Construction method of dynamic node admittance matrix of coupling system

Abstract

The invention relates to the technical field of power flow calculation of a power system, and discloses a method for constructing a dynamic node admittance matrix of a coupling system, which comprises the following steps of: counting position information and uplink and downlink states of a motor train unit at each moment in a driving working diagram by combining the driving working diagram, and taking the position of the motor train unit as a load node; a position matrix about load nodes of the motor train unit is generated in combination with uplink and downlink states of the motor train unit; combining the position matrix with power grid side nodes to construct a node matrix of the coupling system; enabling any two adjacent nodes to form a branch, and constructing a branch connection matrix; aiming at each branch of the branch connection matrix, constructing a branch admittance matrix; and constructing a dynamic node admittance matrix according to the branch connection relationship in the branch connection matrix and in combination with the branch admittance matrix. The dynamic node admittance matrix covering the power grid and the traction network along the whole railway is formed, and a foundation is laid for dynamic load flow calculation of a new energy-power grid-traffic network coupling system.

Description

Technical Field

[0001] The present invention relates to the technical field of power system flow calculation, and in particular to a method for constructing a dynamic node admittance matrix of a coupling system. Background Art

[0002] Railways in high-altitude areas are a key development strategy for the country. High-altitude electrified railways are high-power loads and require a lot of power support. Especially in remote mountainous railway areas, the proportion of traction loads may reach 30% to 40%. In addition, with the vigorous development of clean and renewable energy, a large number of new energy sources are also connected to the grid along the railway. Therefore, there is a strong coupling of new energy, power grid and transportation network along the railway in high-altitude areas. The output of new energy is random, intermittent and uncertain, while the traction load is impulsive and intermittent. In addition, due to the existence of long and long slopes, there may be frequent and large-value regenerative braking power that is different from the conventional line load, which aggravates the uncertainty at the load end. However, the existing power flow calculation method only considers the grid side or only the traction side, and few algorithms consider the two as a coupled network for power flow calculation. Summary of the invention

[0003] The technical problem to be solved by the present invention is that the existing technology cannot directly carry out detailed power flow calculations on the "new energy-power grid-transportation network" coupling system. The reason is that the construction of the dynamic node admittance matrix of the "new energy-power grid-transportation network" coupling system is complex. In response to this problem, the purpose of the present invention is to provide a method for constructing a dynamic node admittance matrix of the "new energy-power grid-transportation network" coupling system. By constructing a grid-side branch admittance matrix, a traction-side branch admittance matrix and a coupled traction transformer branch admittance matrix, and combining them with a train operation diagram, a dynamic node admittance matrix covering the entire railway grid and traction network is formed, laying the foundation for the dynamic power flow calculation of the "new energy-power grid-transportation network" coupling system.

[0004] The present invention is achieved through the following technical solutions:

[0005] A method for constructing a dynamic node admittance matrix of a coupled system, comprising:

[0006] Combined with the train operation diagram, the position information and up and down status of the EMU at each moment in the train operation diagram are counted, the position of the EMU is regarded as a load node, and combined with the up and down status of the EMU, a position matrix of the EMU load node is generated;

[0007] The position matrix is ​​combined with the grid-side nodes to construct a node matrix bus of the coupling system, wherein the node matrix includes a node number of each node and a node type of each node;

[0008] Any two adjacent nodes are made to form a branch, and the nodes at both ends of the branch are set as an egress node and an ingress node, thereby constructing a branch connection matrix branch;

[0009] For each branch of the branch connection matrix, construct a branch admittance matrix;

[0010] According to the branch connection relationship in the branch connection matrix and in combination with the branch admittance matrix, a dynamic node admittance matrix is ​​constructed.

[0011] As an optimization, combined with the train operation diagram, the position information and up and down status information of the EMU at each moment in the train operation diagram are counted, the position of the EMU is taken as a load node, and the specific process of generating the position matrix of several load nodes is as follows:

[0012] T1. According to the train operation diagram, the position information of each EMU load node is counted;

[0013] T2, determine whether the EMU is located in the electrical phase separation area, if so, delete the EMU and then enter T3, otherwise directly enter T3;

[0014] T3, deleting the duplicated load nodes and retaining only one load node, then merging the non-duplicate load nodes to generate a position matrix, and sorting them from small to large according to the kilometer mark;

[0015] T4. Set the node numbers of the load nodes according to spatial order.

