Distribution parameter model, construction method, determination method, computer equipment and medium

Abstract

The invention provides a distributed parameter model, a construction method, a determination method, computer equipment and a medium. The construction method comprises the following steps: constructing a first distribution parameter model of the high-voltage single-phase cable; based on the first distribution parameter model, establishing a voltage and current constraint relationship between the head end of the cable and any wire core and sheath in the line to obtain a second distribution parameter model; and converting different inter-phase coupled phasors into independent moduli for calculation, and establishing an accurate distribution parameter model of the three-phase high-voltage single-core cable. The model is obtained by the method. The determination method is implemented based on the established model. The computer equipment comprises a processor and a memory in which program instructions for executing the method are stored. Program instructions are stored in the storage medium. According to the invention, the simulation of the actual cable is more accurate, the optimization of the fault positioning technology is facilitated, and the stability and reliability of the power system are improved.

Description

Technical Field

[0001] The present invention relates to the field of cable model construction, and in particular to a distributed parameter model and construction method of a high-voltage single-core cable, a data determination method, a computer device and a computer-readable storage medium. Background Art

[0002] The line model in the power system plays a vital role in the simulation of voltage and current in the line, fault diagnosis and location. In urban power grids, compared with overhead lines, high-voltage cables laid underground are more and more widely used because of their small geographical restrictions and low environmental impact. At present, the existing high-voltage single-core cable models are divided into lumped parameter models and distributed parameter models. Compared with the lumped parameter model, the distributed parameter model takes into account the distribution effect of the cable line and can more realistically reflect the physical state and transmission characteristics of the cable. The existing distributed parameter models include the Berylon model, the Norton model, etc., which have the disadvantages of incomplete distributed parameter characteristics and do not consider the cable core and sheath structure. Summary of the invention

[0003] The purpose of the present invention is to solve at least one of the above-mentioned deficiencies in the prior art. For example, one of the purposes of the present invention is to achieve a more accurate simulation of an actual cable.

[0004] In order to achieve the above objectives, the present invention provides, on one hand, a method for constructing an accurate distributed parameter model of a high-voltage single-core cable.

[0005] The construction method may include the following steps: constructing a first distributed parameter model of a single-phase high-voltage single-core cable; based on the first distributed parameter model, establishing a voltage and current constraint relationship between the head end of the single-phase high-voltage single-core cable and the core and sheath at any point in the line, thereby obtaining a second distributed parameter model of the single-phase high-voltage single-core cable; converting the phasors of different phase couplings into a number of independent moduli for calculation, thereby establishing an accurate distributed parameter model of the three-phase high-voltage single-core cable based on the second distributed parameter model.

[0006] Another aspect of the present invention provides an accurate distributed parameter model of a high voltage single core cable.

[0007] The model can be obtained by the construction method described above.

[0008] Another aspect of the present invention provides a method for determining voltage and current in a high-voltage single-core cable line.

[0009] The method may include: simulating the line based on the above-mentioned high-voltage single-core cable accurate distributed parameter model to obtain voltage and current data of the core and sheath at any point in the line.

[0010] Yet another aspect of the present invention provides a computer device.

[0011] The computer device comprises: at least one processor; and a memory storing program instructions, wherein the program instructions are configured to be executed by the at least one processor, and the program instructions include instructions for a method for constructing a precise distributed parameter model of a high-voltage single-core cable as described above.

[0012] Furthermore, the method includes: collecting voltage and current data of the wire core and sheath at the head end, and importing them into the model; adjusting the cable length l so that the model calculates the voltage and current data of the wire core and sheath at the end.

[0013] Yet another aspect of the present invention provides a computer-readable storage medium.

[0014] Computer program instructions are stored on the computer-readable storage medium, and when the computer program instructions are executed by the processor, the method for constructing the accurate distributed parameter model of the high-voltage single-core cable as described above is implemented.

[0015] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0016] (1) The present invention uses a completely distributed parameter form, which makes the simulation of the actual cable more accurate.

[0017] (2) The present invention is conducive to further parameter identification of high-voltage cables and fault research of grounding systems.

