CN111342450A - Robust energy management method considering uncertain photovoltaic and load for traction power supply system - Google Patents
Robust energy management method considering uncertain photovoltaic and load for traction power supply system 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
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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
- H02J3/26—Arrangements for eliminating or reducing asymmetry in polyphase 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
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
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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
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
- H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
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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
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
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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
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/345—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering using capacitors as storage or buffering devices
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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
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/35—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells
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- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/50—Arrangements for eliminating or reducing asymmetry in polyphase networks
Abstract
The invention discloses a robust energy management method for a traction power supply system considering uncertain photovoltaic and load, which comprises the following steps of: 1. acquiring photovoltaic output data in a load process of a traction substation, and constructing an uncertain set; 2. establishing an objective function of a robust optimization model; 3. establishing a constraint condition of a robust optimization model, and linearizing the constraint condition of the optimization model; 4. establishing a two-stage robust optimization model according to the objective function obtained in the step (2) and the constraint condition obtained in the step (3); 5. solving the model obtained in the step 4 by using a column and constraint generation algorithm to obtain a traction substation power flow controller, a hybrid energy storage device and a photovoltaic optimal operation plan in the worst scene, namely completing robust energy management of a traction power supply system; the method overcomes the influence of uncertainty of photovoltaic and traction load on the operation of the traction power supply system, improves the operation economy of the traction substation in severe operation environment, and is closer to the reality.
Description
Technical Field
The invention belongs to the field of energy management optimization of a traction power supply system, and particularly relates to a robust energy management method of the traction power supply system considering uncertain photovoltaic and load.
Background
Renewable energy sources in China develop rapidly in recent years, and photovoltaic power generation has the advantages of no pollution, no noise, small regional limitation and the like. Meanwhile, electrified railways represented by high-speed railways and heavy haul railways are constructed and operated in large scale in China, and the operation mileage of high-speed railways in China exceeds 3.5 kilometers by 2019. The electrified railway has the following features: 1) the regional distribution is wide, and the traffic network and the renewable energy network have more geographical intersections, such as Lanzhou New (Wulumangoqi) high-speed rails and Sichuan (Chengdu) Tibetan (Lasa) railways crossing southwest and northwest areas with rich wind and light resources; 2) the traction load is high in demand and has high consumption potential, and particularly, in weak areas of an external power supply, the access of renewable energy sources can also play an important supporting role. Therefore, the photovoltaic-based renewable energy is connected into the traction power supply system to promote local consumption and improve the permeability of the renewable energy.
On the other hand, the electric power department in China charges the electric charges for the electrified railway by adopting two large-scale industrial electricity-consumption power rates, wherein the basic electric charges are charged according to the basic capacity or the maximum demand. Maximum demand charging also sets a "threshold" for minimum installed capacity. From the statistics of railway operation departments, the electricity fee has become one of the main operation payment fees. If the hybrid energy storage system is accessed, peak clipping and valley filling of the traction load can be effectively realized, the required electric charge and the electric charge are greatly reduced, the utilization of the regenerative braking energy of the traction power supply system is promoted, and the system operation efficiency is improved. In addition, the requirement of the system on the capacity of the power supply equipment can be reduced. Therefore, the photovoltaic access and hybrid energy storage system in the traction power supply system of the electrified railway are increasingly concerned.
However, the random ripple characteristics of the traction load and the distributed power output represented by photovoltaic power present challenges to the operation of the traction power supply system. How to effectively deal with uncertain factors in a traction power supply system and realize safe, high-quality and high-efficiency operation is the key for solving the problem of energy management of the traction power supply system.
Disclosure of Invention
In order to overcome the influence of photovoltaic and load uncertainty on a traction power supply system, the electricity charge expenditure cost of a railway department is reduced in the worst scene, and the energy management optimization method is closer to reality. The invention provides a robust energy management method of a traction power supply system considering uncertain photovoltaic and load.
The invention discloses a robust energy management method of a traction power supply system considering uncertain photovoltaic and load, which comprises the following steps:
step 1: acquiring predicted values and fluctuation intervals of traction substation load process data and photovoltaic output data, and constructing uncertain sets of traction loads and photovoltaic outputs;
step 2: establishing a target function of a robust optimization model according to the electric charge parameters and the intervals of the load process data and the photovoltaic output data of the traction substation obtained in the step 1;
and step 3: according to power capacity parameters and three-phase voltage unbalance international parameters of the hybrid energy storage system and the photovoltaic system, establishing constraint conditions of a robust optimization model based on the traction substation load process data and the photovoltaic output data interval obtained in the step 1, and linearizing the constraint conditions of the robust optimization model;
and 4, step 4: establishing a robust energy management method of the traction power supply system based on a two-stage robust optimization model according to the objective function obtained in the step 2 and the constraint condition obtained in the step 3;
and 5: and (4) solving the model obtained in the step (4) by using a column and constraint generation algorithm to obtain the optimal charging and discharging power of the hybrid energy storage device, the optimal photovoltaic grid-connected power and the optimal power flow power of a back-to-back converter in the power flow controller under the worst scene, namely completing the robust energy management optimization of the traction power supply system.