[0016] As an optimization, the nodes include EMUs, AT stations, traction stations and all nodes on the power grid side.

[0017] As an optimization, the specific process of T1 is:

[0018] T11, sorting the position information of the EMU in order and expressing it with PCRH;

[0019] T12, the up and down conditions of the EMU are represented by StCRH, where the elements in StCRH are 1 or -1, 1 represents up and -1 represents down;

[0020] T13, the location information of the AT or the connection point is represented by PAT;

[0021] T14. The position information of the traction station is represented by PTF, wherein the position information of the left power supply arm outlet and the right power supply arm outlet of the traction station are represented by PTFα and PTFβ respectively.

[0022] As an optimization, the grid-side nodes include new energy nodes, generator nodes, substation nodes and user nodes.

[0023] As an optimization, the branch admittance matrix includes the branch admittance matrix Y of the three-phase transmission line br , 500kV transformer branch admittance matrix The branch admittance matrix Y of the traction transformer V,v and the branch admittance matrix of the traction network.

[0024] As an optimization, the branch admittance matrix of the traction network includes the traction network unit length series admittance matrix Y s And the parallel admittance matrix Y1 of multiple conductors per unit length in the traction network.

[0025] As an optimization, according to the branch connection relationship in the branch connection matrix, the specific process of building a dynamic node admittance matrix in combination with the branch admittance matrix is ​​as follows:

[0026] A1. Define two connection matrices C f and C t , where C f is the branch-out node connection matrix, C t is the branch-input node connection matrix;

[0027] A2, based on the two connection matrices C f and C t , derive the node voltage connection relationship and the node injection current connection relationship;

[0028] A3. Based on the node voltage connection relationship and the node injection current connection relationship, derive the node admittance matrix expression.

[0029] As an optimization, the branch-out node connection matrix C f and branch-input node connection matrix C t The specific expression is:

[0030]

[0031] Where p is the branch number, f is the egress node of branch p, t is the ingress node of branch p, C f and C t The dimension is n l ×n b , n l Indicates the number of branches, n b represents the total number of nodes in the node matrix, branch(p,f) represents the outgoing node of the p-th branch, branch(p,t) represents the incoming node of the p-th branch, C f (p,q) represents the element in the pth row and qth column of the matrix Cf. t (p,k) represents the matrix C tThe element of the p-th row and k-th column of ;

[0032] The specific expressions of the node voltage connection relationship and the node injection current connection relationship are:

[0033]

[0034] Where I is the node injection current vector, I f The current vector injected into the output node, I t is the node injection current vector, V is the total node voltage vector, V f is the output node voltage vector, V t is the input node voltage vector, V f and V t The dimensions are all n b ×1, Respectively represent the branch-out node connection matrix C f and branch-input node connection matrix C t The transpose of .

[0035] As an optimization, in A3, based on the node voltage connection relationship and the node injection current connection relationship, the specific process of deriving the node admittance matrix expression is:

[0036] A3.1. List the node injection current vector I f and the current vector I injected into the node t The expression is:

[0037]

[0038] Among them, [Y ff ]、[Y ft ]、[Y tt ]、[Y tf ] represent the elements Y ff , Y ft , Y tt , Y tf is a matrix with diagonal elements, where Y ff , Y ft , Y tf , Y tt denote the branch out-out admittance matrix, the branch out-in admittance matrix, the branch in-out admittance matrix, and the branch in-in admittance matrix, respectively, and Y ff =Y io +Y ij , Y ft =-Y ij , Y tf =-Y ji , Y tt =Y jo +Yij , Y io , Y ij , Y jo They represent the admittance matrix of node i to the ground, the admittance matrix between node i and node j, and the admittance matrix of node j to the ground respectively;

[0039] A3.2. Combining the formula in step A3.1 with the node voltage connection relationship and the node injection current connection relationship, we obtain:

