij
The maximum current of carrying；
VSC converter station runs inequality constraints:
Wherein, IcimaxThe maximum current that can be carried for commutation components；UcimaxThe maximum exchange end that can be generated for inverter
Mouth voltage；UciminFor inverter AC port lower voltage limit；SvsciFor the maximum capacity of i-th of converter station.
Further, in the step 3, alternating current-direct current power distribution network optimal load flow model is carried out using dual particle swarm algorithm
It establishes and solves, comprising steps of
(1) particle position and speed of continuous part and discrete portions are initialized, passes through alternating current-direct current tide in initialization procedure
Stream calculation is screened, it is made to meet operation constraint condition；
(2) alternating current-direct current Load flow calculation is carried out to the corresponding operating status of all particles and seeks its target function value, to discontented
What is constrained enough applies penalty term to its target function value；
(3) individual extreme value and global extremum are sought, the speed of all particle next iterations, the position of more new particle are calculated
It sets；
(4) return step (2) is iterated calculating until maximum number of iterations；
(5) the corresponding all operating parameters of global extremum and correlated results are returned.
Further, alternating current-direct current Load flow calculation uses alternating current-direct current alternating iteration power flow algorithm, specifically includes: by the VSC change of current
The different control modes stood carry out decoupling respectively in alternating current-direct current side it is equivalent, first carry out DC grid trend iteration, after exchanged
Electric network swim iteration, the two is by global iterative variable, and alternating iteration calculates until DC grid, converter station and AC network are complete
Portion's convergence.
The utility model has the advantages that the alternating current-direct current power distribution network optimal load flow calculation method of meter of the present invention and VSC control mode, effectively cuts down
The network loss of alternating current-direct current distribution network system, improves system voltage level, and network suitable for different alternating current-direct current power distribution networks is opened up
Structure, different converter station control modes and different converter station voltage control modes are flutterred, can directly be interconnected containing multiterminal are soft
Alternating current-direct current power distribution network Optimal Operation Analysis is offered reference.The present invention is based on alternating current-direct current alternating iteration power flow algorithms and dual population
Algorithm is established and is solved to the model, and the convergence rate of calculated result is effectively accelerated.
Detailed description of the invention
Fig. 1 is the alternating current-direct current power distribution network optimal load flow calculation method flow chart of meter and VSC control mode；
Fig. 2 is VSC converter station structure chart；
Fig. 3 is VSC converter station equivalent circuit diagram；
Fig. 4 is VSC converter station control mode classification chart
Fig. 5 is alternating current-direct current alternative and iterative algorithm flow chart；
Fig. 6 is revised IEEE33 node system network frame topology structure chart；
Fig. 7 is DC network topology diagram；
Fig. 8 is the soft revised IEEE33 system-computed result figure directly interconnected of different scenes multiterminal；
Fig. 9 is different scenes optimal load flow convergent figure.
Specific embodiment
Further description of the technical solution of the present invention with reference to the accompanying drawings and examples.
As shown in Figure 1, the alternating current-direct current power distribution network optimal load flow calculation method of meter of the present invention and VSC control mode,
The VSC converter station steady-state model for considering meter and being accurately lost, the alternating current-direct current power distribution network for establishing the interconnection of flexible direct current containing multiterminal are optimal
Tide model considers active management equipment and converter station control mode in AC distribution net, and uses alternating current-direct current alternating iteration
Tidal current computing method and dual particle swarm intelligence algorithm carry out foundation solution to constructed optimal load flow model.
Specific steps include:
(1) VSC converter station steady-state model is established, the active loss of VSC converter station is calculated；
As shown in Fig. 2, VSC converter station steady-state model structure, AC network is using ac bus points of common connection (PCC) electricity
Potential source replaces, and by transformer, filter and commutating reactor, is connected to VSC converter station.VSC converter station uses two level, three
Level neutral-point-clamped or modularization multi-level converter (MMC) structure.VSC converter station DC side uses bipolar wiring, and connects
To DC bus.