[0018] (3) The present invention improves the accuracy of the cable simulation model and the accuracy of the cable fault protection algorithm, which helps to optimize the fault location technology and improve the stability and reliability of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects and / or features of the present invention will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0020] Figure 1 The cable microelement equivalent circuit diagram is shown;

[0021] Figure 2 A schematic diagram showing the coupling relationship between the wire cores and the sheaths of different phases is shown;

[0022] Figure 3 A flow chart for constructing a distributed parameter model for a high-voltage single-core cable is shown;

[0023] Figure 4 A comparison diagram of the calculated and simulated voltage of the third small section of the cross-connected three-phase cable core is shown;

[0024] Figure 5A comparison diagram of the calculated and simulated voltage of the third small section of the cross-connected three-phase cable core is shown;

[0025] Figure 6 A comparison diagram of the calculated and simulated sheath voltage of the third small section of the cross-connected three-phase cable is shown;

[0026] Figure 7 A comparison chart between the calculated and simulated sheath current of the third small section of the cross-connected three-phase cable is shown. DETAILED DESCRIPTION

[0027] Hereinafter, the present invention will be described in detail with reference to exemplary embodiments.

[0028] Exemplary Embodiment 1

[0029] The present invention can construct a model and simulate the high-voltage single-core cable according to the cable structural parameters and the voltage and current data of the core and sheath at one end of the line, and the simulation can obtain the voltage and current data of the core and sheath at any point in the line. Among them, the present invention is based on the structure of the high-voltage single-core cable and the distributed parameter model of the transmission line. The cable line is regarded as a cascade of infinitely many micro-element cables, which are derived from one end of the cable line to the other end. The constraint relationship between the voltage and current at both ends of the line is established by mathematical methods, thereby obtaining a mathematical model in the time domain.

[0030] This exemplary embodiment includes a method for constructing an accurate distributed parameter model of a high-voltage single-core cable and a method for determining voltage and current in a high-voltage single-core cable line. The specific technical solution of this exemplary embodiment is as follows:

[0031] Step 1: Based on the structure and arrangement of the high-voltage single-core cable, the electrical parameters of the cable are calculated to construct a single-phase distributed parameter model of the high-voltage cable, that is, a first distributed parameter model.

[0032] Step 2: By using mathematical methods such as mathematical induction, differentiation, and matrix method, a voltage and current constraint relationship between the head end of the high-voltage single-phase cable and the core and sheath at any point in the line is established to obtain a distributed parameter model of the high-voltage single-phase cable. In other words, based on the distributed parameter model obtained in the first step, a voltage and current constraint relationship between the head end of the high-voltage single-phase cable and the core and sheath at any point in the line is established to obtain a distributed parameter model of a single-phase high-voltage single-core cable, i.e., a second distributed parameter model.

[0033] Step 3: In the power system, the cable line is a three-phase conductor. There is a complex electromagnetic coupling relationship between the core and the sheath of each phase conductor. For the convenience of calculation, the line is decoupled and the phase quantities of different phase coupling are converted into several independent moduli for calculation. In this way, the line model derived based on the single-phase uniform cable can be applied to the three-phase cable line, and the distributed parameter model of the high-voltage three-phase cable is established, that is, the precise distributed parameter model of the high-voltage single-core cable.

[0034] Step 4: Use the accurate distributed parameter model of high-voltage single-core cable for simulation modeling.

[0035] Step 5: Input the voltage and current data of the core and sheath at the head end, and obtain the core and sheath voltage and current at any point in the cable line by adjusting the cable length l in the distributed parameter model.

[0036] In this embodiment, step one may specifically include:

[0037] Using the idea of ​​differentiation, the cable line is regarded as a cascade of infinitely many micro-element cables, which are derived from one end of the cable line to the other end. The constraint relationship between the voltage and current at both ends of the line is established through mathematical methods, thereby obtaining the mathematical model in the time domain, namely the following formulas 9 and 10.

