Urban rail transit tide tracking method and device

Abstract

Embodiments of the present application relate to a kind of urban rail transit tide flow tracking method and device, comprising: constructing the equivalent circuit model of urban rail traction power supply system;Based on the node voltage equation corresponding to the equivalent circuit model of urban rail traction power supply system is written;By solving the node voltage equation, the current tracking of the urban rail traction power supply system is carried out, the proportional relationship between the source current and load current in the system is quantitatively characterized, wherein, source includes substation and brake train, and load includes traction train and line impedance;Based on the proportional relationship between the source current and load current in the system, the power tracking of urban rail traction power supply system is carried out, and the specific distribution coefficient between source power and load power is obtained;Based on the proportional relationship between the source current and load current in the system and the specific distribution coefficient between the source power and load power, the tide flow tracking result of the urban rail traction power supply system is determined;Therefore, urban rail transit tide flow tracking can be realized, which provides theoretical support for subsequent optimization of urban rail system energy storage system capacity configuration and coordination control between multiple energy storage systems.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of urban rail transit, and in particular to a method and apparatus for tracking urban rail transit traffic flow. Background Technology

[0002] In recent years, urban rail transit has experienced rapid development due to its advantages such as speed, safety, punctuality, high capacity, and low pollution. However, with the increasing operating mileage of urban rail lines year by year, its energy consumption cannot be underestimated. Quantitatively and intuitively describing the power supply relationship between various substations, traction trains, and braking trains in the traction power supply system is the foundation and prerequisite for conducting research on energy conservation and consumption reduction in urban rail systems.

[0003] Current research on power distribution in urban rail transit traction power supply systems primarily focuses on power flow calculations. Examples include: using improved current injection methods to address the nonlinearity and topological complexity of traction power supply systems; employing improved Newton-Raphson and Gauss-Seidel methods to solve power flow problems in urban rail transit power supply systems; conducting simulations of urban rail transit traction power supply systems with single / bidirectional substations, on-board / ground energy storage systems, and train overvoltage / overcurrent protection; and comparing the advantages and disadvantages of power flow calculation methods such as the Gauss-Seidel method, Newton-Raphson method, and current injection method in terms of calculation accuracy, iteration count, execution time, and memory requirements. However, for scenarios involving multiple substations and multiple trains operating collaboratively, regardless of the aforementioned power flow calculation methods, the results only provide the magnitude of the current in each branch of the system at that specific moment. Due to the numerous nodes in the urban rail transit traction power supply system, resulting in complex current flow paths, it is impossible to accurately determine the current and power distribution relationships between substations, traction trains, and braking trains at a given moment through power flow calculations.

[0004] In the field of power systems, power flow tracing is used to accurately analyze the source-flow relationships of the power grid. Power flow tracing refers to analyzing and calculating the power generated by each generator at a given moment to determine which loads are utilizing the power, and by what proportion, the power utilized by each load comes from which generators, and by what proportion. Through power flow tracing, transmission cost and network loss allocation, congestion management, reactive power pricing, and safety and stability control of the power system become more scientific, fair, and reasonable. Based on this theory, existing technologies have also proposed using graph theory to quickly calculate the power composition of transmission lines and the actual power transmission relationship between generators and loads. However, this method requires converting the system into a directed graph and determining the tracing order of nodes, making the calculation process relatively cumbersome. Furthermore, while the proportional allocation principle is simple, intuitive, and easily accepted by users, it lacks rigorous mathematical proof. Existing technologies also directly start from the results of power flow calculations, without relying on the proportional allocation principle, to establish a generator-load allocation coefficient matrix. However, this method requires shifting line impedance losses to both ends of the line as loads, thus treating the system as a lossless network. An improved power flow tracing analytical algorithm based on equivalent admittance matrix operations defines four equivalent admittance matrices using generator current, load current, line susceptance, and bus parallel admittance. Then, through rigorous mathematical derivation and matrix operations, it obtains the analytical expression of complex power distribution among generators, loads, and lines. Existing technologies also perform upstream and downstream tracing of the current distribution relationship between generators and loads in the network based on circuit theory, and then further derive the power distribution relationship between generators and loads based on the results of current tracing.

[0005] Compared to traditional power systems, the topology of urban rail traction power supply systems is time-varying due to train movement and the transition between traction and braking states. The types of "sources" and "loads" in urban rail systems are also more complex. Trains are "loads" when in traction and become "sources" when braking. Complex energy interactions exist between traction and braking trains. Furthermore, the bidirectional operation of urban rail lines further complicates the power flow path. Currently, research on power flow tracing in the urban rail field is still in its early stages. Existing technologies only consider the current distribution relationship between traction trains and substations, neglecting the current interaction between braking and traction trains, and failing to consider the power supply relationships between different parts of the system. Power flow calculations simply utilize mathematical methods, performing power flow tracing from a matrix operation perspective, ignoring the circuit constraints of the traction power supply system itself, thus resulting in inaccurate solutions. Summary of the Invention

[0006] In view of this, in order to solve the above-mentioned technical problems or some of the technical problems, the present invention provides a method and apparatus for tracking urban rail transit flow.

