A bidirectional converter site selection and characteristic collaborative optimization method

Abstract

The application provides a bidirectional converter site selection and characteristic collaborative optimization method, relates to the field of track traffic power supply traction reconstruction and optimization, and comprises the following steps: obtaining traction station data and train operation data in each period as the basis for bidirectional converter site selection and characteristic optimization; initializing the site selection and characteristic scheme of the bidirectional converter; constructing a circuit topology to perform power flow calculation to obtain the power of each time point substation; constructing an optimization model with the lowest daily average cost as the target after bidirectional converter site selection and characteristic collaborative optimization; and solving the optimization model to obtain the bidirectional converter site selection and characteristic scheme with the lowest daily average cost. The application provides an optimal scheme for adding bidirectional converters in the current urban track traffic traction station reconstruction, including the number, position and corresponding characteristics, under the premise of ensuring train operation power supply demand, and solves the problem of bidirectional converter site selection and parameter setting in traction substations.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of track traffic power supply traction reconstruction and optimization, and particularly relates to a bidirectional converter site selection and characteristic collaborative optimization method. BACKGROUND

[0002] Currently, the track traffic power supply built at home and abroad is mainly rectifier traction substation, which cannot effectively recover the regenerative energy of the train. The bidirectional converter has the functions of rectification and inversion and is applied to track traffic to feed the regenerative energy back to the loop network and improve the utilization rate of regenerative energy. Therefore, the current operators start to reconstruct the current rectifier traction substation based on the bidirectional converter to reduce the system operation cost. Considering the construction and maintenance cost of adding the bidirectional converter and the site selection and characteristic parameters of the bidirectional converter, both of which will affect the system power flow and energy consumption. Therefore, an optimization model is established to minimize the system cost under train operation, and a bidirectional converter site selection and characteristic collaborative optimization method for urban track traffic traction substation reconstruction is proposed to improve the economy of track traffic operation.

[0003] Currently, there is no relevant literature and patent to solve the bidirectional converter site selection and characteristic problem for urban track traffic traction substation reconstruction. The conventional site selection optimization problem, such as the site selection and capacity of the energy storage system, usually considers the capacity of the device, but this parameter does not affect the energy consumption of the system. The characteristic parameters of the bidirectional converter in this patent affect the system power and voltage. Under the condition that the train operation is unchanged, the characteristic parameters of the bidirectional converter will affect the system energy consumption. Therefore, this patent proposes a bidirectional converter site selection and characteristic collaborative optimization method to reduce the system loss and recover the regenerative energy, thereby reducing the cost comprehensively. SUMMARY

[0004] In view of the above deficiencies in the prior art, the bidirectional converter site selection and characteristic collaborative optimization method provided by the present application is a bidirectional converter site selection and characteristic collaborative optimization for urban track traffic traction substation reconstruction. The present application considers the electricity cost of train operation, the construction and maintenance cost of adding the bidirectional converter, and can obtain the bidirectional converter scheme (bidirectional converter site selection and characteristic scheme) under the lowest operation cost, thereby providing an effective method for bidirectional converter site selection and characteristic optimization in the current track traffic traction substation reconstruction.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: a bidirectional converter site selection and characteristic collaborative optimization method, comprising the following steps:

[0006] Obtain traction substation data and train operation data;

[0007] Determine the bidirectional converter site selection set according to the traction substation data, and determine the position and power information of the train at each time according to the train operation data;

[0008] The site selection and characteristic scheme of the bidirectional converter is initialized, and characteristics of the bidirectional converter are droop slope and inverter start-up voltage;

[0009] Combined with the position and power information of the train at each moment and the site selection and characteristic scheme of the bidirectional converter, the circuit topology is constructed to perform power flow calculation to obtain the power of the substation at each moment;

[0010] Based on the power of the substation at each moment, the train operation electricity cost is calculated, and the construction and maintenance costs are calculated based on the number of added bidirectional converters, and an optimization model is constructed with the lowest daily average cost as the target after the site selection and characteristic optimization of the bidirectional converter;

[0011] The optimization model is solved to obtain the site selection and characteristic scheme of the bidirectional converter that minimizes the daily average cost, and the result of the site selection and characteristic optimization of the bidirectional converter is output, wherein the position of the site selection of the bidirectional converter belongs to the site selection set of the bidirectional converter.