[0038] The microelement circuit model of the cable is as follows: Figure 1 , the upper end of the unit represents the core of the cable, and its parameters are: R, L represent the resistance and inductance of the cable core per unit length, R', L' represent the resistance and inductance of the cable sheath per unit length, M is the mutual inductance (i.e. mutual inductance) of the core and sheath per unit length, C is the equivalent capacitance of the main insulation per unit length, and the above parameters can be obtained by inputting the cable structure and phase spacing parameters in the power cableparam toolbox in matlab. Points A and B represent the beginning and end of the line. x is an arbitrary distance from the head end point A. The resistance, inductance, capacitance, mutual inductance and other parameters of the core and sheath are evenly distributed throughout the cable. The same place on the cable is different at different times and the same time at different places is different, so the current and voltage of the core or sheath are both spatial functions and time functions.

[0039] according to Figure 1 The voltage and current equations of the microelement segment are established by Kirchhoff's law as follows:

[0040] The wire core has:

[0041]

[0042] The sheath has:

[0043]

[0044] Among them, x is the distance between point k1 and the head end, △x is the infinitesimal length, and t is the time;

[0045] u(x, t) is the line core voltage at the point x away from the head end at time t, u'(x, t) is the sheath voltage at the point x away from the head end at time t, u(x+△x, t) is the line core voltage at the point x+△x away from the head end at time t, u'(x+△x, t) is the sheath voltage at the point x+△x away from the head end at time t;

[0046] i(x, t) is the core current at the point x away from the head end at time t, i'(x, t) is the sheath current at the point x away from the head end at time t, i(x+△x, t) is the core current at the point x+△x away from the head end at time t, i'(x+△x, t) is the sheath current at the point x+△x away from the head end at time t;

[0047] R is the resistance per unit length of the cable core, L is the inductance per unit length of the cable core, M is the mutual inductance per unit length between the cable core and the sheath, C is the equivalent capacitance per unit length between the core conductor and the sheath conductor; R' is the resistance per unit length of the cable sheath, and L' is the inductance per unit length of the cable sheath.

[0048] In this embodiment, step 2 may specifically include:

[0049] According to Formula 1 and Formula 2, the voltage and current relationship between the nth and n-1th microelements is:

[0050]

[0051]

[0052] The traditional lumped parameter model ignores the distributed parameter characteristics of the line to simplify the model. Therefore, the relationship between the voltage and current of the core and sheath and the head end of the nth unit lumped formula is obtained:

[0053]

[0054] The precise distribution model obtained from Formula 1 and Formula 2 is as follows:

[0055] The current and voltage of the nth unit are:

[0056]

[0057] Where P n , P n ', Q n It is about R, L, R', L', C, M, n and Δx k (k=0,1,2,3…) polynomial.

[0058] Through mathematical induction, limit method and other mathematical methods, P n (Δx k ), P n '(Δx k ), Q n (Δx k ) polynomial. The constraint relationship between the voltage and current of the core and sheath at any point in the cable and the head end is obtained, namely, formulas 9 and 10.

[0059]

[0060]

[0061] in,

[0062] Among them, u B (t) is the line core voltage phasor at the end of the line (end B) at time t, u' B (t) is the sheath voltage phasor at the line end (end B) at time t; u A (t) is the line core voltage phasor at the line head end (end A) at time t, u' A (t) is the sheath voltage phasor at the line head end (end A) at time t;

[0063] i B (t) is the core current phasor at the end of the line (end B) at time t, i' B (t) is the sheath current phasor at the end of the line (end B) at time t, i A (t) is the core current phasor at the line head end (end A) at time t, i' A (t) is the sheath current phasor at the line head end (end A) at time t;

[0064] l is the line length, that is, the distance between end A and end B; j is the order, P n (j), P' n (j) and Q n (j) is a polynomial of various orders with respect to R, L, C, M, R', L', n, and △x.

[0065] In summary, given the known cable electrical parameters l and R, L, C, R', L', as well as the voltage and current u of the core wire and sheath at the head end A A (t),u' A (t), i A (t), i' A (t) and its derivative combination expression Y(t) i and(u A (t)-u' A (t)) i(i is 0, 1, 2, 3...) After that, the above formula can be used to obtain the voltage and current data of the core and sheath of any length of cable.