[0007] In a first aspect, embodiments of the present invention provide a method for tracking urban rail transit power flow, comprising:

[0008] Construct an equivalent circuit model for the urban rail traction power supply system;

[0009] Based on the equivalent circuit model, write the node voltage equations corresponding to the urban rail traction power supply system.

[0010] The current tracking of the urban rail traction power supply system is performed by solving the node voltage equations to quantitatively characterize the proportional relationship between the source current and the load current in the system. The source includes substations and braking trains, and the load includes traction trains and line impedance.

[0011] Based on the proportional relationship between the source current and the load current in the system, power tracking is performed on the urban rail traction power supply system to obtain the specific allocation coefficient between the source power and the load power.

[0012] Based on the proportional relationship between the source current and the load current in the system and the specific allocation coefficient between the source power and the load power, the power flow tracking result of the urban rail traction power supply system is determined.

[0013] In one possible implementation, the method further includes:

[0014] Obtain the voltage of each substation node, the injected current of each substation node, the voltage of each train node, and the injected current of each train node at any given time.

[0015] The voltage of each substation node, the injected current of each substation node, the voltage of each train node, and the injected current of each train node are converted into vectors to obtain the voltage vector of each substation node, the injected current vector of each substation node, the voltage vector of each train node, and the injected current vector of each train node.

[0016] Substitute the voltage vector of each substation node, the current vector injected into each substation node, the voltage vector of each train node, and the current vector injected into each train node into the node voltage equation.

[0017] Solving the node voltage equations yields the first correlation between the voltage vectors of each substation node, the injected current vectors of each substation node, and the injected current vectors of each train node.

[0018] In one possible implementation, the method further includes:

[0019] Obtain the no-load voltage and equivalent internal resistance of each substation and convert them into no-load voltage vector and equivalent internal resistance vector;

[0020] The output characteristic equations of each substation are determined based on the no-load voltage vector and the equivalent internal resistance vector.

[0021] Based on the first correlation and the output characteristic equations of each substation, and combined with the properties of matrix operations, a second correlation is determined between the injected current vector of each substation node and the injected current vector of each train node.

[0022] In one possible implementation, the method further includes:

[0023] The upstream current allocation coefficient for upstream current tracking is determined based on the second correlation.

[0024] A third correlation relationship between the upstream current allocation coefficients is determined based on the upstream current allocation coefficients;

[0025] Based on the current distribution of the current in each traction train, the downstream current distribution coefficient for downstream current tracking is determined.

[0026] A fourth correlation relationship is determined based on the downstream current allocation coefficients.

[0027] In one possible implementation, the method further includes:

[0028] Based on the upstream current allocation coefficient, the upstream power allocation coefficient for upstream power tracking is determined;

[0029] A fifth correlation relationship between the upstream power allocation coefficients is determined based on the upstream power allocation coefficients;

[0030] Based on the fifth correlation and the upstream power allocation coefficient, the downstream power allocation coefficient for downstream power tracking is determined;

[0031] The sixth correlation between the downstream power allocation coefficients is determined based on the downstream power allocation coefficients.

[0032] In a second aspect, embodiments of the present invention provide an urban rail transit flow tracking device, comprising:

[0033] The model building module is used to construct an equivalent circuit model of the urban rail traction power supply system.

[0034] The equation writing module is used to write the node voltage equations corresponding to the urban rail traction power supply system based on the equivalent circuit model.

[0035] The current tracking module is used to track the current of the urban rail traction power supply system by solving the node voltage equation, and quantitatively characterize the proportional relationship between the source current and the load current in the system. The source includes substations and braking trains, and the load includes traction trains and line impedance.

[0036] The power tracking module is used to perform power tracking on the urban rail traction power supply system based on the ratio between the source current and the load current in the system, and to obtain a specific allocation coefficient between the source power and the load power.

[0037] The determination module is used to determine the power flow tracking result of the urban rail traction power supply system based on the ratio between the source current and the load current in the system and the specific allocation coefficient between the source power and the load power.

[0038] Thirdly, embodiments of the present invention provide a computer device, including a processor and a memory, wherein the processor is configured to execute an urban rail transit flow tracking program stored in the memory to implement the urban rail transit flow tracking method described in the first aspect above.

[0039] Fourthly, embodiments of the present invention provide a storage medium, comprising: the storage medium storing one or more programs, the one or more programs being executable by one or more processors to implement the urban rail transit flow tracking method described in the first aspect above.