When steady-state operation, i-th of VSC converter station can be equivalent to controlled voltage source U in AC system sideci∠δci, in direct current
Side can be equivalent to controllable current source Ic,dci.Harmonic component in voltage and current is ignored in steady-state operation, only considers fundametal compoment, can obtain
The equivalent circuit diagram of inverter loss is considered to i-th of converter station, as shown in Figure 3.
Wherein, transformer impedance Zti=Rti+jXti；Filter admittance is jBfi；Commutating reactor impedance is Zci=Rci+
jXci.The apparent energy S of PCC nodesi=Psi+jQsi, the apparent energy S of transformer nodefsi=Pfsi+jQfsi, filter node
Apparent energy Sfi=jQfi, the apparent energy S of commutating reactor nodecfi=Pcfi+jQcfi, VSC exchange side gusset view exist
Power Sci=Pci+jQci。
Take power direction for forward direction, can obtain VSC DC side with exchange the active power balance equation of side, that is, VSC converter station
Steady-state model are as follows:
Pc,dci=-Pci-Pc,lossi
Wherein, Pc,lossiFor VSC power loss, since power electronic devices on-state loss, switching loss etc. cause, PciFor
VSC exchanges the active power of side gusset, Pc,dciThe direct current injecting power of DC node is flowed to for VSC.
The suggestion of IEC62751 standard is calculated using electromagnetic transient simulation, then obtains accurate model by curve matching.
The quadratic function of Inverter circuit, that is, the active loss of VSC converter station is shown below:
Wherein, ai、biAnd ciFor loss characteristic parameter；IciFor the alternating current per unit value that VSC flows through, coefficient aiSimulation with
IciSquare directly proportional loss, coefficient biSimulation and IciDirectly proportional loss, coefficient ciSimulate fixed loss, IciIt can ask as the following formula
.
Wherein, UciSide gusset voltage is exchanged for VSC；UfiFor filter node voltage；PciAnd QciRespectively indicate VSC exchange
The active power and reactive power of side gusset；PcfiAnd QcfiRespectively indicate the active power and reactive power of filter node.
(2) alternating current-direct current power distribution network optimal load flow model is established, objective function is that the friendship comprising VSC converter station active loss is straight
The active via net loss of power distribution network is flowed, decision variable is active management element and the specific control of VSC converter station of AC distribution net
Control variable under mode；
Objective function are as follows:
Wherein,It is lost for DC network,It is lost for AC network,For the loss of all VSC converter stations.
Under alternating current-direct current power distribution network optimal load flow frame, the active management element of AC system part includes: on-load voltage regulation
Transformer (on-load tap changer, OLTC)；Reactive power compensator, including discrete reactive compensation (shunt
Capacitor, SCP) and Continuous Var Compensation (static var generator, SVG)；Active regulating device, including it is controllable
Generating set (controlled generator, CG) and flexible load (flexible load, FL).Optimal load flow target letter
Number is generally linear, therefore for AC distribution mesh portions primary concern is that in the operation for meeting the above active management element
Under constraint condition, optimizing decision is carried out to its parameter.
The control mode of VSC converter station is flexible and changeable, it can be achieved that various control target, holding even exchange node voltage perseverance
It is fixed, pass through Reasonable Regulation And Control inverter port voltage Uci∠δci, can be realized the decoupling control to active variable and idle variable.
As shown in figure 4, main operation control method includes 3 kinds of active component controls and 2 kinds of reactive component controls, active component control packet
It includes and determines direct current control, determines active power controller and the sagging control of active-voltage, reactive component control includes determining reactive power control
Make and determine alternating voltage control.
In alternating current-direct current Load flow calculation, each VSC need to select two control targets, generally common are following group
It closes: 1) determining Udc, determines Qs control；2) determine Udc, determine Us control；3) determine Ps, determine Qs control；4) determine Ps, determine Us control；5) under voltage
It hangs down, determine Qs control；6) voltage is sagging, determines Us control.Different control modes for during Load flow calculation equivalent way and place
Reason method different from.In ac and dc systems operational process, the control mode of VSC converter station and the selection of variable is controlled all
Alternating current-direct current steady-state load flow will be directly affected.