Further, in the step 1, the load process data of the traction substation in the existing line can be obtained from the historical load data, and the traction substation in the newly-built line can be obtained by calculating load process simulation software, such as elbase/WEBANET, according to the high-speed railway line, the train and the schedule.
Further, the uncertain set of photovoltaic output and load in step 1 is:
in the formula: p, A and R are the uncertain set of photovoltaic power output, active load and reactive load, p, respectivelyt、atAnd rtFor photovoltaic power output, active load and reactiveUncertainty variable of load, Δ pt、ΔatAnd Δ rtRespectively represent predicted values pt f、at fAnd rt fDeviation value of, parameter Γp、ΓaAnd ΓrRepresenting uncertainty margin, i.e. the total relative deviation of the uncertainty variable from the predicted value, which ranges from 0 to the total time period N of the dayTIn the meantime.
Further, the objective function in step 2 is:
in the formula: f is an objective function and represents daily operation cost of the traction substation, t is a time period and P ist grid,buyElectric power purchased from the grid for traction substations, Pt grid,fedElectric power P fed back to the grid by the traction substationt PVFor photovoltaic output, Pt b,disFor discharging power of the battery, Pt b,chCharging power for batteries, Pt u,disDischarging power, P, for the super-capacitort u,chCharging power to the super capacitor, Pt demIn order to demand the power, the power supply is,in order to achieve the cost price of photovoltaic operation and maintenance,in order to maintain the cost price of the battery operation,cost price for operating and maintaining super capacitor, cdemThe price of the required electricity charge is calculated,the price of the electricity purchased by the traction substation is,charge price levied for feedback back to the grid power, NdayFor the number of days of operation per month,andare all binary variables;
further, the constraint conditions in the step 3 comprise power balance constraint, hybrid energy storage system constraint, public power grid power constraint, photovoltaic power generation constraint, back-to-back converter constraint and three-phase voltage unbalance constraint; the method specifically comprises the following steps:
power balance constraint conditions:
Pt grid,buy-Pt grid,fed=Pt T+Pt α(6)
Pt α+Pt b,dis+Pt u,dis+Pt PV=Pt β+Pt b,ch+Pt u,ch(7)
Pt T+Pt β=at(8)
in the formula: pt TFor active power of traction transformers, Pt αFor α phase active power, P, of the back-to-back convertert βFor β phase active power, Q, of back-to-back convertert ββ phase reactive power P for back-to-back convertert PVThe photovoltaic output is obtained;is the maximum limit value of the interaction power between the traction substation and the power grid,is a binary variable representing the direction of power interaction between the traction substation and the grid,indicating that the interactive power flows from the grid to the traction substation,and the representation interactive power is fed back to the power grid by the traction substation.
Hybrid energy storage system constraint conditions:
in the formula: epsilonbIs the self-discharge rate of the battery, epsilonbIs the self-discharge rate of the super capacitor, ηb,disFor the discharge efficiency of the battery, ηb,chFor the charging efficiency of the battery, ηu,disFor the discharge efficiency of the supercapacitor, ηu,chTo the charging efficiency of the super capacitor, Δ t is the unit time period,for the electric energy stored in the battery during the time period t +1, Et bStoring the electric energy for the battery in the time period t;the electric energy stored by the super capacitor in the time period of t +1,the electric energy stored for the super capacitor in the time period t;is the rated power of the battery and is,the power of the super capacitor is rated,is the minimum state of charge of the battery,the maximum state of charge of the battery is,for rating the capacity of the battery,The capacity of the super capacitor is rated,the electrical energy stored by the battery for the time period t-1,the electric energy stored by the super capacitor in the period of t-1,the minimum state of charge of the super capacitor is obtained,the maximum charge state of the super capacitor;the electrical energy stored in the battery for the initial period of time each day,the electrical energy stored in the battery for the last period of the day,for the purpose of the initial state of charge per day,the super capacitor stores electric energy for the initial time period every day,the electric energy stored by the super capacitor for the last time period of each day,the initial charge state of the super capacitor every day;andare all binary variables.
Photovoltaic power generation constraint:
0≤Pt PV≤pt(19)
in the formula: p is a radical oftThe photovoltaic output uncertain variable is the solar photovoltaic output upper limit value.
Back-to-back converter constraint:
in the formula:for the capacity of the back-to-back inverter α phases,the capacity of the back-to-back inverter β phases.
And (3) three-phase voltage unbalance degree constraint:
in the formula: epsilonUFor traction substation power grid side three-phase voltage unbalance degree, USFor the grid side line voltage, ScapFor the short-circuit capacity of the side line of the power grid,is the upper limit value of the unbalance degree of the three-phase voltage in the national standard,for grid side negative sequence current, UTFor the voltage at the outlet of the traction transformer, UαIs the voltage at the α phase outlet of the back-to-back converter, N1For single-phase traction transformer transformation ratio, N2For high voltage matching transformer transformation ratio, a is complex operator ej120°,Is the voltage-current phase angle difference of the single-phase traction transformer,is the voltage-current phase angle difference, I, of α phases of the back-to-back current transformerTFor drawing transformer currents, IαIs the current of the back-to-back current transformer α phases.