[0040] The urban rail transit power flow tracing scheme provided in this invention constructs an equivalent circuit model of the urban rail traction power supply system; based on the equivalent circuit model, it writes the corresponding node voltage equations for the urban rail traction power supply system; by solving the node voltage equations, it performs current tracing of the urban rail traction power supply system to quantitatively characterize the proportional relationship between source current and load current in the system, where the source includes substations and braking trains, and the load includes traction trains and line impedance; based on the proportional relationship between source current and load current in the system, it performs power tracing of the urban rail traction power supply system to obtain the specific allocation coefficient between source power and load power; based on the proportional relationship between source current and load current in the system and the specific allocation coefficient between source power and load power, it determines the power flow tracing result of the urban rail traction power supply system. Compared with existing power flow calculation methods that can only obtain the magnitude of the current in each branch of the system at each time, this scheme performs power flow tracing of the urban rail traction power supply system through circuit theory, which can accurately obtain the current and power allocation relationship between each substation, traction train, and braking train in the system at each time, providing theoretical support for subsequent optimization of the energy storage system capacity configuration and coordinated control between multiple energy storage systems in the urban rail system. Attached Figure Description

[0041] Figure 1 A flowchart illustrating a method for tracking urban rail transit power flow according to an embodiment of the present invention;

[0042] Figure 2 This is a flowchart illustrating a current tracking method provided in an embodiment of the present invention;

[0043] Figure 3 A flowchart illustrating a power tracking method provided in an embodiment of the present invention;

[0044] Figure 4 An equivalent circuit diagram of a DC traction power supply system for urban rail transit is provided in an embodiment of the present invention;

[0045] Figure 5 This is a schematic diagram of an upstream current tracking result provided in an embodiment of the present invention;

[0046] Figure 6 This is a schematic diagram of a downstream current tracking result provided in an embodiment of the present invention;

[0047] Figure 7 This is a schematic diagram of an upstream power tracking result provided in an embodiment of the present invention;

[0048] Figure 8 This is a schematic diagram of a downstream power tracking result provided in an embodiment of the present invention;

[0049] Figure 9 This is a schematic diagram of the structure of an urban rail transit power flow tracking device provided in an embodiment of the present invention;

[0050] Figure 10 This is a schematic diagram of the structure of a computer device provided in an embodiment of the present invention. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] To facilitate understanding of the embodiments of the present invention, further explanations and descriptions will be provided below with reference to the accompanying drawings and specific embodiments. These embodiments do not constitute a limitation on the embodiments of the present invention.

[0053] Figure 1 This is a flowchart illustrating a method for tracking urban rail transit power flow according to an embodiment of the present invention, as shown below. Figure 1 As shown, the method specifically includes:

[0054] This invention, based on circuit theory, performs upstream and downstream current tracking on the urban rail traction power supply system to quantitatively characterize the proportional relationship between substation current and braking train current and traction train current. Based on the current tracking results, upstream and downstream power tracking is performed on the urban rail traction power supply system to obtain specific allocation coefficients between substation output power, braking train power, traction train power, and line losses. Power flow tracking intuitively and quantitatively demonstrates the power flow path of the system, providing theoretical support for subsequent optimization of energy storage system capacity configuration and coordinated control among multiple energy storage systems.

[0055] S11. Construct an equivalent circuit model of the urban rail traction power supply system.

[0056] An equivalent circuit model is constructed based on the external characteristics of substations, traction trains, braking trains, and other components in the urban rail traction power supply system, such as... Figure 4 The diagram shows the equivalent circuit model corresponding to the scenario of three substations, two traction trains, and one braking train.

[0057] S12. Based on the equivalent circuit model, write the node voltage equations corresponding to the urban rail traction power supply system.

[0058] S13. By solving the node voltage equation, the current tracking of the urban rail traction power supply system is performed to quantitatively characterize the proportional relationship between the source current and the load current in the system.

[0059] In this embodiment of the invention, current tracking is used to calculate the current distribution between the source and the load in the traction power supply system. Based on the tracking direction, current tracking can be divided into two categories: upstream current tracking and downstream current tracking.

[0060] Among them, upstream current tracking: the current required for traction trains is jointly provided by each substation and the braking train, that is, the traction train current can be expressed as a linear combination of the currents of each substation and the braking train, as shown in equation (1). This represents the current required to traction train j at time t. This represents the current output by substation i at time t. This represents the braking current of the train k at time t.

[0061]

[0062] Downstream current tracking: In contrast to upstream current tracking, downstream current tracking characterizes the distribution of current in the substation and braking trains on each traction train. Specifically, the current in the substation and braking trains can be expressed as a linear combination of the currents of each traction train, as shown in equations (2) and (3).

[0063]

[0064]

[0065] For current tracking of the DC traction power supply system of urban rail transit, it is necessary to calculate the current distribution coefficients α, β, μ, and λ in formulas (1) to (3) at time t. The specific calculation method is as follows: Figure 2 The corresponding embodiments will be described in detail, but will not be elaborated here.

[0066] S14. Based on the proportional relationship between the source current and the load current in the system, power tracking is performed on the urban rail traction power supply system to obtain the specific allocation coefficient between the source power and the load power.