[0040]

[0041] A3.3. Transform the formula of step A3.2 to obtain the node admittance matrix:

[0042]

[0043] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0044] The present invention constructs a grid-side branch admittance matrix, a traction-side branch admittance matrix and a coupled traction transformer branch admittance matrix, and combines them with a train operation diagram to form a dynamic node admittance matrix covering the entire railway grid and traction network, laying the foundation for the dynamic power flow calculation of the "new energy-power grid-transportation network" coupling system. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0046] Figure 1 It is a flow chart of a method for constructing a dynamic node admittance matrix of a coupling system according to the present invention;

[0047] Figure 2 It is the equivalent circuit diagram of three-phase transmission line;

[0048] Figure 3 It is the overall π-type equivalent circuit of the three-phase line;

[0049] Figure 4 It is the equivalent circuit of 500kV single-phase autotransformer;

[0050] Figure 5 This is the wiring diagram of the V / v0 connection transformer under the three-phase ABC incoming line mode;

[0051] Figure 6 Schematic diagram of the conductor and its mirror image structure. DETAILED DESCRIPTION

[0052] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0053] This embodiment 1 provides a method for constructing a dynamic node admittance matrix of a coupling system, including:

[0054] S1. Combined with the train operation diagram, the position information and up and down status of the EMU at each moment in the train operation diagram are counted, the position of the EMU is regarded as a load node, and combined with the up and down status of the EMU, a position matrix of the EMU load node is generated;

[0055] The train operation diagram refers to the time and location diagram of the EMUs formed by the dispatching center's arrangement of when the EMUs will arrive at which stations.

[0056] Here, the position matrix can be represented by PositionAll.

[0057] In some embodiments, the load nodes include EMUs, AT depots, and traction depots.

[0058] In some embodiments, in combination with the train operation diagram, the position information and uplink and downlink status information of the EMU at each moment in the train operation diagram are counted, the position of the EMU is taken as a load node, and the specific process of generating a position matrix of several load nodes is as follows:

[0059] T1. According to the train operation diagram, the position information of each EMU load node is counted;

[0060] Here, the location information of the load node of the EMU refers to the kilometer mark, which can be found on the railway.

[0061] T2, determine whether the EMU is located in the phase separation area, if so, delete the EMU and then enter T3, otherwise directly enter T3;

[0062] This is a relatively unique and professional knowledge on the railway. Since the railway line is very long and the power grid is three-phase transmission, the railway only uses one phase of the three phases for power supply, such as phase A, so it is necessary to change phases every dozens of kilometers to change to phase B. The phases cannot be connected in the middle of the phase change, otherwise the AB phases will be short-circuited. Therefore, the EMU cannot draw power in the phase separation area, which is about 1 to 200 meters. Therefore, the EMU does not consume power in this section and needs to be deleted.

[0063] T3. Delete the repeated load nodes and keep only one load node, then merge the non-repeated load nodes to generate a position matrix, and sort them from small to large according to the kilometer mark; the purpose is to facilitate the numbering of the matrix, and the size of the number is based on the kilometer mark.

[0064] T4. Set the node number of the load node according to the spatial order. The spatial order here refers to the kilometer mark. The purpose of numbering is that since the system has many nodes, each node needs to be numbered to form a matrix.

[0065] In some embodiments, the specific process of T1 is:

[0066] T11, sorting the position information of the EMU in order and expressing it with PCRH, for example, PCRH=[5,15], where 5 and 15 represent the kilometer mark of the EMU at that moment;

[0067] T12. The up and down conditions of the EMU are represented by StCRH, where the elements in StCRH are 1 or -1, 1 represents up and -1 represents down; then the matrix PCRH will be naturally decomposed into two, PCRHUP and PCRHDOWN.

[0068] T13, the position information of the AT or the parallel point is represented by PAT, such as PAT = [0, 10, 20], where the numbers represent kilometer marks;

[0069] T14, the position information of the traction station is represented by PTF, wherein the position information of the left power supply arm outlet and the right power supply arm outlet of the traction station are represented by PTFα and PTFβ respectively. The position information of the traction station is still represented as [0, 10, 20].