Further, the constraint condition linearization method in step 3 is as follows:
the max function in equation (5) is linearized by the following equation:
max(Pt dem)=Pdem,max(25)
in the formula: pdem,maxIs an auxiliary variable representing the maximum demand value during the day.
The formula (21) after linearization is given by:
in the formula: n is a radical ofpThe number of the fan-shaped PQ semicircles is equal to that of the fan-shaped PQ semicircles, and the Q is more than or equal to 0; delta theta is the sector angle, (P)k,Qk) Is the division point coordinate of the fan shape and the PQ semicircle.
Equation (24) is linearized as follows:
in the formula:andare all auxiliary variables, and are all the auxiliary variables,is a binary variable.
Further, the two-stage robust optimization model for robust energy management of the traction power supply system established in step 4 is as follows:
in the formula: x represents the binary decision variable vector of the first stage,y denotes a second stage continuous decision variable vector, c. b, D, D, E, E, F, F, G, H and I are parameter matrixes or parameter vectors.
Further, in step 5, based on the robust energy management model of the traction power supply system obtained in step 4, a main model and a sub model of the robust energy management model of the traction power supply system are formed through a column and constraint generation algorithm, and finally the main model and the sub model are solved in an iterative loop manner until a convergence standard is met.
Wherein, the expression of the main model is as follows:
s.t.x∈{0,1} (37)
in the formula: k is the number of iterative solution times, ylThe decision variables added to the main model at the first loop,to solve for the worst photovoltaic output obtained by the submodel,for solving the worst active load scenario, r, obtained for the submodell *And the worst reactive load scene obtained by solving the submodel is shown.
The sub-model expression is:
s.t.By≤d,(γ1) (46)
Dy=e,(γ2) (47)
Fy≤f-Ex*,(γ3) (48)
Gy≤p,(γ4) (49)
Hy=a,(γ5) (50)
Iy=r,(γ6) (51)
in the formula: x is the number of*For the optimal solution of the main model, { gamma {1,γ2,γ3,γ4,γ5,γ6Is a dual variable of the constraint.
The submodel equivalent representation method is as follows:
worst scenario p in sub-model*、a*And r*To not determine the extreme values in sets P, A and R, equations (1) - (3) are therefore equivalent to:
Based on strong dual theory, submodels (45) - (51) are equivalent to:
-BTγ1+DTγ2-FTγ3-GTγ4+HTγ5+ITγ6=cT(56)
γ1≥0,γ3≥0,γ4≥0,γ2,γ5,γ6is a free variable (57)
In the formula: lambda, mu, omega1And ω2Are all auxiliary variables, and are all the auxiliary variables,
the invention has the beneficial effects that:
1. the robust energy management optimization method for the traction power supply system can overcome the influence of uncertainty of photovoltaic and traction load on safe and efficient operation of the traction power supply system, effectively reduces the electric charge expenditure of railway departments, and accords with the development trend of green and intelligent traffic.
2. The robust energy management optimization model of the traction power supply system is established based on the uncertain set of photovoltaic output and traction load, the robustness of the energy management model of the traditional traction power supply system is improved, and the optimality of the traction power supply system in the worst scene is ensured;
3. the method establishes the mixed integer linear programming model by carrying out linearization treatment on the nonlinear elements in the objective function and the constraint condition, is convenient for directly solving by utilizing an optimization solver, and avoids the complexity of solving the mixed integer nonlinear model.
Drawings
Fig. 1 is a schematic diagram of a robust energy management structure of a traction power supply system in the invention.
FIG. 2 is a schematic flow chart of the present invention.
Detailed Description
The invention is further described with reference to the following figures and specific embodiments.
The structure of a traction power supply system aimed at by the invention is shown in fig. 1, and the flow of the robust energy management method of the traction power supply system considering uncertain photovoltaic and load is shown in fig. 2, specifically:
step 1: based on the actual measurement historical data, obtaining the predicted values and fluctuation intervals of the load process data and the photovoltaic output data of the traction substation, and establishing an uncertain set of traction load and photovoltaic output:
in the formula: p, A and R are the uncertain set of photovoltaic power output, active load and reactive load, p, respectivelyt、atAnd rtFor uncertain variables of photovoltaic contribution, active load and reactive load, Δ pt、ΔatAnd Δ rtRespectively represent predicted valuesAnddeviation value of, parameter Γp、ΓaAnd ΓrRepresenting uncertainty margin, i.e. the total relative deviation of the uncertainty variable from the predicted value, which ranges from 0 to the total time period N of the dayTIn the meantime.