[0067] Based on the aforementioned proportional relationship between source current and load current, power tracking is used to calculate the power distribution between the source and load in the traction power supply system. Upstream power tracking and downstream power tracking are defined separately to obtain the power tracking results between each substation, each traction train, and each braking train in the urban rail traction power supply system. Power tracking involves determining the power provided by each substation and each braking train to each traction train, as well as the power consumed by the line impedance, and its distribution coefficients across each traction train and each line impedance. Specific calculation methods are detailed in [the relevant section]. Figure 3 The corresponding embodiments will be described in detail, but will not be elaborated here.

[0068] S15. Based on the proportional relationship between the source current and the load current in the system and the specific allocation coefficient between the source power and the load power, determine the power flow tracking result of the urban rail traction power supply system.

[0069] The power flow tracking result of the urban rail traction power supply system is determined by the ratio between the source current and the load current obtained above and the specific distribution coefficient between the source power and the load power.

[0070] The urban rail transit power flow tracing method provided in this invention constructs an equivalent circuit model of the urban rail traction power supply system; writes the node voltage equations corresponding to the urban rail traction power supply system based on the equivalent circuit model; performs current tracing on the urban rail traction power supply system by solving the node voltage equations to quantitatively characterize the proportional relationship between source current and load current in the system, wherein the source includes substations and braking trains, and the load includes traction trains and line impedance; performs power tracing on the urban rail traction power supply system based on the proportional relationship between source current and load current in the system to obtain the specific allocation coefficient between source power and load power; and determines the power flow tracing result of the urban rail traction power supply system based on the proportional relationship between source current and load current in the system and the specific allocation coefficient between source power and load power. Compared to existing technologies that only provide the magnitude of the current in each branch of the system at various times, and cannot accurately determine the current and power distribution relationships between substations, traction trains, and braking trains at a single moment through power flow calculations, this method, based on circuit theory, performs upstream and downstream tracking of the current distribution in the urban rail traction power supply system, quantitatively characterizing the proportional relationship between the current of substations and braking trains and the current of traction trains. Based on the results of current tracking, upstream and downstream tracking of the power distribution in the urban rail traction power supply system is performed to obtain the specific distribution coefficients between the output power of substations, the power of braking trains, the power of traction trains, and line losses, thus realizing power flow tracking in urban rail transit. Through power flow tracking, theoretical support is provided for subsequent optimization of the capacity configuration of energy storage systems in urban rail systems and coordinated control among multiple energy storage systems.

[0071] Figure 2 This is a flowchart illustrating a current tracking method provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the method specifically includes:

[0072] S21. Obtain the voltage of each substation node, the injected current of each substation node, the voltage of each train node, and the injected current of each train node at any given time.

[0073] S22. Convert the voltage of each substation node, the injected current of each substation node, the voltage of each train node, and the injected current of each train node into vectors respectively to obtain the voltage vector of each substation node, the injected current vector of each substation node, the voltage vector of each train node, and the injected current vector of each train node.

[0074] S23. Substitute the voltage vectors of each substation node, the injected current vectors of each substation node, the voltage vectors of each train node, and the injected current vectors of each train node into the node voltage equation.

[0075] S24. Solve the node voltage equations to obtain the first correlation between the voltage vector of each substation node, the injected current vector of each substation node, and the injected current vector of each train node.

[0076] The following provides a unified explanation of S21 to S24:

[0077] In this embodiment of the invention, the voltage of each substation node, the injected current of each substation node, the voltage of each train node, and the injected current of each train node are obtained at any time t. The voltage vector of the substation nodes in the urban rail traction power supply system at time t is denoted as... The node injection current vector is Train node voltage vector is The node injection current vector is The nodal voltage equations of the system are written as shown in equation (4). SS Y SV Y VV It is a block matrix of the system admittance matrix Y, where This indicates the self-conduction of substation nodes and the mutual conduction between substation nodes; This indicates the mutual conduction between the train node and the substation node; This indicates the self-guidance of train nodes and the mutual guidance between train nodes.

[0078]

[0079] Solving equation (4) yields the voltage vector U of each substation node. S Injected current vector I at each substation node S And the first correlation between the injected current vectors Iv of each train node, as shown in equation (5).

[0080] U S =Λ -1 ·(I S -Ψ·I V (5)

[0081] in,

[0082]

[0083]

[0084] S25. Obtain the no-load voltage and equivalent internal resistance of each substation and convert them into no-load voltage vector and equivalent internal resistance vector.

[0085] S26. Determine the output characteristic equations of each substation based on the no-load voltage vector and the equivalent internal resistance vector.

[0086] S27. Based on the first correlation relationship and the output characteristic equations of each substation, and combined with the properties of matrix operations, determine the second correlation relationship between the injected current vector of each substation node and the injected current vector of each train node.

[0087] The following provides a unified explanation of S25 to S27:

[0088] The output characteristics of the substation are shown in equation (8), where This represents the no-load voltage vector of the substation. This represents the equivalent internal resistance vector of the substation.

[0089] I S =[diag(R) S )] -1 ·(U s0 -U S (8)

[0090] Solving by combining equations (5) and (8) simultaneously yields the injected current vector I at each substation node. S The second correlation between the injected current vector Iv of each train node is shown in Equation (9), where E is the identity matrix.