[0066] In this embodiment, step three may specifically include:

[0067] The theoretical derivation of the above-mentioned line distributed parameter model is based on a single uniform conductor. In the power system, the cable line is a three-phase conductor, and there is a complex electromagnetic coupling relationship between the core and the sheath of each phase conductor, such as Figure 2 shown.

[0068] Assuming that the three-phase cables have the same structure and are arranged in an equilateral triangle, the phase-to-phase coupling impedance of the three-phase cables is the same. Figure 2 In the equation, e represents the self-impedance of the core, f represents the self-impedance of the sheath, a represents the coupling impedance between the core and sheath of each phase cable, b represents the coupling impedance of the core and sheath of a certain phase to the core and sheath of other phases, and c is the equivalent capacitance of the main insulation of each phase cable.

[0069] In a single-circuit three-phase line, the relationship between phase voltage, phase current and line impedance is:

[0070]

[0071] The impedance matrix Z of the three-phase cable is:

[0072]

[0073] In order to eliminate the influence of phase-to-phase coupling impedance, i.e., b, the impedance matrix needs to be incompletely diagonalized through equivalent matrix transformation. At this time, the phase quantities are converted into independent moduli, and each modulus can be directly calculated through the single-phase high-voltage cable distributed parameter model. Here, the conversion matrix of the three-phase cable line is:

[0074]

[0075] In formula 14:

[0076] Z mod =Q -1 *Z*Q(Formula 16)

[0077]

[0078] In formula 15, f mod is the modulus of voltage and current in the core and sheath of the three-phase cable, f ABC The impedance matrix Z is decoupled into the modulus impedance matrix Z in formula 17 by formula 16. mod In the form of Z modIt only includes the mutual impedance between the core and sheath of each phase cable, eliminating the mutual impedance between phases. Finally, the constraint relationship between the voltage and current of the core and sheath at any point in the single-mode cable is obtained as follows:

[0079]

[0080] in,

[0081]

[0082] Among them, u B-mod (t) is the voltage modulus of the line core at the end of the line (end B) at time t, u' B-mod (t) is the voltage modulus of the line core at the end of the line (end B) at time t; u A-mod (t) is the voltage modulus of the line core at the line head end (end A) at time t, u' A-mod (t) is the voltage modulus of the sheath at the line head end (end A) at time t;

[0083] i B-mod (t) is the current modulus of the line core at the end of the line (end B) at time t, i' B-mod (t) is the sheath current modulus at the line end (end B) at time t, i A-mod (t) is the current modulus of the line core at the beginning (end A) of the line at time t, i' A-mod (t) is the sheath current modulus at the line head end (end A) at time t;

[0084] P n-mod (j), P' n-mod (j) and Q n-mod (j) is the value of R -mod , L -mod , C -mod , R' -mod , L' -mod 、M -mod , n, △x polynomials of various orders.

[0085] In this embodiment, step 4 may specifically include:

[0086] For cables grounded at both ends or at one end, the three-phase distributed parameter model of the high-voltage cable (Formulas 18 and 19 above) can be used directly for modeling, such as Matlab, python, etc.

[0087] In this embodiment, step five may specifically include:

[0088] The voltage and current data of the core and sheath over a certain period of time are collected at the head end of the cable line and input into the distributed parameter model. By adjusting the cable length l in the model, the voltage and current of the core and sheath at l can be obtained.

[0089] Figure 3 Construct a flow chart for the distributed parameter model of high voltage single core cable. Figure 3 As shown in the figure, first, the cable model and arrangement of the high-voltage single-core cable are obtained to calculate the electrical parameters of the cable per unit length, and the distributed parameter model of the cable is constructed in combination with the sheath grounding method. The voltage and current data of the core and sheath at the head end of the running cable over a period of time are obtained and input into the distributed parameter model. By adjusting the cable length in the output, the voltage and current data of the core and sheath at any point in the cable can be obtained.