Step 2: establishing an objective function of an optimization model according to the electric charge parameters and the intervals of the load process data and the photovoltaic output data of the traction substation obtained in the step 1;
the target function expression is:
in the formula: f is an objective function and represents daily operation cost of the traction substation, t is a time period and P ist grid,buyElectric power purchased from the grid for traction substations, Pt grid,fedWith traction substation feeding back to the gridElectric power, Pt PVFor photovoltaic output, Pt b,disFor discharging power of the battery, Pt b,chCharging power for batteries, Pt u,disDischarging power, P, for the super-capacitort u,chCharging power to the super capacitor, Pt demIn order to demand the power, the power supply is,in order to achieve the cost price of photovoltaic operation and maintenance,in order to maintain the cost price of the battery operation,cost price for operating and maintaining super capacitor, cdemThe price of the required electricity charge is calculated,the price of the electricity purchased by the traction substation is,charge price levied for feedback back to the grid power, NdayFor the number of days of operation per month,andare all binary variables;
and step 3: establishing constraint conditions of an optimization model based on the traction substation load process data and the photovoltaic output data interval obtained in the step 1 according to power capacity parameters and three-phase voltage unbalance international parameters of the hybrid energy storage system and the photovoltaic system, and linearizing the constraint conditions of the optimization model;
the constraint conditions comprise power balance constraint, hybrid energy storage system constraint, public power grid power constraint, photovoltaic power generation constraint, back-to-back converter constraint in a power flow controller and three-phase unbalance constraint.
The constraints are as follows:
power balance constraint conditions:
Pt grid,buy-Pt grid,fed=Pt T+Pt α(6)
Pt α+Pt b,dis+Pt u,dis+Pt PV=Pt β+Pt b,ch+Pt u,ch(7)
Pt T+Pt β=at(8)
in the formula: pt TFor active power of traction transformers, Pt αFor α phase active power, P, of the back-to-back convertert βFor the back-to-back converter β phase active power,β phase reactive power P for back-to-back convertert PVThe photovoltaic output is obtained;is the maximum limit value of the interaction power between the traction substation and the power grid,is a binary variable representing the direction of power interaction between the traction substation and the grid,indicating that the interactive power flows from the grid to the traction substation,and the representation interactive power is fed back to the power grid by the traction substation.
Hybrid energy storage system constraint conditions:
in the formula: epsilonbIs the self-discharge rate of the battery, epsilonbIs the self-discharge rate of the super capacitor, ηb,disFor the discharge efficiency of the battery, ηb,chFor the charging efficiency of the battery, ηu,disFor the discharge efficiency of the supercapacitor, ηu,chTo the charging efficiency of the super capacitor, Δ t is the unit time period,for the electrical energy stored by the battery during the time period t +1,storing the electric energy for the battery in the time period t;the electric energy stored by the super capacitor in the time period of t +1,the electric energy stored for the super capacitor in the time period t;is the rated power of the battery and is,the power of the super capacitor is rated,is the minimum state of charge of the battery,the maximum state of charge of the battery is,is the rated capacity of the battery,the capacity of the super capacitor is rated,the electrical energy stored by the battery for the time period t-1,electric energy stored for super capacitor in t-1 period,The minimum state of charge of the super capacitor is obtained,the maximum charge state of the super capacitor;the electrical energy stored in the battery for the initial period of time each day,the electrical energy stored in the battery for the last period of the day,for the purpose of the initial state of charge per day,the super capacitor stores electric energy for the initial time period every day,the electric energy stored by the super capacitor for the last time period of each day,the initial charge state of the super capacitor every day;andare all binary variables.
Photovoltaic power generation constraint:
0≤Pt PV≤pt(19)
in the formula: p is a radical oftThe photovoltaic output uncertain variable is the solar photovoltaic output upper limit value.
Back-to-back converter constraint:
in the formula:for the capacity of the back-to-back inverter α phases,the capacity of the back-to-back inverter β phases.
And (3) three-phase voltage unbalance degree constraint:
in the formula: epsilonUFor traction substation power grid side three-phase voltage unbalance degree, USFor the grid side line voltage, ScapFor the short-circuit capacity of the side line of the power grid,is the upper limit value of the unbalance degree of the three-phase voltage in the national standard,for grid side negative sequence current, UTFor the voltage at the outlet of the traction transformer, UαIs the voltage at the α phase outlet of the back-to-back converter, N1For single-phase traction transformer transformation ratio, N2For high voltage matching transformer transformation ratio, a is complex operator ej120°,Is the voltage-current phase angle difference of the single-phase traction transformer,is the voltage-current phase angle difference, I, of α phases of the back-to-back current transformerTFor drawing transformer currents, IαIs the current of the back-to-back current transformer α phases.
The constraint linearization method is as follows:
the max function in equation (5) is linearized by the following equation:
max(Pt dem)=Pdem,max(25)
in the formula: pdem,maxIs an auxiliary variable representing the maximum demand value during the day.
The formula (21) after linearization is given by:
in the formula: n is a radical ofpThe number of the fan-shaped PQ semicircles is equal to that of the fan-shaped PQ semicircles, and the Q is more than or equal to 0; delta theta is the sector angle, (P)k,Qk) Is the division point coordinate of the fan shape and the PQ semicircle.