[0091] I S =[E+Λ·diag(R) S )] -1 Λ·U S0 +[E+Λ·diag(R S )] -1 Ψ·I V (9)

[0092] Furthermore, the second correlation is simplified and transformed based on the properties of matrix operations.

[0093] because The Λ matrix represents the system node admittance matrix considering only the substation, therefore it is a symmetric matrix, and the sum of its row (column) elements is 0. According to the properties of matrix multiplication, the first term in equation (9) is 0, therefore the simplified I S with I v The relationship between them is shown in (10).

[0094] I S =[E+Λ·diag(R) S )] -1 Ψ·I V (10)

[0095] Due to matrices E, Λ, diag(R) SBoth are symmetric matrices. The sum of the elements in each column (row) of matrix E is 1, and the sum of the elements in each column (row) of matrix Λ is 0. By the properties of matrix multiplication and inverse operations, we know that matrix [E + Λ · diag(R)] = 1. S )] -1 It is a symmetric matrix, and the sum of its column (row) elements is 1.

[0096] As shown in equation (11), the matrix It represents the proportion of the impedance between the substation and the train to the impedance of the single-track line in the section.

[0097]

[0098] Where r i-j The impedance R between substation i and train j j This refers to the single-track impedance of the section where train j is located. Therefore, it can be seen that only two elements in each column of matrix Ψ are non-zero, and the sum of all elements in each column is -1. Let Γ = [E + Λ·diag(R)]. S )] -1 If Ψ, then equation (10) is transformed into equation (12).

[0099] I S =Γ·I V (12)

[0100] From the properties of matrix multiplication, we can obtain that the matrix The sum of the elements in each column is -1.

[0101] For urban rail traction power supply systems, the "sources" in the system include not only substations but also braking trains. In order to accurately analyze the current distribution between the "sources" and "loads" in urban rail traction power supply systems, the matrices Γ and I in equation (12) are analyzed. V By dividing the material into blocks, we obtain equation (13):

[0102] I S =[Γ tr ,Γ br ]·[-I tr ,I br ] T (13)

[0103] in Rearrange equation (13) as shown in equation (14), where the left side of the equation represents the current provided by each "source" in the system, including the substation current and the braking train current, and the right side of the equation represents the current consumed by each "load" in the system, i.e., the traction train current.

[0104]

[0105] because The sum of the elements in each column is -1. From equation (14), we can obtain I. tr with I s I br The relationship between them is shown in equation (15):

[0106]

[0107] S28. Determine the upstream current allocation coefficient for upstream current tracking based on the second correlation.

[0108] By referring to equation (1), the upstream current distribution coefficients can be obtained as equations (16) and (17):

[0109]

[0110]

[0111] S29. Determine the third correlation relationship between the upstream current allocation coefficients based on the upstream current allocation coefficients.

[0112] From equation (14), we can see that

[0113]

[0114] so,

[0115]

[0116] And because The sum of the elements in each column is -1, therefore:

[0117]

[0118] S210. Based on the current distribution of the current in each traction train, determine the downstream current distribution coefficient for downstream current tracking.

[0119] because so

[0120]

[0121]

[0122] Comparing equations (2) and (3), the downstream current distribution coefficients can be obtained as equations (23) and (24):

[0123]

[0124]

[0125] S211. Determine the fourth correlation relationship between the downstream current allocation coefficients based on the downstream current allocation coefficients.

[0126] Combining equation (1), the fourth correlation between downstream current tracking coefficients can be derived, and the fourth correlation equation is shown in equation (25):

[0127]

[0128] Figure 3 This is a flowchart illustrating a power tracking method provided in an embodiment of the present invention, as shown below. Figure 3 As shown, the method specifically includes:

[0129] In this embodiment of the invention, based on the results of the current tracking described above, power tracking is used to calculate the power distribution between the source and the load in the traction power supply system. Upstream power tracking and downstream power tracking are defined as follows:

[0130] Upstream power tracking: The power required by the traction train and the power consumed by the line impedance are jointly provided by each substation and the braking train. That is, the power required by the traction train and the power consumed by the line impedance can be expressed as a linear combination of the currents of each substation and the braking train, as shown in equations (26) and (27). Where, P represents the power required to traction train j at time t. Loss (t) represents the power consumed by the line impedance at time t, P i s (t) represents the power output of substation i at time t. This represents the power provided by the braking train k at time t.

[0131]

[0132]

[0133] Downstream power tracking: In contrast to upstream power tracking, downstream power tracking characterizes the distribution of power of substations and braking trains across each traction train and the line impedance. Specifically, the power of substations and braking trains can be expressed as a linear combination of the power required by each traction train and the power consumed by the line impedance, as shown in equations (28) and (29).

[0134]

[0135]

[0136] For power tracking of the DC traction power supply system of urban rail transit, the power distribution coefficients γ, ω, ρ, θ, ξ, η, δ, and σ in formulas (26) to (29) at time t are calculated.