Part is optimized for DC grid, considers the adjusting of the control variable of the VSC converter station under specific control mode.It is right
In AC distribution mesh portions part, consider that the parameter of active management element is adjusted.
Single point voltage control: [Udc Ps Qs Us MAC]
The sagging control of voltage: [kp Udcref Pdcref Ps Qs Us MAC]
In formula: UdcThe DC voltage of DC bus, P are corresponded to for converter stations、Qs、UsRespectively PCC node flows into alternating current
The active power of net, reactive power, PCC node alternating voltage, MACFor active management element parameter matrix in AC distribution net,
kpFor the sagging coefficient of converter station voltage, Pdcref、UdcrefThe respectively active setting value and voltage setting value of original reference operating point.
It should be noted that the sagging control of voltage is preset according to conditions such as design capacity, the operating conditions of converter station
Sagging coefficient enables the changed power of whole network to share according to a certain percentage to multiple converter stations, therefore practical
It cannot be to k in operationpIt is frequently adjusted, chooses original active setting value PdcrefWith primary voltage setting value UdcrefAs control
Variable processed.
The constraint condition for meeting active management element and the specific control mode of VSC converter station includes:
Equality constraint, the active balance equation of main trend equilibrium equation and DC grid including AC system.
Wherein, Δ PiWith Δ QiFor the power deviation for exchanging node i；Pgi、QgiActive, the nothing of respectively i-th generator
Function power output；PdiAnd QdiThe power of exchange node i is injected for converter station；θijPhase angle difference between node i and j；Gij+jBijFor
Admittance between node i and j.
Inequality constraints, mainly includes AC system inequality constraints, and DC grid runs inequality constraints and the VSC change of current
It stands and runs inequality constraints.
AC system inequality constraints, including the active and idle power output of power supply boundary limitation, node voltage amplitude it is upper
Lower limit and line energizing flow capacity-constrained.
Wherein, PGimax、PGiminFor generated power power output bound；QGimax、QGiminUp and down for generator reactive power output
Limit；Uimax、UiminFor node voltage bound；PijmaxFor the branch ij trend upper limit.
DC grid runs inequality constraints, also needs the constraint for meeting node voltage and line current.
Wherein, Udcimax、UdciminThe permitted voltage upper and lower limit of respectively DC node i；IdcimaxFor DC line ij
The maximum current that can be carried.
VSC converter station runs inequality constraints, and to ensure converter station safe operation, the steady-state operation point of VSC must be at it
Within the scope of PQ capacity limit, area size, which is primarily limited to commutation components, can carry the limit that electric current exchanges side ports voltage with VSC
System.
Wherein, IcimaxCapacity limit for the maximum current that commutation components can carry, corresponding to inverter apparent energy；
UcimaxIt is expressed as avoiding the occurrence of ovennodulation, the maximum AC port voltage that inverter can generate；UciminEnd is exchanged for inverter
Mouth lower voltage limit corresponds to minimum idle export-restriction, and the constraint, S can be ignored in MMC and the VSC without idle export-restrictionvsci
For the maximum capacity of i-th of converter station.
(3) model is solved based on alternating current-direct current alternating iteration power flow algorithm and dual particle swarm algorithm.
The AC/DC network tide for the DC grid containing voltage source converter that the present invention is accurately lost using meter and converter station
Stream alternating iteration method calculates the trend in alternating current-direct current power distribution network, and calculation of tidal current is used to seek the mesh of optimal load flow
Offer of tender numerical value.
Alternating current-direct current alternating iteration power flow algorithm decouples the different control modes of VSC converter station in alternating current-direct current side respectively
It is equivalent, DC grid trend iteration is first carried out, rear to carry out AC network trend iteration, the two passes through global iterative variable Ps、Qs、
Us、δs, realize reciprocal effect, alternating iteration calculates until all convergences of DC grid, converter station and AC network, detailed process
As shown in Figure 5.
Alternating current-direct current alternating iteration tidal current computing method is by VSC converter station control mode and controling parameter in Load flow calculation process
Middle decoupling, which comes out, to be independently controlled and adjusts, after in optimal load flow model framework, being easy to implement the adjustment of VSC control parameter
Load Flow Solution and target function value calculating.