Equation (24) is linearized as follows:
in the formula:andare all auxiliary variables, and are all the auxiliary variables,is a binary variable.
And 4, step 4: establishing a two-stage robust optimization model of robust energy management of the traction power supply system according to the objective function obtained in the step (2) and the constraint condition obtained in the step (3);
the two-stage robust optimization model for robust energy management of the traction power supply system comprises the following steps:
in the formula: x represents the binary decision variable vector of the first stage,y denotes a second stage continuous decision variable vector, c. b, D, D, E, E, F, F, G, H and I are parameter matrixes or parameter vectors.
And 5: and forming a main model and a sub model of the robust energy management model of the traction power supply system through a column and constraint generation algorithm, and finally, circularly and iteratively solving the main model and the sub model by using optimization software (such as a hybrid integer optimization solver CPLEX in a Matlab environment) to obtain the optimal charging and discharging power of the hybrid energy storage device, the optimal photovoltaic grid-connected power and the optimal power flow power of a back-to-back converter in a power flow controller under the worst scene, namely completing the robust energy management optimization of the traction power supply system.
The main model expression is:
s.t.x∈{0,1} (37)
in the formula: k is the number of iterative solution times, ylThe decision variables added to the main model at the first loop,to solve for the worst photovoltaic output obtained by the submodel,for solving the worst active load scenario, r, obtained for the submodell *Representing the worst reactive load scene obtained by solving the submodel;
the sub-model expression is:
s.t.By≤d,(γ1) (46)
Dy=e,(γ2) (47)
Fy≤f-Ex*,(γ3) (48)
Gy≤p,(γ4) (49)
Hy=a,(γ5) (50)
Iy=r,(γ6) (51)
in the formula: x is the number of*For the optimal solution of the main model, { gamma {1,γ2,γ3,γ4,γ5,γ6Is a constraint dual variable;
the submodel equivalent representation method is as follows:
worst scenario p in sub-model*、a*And r*To not determine the extreme values in sets P, A and R, equations (1) - (3) are therefore equivalent to:
based on strong dual theory, submodels (45) - (51) are equivalent to:
-BTγ1+DTγ2-FTγ3-GTγ4+HTγ5+ITγ6=cT(56)
γ1≥0,γ3≥0,γ4≥0,γ2,γ5,γ6is a free variable (57)
examples
The robust energy management structure of the electrified railway traction power supply system considering uncertain photovoltaic and load is shown in figure 1, the parameters of the energy storage system are shown in table 1, the parameters of a traction substation are shown in table 2, and the power price parameters of a power grid are shown in table 3.
TABLE 1 hybrid energy storage System parameters
TABLE 2 traction substation parameters
TABLE 3 Electricity price parameter
The operating and maintenance costs of other parameters, such as photovoltaic, battery and super capacitor are all 0.1 ¥/kWh, and the charging of feedback electric energy is cfed=-0.8cbuyIn linearization of PFC converter, the fan angle Δ θ is 30 °, C&The CG algorithm iteration convergence precision epsilon is 0.01. The uncertain interval of the photovoltaic output and the traction load is expressed as [ 1-lambda ]p,1+λp]pf、[1-λa,1+λa]afAnd [ 1-lambda ]r,1+λr]rfWherein λ isp、λaAnd λrFor predicting the deviation coefficients, 0.1 is taken.
The robust energy management optimization method of the traction power supply system is compared with the traditional deterministic energy management method, and the results are shown in tables 4 and 5 after simulation calculation.
TABLE 4 comparison of results of deterministic method and robust method under different uncertainty margins
TABLE 5 comparison of deterministic and robust method results under different prediction biases
As can be seen from tables 4 and 5, with the increase of the uncertainty margin and the prediction deviation coefficient, compared with the conventional deterministic energy management method, the robust energy management optimization method for the traction power supply system has the advantages that the total operating cost is lower in the worst scenario, and the saving rate is continuously increased. Particularly, when the prediction deviation coefficient reaches 0.6, the traditional deterministic energy management method has the situation of being unsolvable, so the robustness is low, and the robust energy management optimization method can be solvated in all scenes, so the robustness is high.
The invention provides a double-stage robust model-based energy management robust optimization method for a traction power supply system, which aims at the traction power supply system connected with a photovoltaic power generation system and an energy storage device, takes photovoltaic output and traction load uncertainty into consideration, and provides the double-stage robust model-based energy management robust optimization method for the traction power supply system. According to the method, in the first stage, based on photovoltaic output and traction load prediction information, a charging and discharging strategy of an energy storage device and an electric quantity trading scheme with a power grid are formulated, and in the second stage, the worst scene of the photovoltaic output and traction load and the corresponding optimal power flow are found. The column and constraint generation algorithm is adopted to solve the two-stage robust optimization model, and the result shows that compared with the traditional deterministic energy management method, the robust energy management optimization method has the advantages of optimality and robustness, especially under the condition that the uncertainty of the operating environment is increased. The method makes the energy management method of the traction power supply system more practical and provides a foundation for the access and engineering application of renewable energy sources and energy storage systems in future electrified railways.