[0012] Further, the expression of the power information of the train k is as follows:

[0013]

[0014] wherein, F k (t)v k (t) and represent the power, control force, speed and auxiliary system power of the train k at time t, and t represents time.

[0015] Further, the site selection and characteristic scheme of the bidirectional converter is represented as:

[0016] X=[x1,x2,...,x N ,U st1 ,U st2 ,...,U stN ,k1,k2,...,k N ]

[0017] wherein, X represents the site selection and characteristic scheme of the bidirectional converter, N represents the number of traction stations, x i represents whether the bidirectional converter is added in the i th traction station in the site selection set of the bidirectional converter, x N represents whether the bidirectional converter is added in the N th traction station, U sti and k i represent the inverter start-up voltage and droop slope of the bidirectional converter added in the i th traction station, U stN and k N represent the inverter start-up voltage and droop slope of the bidirectional converter added in the N th traction station, i=1,2,3,...,N.

[0018] Further, the combination of the position of the train at each time, power information and the site selection and characteristic scheme of the bidirectional converter, the circuit topology is constructed, which is specifically:

[0019] The train is taken as the power source node, and the position at different times is different, which determines the connection scheme and connection impedance of each power source node; the traction is taken as the voltage node, and the rectifier is added to the bidirectional converter to become a hybrid traction substation, which has the functions of inversion and rectification. The characteristics of the hybrid traction substation are obtained by the equivalent circuit parallel connection of the droop characteristics of the rectifier and the inversion opening voltage, droop characteristic parameters of the bidirectional converter.

[0020] Further, the power flow calculation is specifically:

[0021] Based on the circuit topology, the node voltage equation is constructed, and based on the Newton-Raphson method or Gauss-Seidel, the power flow iteration is carried out to obtain the voltage and power information of each node. This process is called power flow settlement, wherein the power of the substation at each time is obtained by the node voltage matrix power flow calculation based on the circuit topology, which is represented as:

[0022]

[0023] Wherein, f represents the power flow calculation process, P train (t) represents the power information of all trains on the line at t time, S train (t) represents the position information of all trains on the line at t time, Sub(X) represents the site selection and characteristic scheme information of the added bidirectional converter, and respectively represent the power information of the traction substation i and the power information and position information of the train k at t time, and respectively represent the power information of the traction substation N and the power information and position information of the train K at t time.

[0024] Further, the expression of the train operation electricity cost is as follows:

[0025]

[0026] Wherein, C ele represents the daily train operation electricity cost, c e (t) represents the electricity price, P sub (t) represents the power of the substation at t time, t0 and t f respectively represent the operation start and end time of the train per day.

[0027] Further, the expression of the construction and maintenance cost is as follows:

[0028]

[0029] wherein, C BC represents the daily average cost of construction and maintenance of the added bidirectional converter, N' represents the number of added bidirectional converters, c1 and c2 respectively represent the construction and annual maintenance unit price of a single bidirectional converter, Y represents the service life cycle of the bidirectional converter, and γ represents the annual economic inflation rate.

[0030] Further, the expression of the objective function of the optimization model is as follows:

[0031] J = min (C ele + C BC )

[0032] wherein, J represents the objective function of the optimization model, C ele represents the daily train operation electricity cost, C BC represents the daily average cost of construction and maintenance of the added bidirectional converter, and min represents the minimum value.

[0033] Further, the constraint condition of the optimization model is that the value range of the decision variable is represented as:

[0034]

[0035] wherein, U stmin and U stmax respectively represent the minimum and maximum values of the bidirectional converter inverter start voltage, k min and k max respectively represent the minimum and maximum values of the droop slope, x i represents whether the bidirectional converter is added at the i-th traction substation, k i represents the droop slope of the bidirectional converter added at the i-th traction substation, and U sti represents the inverter start voltage of the bidirectional converter added at the i-th traction substation.

[0036] The beneficial effects of the present application are:

[0037] (1) The bidirectional converter site selection and characteristic collaborative optimization method for urban rail transit traction substation reconstruction of the present application determines the bidirectional converter site selection set and the demand power of the train based on the line traction substation distribution and the actual train operation, and the operation demand of the train can be met after adding the bidirectional converter.