The present invention is using dual population (dualparticle swarm optimization, DPSO) algorithm to containing more
The power distribution network optimal load flow model of kind controlled variable is established and is solved.
The speed that population is advanced includes size and Orientation, is total with particle present speed, individual extreme value and global extremum
It is determined with weighting.Population location update formula:
Wherein, i is particle number, and t is the number of iterations,The individual extreme value for being i-th of particle in the t times iteration,For the global extremum of all particles in the t times iteration,Speed of respectively i-th of the particle in the t times iteration
And position, ω, c1And c2Weight coefficient when updating for speed, rand1 (), rand2 () generate the random number between 0 to 1.
Every one-dimensional x of particle positionidIt is limited to 0 or 1, for speed vidThen without this limitation, velocity amplitude represents particle
It is closely located to 1 probability.Discrete particle cluster state more new formula:
Wherein,Indicate that the d of i-th of particle after the t+1 times iteration ties up phasor,For Sigmoid letter
Number, for guaranteeingEach component be 0 or 1, xidFor predetermined threshold, commonly using random number is indicated.Discrete particle cluster its
Remaining content is consistent with continuous population.
The specific steps of optimal load flow algorithm:
(1) particle position and speed of continuous part and discrete portions are initialized, passes through alternating current-direct current tide in initialization procedure
Stream calculation is screened, it is made to meet operation constraint condition；
(2) Load flow calculation is carried out to the corresponding operating status of all particles and seeks its target function value, to being unsatisfactory for constraining
To its target function value apply penalty term；
(3) individual extreme value and global extremum are sought, the speed of all particle next iterations, the position of more new particle are calculated
It sets；
(4) return step (2) is iterated calculating until maximum number of iterations；
(5) the corresponding all operating parameters of global extremum and correlated results are returned.
The present invention is based on Matlab2015a to have carried out model foundation and verifying.The present invention is done below by an example
Further instruction.
With the revised IEEE33 node system interconnected with DC grid to the alternating current-direct current power distribution network optimal load flow of proposition
Model carries out modeling analysis.As shown in fig. 6, the network frame topology structure of revised IEEE33 node system, on node voltage
Lower limit is respectively 1.05 and 0.95 (per unit value).In AC network part, it is added to on-load regulator transformer (OLTC), nothing in parallel
Function compensator (SCP), static reactive generator (SVG), adjustable unit (CG) and flexible load (FL), design parameter be shown in Table 1 with
Table 2.In addition, including two Wind turbines and a photovoltaic in AC network, it is located at node 5,26 and 17, is predicted active
Power output is respectively 350kW, 400kW and 250kW, and wherein wind power factor is taken as 0.9.
Table 1
Table 2
The 3 end VSC DC networks that a voltage class is ± 7.5kV are increased in IEEE33 node system, it is specific
Topological structure is as shown in Figure 7.Alternating current-direct current distribution network reference capacity is unified for 10MVA, and the reference voltage of DC network part is
7.5kV.Wherein change of current tiny node 1,2,3 is connected with 1,12,30 node of AC distribution net node respectively, and DC node 4,5 and 6 is
Pure DC node, converter station exchange side parameter and DC grid node are shown in Table 3, and DC grid line parameter circuit value is shown in Table 4.DC node
4 are connected to electric automobile load, and node 5 is connected to direct current photo-voltaic power supply and DC load, and node 6 is connected to energy storage device, wind-powered electricity generation power supply
And DC load, DC power supply and DC load are directly equivalent in table.