[0070] The position matrix PositionAll is a combination of all elements in the above matrices PCRHUP, PCRHDOWN, PAT, PTF, PTFα and PTFβ, and arranges them in order.

[0071] S2, combining the position matrix with the grid-side nodes to construct a node matrix bus of the coupling system, wherein the node matrix includes a node number of each node and a node type of each node, and the number of nodes in the node matrix bus is equal to the number of rows of the node matrix bus;

[0072] In some embodiments, the grid-side nodes include new energy nodes, generator nodes, substation nodes and user nodes.

[0073] In other words, the grid-side nodes include new energy and power grids.

[0074] In the node matrix bus, each node (including load nodes and grid-side nodes) is a row.

[0075] S3. Let any two adjacent nodes form a branch, and the nodes at both ends of the branch are set as an egress node and an ingress node, so as to construct a branch connection matrix branch.

[0076] That is to say, adjacent nodes on the grid side form a branch, and adjacent nodes in the PositionAll matrix also form a branch. The nodes at both ends of the branch are set as egress nodes and ingress nodes, thereby constructing a branch connection matrix branch.

[0077] S4. Constructing a branch admittance matrix for each branch of the branch connection matrix;

[0078] In some embodiments, the branch admittance matrix includes a branch admittance matrix Y of a three-phase transmission line. br , 500kV transformer branch admittance matrix The branch admittance matrix Y of the traction transformer V,v and the branch admittance matrix of the traction network.

[0079] In some embodiments, the branch admittance matrix of the traction network includes a traction network unit length series admittance matrix Y s And / or the traction network multi-conductor unit length parallel admittance matrix Y1.

[0080] Next, the construction process of various branch admittance matrices is introduced in detail.

[0081] S41. Construct the branch admittance matrix Y of the three-phase transmission line br :

[0082] (1) Single-circuit three-phase transmission line model

[0083] The equivalent circuit of a three-phase transmission line represented by concentrated parameters is as follows Figure 2 As shown. A, B, and C three phases use a π-type equivalent circuit, and there is mutual inductance and mutual capacitance between the two phases. Among them, z ijaa 、z ijbb and z ijcc Respectively represent the A phase, B phase and C phase self-impedance between nodes i and j. ijao , C ijbo and C ijco Respectively represent the capacitance of phase A, phase B and phase C between nodes i and j to ground. ijab , C ijbc and C ijac Respectively represent the mutual capacitance of AB phase, BC phase and AC phase between nodes i and j. ijab 、x ijbc and xijac They represent the mutual inductances of the AB phase, BC phase, and AC phase between nodes i and j, respectively.

[0084] It is worth noting that the whole can also be represented by a π-type equivalent circuit, such as Figure 3 As shown, the relationship between the node injection current and the node voltage of branch ij can be written as:

[0085] in, represents the injected current phasor of node i, represents the injected current phasor of node j, represents the voltage phasor at node i, represents the voltage phasor of node j, Y io represents the admittance matrix of node i to the ground, Y jo represents the ground admittance matrix of node j, Y ij represents the admittance matrix between node i and node j, Y ji represents the admittance matrix between node j and node i.

[0086] Therefore, the branch admittance matrix of branch ij of the three-phase transmission line can be obtained as follows:

[0087]

[0088] Among them, Y br Y represents the branch admittance matrix. ff Y represents the branch outgoing-outgoing admittance matrix. ft Y represents the branch input-output admittance matrix. tf Y represents the branch input-output admittance matrix. tt represents the branch input-output admittance matrix.

[0089] S42. Construct the branch admittance matrix of 500kV transformer:

[0090] 500kV transformers generally use autotransformers to save costs, and because of their large size, they are split-type. The high and medium voltage sides are connected in star shape by three single-phase transformers, and the low voltage side is generally connected in a triangle shape. Since the low voltage side of a 500kV transformer is generally not connected to a large load, it can be ignored in the power flow calculation.

[0091] Since it adopts a split design, there is no magnetic coupling between phases. Therefore, its single-phase equivalent circuit is as follows Figure 4 As shown. K is the transformer ratio, Y is the admittance of the 500KV transformer converted to the L side. H and L are the two ends of the 500KV transformer.