[0137] S31. Based on the upstream current allocation coefficient, determine the upstream power allocation coefficient for upstream power tracking.

[0138] Based on the current tracking results,

[0139]

[0140]

[0141] Comparing equations (26) and (27), the upstream power allocation coefficient for upstream power tracking can be obtained as follows:

[0142]

[0143]

[0144]

[0145]

[0146] S32. Determine the fifth correlation relationship between the upstream power allocation coefficients based on the upstream power allocation coefficients.

[0147] The fifth correlation between upstream power tracking coefficients can be determined from the above formula. The fifth correlation formula is as follows:

[0148]

[0149]

[0150] S33. Based on the fifth correlation and the upstream power allocation coefficient, determine the downstream power allocation coefficient for downstream power tracking.

[0151] because so:

[0152]

[0153]

[0154] Comparing equations (28) and (29), the downstream power allocation coefficient for downstream power tracking can be obtained as follows:

[0155]

[0156]

[0157]

[0158]

[0159] S34. Determine the sixth correlation relationship between the downstream power allocation coefficients based on the downstream power allocation coefficients.

[0160] Combining equations (26) and (27), the sixth correlation between downstream power tracking coefficients can be obtained, and the sixth correlation equation is as follows:

[0161]

[0162]

[0163] The urban rail transit power flow tracking method provided in this invention, based on circuit theory, performs upstream and downstream current tracking on the current distribution of the urban rail traction power supply system, quantitatively characterizing the proportional relationship between substation current and braking train current and traction train current; based on the results of current tracking, it performs upstream and downstream power tracking on the power distribution of the urban rail traction power supply system, obtaining specific allocation coefficients between substation output power, braking train power, traction train power, and line losses, thereby realizing power tracking for urban rail transit.

[0164] This invention, based on circuit theory, performs upstream and downstream tracking of current distribution in urban rail traction power supply systems, quantitatively characterizing the proportional relationship between substation and braking train currents and traction train currents. Based on the current tracking results, upstream and downstream tracking is performed on power distribution in the urban rail traction power supply system to obtain specific allocation coefficients between substation output power, braking train power, traction train power, and line losses. Finally, numerical examples verify the effectiveness and correctness of the proposed power flow tracking algorithm. Power flow tracking intuitively and quantitatively demonstrates the power flow path of the system, providing theoretical support for subsequent optimization of energy storage system capacity configuration and coordinated control among multiple energy storage systems.

[0165] To verify the effectiveness of the algorithm proposed in this invention, Figure 4 Taking a scenario with three substations, two traction trains, and one braking train as an example, upstream and downstream current tracking and power tracking are performed. The traction power supply system parameters at a certain moment are shown in Table 1:

[0166] Table 1

[0167]

[0168] Current tracking: The method proposed in the embodiments of this invention can be used to obtain... Figure 5The upstream current tracking results of the urban rail system are shown in equation (46). From this equation, the distribution of the output current from each "source" to each "load" can be obtained: 83.1% of the current from substation 1 is supplied to traction train 1, and 16.9% is supplied to traction train 2; 48.86% of the current from substation 2 is supplied to traction train 1, and 51.14% is supplied to traction train 2; 48.86% of the current from substation 3 is supplied to traction train 1, and 51.14% is supplied to traction train 2; 64.47% of the current from braking train 1 is supplied to traction train 1, and 35.53% is supplied to traction train 2, as shown in equation (46). Figure 5 As shown.

[0169]

[0170]

[0171] Similarly, the downstream current tracking results are shown in equation (47). This equation reflects the current drawn from each "source" for each "load": 34.52% of the current required by traction train 1 is provided by substation 1, 9.88% by substation 2, 4.02% by substation 3, and 51.58% by braking train 1; 14.04% of the current required by traction train 2 is provided by substation 1, 20.69% by substation 2, 8.43% by substation 3, and 56.84% by braking train 1; as shown in equation (47). Figure 6 As shown.

[0172]

[0173]

[0174]

[0175]

[0176] Since there is no loss of current during the flow, the current provided by the substation and the braking train is equal to the current consumed by the traction train, which satisfies Kirchhoff's current law, that is, the sum of each column of the upstream / downstream current distribution coefficient matrix is ​​1, which is consistent with the equations (19), (20), and (25).

[0177] Power point tracking: Based on the current tracking results above, we can obtain Figure 7The upstream power tracking results of the urban rail system are shown in Equation (48). From this equation, we can obtain that 82.61% of the power from substation 1 is supplied to traction train 1, 17% to traction train 2, and 0.39% is consumed by line impedance; 48.18% of the power from substation 2 is supplied to traction train 1, 51.01% to traction train 2, and 0.81% is consumed by line impedance; 47.96% of the power from substation 3 is supplied to traction train 1, 50.78% to traction train 2, and 1.26% is consumed by line impedance; 62.89% of the power from braking train 1 is supplied to traction train 1, 35.05% to traction train 2, and 2.06% is consumed by line impedance, as shown in Equation (48). Figure 7 As shown.