Table 3
Table 4
The present invention is based on the alternating current-direct current power distribution network optimal load flow models of proposition, for what is interconnected with three end VSC DC networks
Revised IEEE33 distribution network system carries out Simulation Example.Respectively to single point voltage control and voltage two kinds of voltages of sagging control
Control mode carries out model verifying, and single point voltage control chooses VSC1 and is voltage station, determines Qs control, and the sagging control of voltage is chosen
VSC1 and VSC2 is voltage station, and sagging coefficient ρ is 0.04, determines Qs control, remaining VSC converter station is to determine Ps, determine Qs controlling party
Formula.Different scenes in example are described as follows, case1:IEEE33 original scene, case2:IEEE33 (no direct current interconnection) pure friendship
Flow control, case3: pure DC control under single point voltage control, case4: pure DC control under the sagging control of voltage, case5: single
Point voltage controls lower alternating current-direct current control, and case6: alternating current-direct current controls under the sagging control of voltage, and table 5 is converter station control under different scenes
Mode and its operating parameter processed.Particle swarm algorithm is initially generated 100 particles, and maximum number of iterations is set as 40, c1=1；c2
=2；W=0.5.
Table 5
Fig. 8 gives under different scenes, the soft revised IEEE33 node system optimal load flow meter directly interconnected of multiterminal
Calculate result.Obviously, when only considering AC system Reactive-power control equipment and flexible load adjustment effect, the network loss of case2 is cut down
132.9kW.Only consider DC converter station adjustment effect when, system losses be similarly obtained apparent reduction (case3,
Case4 respectively reduces about 136.5kW and 138.5kW).It can be seen that system can be improved by the operating parameter for optimizing VSC converter station
Overall operation operating condition reaches or even surmounts the power flow regulating effect of a variety of controllable devices in AC distribution net.Further considering
After Reactive-power control equipment and flexible load in AC system, the system losses of case5 and case6 relative to case3 and case4
Further reduce 16kW, 15.4kW.While reducing System Reactive Power flowing and reducing network loss, exchange node voltage level is whole
Body is improved.By comparison it can be found that exchange node voltage and DC node voltage compare voltage when single point voltage controls
Whole improvement better off when sagging control.
Fig. 9 gives the convergent of example optimal load flow result of the present invention, and the optimal load flow result under different scenes is equal
It is intended to convergency value after 5-10 iteration, has good constringency performance.Table 6 and table 7 then give under different scenes, multiterminal
The soft corresponding decision variable value of revised IEEE33 node system optimal load flow result directly interconnected.
Table 6
Table 7
Claims (6)
1. the alternating current-direct current power distribution network optimal load flow calculation method of a kind of meter and VSC control mode, which is characterized in that comprising steps of
(1) VSC converter station steady-state model is established, the active loss of VSC converter station is calculated；
(2) alternating current-direct current power distribution network optimal load flow model is established, objective function is that the alternating current-direct current comprising VSC converter station active loss is matched
The active via net loss of power grid, decision variable are the active management element and the specific control mode of VSC converter station of AC distribution net
Under control variable；
(3) model is solved based on alternating current-direct current alternating iteration power flow algorithm and dual particle swarm algorithm.
2. the alternating current-direct current power distribution network optimal load flow calculation method of meter according to claim 1 and VSC control mode, feature
It is, in the step 1, VSC converter station steady-state model are as follows:
Pc,dci=-Pci-Pc,lossi
Wherein, Pc,lossiFor VSC power loss, PciThe active power of side gusset, P are exchanged for VSCc,dciDirect current section is flowed to for VSC
The direct current injecting power of point；
The active loss of VSC converter station are as follows:
Wherein, ai、biAnd ciFor loss characteristic parameter；IciFor the alternating current per unit value that VSC flows through, coefficient aiSimulation and IciIt is flat
The directly proportional loss in side, coefficient biSimulation and IciDirectly proportional loss, coefficient ciSimulate fixed loss.
3. the alternating current-direct current power distribution network optimal load flow calculation method of meter according to claim 1 and VSC control mode, feature
It is, in the step 2, objective function are as follows:
Wherein,For the active via net loss of direct current,To exchange active via net loss,For the active of VSC converter station
Loss；
The active management element of AC distribution net includes on-load regulator transformer, reactive power compensator, active regulating device；
VSC converter station control mode includes active component control and reactive component control, and active component control includes determining direct current
Active power controller and the sagging control of active-voltage are determined in control, and reactive component control includes determining Reactive Power Control to exchange with fixed
Voltage control.