Claims (7)
1. The method for managing the robust energy of the traction power supply system in consideration of uncertain photovoltaic and load is characterized by comprising the following steps of:
step 1: acquiring predicted values and fluctuation intervals of traction substation load process data and photovoltaic output data, and constructing uncertain sets of traction loads and photovoltaic outputs;
step 2: establishing a target function of a robust optimization model according to the electric charge parameters and the intervals of the load process data and the photovoltaic output data of the traction substation obtained in the step 1;
and step 3: according to power capacity parameters of a hybrid energy storage system and a photovoltaic system and national standard limit values of three-phase voltage unbalance, establishing constraint conditions of a robust optimization model based on the traction substation load process data and the photovoltaic output data interval obtained in the step 1, and linearizing the constraint conditions of the robust optimization model;
and 4, step 4: establishing a robust energy management method of the traction power supply system based on a two-stage robust optimization model according to the objective function obtained in the step 2 and the constraint condition obtained in the step 3;
and 5: and (4) solving the model obtained in the step (4) by using a column and constraint generation algorithm to obtain the optimal charging and discharging power of the hybrid energy storage device, the optimal photovoltaic grid-connected power and the optimal power flow power of a back-to-back converter in the power flow controller under the worst scene, namely completing the robust energy management optimization of the traction power supply system.
2. The method for robust energy management of a traction power supply system considering uncertain photovoltaic and load according to claim 1, wherein the uncertain set of photovoltaic output and load in step 1 is:
in the formula: p, A and R are the uncertain set of photovoltaic power output, active load and reactive load, p, respectivelyt、atAnd rtIs light ofUncertain variable, Δ p, of the outages, active and reactive loadst、ΔatAnd Δ rtRespectively represent predicted valuesAnd rt fDeviation value of, parameter Γp、ΓaAnd ΓrRepresenting uncertainty margin, i.e. the total relative deviation of the uncertainty variable from the predicted value, which ranges from 0 to the total time period N of the dayTIn the meantime.
3. The method for robust energy management of a traction power supply system considering uncertain photovoltaic and load according to claim 1, wherein the objective function in the step 2 is as follows:
in the formula: f is an objective function and represents daily operation cost of the traction substation, t is a time period and P ist grid,buyElectric power purchased from the grid for traction substations, Pt grid,fedElectric power P fed back to the grid by the traction substationt PVFor photovoltaic output, Pt b,disFor discharging power of the battery, Pt b,chCharging power for batteries, Pt u,disDischarging power, P, for the super-capacitort u,chCharging power to the super capacitor, Pt demIn order to demand the power, the power supply is,in order to achieve the cost price of photovoltaic operation and maintenance,for transporting batteriesThe cost price of the maintenance of the line,cost price for operating and maintaining super capacitor, cdemThe price of the required electricity charge is calculated,the price of the electricity purchased by the traction substation is,charge price levied for feedback back to the grid power, NdayFor the number of days of operation per month,andare all binary variables;
4. the method for robust energy management of a traction power supply system considering uncertain photovoltaic and load according to claim 1, wherein the constraint conditions in the step 3 are as follows:
power balance constraint conditions:
Pt grid,buy-Pt grid,fed=Pt T+Pt α(6)
Pt α+Pt b,dis+Pt u,dis+Pt PV=Pt β+Pt b,ch+Pt u,ch(7)
Pt T+Pt β=at(8)
in the formula: pt TFor active power of traction transformers, Pt αFor α phase active power, P, of the back-to-back convertert βFor the back-to-back converter β phase active power,β phase reactive power P for back-to-back convertert PVThe photovoltaic output is obtained;is the maximum limit value of the interaction power between the traction substation and the power grid,is a binary variable representing the direction of power interaction between the traction substation and the grid,indicating that the interactive power flows from the grid to the traction substation,representing that the interactive power is fed back to the power grid by the traction substation;
hybrid energy storage system constraint conditions:
in the formula: epsilonbIs the self-discharge rate of the battery, epsilonbIs the self-discharge rate of the super capacitor, ηb,disFor the discharge efficiency of the battery, ηb,chFor the charging efficiency of the battery, ηu,disFor the discharge efficiency of the supercapacitor, ηu,chTo the charging efficiency of the super capacitor, Δ t is the unit time period,for the electrical energy stored by the battery during the time period t +1,storing the electric energy for the battery in the time period t;the electric energy stored by the super capacitor in the time period of t +1,the electric energy stored for the super capacitor in the time period t;is the rated power of the battery and is,the power of the super capacitor is rated, bSOCis the minimum state of charge of the battery,the maximum state of charge of the battery is,is the rated capacity of the battery,the capacity of the super capacitor is rated,the electrical energy stored by the battery for the time period t-1,the electric energy stored by the super capacitor in the period of t-1, uSOCthe minimum state of charge of the super capacitor is obtained,the maximum charge state of the super capacitor;the electrical energy stored in the battery for the initial period of time each day,the electrical energy stored in the battery for the last period of the day,for the purpose of the initial state of charge per day,the super capacitor stores electric energy for the initial time period every day,the electric energy stored by the super capacitor for the last time period of each day,the initial charge state of the super capacitor every day;andare all binary variables;
photovoltaic power generation constraint:
0≤Pt PV≤pt(19)
in the formula: p is a radical oftThe photovoltaic output uncertain variable is an intra-day photovoltaic output upper limit value;
back-to-back converter constraint:
in the formula:for the capacity of the back-to-back inverter α phases,capacity of the back-to-back inverter β phases;
and (3) three-phase voltage unbalance degree constraint:
in the formula: epsilonUFor traction substation power grid side three-phase voltage unbalance degree, USFor the grid side line voltage, ScapFor the short-circuit capacity of the side line of the power grid,is the upper limit value of the unbalance degree of the three-phase voltage in the national standard,for grid side negative sequence current, UTFor the voltage at the outlet of the traction transformer, UαIs the voltage at the α phase outlet of the back-to-back converter, N1For single-phase traction transformer transformation ratio, N2For high voltage matching transformer transformation ratio, a is complex operator ej120°,Is the voltage-current phase angle difference of the single-phase traction transformer,is the voltage-current phase angle difference, I, of α phases of the back-to-back current transformerTFor drawing transformer currents, IαIs the current of the back-to-back current transformer α phases.
5. The method for robust energy management of a traction power supply system considering uncertain photovoltaic and load according to claim 1, wherein the constraint condition linearization method in the step 3 is as follows:
the max function in equation (5) is linearized by the following equation:
max(Pt dem)=Pdem,max(25)
in the formula: pdem,maxIs an auxiliary variable representing the maximum demand value during the day;
the formula (21) after linearization is given by:
in the formula: n is a radical ofpThe number of the fan-shaped PQ semicircles is equal to that of the fan-shaped PQ semicircles, and the Q is more than or equal to 0; delta theta is the sector angle, (P)k,Qk) The coordinates of the division points of the fan shape and the PQ semicircle;
equation (24) is linearized as follows:
6. The method for robust energy management of a traction power supply system considering uncertain photovoltaic and load according to claim 1, wherein the two-stage robust optimization model for robust energy management of the traction power supply system established in the step 4 is as follows:
7. The method for managing the robust energy of the traction power supply system in consideration of uncertain photovoltaic and load according to claim 1, wherein a main model and a sub model of the robust energy management model of the traction power supply system are formed through a column and constraint generation algorithm in the step 5, the main model and the sub model are solved in a circulating iteration mode to obtain the optimal charging and discharging power of the hybrid energy storage device in the worst scene, the optimal photovoltaic grid-connected power and the optimal power flow power of a back-to-back converter in a power flow controller, and therefore the robust energy management optimization of the traction power supply system is completed;
wherein, the expression of the main model is as follows:
s.t.x∈{0,1} (37)
in the formula: k is the number of iterative solution times, ylThe decision variables added to the main model at the first loop,to solve for the worst photovoltaic output obtained by the submodel,for solving the worst active load scenario, r, obtained for the submodell *Representing the worst reactive load scene obtained by solving the submodel;
the sub-model expression is:
s.t.By≤d,(γ1) (46)
Dy=e,(γ2) (47)
Fy≤f-Ex*,(γ3) (48)
Gy≤p,(γ4) (49)
Hy=a,(γ5) (50)
Iy=r,(γ6) (51)
in the formula: x is the number of*For the optimal solution of the main model, { gamma {1,γ2,γ3,γ4,γ5,γ6Is a constraint dual variable;
the submodel equivalent representation method is as follows:
worst scenario p in sub-model*、a*And r*To not determine the extreme values in sets P, A and R, equations (1) - (3) are therefore equivalent to:
based on strong dual theory, submodels (45) - (51) are equivalent to:
-BTγ1+DTγ2-FTγ3-GTγ4+HTγ5+ITγ6=cT(56)
γ1≥0,γ3≥0,γ4≥0,γ2,γ5,γ6is a free variable (57)