[0092] The relationship between voltage and current is as follows:

[0093]

[0094] X = A, B, C;

[0095] That is, X is phase A, phase B, and phase C.

[0096]

[0097] in, represents the X-phase voltage at point H′, Indicates the X-phase voltage at point H, represents the X-phase current at point H′, Represents the X-phase current at point H, Indicates the X-phase voltage at point L, represents the X-phase current at point L, and Y represents the admittance.

[0098] The 500kV transformer branch admittance matrix is ​​obtained as follows:

[0099]

[0100] represents the transformer branch admittance matrix.

[0101] S43. Construct the branch admittance matrix of the traction transformer:

[0102] The wiring diagram of the V / v0 connection transformer under the three-phase ABC incoming line mode is as follows Figure 5 As shown in the figure, the equivalent admittance of the primary coil is y1, the equivalent admittance of the two secondary windings is y2, and K is the transformer ratio, K = 220kV / 27.5kV.

[0103] By writing the transformer voltage balance equation and magnetomotive force balance equation, the node admittance equation of the traction transformer can be obtained, as shown below.

[0104]

[0105] Among them, Y Vv Represents the branch admittance matrix of a V / v0 connected transformer.

[0106] S44. Construct the branch admittance matrix of the traction network:

[0107] The traction network can be regarded as a multi-conductor transmission system structure. The Carson theory is generally used to calculate the unit length series impedance matrix Z1 of the roadbed section traction network. Its elements are as follows:

[0108]

[0109] Among them, D grepresents the equivalent depth of the earth (m); σ represents the soil conductivity, which can generally be taken as 10 -4 / (Ω·cm); f represents the current frequency; r i Indicates the conductor resistance (Ω / km); r e Represents earth resistance, which is 0.0493Ω / km; R εi is the equivalent radius of each conductor (m); R i is the calculated radius of each conductor (m); μ represents the relative magnetic permeability of the conductor material; D mn is the spatial distance between conductors m and n (m), z ii represents the self-impedance of the traction network, z ij Represents the mutual impedance of the traction network. For the through-ground wire, since it is buried underground, the mutual impedance between it and other conductors is ignored. The conductor structure parameters in the formula are as follows: Figure 6 shown.

[0110] The series admittance matrix per unit length of the traction network is:

[0111]

[0112] According to electromagnetic field theory, the capacitance matrix per unit length of the traction network can be calculated using the mirror method. Let the potential coefficient matrix per unit length of the traction network be P, and its elements can be calculated by the formula.

[0113]

[0114] In the formula, p mm is the self-potential coefficient of the mth conductor; p mn is the mutual potential coefficient between the mth conductor and the mth conductor; ε0 is the vacuum dielectric constant, which is 10 -6 / 36π(F / km);H mm The distance between the mth conductor and the mirror image conductor m′ of the nth conductor, R m Indicates the calculated radius of the mth wire.

[0115] Therefore, the capacitance matrix per unit length of the multi-conductor section of the traction network is:

[0116] C=P -1 (8)

[0117] The parallel admittance matrix per unit length of multiple conductors in the traction network is:

[0118] Y1=j2πf·C (9)

[0119] S5. According to the branch connection relationship in the branch connection matrix and the uplink and downlink matrices of the EMU, a dynamic node admittance matrix is ​​constructed in combination with the branch admittance matrix.

[0120] In some embodiments, the specific process of S5 is:

[0121] A1. Define two connection matrices C f and C t , where C f is the branch-out node connection matrix, C t is the branch-input node connection matrix;

[0122] In some embodiments, the branch-egress node connection matrix C f and branch-input node connection matrix C t The specific expression is:

[0123]

[0124] Among them, p is the branch number, f is the exit node of branch p, t is the entry node of branch p, and its dimension is n l ×n b , n l Indicates the number of branches, n b represents the total number of nodes in the node matrix, branch(p,f) represents the outgoing node of the p-th branch, branch(p,t) represents the incoming node of the p-th branch, C f (p,q) represents the qth outgoing node of the pth branch, C t (p,k) represents the kth ingress node of the pth branch;