4. the alternating current-direct current power distribution network optimal load flow calculation method of meter according to claim 3 and VSC control mode, feature
It is, the constraint condition for meeting active management element and the specific control mode of VSC converter station includes:
Equality constraint includes:
The trend equilibrium equation of AC system and the active balance equation of DC grid:
Wherein, Δ Pi、ΔQiRespectively exchange active power deviation, the reactive power deviation of node i；Pgi、QgiRespectively i-th
The active power output of generator, idle power output；Pdi、QdiRespectively active power, the reactive power of converter station injection exchange node i；
θijPhase angle difference between node i and j；Gij+jBijAdmittance between node i and j；
Inequality constraints condition includes:
AC system inequality constraints:
Wherein, PGimax、PGiminFor generated power power output bound；QGimax、QGiminFor generator reactive power output bound；
Uimax、UiminFor node voltage bound；PijmaxFor the branch ij trend upper limit；
DC grid runs inequality constraints:
Wherein, Udcimax、UdciminThe permitted voltage bound of respectively DC node i；IdcimaxIt can be carried for DC line ij
Maximum current；
VSC converter station runs inequality constraints:
Wherein, IcimaxThe maximum current that can be carried for commutation components；UcimaxThe maximum AC port electricity that can be generated for inverter
Pressure；UciminFor inverter AC port lower voltage limit；SvsciFor the maximum capacity of i-th of converter station.
5. the alternating current-direct current power distribution network optimal load flow calculation method of meter according to claim 1 and VSC control mode, feature
It is, in the step 3, alternating current-direct current power distribution network optimal load flow model is established and solved using dual particle swarm algorithm,
Comprising steps of
(1) particle position and speed of continuous part and discrete portions are initialized, passes through alternating current-direct current trend meter in initialization procedure
Calculation is screened, it is made to meet operation constraint condition；
(2) alternating current-direct current Load flow calculation is carried out to the corresponding operating status of all particles and seeks its target function value, to being unsatisfactory for about
Beam applies penalty term to its target function value；
(3) individual extreme value and global extremum are sought, the speed of all particle next iterations, the position of more new particle are calculated；
(4) return step (2) is iterated calculating until maximum number of iterations；
(5) the corresponding all operating parameters of global extremum and correlated results are returned.
6. the alternating current-direct current power distribution network optimal load flow calculation method of meter according to claim 5 and VSC control mode, feature
It is, alternating current-direct current Load flow calculation uses alternating current-direct current alternating iteration power flow algorithm, specifically includes: the difference of VSC converter station is controlled
Mode carries out decoupling respectively equivalent in alternating current-direct current side, first carries out DC grid trend iteration, rear to carry out AC network trend iteration,
The two is by global iterative variable, and alternating iteration calculates until DC grid, converter station and AC network are all restrained.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910753366.9A CN110504691A (en) | 2019-08-15 | 2019-08-15 | It is a kind of meter and VSC control mode alternating current-direct current power distribution network optimal load flow calculation method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910753366.9A CN110504691A (en) | 2019-08-15 | 2019-08-15 | It is a kind of meter and VSC control mode alternating current-direct current power distribution network optimal load flow calculation method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110504691A true CN110504691A (en) | 2019-11-26 |
Family
ID=68586552
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910753366.9A Pending CN110504691A (en) | 2019-08-15 | 2019-08-15 | It is a kind of meter and VSC control mode alternating current-direct current power distribution network optimal load flow calculation method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110504691A (en) |