[0038] (2) When constructing the objective function of train operation and bidirectional converter construction and maintenance costs, the present invention comprehensively considers the operating electricity costs of the train at different times of the day and the life cycle maintenance costs of the bidirectional converter, establishes a daily average cost, and accurately evaluates the economic feasibility of the scheme; and performs coordinated optimization of the site selection and characteristics of the bidirectional converter, so that the final site selection and characteristic scheme has better results. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Flow chart of the method of the present invention. DETAILED DESCRIPTION

[0040] The specific embodiments of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations utilizing the concepts of the present invention are protected.

[0041] Example

[0042] like Figure 1 As shown, the present invention provides a method for coordinated optimization of bidirectional converter site selection and characteristics, which is implemented as follows:

[0043] S1. Obtain traction depot data and train operation data;

[0044] S2. Determine the bidirectional converter location set based on the traction depot data, and determine the train location and power information at each time based on the train operation data;

[0045] In this embodiment, the characteristics of the bidirectional converter are the droop slope and the inverter start-up voltage, both of which affect the system power and energy consumption.

[0046] In this embodiment, the acquired traction depot data includes the location of the traction depot, and the acquired train data includes the power of the onboard auxiliary system, the location, speed and control force of the train at different times.

[0047] In this embodiment, the bidirectional converter location set is the location set S of all traction depots. The train operation data includes train position, speed, control force, and onboard auxiliary system power. The train power is obtained by the following formula:

[0048] P train (t)=F(t)v(t)+P aux

[0049] Among them, P train (t), F(t) and v(t) represent the power, control force and speed of the train at time t respectively, P auxP (t) represents auxiliary system power, and t represents time.

[0050] In this embodiment, the train operation electricity cost is the electricity cost of the substation, and is represented as:

[0051]

[0052] C (t) = P (t) * c (t), t = t0, t0+1, t0+2, …, t0+24 ele P (t) represents the train operation electricity cost of a single day, and c (t) represents the electricity price. e P (t) represents the train operation electricity cost of a single day, and c (t) represents the electricity price. sub P (t) represents the power of the substation at time t, t0 and t f t0 and t

[0053] S3, initialize the addressing and characteristic scheme of the bidirectional converter, wherein the characteristics of the bidirectional converter are droop slope and inverter start-up voltage;

[0054] In this embodiment, the addressing and characteristic scheme of the bidirectional converter is represented as:

[0055] X = [x1, x2, …, x N U st1 U st2 ..., U stN k1, k2, …, k N ]

[0056] X represents the addressing and characteristic scheme of the bidirectional converter, N represents the number of traction substations, x i represents whether the i-th traction substation in the bidirectional converter addressing set is additionally provided with a bidirectional converter, x N represents whether the N-th traction substation is additionally provided with a bidirectional converter, U sti and k i respectively represent the inverter start-up voltage and the droop slope of the bidirectional converter additionally provided at the i-th traction substation, U stN and k N respectively represent the inverter start-up voltage and the droop slope of the bidirectional converter additionally provided at the N-th traction substation, i = 1, 2, 3, …, N.

[0057] S4, combine the position and power information of the train at each time and the addressing and characteristic scheme of the bidirectional converter to construct a circuit topology for power flow calculation to obtain the power of the substation at each time.

[0058] In this embodiment, the position and power information of the train at each time and the addressing and characteristic scheme of the bidirectional converter are combined to construct a circuit topology, which is specifically:

[0059] The train is taken as a power source node, and the position at different time determines the connection scheme and connection impedance of each power source node; the traction substation is taken as a voltage node, and the rectifier is added with a bidirectional converter to become a hybrid traction substation, which has the functions of inversion and rectification, and the characteristics of the hybrid traction substation are obtained by the equivalent circuit parallel connection of the droop characteristics of the rectifier and the inversion opening voltage and droop characteristic parameters of the bidirectional converter.

