Parameter estimation method and device for same-tower double-circuit transmission line based on parameter set selection

Abstract

This application relates to a method and apparatus for estimating parameters of a double-circuit transmission line on the same tower based on parameter set selection, specifically in the field of power system technology. The method includes: acquiring the line parameters corresponding to the double-circuit transmission line on the same tower; determining the equivalent independent parameters and equivalent mutual parameters corresponding to the line parameters based on the tower structural characteristics of the double-circuit transmission line on the same tower, and acquiring the parameter set corresponding to the equivalent independent parameters and equivalent mutual parameters; acquiring the electrical quantity data corresponding to the double-circuit transmission line on the same tower in response to an external fault; estimating the estimated values ​​of the line parameters corresponding to the line parameters based on the objective function corresponding to the parameter set and the electrical quantity data. The estimated values ​​of the line parameters are used for line maintenance of the double-circuit transmission line on the same tower, and the objective function is used to solve for the zero-sequence parameters of the newly built second circuit in the double-circuit transmission line on the same tower based on the zero-sequence parameters of the first circuit in the double-circuit transmission line that is put into operation.

Description

Technical Field

[0001] This application relates to the field of power system technology, and in particular to a method and apparatus for estimating parameters of a double-circuit transmission line on the same tower based on parameter set selection. Background Technology

[0002] Double-circuit transmission lines sharing the same tower are a widely used line structure in high-voltage and ultra-high-voltage transmission systems. Because the two circuits share the same tower, they effectively save corridor resources, reduce land occupation, and improve the utilization efficiency of transmission channels. However, the electrical characteristics of double-circuit transmission lines are relatively complex, and there is a significant electromagnetic coupling effect between the lines. Especially in practical engineering applications, it is common to see situations where an existing transmission line has already been built and put into operation, and a second line is subsequently constructed. Therefore, it is necessary to estimate the overall parameters of the double-circuit transmission line, as these parameters are crucial for accurately reflecting the coupling effect of the double-circuit line and ensuring the safe and stable operation of the power system.

[0003] Currently, the estimation methods for parameters of double-circuit transmission lines on the same tower mainly rely on manual measurement. For example, when the line is out of service, an electrical signal of power frequency or a specific frequency is applied to the line, and the parameters of the double-circuit transmission line on the same tower are estimated by measuring the response at the line port. However, this method not only requires the line to be shut down for offline measurement, but also poses significant safety hazards in high-voltage or ultra-high-voltage environments. Summary of the Invention

[0004] In view of this, this application provides a method and apparatus for estimating parameters of a double-circuit transmission line on the same tower based on parameter set selection. The main purpose is to improve the technical problems in related technologies, which not only require the line to be shut down for offline measurement, but also pose significant safety hazards for manual measurement in high-voltage or ultra-high-voltage environments.

[0005] Firstly, this application provides a parameter estimation method for a double-circuit transmission line on the same tower based on parameter set selection, the method comprising:

[0006] Obtain the line parameters corresponding to a double-circuit transmission line on the same tower;

[0007] Based on the tower structure characteristics of the double-circuit transmission line on the same tower, the equivalent self-parameters and equivalent mutual parameters corresponding to the line parameters are determined, and the parameter sets corresponding to the equivalent self-parameters and equivalent mutual parameters are obtained.

[0008] In response to an external fault occurring on a double-circuit transmission line on the same tower, acquire electrical quantity data during the operation of the double-circuit transmission line on the same tower;

[0009] Based on the objective function and electrical quantity data corresponding to the parameter set, the estimated values ​​of the line parameters are estimated. The estimated values ​​of the line parameters are used for line maintenance of double-circuit transmission lines on the same tower. The objective function is used to solve for the zero-sequence parameters of the newly built second circuit in the double-circuit transmission line on the same tower based on the zero-sequence parameters of the first circuit in the double-circuit transmission line that is put into operation.

[0010] Secondly, this application provides a parameter estimation device for a double-circuit transmission line on the same tower based on parameter set selection. The device includes:

[0011] The acquisition module is configured to acquire the line parameters corresponding to the double-circuit transmission line on the same tower.