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113422364A (en) * | 2021-05-06 | 2021-09-21 | 华翔翔能科技股份有限公司 | Fully-buried variable load management method considering two power generation prices |
CN117060491A (en) * | 2023-10-11 | 2023-11-14 | 中国电建集团西北勘测设计研究院有限公司 | Operation optimization method, system, medium and equipment of wind-solar hybrid energy storage system |
Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170070044A1 (en) * | 2015-09-06 | 2017-03-09 | Tsinghua University | Robust restoration method for active distribution network |
CN107887903A (en) * | 2017-10-31 | 2018-04-06 | 深圳供电局有限公司 | Consider the micro-capacitance sensor robust Optimization Scheduling of element frequency characteristic |
CN107979111A (en) * | 2017-07-21 | 2018-05-01 | 天津大学 | A kind of energy management method for micro-grid based on the optimization of two benches robust |
CN108108846A (en) * | 2017-12-28 | 2018-06-01 | 东南大学 | A kind of alternating current-direct current mixing microgrid robust optimizes coordinated scheduling method |
CN108233415A (en) * | 2018-01-15 | 2018-06-29 | 合肥工业大学 | Two-stage type photovoltaic DC-to-AC converter virtual synchronous generator control method |
CN108258695A (en) * | 2018-02-28 | 2018-07-06 | 东南大学 | A kind of random robust coupled mode Optimization Scheduling of alternating current-direct current series-parallel connection microgrid |
CN108321854A (en) * | 2018-03-13 | 2018-07-24 | 燕山大学 | It is a kind of to consider that the micro-capacitance sensor event of communication time lag triggers hierarchical control method |
CN109274134A (en) * | 2018-11-08 | 2019-01-25 | 东南大学 | A kind of active distribution network robust active reactive coordination optimizing method based on time series scene analysis |
CN109659980A (en) * | 2019-01-22 | 2019-04-19 | 西南交通大学 | The tractive power supply system energy management optimization method of integrated hybrid energy-storing and photovoltaic devices |
CN110390467A (en) * | 2019-06-25 | 2019-10-29 | 河海大学 | A kind of random ADAPTIVE ROBUST Optimization Scheduling of virtual plant distinguished based on key scenes |
CN110474367A (en) * | 2019-08-05 | 2019-11-19 | 广东工业大学 | A kind of micro-capacitance sensor capacity configuration optimization method considering risk of loss |
CN110829433A (en) * | 2019-11-14 | 2020-02-21 | 青岛特锐德高压设备有限公司 | Novel electric energy interaction system |
-
2020
- 2020-03-07 CN CN202010154115.1A patent/CN111342450B/en active Active
Patent Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170070044A1 (en) * | 2015-09-06 | 2017-03-09 | Tsinghua University | Robust restoration method for active distribution network |
CN107979111A (en) * | 2017-07-21 | 2018-05-01 | 天津大学 | A kind of energy management method for micro-grid based on the optimization of two benches robust |
CN107887903A (en) * | 2017-10-31 | 2018-04-06 | 深圳供电局有限公司 | Consider the micro-capacitance sensor robust Optimization Scheduling of element frequency characteristic |
CN108108846A (en) * | 2017-12-28 | 2018-06-01 | 东南大学 | A kind of alternating current-direct current mixing microgrid robust optimizes coordinated scheduling method |
CN108233415A (en) * | 2018-01-15 | 2018-06-29 | 合肥工业大学 | Two-stage type photovoltaic DC-to-AC converter virtual synchronous generator control method |
CN108258695A (en) * | 2018-02-28 | 2018-07-06 | 东南大学 | A kind of random robust coupled mode Optimization Scheduling of alternating current-direct current series-parallel connection microgrid |
CN108321854A (en) * | 2018-03-13 | 2018-07-24 | 燕山大学 | It is a kind of to consider that the micro-capacitance sensor event of communication time lag triggers hierarchical control method |
CN109274134A (en) * | 2018-11-08 | 2019-01-25 | 东南大学 | A kind of active distribution network robust active reactive coordination optimizing method based on time series scene analysis |
CN109659980A (en) * | 2019-01-22 | 2019-04-19 | 西南交通大学 | The tractive power supply system energy management optimization method of integrated hybrid energy-storing and photovoltaic devices |
CN110390467A (en) * | 2019-06-25 | 2019-10-29 | 河海大学 | A kind of random ADAPTIVE ROBUST Optimization Scheduling of virtual plant distinguished based on key scenes |
CN110474367A (en) * | 2019-08-05 | 2019-11-19 | 广东工业大学 | A kind of micro-capacitance sensor capacity configuration optimization method considering risk of loss |
CN110829433A (en) * | 2019-11-14 | 2020-02-21 | 青岛特锐德高压设备有限公司 | Novel electric energy interaction system |
Non-Patent Citations (2)
Title |
---|
YUANLI LIU ET AL: "Energy Management of Connected Co-Phase Traction Power System Considering HESS and PV", 《2019 14TH IEEE CONFERENCE ON INDUSTRIAL ELECTRONICS AND APPLICATIONS (ICIEA)》 * |
张刚等: "考虑碳排放交易的日前调度双阶段鲁棒优化模型", 《中国电机工程学报》 * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113422364A (en) * | 2021-05-06 | 2021-09-21 | 华翔翔能科技股份有限公司 | Fully-buried variable load management method considering two power generation prices |
CN117060491A (en) * | 2023-10-11 | 2023-11-14 | 中国电建集团西北勘测设计研究院有限公司 | Operation optimization method, system, medium and equipment of wind-solar hybrid energy storage system |
CN117060491B (en) * | 2023-10-11 | 2024-01-30 | 中国电建集团西北勘测设计研究院有限公司 | Operation optimization method, system, medium and equipment of wind-solar hybrid energy storage system |
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