[0060] In the embodiment, the power flow calculation is specifically:

[0061] The node voltage equation is constructed based on the circuit topology, the power flow iteration is carried out based on the Newton-Raphson method or Gauss-Seidel, and the voltage and power information of each node are obtained, which is called power flow settlement, wherein the power of each substation at each time is obtained by the node voltage matrix power flow calculation based on the circuit topology, and is expressed as:

[0062]

[0063] Wherein, f represents the power flow calculation process, P train (t) represents the power information of all trains on the line at t time, S train (t) represents the position information of all trains on the line at t time, Sub(X) represents the site selection and characteristic scheme information of the added bidirectional converter, and respectively represent the power information of the traction substation i and the power information and position information of the train k at t time, and respectively represent the power information of the traction substation N and the power information and position information of the train K at t time.

[0064] S5, based on the power of each substation at each time, the train operation electricity cost is calculated, and the construction and maintenance cost of the added bidirectional converter is calculated, and an optimization model is constructed, which takes the lowest average cost after the coordinated optimization of the bidirectional converter site selection and characteristics as the target;

[0065] In the embodiment, the expression of the train operation electricity cost is as follows:

[0066]

[0067] Wherein, C ele represents the daily train operation electricity cost, c e (t) represents the electricity price, P sub (t) represents the power of the substation at t time, t0 and t f respectively represent the operation start and end time of the train per day.

[0068] In the embodiment, the construction and maintenance cost of the added bidirectional converter is expressed as:

[0069]

[0070] Among them, C BC represents the average daily cost of construction and maintenance of additional bidirectional converters, N' represents the number of additional bidirectional converters, c1 and c2 represent the construction and annual maintenance unit prices of a single bidirectional converter, respectively, Y represents the service life of the bidirectional converter, and γ represents the annual economic inflation rate.

[0071] In this embodiment, an optimization model is designed to minimize the daily average cost after coordinated optimization of bidirectional converter site selection and characteristics. The objective function of the optimization model is expressed as:

[0072] J=min(C ele +C BC )

[0073] Among them, J represents the objective function of the optimization model, C ele represents the electricity cost of train operation per day, C BC represents the average daily cost of construction and maintenance of an additional bidirectional converter, and min represents the minimum value.

[0074] In this embodiment, the decision variables of the optimization model are the location and characteristics of the bidirectional converter, which are expressed as:

[0075] X=[x1,x2,...,x N ,U st1 ,U st2 ,...,U stN ,k1,k2,...,k N ]

[0076] Among them, X represents the decision variable of the optimization model, N represents the number of traction stations, and x i Indicates whether a bidirectional converter is added to the ith traction station, x N Indicates whether a bidirectional converter is added to the Nth traction station, U sti and k i They represent the inverter start-up voltage and droop slope of the bidirectional converter added in the i-th traction station, U stN and k N These are the inverter start-up voltage and droop slope i=1, 2, 3, ..., N of the bidirectional converter added in the Nth traction station.

[0077] The constraints of the optimization model are the value ranges of the decision variables, which can be expressed as:

[0078]

[0079] Among them, U stmin and U stmaxrespectively represent the minimum and maximum values of the inverter opening voltage of the bi-directional converter, k min and k max respectively represent the minimum and maximum values of the droop slope, x i represents whether the bi-directional converter is added at the i-th traction substation, k i represents the droop slope of the bi-directional converter added at the i-th traction substation.

[0080] S6, solving the optimization model to obtain the bi-directional converter site selection and characteristic scheme that makes the daily average cost lowest, and outputting the result of the bi-directional converter site selection and characteristic coordination optimization, wherein the position of the bi-directional converter site selection belongs to the bi-directional converter site selection set.

[0081] In the embodiment, the solving of the optimization model can be based on a heuristic algorithm or a planning algorithm.

[0082] Those skilled in the art will realize that the embodiments described herein are for the purpose of helping the reader understand the principles of the present application and should be understood as not limiting the scope of protection of the present application to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations according to the technical inspiration disclosed in the present application without departing from the essence of the present application, and these modifications and combinations are still within the scope of protection of the present application.