[0178]

[0179]

[0180]

[0181] Similarly, the downstream power tracking result is shown in equation (49). From this equation, it can be seen that 34.52% of the power required by traction train 1 is provided by substation 1, 9.88% by substation 2, 4.02% by substation 3, and 51.58% by braking train 1; 14.04% of the power required by traction train 2 is provided by substation 1, 20.69% by substation 2, 8.43% by substation 3, and 56.84% by braking train 1; 7.71% of the power consumed by line impedance is provided by substation 1, 7.82% by substation 2, 4.97% by substation 3, and 79.5% by braking train 2, as shown in equation (49). Figure 8 As shown.

[0182]

[0183]

[0184]

[0185]

[0186] Figure 9 A schematic diagram of the structure of an urban rail transit trend tracking device according to an embodiment of the present invention is shown, as follows: Figure 9 As shown, the device includes:

[0187] Model building module 901 constructs an equivalent circuit model of the urban rail traction power supply system. For detailed explanations, please refer to the relevant descriptions in the above method embodiments; they will not be repeated here.

[0188] The equation writing module 902 is used to write the node voltage equations corresponding to the urban rail traction power supply system based on the equivalent circuit model. For detailed explanations, please refer to the relevant descriptions in the above method embodiments; they will not be repeated here.

[0189] The current tracking module 903 is used to perform current tracking on the urban rail traction power supply system by solving the node voltage equations, quantitatively characterizing the proportional relationship between source current and load current in the system. The sources include substations and braking trains, and the loads include traction trains and line impedance. For detailed explanations, please refer to the relevant descriptions in the above method embodiments; they will not be repeated here.

[0190] The power point tracking module 904 is used to perform power point tracking on the urban rail traction power supply system based on the ratio between the source current and the load current in the system, and to obtain a specific allocation coefficient between the source power and the load power. For detailed explanations, please refer to the relevant descriptions in the above method embodiments; they will not be repeated here.

[0191] The determination module 905 is used to determine the power flow tracking result of the urban rail traction power supply system based on the proportional relationship between the source current and the load current in the system and the specific allocation coefficient between the source power and the load power. For detailed explanations, please refer to the relevant descriptions in the above method embodiments, which will not be repeated here.

[0192] The urban rail transit power flow tracking device provided in this embodiment of the invention is used to execute the urban rail transit power flow tracking method provided in the above embodiment. Its implementation method and principle are the same. For details, please refer to the relevant description of the above method embodiment, which will not be repeated here.

[0193] Figure 10 A computer device according to an embodiment of the present invention is shown, such as Figure 10 As shown, the computer device may include a processor 1001 and a memory 1002, wherein the processor 1001 and the memory 1002 may be connected via a bus or other means. Figure 10 Taking the example of a connection between China and Israel via a bus.

[0194] Processor 1001 may be a central processing unit (CPU). Processor 1001 may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or combinations thereof.

[0195] The memory 1002, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the methods provided in the embodiments of the present invention. The processor 1001 executes various functional applications and data processing of the processor by running the non-transitory software programs, instructions, and modules stored in the memory 1002, thereby implementing the methods in the above-described method embodiments.

[0196] The memory 1002 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created by the processor 1001, etc. Furthermore, the memory 1002 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 1002 may optionally include memory remotely located relative to the processor 1001, and these remote memories may be connected to the processor 1001 via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0197] One or more modules are stored in memory 1002 and, when executed by processor 1001, perform the methods described in the above method embodiments.

[0198] The specific details of the aforementioned computer equipment can be understood by referring to the relevant descriptions and effects in the above method embodiments, and will not be repeated here.

[0199] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium can also include combinations of the above types of memory.