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110912177A (en) * | 2019-12-15 | 2020-03-24 | 兰州交通大学 | Multi-objective optimization design method for multi-terminal flexible direct current power transmission system |
| CN111371115A (en) * | 2020-04-02 | 2020-07-03 | 清华大学 | Load margin evaluation method and system for alternating current-direct current series-parallel power system |
| CN111478335A (en) * | 2020-05-07 | 2020-07-31 | 国网山东省电力公司经济技术研究院 | Power distribution network load flow calculation method and system considering distributed photovoltaic |
| CN111541246A (en) * | 2020-04-30 | 2020-08-14 | 东北电力大学 | All-pure embedded calculation method for alternating current and direct current power flow of electric power system |
| CN111884268A (en) * | 2020-07-14 | 2020-11-03 | 东北电力大学 | Optimal power flow control method of alternating current-direct current hybrid power distribution network considering reliability index |
| CN112446533A (en) * | 2020-09-29 | 2021-03-05 | 东北电力大学 | Multi-target planning method for AC/DC hybrid power distribution network |
| CN112865076A (en) * | 2021-01-12 | 2021-05-28 | 天津大学 | Improved augmented node equation modeling method for power electronic flexible power distribution network |
| CN113595052A (en) * | 2020-04-30 | 2021-11-02 | 南京理工大学 | Multi-objective power flow optimization method for alternating current-direct current power grid considering current power flow controller |
| CN113765151A (en) * | 2020-06-04 | 2021-12-07 | 株洲变流技术国家工程研究中心有限公司 | Energy optimization scheduling method and device |
| CN113794206A (en) * | 2021-11-16 | 2021-12-14 | 华东交通大学 | Alternating current-direct current hybrid power grid load flow calculation method considering VSC control strategy |
| CN114819281A (en) * | 2022-03-29 | 2022-07-29 | 四川大学 | Method for optimizing coordinated power flow between flexible direct-current power grid stations |
| CN115276019A (en) * | 2022-09-22 | 2022-11-01 | 东南大学溧阳研究院 | Power flow optimization method based on self-adaptive droop control |
| CN116154835A (en) * | 2022-09-07 | 2023-05-23 | 东南大学溧阳研究院 | Improved alternating current/direct current (AC/DC) power flow iterative algorithm |
| CN113595052B (en) * | 2020-04-30 | 2024-04-19 | 南京理工大学 | AC/DC power grid multi-target power flow optimization method considering current power flow controller |
-
2019
- 2019-08-15 CN CN201910753366.9A patent/CN110504691A/en active Pending
Non-Patent Citations (1)
| Title |
|---|
| LIU SAI: "Optimal Power Flow in Hybrid AC/DC Distribution Network Considering Different Control Strategies of VSC Stations", 《2018 CHINA INTERNATIONAL CONFERENCE ON ELECTRICITY DISTRIBUTION (CICED)》 * |
Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110912177A (en) * | 2019-12-15 | 2020-03-24 | 兰州交通大学 | Multi-objective optimization design method for multi-terminal flexible direct current power transmission system |
| CN111371115A (en) * | 2020-04-02 | 2020-07-03 | 清华大学 | Load margin evaluation method and system for alternating current-direct current series-parallel power system |
| CN111541246B (en) * | 2020-04-30 | 2022-06-14 | 东北电力大学 | All-pure embedded calculation method for alternating current and direct current power flow of electric power system |
| CN113595052A (en) * | 2020-04-30 | 2021-11-02 | 南京理工大学 | Multi-objective power flow optimization method for alternating current-direct current power grid considering current power flow controller |
| CN113595052B (en) * | 2020-04-30 | 2024-04-19 | 南京理工大学 | AC/DC power grid multi-target power flow optimization method considering current power flow controller |
| CN111541246A (en) * | 2020-04-30 | 2020-08-14 | 东北电力大学 | All-pure embedded calculation method for alternating current and direct current power flow of electric power system |
| CN111478335A (en) * | 2020-05-07 | 2020-07-31 | 国网山东省电力公司经济技术研究院 | Power distribution network load flow calculation method and system considering distributed photovoltaic |
| CN111478335B (en) * | 2020-05-07 | 2021-07-13 | 国网山东省电力公司经济技术研究院 | Power distribution network load flow calculation method and system considering distributed photovoltaic |
| CN113765151A (en) * | 2020-06-04 | 2021-12-07 | 株洲变流技术国家工程研究中心有限公司 | Energy optimization scheduling method and device |
| CN113765151B (en) * | 2020-06-04 | 2023-09-22 | 株洲变流技术国家工程研究中心有限公司 | Energy optimization scheduling method and device |
| CN111884268A (en) * | 2020-07-14 | 2020-11-03 | 东北电力大学 | Optimal power flow control method of alternating current-direct current hybrid power distribution network considering reliability index |