Claims

1. A method for collaborative optimization of bidirectional converter site selection and characteristics, characterized in that: The method comprises the following steps: obtaining traction substation data and train operation data; determining a bidirectional converter site selection set according to the traction substation data, and determining the position and power information of the train at each time according to the train operation data; initializing the site selection and characteristic scheme of the bidirectional converter, wherein the characteristics of the bidirectional converter are droop slope and inverter start-up voltage; combining the position and power information of the train at each time and the site selection and characteristic scheme of the bidirectional converter, constructing a circuit topology for power flow calculation to obtain the power of the substation at each time; the combination of the position and power information of the train at each time and the site selection and characteristic scheme of the bidirectional converter, which is specifically: the train is regarded as a power source node, and the position at different times determines the connection scheme and connection impedance of each power source node; the traction substation is a voltage node, and after the bidirectional converter is added to the rectifier traction substation, it becomes a hybrid traction substation, which has the functions of inversion and rectification, and the characteristics of the hybrid traction substation are obtained by the equivalent circuit parallel connection of the droop characteristics of the rectifier and the equivalent circuit parallel connection of the inversion start-up voltage and the droop characteristic parameters of the bidirectional converter; the power flow calculation, which is specifically: based on the circuit topology, a node voltage equation is constructed, and based on the Newton-Raphson method or Gauss-Seidel, a power flow iteration is performed to obtain the voltage and power information of each node. This process is called power flow settlement, wherein the power of the substation at each time is obtained by the node voltage matrix power flow calculation based on the circuit topology, and is expressed as: in, f represents the power flow calculation process, express t Power information of all trains on the line at that time, express t The location information of all trains on the line at the specified time, Sub ( X ) indicates the location and characteristic scheme information of adding a bidirectional converter. ( t ), and Respectively t Time traction station i Power information, train k Power information and location information, ( t ), and Respectively t Time traction station N Power information, train Power information and location information; based on the power of the substation at each time, the train operation electricity cost is calculated, and based on the number of added bidirectional converters, the construction and maintenance cost is calculated, and an optimization model is constructed, which takes the lowest daily average cost after the site selection and characteristic coordination optimization of the bidirectional converter as the target; the optimization model is solved to obtain the site selection and characteristic scheme of the bidirectional converter that makes the daily average cost lowest, and the result of the site selection and characteristic coordination optimization of the bidirectional converter is output, wherein the position of the site selection of the bidirectional converter belongs to the bidirectional converter site selection set.

2. The bidirectional converter siting and characteristic co-optimization method of claim 1, wherein, Train k The expression of the power information of the train is as follows: wherein, , and respectively represent t power, control force, speed and auxiliary system power of the train at the time, k t denotes the time.​ 3. The bidirectional converter siting and characteristic co-optimization method of claim 1, wherein, the site selection and characteristic scheme of the bidirectional converter is expressed as: wherein, represents a site selection and characteristic scheme of the bidirectional converter, represents a number of traction substations, represents whether a bidirectional converter is added to the th traction substation in the bidirectional converter site selection set, represents whether a bidirectional converter is added to the th traction substation, and respectively represent an inverter start-up voltage and a droop slope of the bidirectional converter added to the th traction substation, and respectively represent an inverter start-up voltage and a droop slope of the bidirectional converter added to the th traction substation, .

4. The bidirectional converter siting and characteristic co-optimization method of claim 1, wherein, the expression of the train operation electricity cost is as follows: wherein, denotes the train operation electricity cost of a single day, denotes the electricity price per unit, denotes the power of the substation at the time, and denote the operation start and end time of the train of a single day, respectively.

5. The bidirectional converter siting and characteristic co-optimization method of claim 1, wherein, the expression of the construction and maintenance cost is as follows: wherein, represents the daily average cost of construction and maintenance of the added bi-directional converter, represents the number of added bi-directional converters, and respectively represent the construction and annual maintenance unit price of a single bi-directional converter, represents the service life of the bi-directional converter, γ represents the annual economic inflation rate.

6. The bidirectional converter siting and characteristic co-optimization method of claim 1, wherein, the expression of the objective function of the optimization model is as follows: wherein, represents an objective function of the optimization model, represents the daily train operation electricity cost, represents the daily average cost of construction and maintenance of the added bidirectional converter, represents taking the minimum value.

7. The bidirectional converter siting and characteristic co-optimization method of claim 1, wherein, the constraint condition of the optimization model is the value range of the decision variable, which is expressed as: wherein, and respectively represent minimum and maximum values of the inverter start voltage of the bidirectional converter, and respectively represent minimum and maximum values of the droop slope, represents whether the bidirectional converter is added to the th traction substation, represents the droop slope of the bidirectional converter added to the th traction substation, represents the inverter start voltage of the bidirectional converter added to the th traction substation.

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