[0125] A2, based on the two connection matrices C f and C t , derive the node voltage connection relationship and the node injection current connection relationship;

[0126] The specific expressions of the node voltage connection relationship and the node injection current connection relationship are:

[0127]

[0128] Where I is the total node injection current vector, I f The current vector injected into the output node, I t is the node injection current vector, V is the total node voltage vector, V f is the output node voltage vector, V t is the input node voltage vector, whose (V f and V t ) dimensions are all n b ×1, Respectively represent the branch-out node connection matrix C f and branch-input node connection matrix C t The transpose of .

[0129] The node voltage connection relationship indicates that the node voltage vector V f The connection relationship between all node voltage vectors.

[0130] A3. Based on the node voltage connection relationship and the node injection current connection relationship, derive the node admittance matrix expression.

[0131] Derive the node admittance matrix expression. According to the branch admittance matrix:

[0132]

[0133] Among them, [Y ff ]、[Y ft ]、[Y tt ]、[Y tf ] represent the elements Y ff , Y ft , Y tt , Y tf is a matrix with diagonal elements, where Y ff , Y ft , Y tf , Y tt denote the branch out-out admittance matrix, the branch out-in admittance matrix, the branch in-out admittance matrix, and the branch in-in admittance matrix, respectively, and Y ff =Y io +Y ij , Y ft =-Y ij , Y tf =-Y ij , Y tt =Y jo +Y ij , Y io , Y ij , Y jo They represent the admittance matrix of node i to the ground, the admittance matrix between node i and node j, and the admittance matrix of node j to the ground respectively.

[0134] It is not only related to three-phase transmission lines. In the power grid-traction network coupling system, each branch has this branch admittance matrix, such as 500kV transformer branch, traction transformer branch, and traction network branch. They are all derived in the text. Otherwise, it is impossible to establish the node admittance matrix of the entire system.

[0135] Substituting equation (14) into equation (13), we have

[0136]

[0137] Therefore, the node admittance matrix of the system is

[0138]

[0139] It should be noted that since the PositionAll matrix changes with time, Y bus It also changes with time, so Y bus It is the dynamic node admittance matrix of the "new energy-power grid-transportation network" coupling system.

[0140] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for constructing a dynamic node admittance matrix of a coupled system, characterized in that: include: Combined with the train operation diagram, the position information and up and down status of the EMU at each moment in the train operation diagram are counted, the position of the EMU is regarded as a load node, and combined with the up and down status of the EMU, a position matrix of the EMU load node is generated; The position matrix is ​​combined with the grid-side nodes to construct a node matrix bus of the coupling system, wherein the node matrix includes a node number of each node and a node type of each node; Any two adjacent nodes are made to form a branch, and the nodes at both ends of the branch are set as an egress node and an ingress node, thereby constructing a branch connection matrix branch; For each branch of the branch connection matrix, construct a branch admittance matrix; According to the branch connection relationship in the branch connection matrix and in combination with the branch admittance matrix, a dynamic node admittance matrix is ​​constructed.

2. The method for constructing a dynamic node admittance matrix of a coupling system according to claim 1, characterized in that: Combined with the train operation diagram, the position information and up and down state information of the EMU at each moment in the train operation diagram are counted, the position of the EMU is regarded as a load node, and the specific process of generating the position matrix of several load nodes is as follows: T1. According to the train operation diagram, the position information of each EMU load node is counted; T2, determine whether the EMU is located in the electrical phase separation area, if so, delete the EMU and then enter T3, otherwise directly enter T3; T3, deleting the duplicated load nodes and retaining only one load node, then merging the non-duplicate load nodes to generate a position matrix, and sorting them from small to large according to the kilometer mark; T4. Set the node numbers of the load nodes according to spatial order.

3. The method for constructing a dynamic node admittance matrix of a coupling system according to claim 2, characterized in that: The nodes include EMUs, AT stations, traction stations and all nodes on the power grid side.