[0200] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for tracking the power flow of urban rail transit, characterized in that, include: Construct an equivalent circuit model for the urban rail traction power supply system; Based on the equivalent circuit model, write the node voltage equations corresponding to the urban rail traction power supply system. The current tracking of the urban rail traction power supply system is performed by solving the node voltage equations to quantitatively characterize the proportional relationship between the source current and the load current in the system. The source includes substations and braking trains, and the load includes traction trains and line impedance. Based on the proportional relationship between the source current and the load current in the system, power tracking is performed on the urban rail traction power supply system to obtain the specific allocation coefficient between the source power and the load power. Based on the proportional relationship between the source current and the load current in the system and the specific allocation coefficient between the source power and the load power, the power flow tracking result of the urban rail traction power supply system is determined. The method of performing current tracking on the urban rail traction power supply system by solving the nodal voltage equations to quantitatively characterize the proportional relationship between the source current and the load current in the system includes: Obtain the voltage of each substation node, the injected current of each substation node, the voltage of each train node, and the injected current of each train node at any given time. The voltage of each substation node, the injected current of each substation node, the voltage of each train node, and the injected current of each train node are converted into vectors to obtain the voltage vector of each substation node, the injected current vector of each substation node, the voltage vector of each train node, and the injected current vector of each train node. Substitute the voltage vector of each substation node, the current vector injected into each substation node, the voltage vector of each train node, and the current vector injected into each train node into the node voltage equation. Solving the node voltage equations yields the first correlation between the voltage vector of each substation node, the injected current vector of each substation node, and the injected current vector of each train node. Obtain the no-load voltage and equivalent internal resistance of each substation and convert them into no-load voltage vector and equivalent internal resistance vector; The output characteristic equations of each substation are determined based on the no-load voltage vector and the equivalent internal resistance vector. Based on the first correlation relationship and the output characteristic equations of each substation, and combined with the properties of matrix operations, a second correlation relationship is determined between the injected current vector of each substation node and the injected current vector of each train node. Based on the second correlation, the upstream current allocation coefficient for upstream current tracking is determined. The upstream current tracking means that the current required by the traction train is jointly provided by each substation and the braking train. That is, the traction train current can be expressed as a linear combination of the currents of each substation and the braking train. A third correlation relationship between the upstream current allocation coefficients is determined based on the upstream current allocation coefficients; Based on the current distribution of the current in each traction train, the downstream current distribution coefficient of the downstream current tracking is determined. The downstream current tracking refers to the opposite of the upstream current tracking, which characterizes the distribution of the current of the substation and the braking train in each traction train. A fourth correlation relationship is determined based on the downstream current allocation coefficients.

2. The method according to claim 1, characterized in that, The power tracking of the urban rail traction power supply system based on the ratio between the source current and the load current in the system yields a specific allocation coefficient between the source power and the load power, including: Based on the upstream current allocation coefficient, the upstream power allocation coefficient for upstream power tracking is determined. The upstream power tracking means that the power required by each traction train and the power consumed by the line impedance are jointly provided by each substation and the braking train. A fifth correlation relationship between the upstream power allocation coefficients is determined based on the upstream power allocation coefficients; Based on the fifth correlation and the upstream power allocation coefficient, the downstream power allocation coefficient for downstream power tracking is determined. The downstream power tracking refers to the duality of upstream power tracking, which characterizes the distribution of power of the substation and the braking train in each traction train and the line impedance. The sixth correlation between the downstream power allocation coefficients is determined based on the downstream power allocation coefficients.

3. A trend tracking device for urban rail transit, characterized in that, include: The model building module is used to construct an equivalent circuit model of the urban rail traction power supply system. The equation writing module is used to write the node voltage equations corresponding to the urban rail traction power supply system based on the equivalent circuit model. The current tracking module is used to perform current tracking on the urban rail traction power supply system by solving the node voltage equations, quantitatively characterizing the proportional relationship between source current and load current in the system. The sources include substations and braking trains, and the loads include traction trains and line impedance. Specifically, the current tracking module is used to: acquire the substation node voltage, substation node injected current, train node voltage, and train node injected current at any given time; convert these values ​​into vectors to obtain substation node voltage vectors, substation node injected current vectors, train node voltage vectors, and train node injected current vectors; substitute these vectors into the node voltage equations; and solve the node voltage equations to obtain the first correlation relationship between the substation node voltage vectors, substation node injected current vectors, and train node injected current vectors. Obtain the no-load voltage and equivalent internal resistance of each substation and convert them into no-load voltage vector and equivalent internal resistance vector; The output characteristic equations of each substation are determined based on the no-load voltage vector and the equivalent internal resistance vector. Based on the first correlation relationship and the output characteristic equations of each substation, and combined with the properties of matrix operations, a second correlation relationship is determined between the injected current vector of each substation node and the injected current vector of each train node. Based on the second correlation, the upstream current allocation coefficient for upstream current tracking is determined. The upstream current tracking means that the current required by the traction train is jointly provided by each substation and the braking train. That is, the traction train current can be expressed as a linear combination of the currents of each substation and the braking train. A third correlation relationship between the upstream current allocation coefficients is determined based on the upstream current allocation coefficients; Based on the current distribution of the current in each traction train, the downstream current distribution coefficient of the downstream current tracking is determined. The downstream current tracking refers to the opposite of the upstream current tracking, which characterizes the distribution of the current of the substation and the braking train in each traction train. A fourth correlation relationship between the downstream current allocation coefficients is determined based on the downstream current allocation coefficients; The power tracking module is used to perform power tracking on the urban rail traction power supply system based on the ratio between the source current and the load current in the system, and to obtain a specific allocation coefficient between the source power and the load power. The determination module is used to determine the power flow tracking result of the urban rail traction power supply system based on the ratio between the source current and the load current in the system and the specific allocation coefficient between the source power and the load power.

4. A computer device, characterized in that, include: A processor and a memory, the processor being configured to execute an urban rail transit flow tracking program stored in the memory to implement the urban rail transit flow tracking method according to any one of claims 1 to 2.

5. A storage medium, characterized in that, The storage medium stores one or more programs, which can be executed by one or more processors to implement the urban rail transit flow tracking method according to any one of claims 1 to 2.

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