[0012] The determination module is configured to determine the equivalent independent parameters and equivalent mutual parameters corresponding to the line parameters based on the tower structure characteristics of the double-circuit transmission line on the same tower, and obtain the parameter set corresponding to the equivalent independent parameters and equivalent mutual parameters;

[0013] The acquisition module is configured to acquire electrical quantity data of the double-circuit transmission line on the same tower during operation in response to an external fault occurring on the double-circuit transmission line on the same tower.

[0014] The estimation module is configured to estimate the line parameters based on the objective function and electrical quantity data corresponding to the parameter set. The estimated line parameters are used for line maintenance of double-circuit transmission lines on the same tower. The objective function is used to solve for the zero-sequence parameters of the newly built second circuit in the double-circuit transmission line on the same tower based on the zero-sequence parameters of the first circuit in the double-circuit transmission line that is put into operation.

[0015] Thirdly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method of the first aspect.

[0016] Fourthly, this application provides an electronic device, including a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, wherein the processor executes the computer program to implement the method of the first aspect.

[0017] Fifthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the method of the first aspect.

[0018] Using the above technical solution, this application provides a parameter estimation method for double-circuit transmission lines on the same tower based on parameter set selection. First, the line parameters corresponding to the double-circuit transmission line on the same tower are obtained. Then, based on the tower structural characteristics of the double-circuit transmission line on the same tower, the equivalent independent parameters and equivalent mutual parameters corresponding to the line parameters are determined, and the parameter set corresponding to the equivalent independent parameters and equivalent mutual parameters is obtained. In response to an external fault occurring in the double-circuit transmission line on the same tower, electrical quantity data during the operation of the double-circuit transmission line on the same tower are obtained. Finally, based on the objective function corresponding to the parameter set and the electrical quantity data, the estimated values ​​of the line parameters corresponding to the line parameters are estimated. The estimated values ​​of the line parameters are used for line maintenance of the double-circuit transmission line on the same tower. The objective function is used to solve for the zero-sequence parameters of the newly built second circuit in the double-circuit transmission line on the same tower based on the zero-sequence parameters of the first circuit in operation. Compared with current related technologies, this application first combines the tower structure characteristics of double-circuit transmission lines on the same tower, and uses equivalent cross parameters and equivalent self parameters to simplify the line parameters and select the parameter set. Then, it uses the electrical quantity data measured during operation and the objective function corresponding to the parameter set to estimate the line parameter estimates. The objective function is used to solve for the zero-sequence parameters of the newly built second circuit in the double-circuit transmission line on the same tower based on the zero-sequence parameters of the first circuit put into operation. In this way, this embodiment can effectively overcome the limitations of traditional reliance on power outage tests and manual measurements, improve the accuracy of parameter estimation, provide support for the safe and stable operation of the smart grid, and reduce the significant safety hazards of manual measurements in high-voltage or ultra-high-voltage environments.

[0019] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This paper illustrates a flowchart of a parameter estimation method for a double-circuit transmission line on the same tower based on parameter set selection, according to an embodiment of this application.

[0023] Figure 2 This illustration shows a schematic diagram of the tower conductor arrangement structure of an example double-circuit transmission line on the same tower, provided by an embodiment of this application.

[0024] Figure 3 A schematic diagram of an improved particle swarm optimization algorithm provided in an embodiment of this application is shown.

[0025] Figure 4 A flowchart illustrating an example provided in an embodiment of this application is shown;

[0026] Figure 5 This paper presents a schematic diagram of a parameter estimation device for a double-circuit transmission line on the same tower based on parameter set selection, according to an embodiment of this application. Detailed Implementation

[0027] To better understand the above-mentioned objectives, features, and advantages of this application, the solution of this application will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0028] Currently, most methods for selecting line parameters assume an ideal swapped state for the entire transmission line, idealizing double-circuit lines to achieve balance in multi-phase lines. These fully idealized assumptions reduce the complexity of transmission line modeling. However, because these methods do not consider the asymmetry of the line parameter matrix for non-swapped double-circuit lines, they may lead to reduced accuracy or limited applicability in practical applications.