[0090] Exemplary Embodiment 2

[0091] This exemplary embodiment provides a method for constructing an accurate distributed parameter model of a high-voltage single-core cable.

[0092] The method may include steps 1 to 3 in the exemplary embodiment 1 above.

[0093] Exemplary Embodiment 3

[0094] This exemplary embodiment provides a method for constructing an accurate distributed parameter model of a high-voltage single-core cable.

[0095] Specifically, based on exemplary embodiment 2, the method may further include step four: performing simulation modeling.

[0096] Example 4

[0097] This exemplary embodiment provides an accurate distributed parameter model of a high-voltage single-core cable.

[0098] The model may be constructed by steps one to three in exemplary embodiment 1, or by the method described in exemplary embodiment 2, or by the method described in exemplary embodiment 3.

[0099] Exemplary Embodiment 5

[0100] This exemplary embodiment provides an accurate distributed parameter model of a high-voltage single-core cable. The model includes:

[0101]

[0102]

[0103] in,

[0104]

[0105] Among them, u B-mod (t) is the voltage modulus of the line core at the end of the line at time t, u' B-mod (t) is the voltage modulus of the line core at the end of the line at time t; u A-mod(t) is the voltage modulus of the line core at the beginning of the line at time t, u' A-mod (t) is the voltage modulus of the sheath at the head end of the line at time t;

[0106] i B-mod (t) is the current modulus of the core at the end of the line at time t, i' B-mod (t) is the current modulus of the sheath at the end of the line at time t, i A-mod (t) is the current modulus of the line core at the beginning of the line at time t, i' A-mod (t) is the current modulus of the sheath at the head end of the line at time t;

[0107] P n-mod (j), P' n-mod (j) and Q n-mod (j) is the value of R -mod , L -mod , C -mod , R' -mod , L' -mod 、M -mod , n, △x polynomials of various orders.

[0108] Exemplary Embodiment 6

[0109] The present exemplary embodiment provides a method for determining voltage and current in a high-voltage single-core cable line.

[0110] The determination method may be implemented based on the model in exemplary embodiment 4 or 5 above.

[0111] For example, it may include: based on the accurate distributed parameter model of high-voltage single-core cable, simulating the line to obtain the voltage and current data of the core and sheath at any point in the line. The simulation of the model here can also refer to calculation, building a cable model at the code level based on impedance and admittance parameters, substituting the voltage and current data of the core and sheath at one end of the cable line into the cable model, and calculating the voltage and current data of the core and sheath at any point in the line.

[0112] In order to better understand the above exemplary embodiments, they are further described below with reference to specific examples.

[0113] Example 1

[0114] The specific implementation process includes the following steps:

[0115] ATP-EMTP is used to simulate the ZR-YJLW03-64 / 110-1*1200 cable, which is a 110kV two-end grounded cable. Both ends of its sheath are grounded through a 1Ω resistor. The cable line is divided into three sections, each 500m long, arranged in an equilateral triangle. The cable is laid 0.5m underground, with a three-phase spacing of 0.2m. The power supply voltage is 110kV, 50Hz three-phase AC, the load of the three-phase core is a 200Ω resistor, and the load current is 778A.

[0116] The voltage and current data of the terminal core and the sheath are determined by the method of the present invention, as follows:

[0117] S1: Calculate the electrical parameters per unit length according to the cable model and arrangement, and build a distributed parameter model of the cable in combination with the sheath grounding method. That is, this step is to establish an accurate distributed parameter model of a high-voltage single-core cable according to steps 1 to 3 in exemplary embodiment 1 of the present invention or the method in exemplary embodiment 2.

[0118] S2: synchronously collect the voltage and current data of the core and sheath at the head end for 0.02s, and import them into the distributed parameter model. The data collected is the ZR-YJLW03-64 / 110-1*1200 cable mentioned above.

[0119] S3: Adjust the cable length l so that the voltage and current data of the end core and sheath can be calculated.