| CN112446533A (en) * | 2020-09-29 | 2021-03-05 | 东北电力大学 | Multi-target planning method for AC/DC hybrid power distribution network |
| CN112865076A (en) * | 2021-01-12 | 2021-05-28 | 天津大学 | Improved augmented node equation modeling method for power electronic flexible power distribution network |
| CN112865076B (en) * | 2021-01-12 | 2022-05-20 | 天津大学 | Improved augmented node equation modeling method for power electronic flexible power distribution network |
| CN113794206A (en) * | 2021-11-16 | 2021-12-14 | 华东交通大学 | Alternating current-direct current hybrid power grid load flow calculation method considering VSC control strategy |
| CN114819281A (en) * | 2022-03-29 | 2022-07-29 | 四川大学 | Method for optimizing coordinated power flow between flexible direct-current power grid stations |
| CN116154835A (en) * | 2022-09-07 | 2023-05-23 | 东南大学溧阳研究院 | Improved alternating current/direct current (AC/DC) power flow iterative algorithm |
| CN115276019A (en) * | 2022-09-22 | 2022-11-01 | 东南大学溧阳研究院 | Power flow optimization method based on self-adaptive droop control |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110504691A (en) | It is a kind of meter and VSC control mode alternating current-direct current power distribution network optimal load flow calculation method | |
| Chai et al. | Network partition and voltage coordination control for distribution networks with high penetration of distributed PV units | |
| Peng et al. | Droop control strategy incorporating coupling compensation and virtual impedance for microgrid application | |
| CN105119280B (en) | Alternating current-direct current mixed structure active power distribution network running optimizatin method based on cone optimization | |
| CN108134401B (en) | Multi-target power flow optimization and control method for alternating current-direct current hybrid system | |
| CN111049173B (en) | Self-organizing droop control method for multi-terminal direct-current distribution network | |
| CN105186500B (en) | A kind of power distribution network power dissipation coordination optimizing method based on weighting acceleration Lagrangian again | |
| Aly et al. | Mitigation of photovoltaic power generation fluctuations using plug‐in hybrid electric vehicles storage batteries | |
| CN103971026B (en) | General method for calculating tide of positive power distribution networks | |
| CN110718918B (en) | Load flow calculation method based on HVAC and LCC-VSC HVDC hybrid system | |
| CN106712552B (en) | A kind of aviation more electric engin VIENNA rectifier control method | |
| CN113541146B (en) | Power flow calculation optimization method of power system considering distributed power supply | |
| CN109066694A (en) | Multiple target tide optimization method containing the electric system of flow controller between line | |
| CN110808597A (en) | Distributed power supply planning method considering three-phase imbalance in active power distribution network | |
| CN109149586A (en) | Active power distribution network subregion distributing voltage control method towards intelligent Sofe Switch | |
| CN106159955B (en) | Electric system distributed optimal power flow method based on continuous punishment Duality Decomposition | |
| CN111799800A (en) | AC-DC hybrid power distribution network load flow calculation method | |
| CN114362267A (en) | Multi-objective optimization considered distributed coordination optimization method for alternating current-direct current hybrid power distribution network | |
| CN108306334A (en) | Idle work optimization strategy inside wind power plant based on particle swarm optimization algorithm | |
| Shuai et al. | A dynamic hybrid var compensator and a two-level collaborative optimization compensation method | |
| CN107332290A (en) | A kind of region load transfer method based on DC line | |
| Lakshmi et al. | Optimal Power Flow with BAT algorithm for a Power System to reduce transmission line losses using SVC | |
| CN106953361B (en) | Exchange micro-grid operational control method and device | |
| Bhandakkar et al. | Optimal placement of unified power flow controller and hybrid power flow controller using optimization technique | |
| Guo et al. | Multi-objective planning for voltage sag compensation of sparse distribution networks with unified power quality conditioner using improved NSGA-III optimization |
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 | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20191126 |
|
| RJ01 | Rejection of invention patent application after publication |