4. The method for constructing a dynamic node admittance matrix of a coupling system according to claim 3, characterized in that: The specific process of T1 is: T11, sorting the position information of the EMU in order and expressing it with PCRH; T12, the up and down conditions of the EMU are represented by StCRH, where the elements in StCRH are 1 or -1, 1 represents up and -1 represents down; T13, the location information of the AT or the connection point is represented by PAT; T14. The position information of the traction station is represented by PTF, wherein the position information of the left power supply arm outlet and the right power supply arm outlet of the traction station are represented by PTFα and PTFβ respectively.

5. The method for constructing a dynamic node admittance matrix of a coupling system according to claim 1, characterized in that: The grid-side nodes include new energy nodes, generator nodes, substation nodes and user nodes.

6. The method for constructing a dynamic node admittance matrix of a coupling system according to claim 1, characterized in that: The branch admittance matrix includes a branch admittance matrix Y of a three-phase transmission line br , 500kV transformer branch admittance matrix The branch admittance matrix Y of the traction transformer V,v and the branch admittance matrix of the traction network.

7. The method for constructing a dynamic node admittance matrix of a coupling system according to claim 6, characterized in that: The branch admittance matrix of the traction network includes the traction network unit length series admittance matrix Y s And the parallel admittance matrix Y1 of multiple conductors per unit length in the traction network.

8. The method for constructing a dynamic node admittance matrix of a coupling system according to claim 1, characterized in that: According to the branch connection relationship in the branch connection matrix, the specific process of building a dynamic node admittance matrix in combination with the branch admittance matrix is ​​as follows: A1. Define two connection matrices C f and C t , where C f is the branch-out node connection matrix, C t is the branch-input node connection matrix; A2, based on the two connection matrices C f and C t , derive the node voltage connection relationship and the node injection current connection relationship; A3. Based on the node voltage connection relationship and the node injection current connection relationship, derive the node admittance matrix expression.

9. The method for constructing a dynamic node admittance matrix of a coupling system according to claim 8, characterized in that: The branch-out node connection matrix C f and branch-input node connection matrix C t The specific expression is: Where p is the branch number, f is the egress node of branch p, t is the ingress node of branch p, C f and C t The dimension is n l ×n b , n l Indicates the number of branches, n b represents the total number of nodes in the node matrix, branch(p,f) represents the outgoing node of the p-th branch, branch(p,t) represents the incoming node of the p-th branch, C f (p,q) represents the element in the pth row and qth column of the matrix Cf, and Ct(p,k) represents the element in the pth row and qth column of the matrix Cf. t The element of the p-th row and k-th column of ; The specific expressions of the node voltage connection relationship and the node injection current connection relationship are: Where I is the node injection current vector, I f The current vector injected into the output node, I t is the node injection current vector, V is the total node voltage vector, V f is the output node voltage vector, V t is the input node voltage vector, V f and V t The dimensions are all n b ×1, Respectively represent the branch-out node connection matrix C f and branch-input node connection matrix C t The transpose of .

10. The method for constructing a dynamic node admittance matrix of a coupling system according to claim 9, characterized in that: In A3, based on the node voltage connection relationship and the node injection current connection relationship, the specific process of deriving the node admittance matrix expression is: A3.

1. List the node injection current vector I f and the current vector I injected into the node t The expression is: Among them, [Y ff ]、[Y ft ]、[Y tt ]、[Y tf ] represent the elements Y ff , Y ft , Y tt , Y tf is a matrix with diagonal elements, where Y ff , Y ft , Y tf , Y rt denote the branch out-out admittance matrix, the branch out-in admittance matrix, the branch in-out admittance matrix, and the branch in-in admittance matrix, respectively, and Y ff =Y io +Y ij , Y ft =-Y ij , Y tf =-Y ji , Y tt =Y jo +Y ij , Y io , Y ij , Y jo They represent the admittance matrix of node i to the ground, the admittance matrix between node i and node j, and the admittance matrix of node j to the ground respectively; A3.

2. Combining the formula in step A3.1 with the node voltage connection relationship and the node injection current connection relationship, we obtain: A3.

3. Transform the formula of step A3.2 to obtain the node admittance matrix:

Images