[0120] Specifically, step S3 is also a simulation. The difference from ATP is that when determining the voltage and current values ​​of the actual cable, the derived model only needs to know the impedance and admittance parameters of the cable and the voltage and current data of the core and sheath at one end. However, ATP simulation of the actual cable requires knowing the ground impedance, load resistance, power supply voltage, etc. of the cable to build a simulation operation platform for the actual cable.

[0121] The voltage and current data of the terminal core and sheath obtained by ATP simulation and calculation based on the distributed parameter model of the present invention are compared.

[0122] Depend on Figure 4-Figure 7 It can be seen that when the ATP simulation uses the PI model, the voltage and current simulation of the cable end core and sheath are basically consistent with the data calculated by the distributed parameter model, proving that the model has a good application effect. The red line representing the calculation in the figure shows the data calculated using the distributed parameter model of the present invention, and the blue short line representing the simulation shows the data obtained by the ATP simulation.

[0123] According to the method for constructing an accurate distributed parameter model of a high-voltage single-core cable of the present invention, it can be programmed as a computer program and the corresponding program code or instructions can be stored in a computer-readable storage medium. When the program code or instructions are executed by a processor, the processor executes the above method. The following processor and memory can be included in a computer device.

[0124] Example 7

[0125] This exemplary embodiment provides a computer device, including:

[0126] at least one processor;

[0127] A memory storing program instructions, wherein the program instructions are configured to be executed by the at least one processor, and the program instructions include instructions for executing the method for constructing the precise distributed parameter model of the high-voltage single-core cable of the present invention, for example, the instructions for the method for constructing the precise distributed parameter model of the high-voltage single-core cable in exemplary embodiment 1, the instructions for the method for constructing in exemplary embodiment 2, or the instructions for the method for constructing in exemplary embodiment 3 can be executed.

[0128] Exemplary Embodiment 8

[0129] The present exemplary embodiment provides a computer-readable storage medium.

[0130] The storage medium stores a computer program, and when the computer program instructions are executed by the processor, the method for constructing the high-voltage single-core cable accurate distributed parameter model of the present invention is implemented. For example, the method for constructing the high-voltage single-core cable accurate distributed parameter model in exemplary embodiment 1, the method for constructing in exemplary embodiment 2, or the method for constructing in exemplary embodiment 3 is implemented.

[0131] The computer-readable storage medium may be any data storage device that stores data that can be read by a computer system. For example, examples of computer-readable storage media may include: read-only memory, random access memory, read-only optical disk, magnetic tape, floppy disk, optical data storage device, and carrier wave (such as data transmission via the Internet via a wired or wireless transmission path).

[0132] Although the present invention has been described above in conjunction with the exemplary embodiments and the accompanying drawings, it should be apparent to those skilled in the art that various modifications may be made to the above-described embodiments without departing from the spirit and scope of the claims.

Claims

1. A method for constructing an accurate distributed parameter model of a high-voltage single-core cable, characterized in that: The method comprises the following steps: Constructing a first distributed parameter model of a single-phase high-voltage single-core cable; Based on the first distributed parameter model, a voltage and current constraint relationship between the head end of a single-phase high-voltage single-core cable and the core and sheath at any point in the line is established, thereby obtaining a second distributed parameter model of the single-phase high-voltage single-core cable; The phase quantities of different phase couplings are converted into a number of independent moduli for calculation, so as to establish an accurate distributed parameter model of a three-phase high-voltage single-core cable based on the second distributed parameter model.

2. The method for constructing a high-voltage single-core cable accurate distributed parameter model according to claim 1, characterized in that: The step of constructing a first distributed parameter model of a single-phase high-voltage single-core cable comprises: Based on the structure and arrangement of the high-voltage single-core cable, the electrical parameters of the cable are calculated, and then the first distributed parameter model is constructed.

3. The method for constructing a high-voltage single-core cable accurate distributed parameter model according to claim 2, characterized in that: The first distributed parameter model includes: The wire core has: The sheath has: Among them, x is the distance from a certain point to the head end, △x is the infinitesimal length, and t is the time; u(x,t) is the line core voltage at the point x length away from the head end at time t, u'(x,t) is the sheath voltage at the point x length away from the head end at time t, u(x+△x,t) is the line core voltage at the point x+△x length away from the head end at time t, u'(x+△x,t) is the sheath voltage at the point x+△x length away from the head end at time t; i(x, t) is the core current at the point x length away from the head end at time t, i'(x, t) is the sheath current at the point x length away from the head end at time t, i(x+△x, t) is the core current at the point x+△x length away from the head end at time t, i'(x+△x, t) is the sheath current at the point x+△x length away from the head end at time t; R is the resistance per unit length of the cable core, L is the inductance per unit length of the cable core, M is the mutual inductance per unit length between the cable core and the sheath, and C is the equivalent capacitance per unit length between the core conductor and the sheath conductor; R' is the resistance per unit length of the cable sheath, and L' is the inductance per unit length of the cable sheath.

4. The method for constructing a high-voltage single-core cable accurate distributed parameter model according to claim 1, characterized in that: The second distributed parameter model includes: in, Among them, u B (t) is the voltage phasor at the end of the line at time t, u' B (t) is the voltage phasor of the sheath at the end of the line at time t; u A (t) is the voltage phasor of the line core at the beginning of the line at time t, u' A (t) is the voltage phasor of the sheath at the head end of the line at time t; i B (t) is the current phase of the core at the end of the line at time t, i' B (t) is the current phasor of the sheath at the end of the line at time t, i A (t) is the current phase of the core line at the beginning of the line at time t, i' A (t) is the sheath current phasor at the line head end at time t; l is the line length, that is, the distance between end A and end B; j is the order, P n (j), P' n (j) and Q n (j) is a polynomial of various orders with respect to R, L, C, M, R', L', n, and △x.

5. The method for constructing a high-voltage single-core cable accurate distributed parameter model according to claim 1, characterized in that: The step of converting the phase quantities of different phase couplings into a plurality of independent modules for calculation includes: incompletely diagonalizing the impedance matrix through equivalent matrix transformation, and then converting the phase quantities into mutually independent modules.

6. The method for constructing a high-voltage single-core cable accurate distributed parameter model according to claim 1, characterized in that: The high-voltage single-core cable accurate distributed parameter model includes: in, Among them, u B-mod (t) is the voltage modulus of the line core at the end of the line at time t, u' B-mod (t) is the voltage modulus of the line core at the end of the line at time t; u A-mod (t) is the voltage modulus of the line core at the beginning of the line at time t, u' A-mod (t) is the voltage modulus of the sheath at the head end of the line at time t; i B-mod (t) is the current modulus of the core at the end of the line at time t, i' B-mod (t) is the current modulus of the sheath at the end of the line at time t, i A-mod (t) is the current modulus of the line core at the beginning of the line at time t, i' A-mod (t) is the current modulus of the sheath at the head end of the line at time t; P n-mod (j), P' n-mod (j) and Q n-mod (j) is the value of R -mod , L -mod , C -mod , R' -mod , L' -mod 、M -mod , n, △x polynomials of various orders.

7. A high-voltage single-core cable accurate distributed parameter model, characterized in that: The model is obtained by the method according to any one of claims 1 to 6.

8. A method for determining voltage and current in a high-voltage single-core cable line, characterized in that: The method comprises: simulating the line based on the model described in claim 7 to obtain voltage and current data of the core and sheath at any point in the line.

9. The method for determining voltage and current in a high-voltage single-core cable line according to claim 8, characterized in that: The method comprises: Collecting voltage and current data of the wire core and sheath at the head end, and importing them into the model; The cable length l is adjusted so that the model can calculate the voltage and current data of the terminal core and sheath.

10. A computer device, characterized in that: include: at least one processor; A memory storing program instructions, wherein the program instructions are configured to be executed by the at least one processor, and the program instructions include instructions for executing the method according to any one of claims 1-6.

11. A computer-readable storage medium having computer program instructions stored thereon, characterized in that: When the computer program instructions are executed by a processor, the method according to any one of claims 1 to 6 is implemented.

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