[0029] With the widespread application of digital relays and intelligent measuring devices, methods for estimating line parameters based on operational data have gradually become a key research focus. Compared to traditional methods relying on power outage tests or manual measurements, parameter estimation techniques based on parameter set selection can combine the structural characteristics of double-circuit transmission lines on the same tower, rationally select key parameter sets, and use electrical quantities collected during operation at both ends of the line for calculation, effectively meeting the power system's requirements for continuous operation. This method not only avoids the safety risks of manual on-site testing but also significantly reduces the economic losses caused by line outages. Therefore, it is urgent to develop a parameter estimation method for double-circuit transmission lines on the same tower based on parameter set selection to improve the setting accuracy of relay protection, enhance the safety and stability of power system operation, and ensure the safety of maintenance and operation personnel.

[0030] To improve upon existing methods for estimating parameters of double-circuit transmission lines on the same tower, which primarily rely on manual measurement—such as applying power frequency or specific frequency electrical signals to the line during shutdown and estimating parameters by measuring the line port responses—this method not only requires offline measurement during line shutdown but also presents significant safety hazards in high-voltage or ultra-high-voltage environments. This embodiment provides a parameter estimation method for double-circuit transmission lines on the same tower based on parameter set selection. Figure 1 As shown, the method includes:

[0031] Step 101: Obtain the line parameters corresponding to the double-circuit transmission line on the same tower.

[0032] In some embodiments, a double-circuit transmission line on the same tower refers to two independent transmission lines erected on the same transmission tower, each of which can operate independently. This design can save land resources, reduce construction costs, and improve the utilization rate of the transmission corridor. It is typically used in high-voltage or ultra-high-voltage transmission systems (such as 220kV, 500kV, etc.). The line parameters of a double-circuit transmission line on the same tower can be used to describe the physical quantities of the electrical characteristics of the transmission line, such as resistance, inductance, conductance, and capacitance. Due to the significant electromagnetic coupling effect between the two circuits, the line parameters may specifically include the self-parameters of each line itself, referring to the electrical characteristics exhibited by a conductor or circuit itself, such as self-impedance, self-inductance, self-admittance, and self-capacitance, as well as the mutual parameters with other lines, referring to the electromagnetic influence of one conductor on another, such as mutual impedance, mutual inductance, mutual admittance, and mutual capacitance.

[0033] Step 102: Based on the tower structure characteristics of the double-circuit transmission line on the same tower, determine the equivalent self-parameters and equivalent mutual parameters corresponding to the line parameters, and obtain the parameter set corresponding to the equivalent self-parameters and equivalent mutual parameters.

[0034] In some embodiments, since the two lines are erected on the same tower, the parameters of the two lines are basically symmetrical, but there is a slight mutual inductance effect. Based on the tower structure characteristics of the double-circuit transmission line on the same tower, the equivalent independent parameters and equivalent mutual parameters corresponding to each line parameter can be determined, and the corresponding parameter set can be constructed based on the equivalent independent parameters and equivalent mutual parameters to reduce the number of independent parameters in the line parameters. The structural characteristics of the transmission tower can be determined based on its geometric characteristics. These characteristics may include conductor arrangement (e.g., horizontal, vertical, triangular, inverted umbrella type), horizontal and vertical spacing between conductors, location of the ground wire (overhead ground wire), phase sequence arrangement (e.g., the phase sequence in the first circuit is A, B, C, and the second circuit uses the same phase sequence; or, the second circuit uses the reverse phase sequence of the first circuit, namely: C, B, A), conductor type, number of splits, sag, etc. These structures directly affect the electromagnetic field distribution. Based on these structural characteristics and the actual electromagnetic field distribution, the equivalent self-parameters and equivalent mutual parameters of each line parameter, as well as the equivalent self-parameters and equivalent mutual parameters between each line parameter, can be determined. Finally, based on the equivalent self-parameters and equivalent mutual parameters of each line parameter, as well as the equivalent self-parameters and equivalent mutual parameters between each line parameter, a parameter set can be obtained. Through equivalent substitution, the number of independent parameters can be reduced.

[0035] For example, equivalent self-parameters may include self-parameters used to equivalently replace line parameters, such as equivalent positive-sequence resistance, equivalent zero-sequence resistance, etc., and equivalent mutual parameters may include mutual parameters used to equivalently replace line parameters, such as equivalent mutual resistance, equivalent mutual resistance, equivalent zero-sequence mutual inductance, etc. Line parameters can be represented in matrix form, such as constructing an initial parameter matrix; parameter sets can be represented in parameter matrix form, which may include impedance matrices, admittance matrices, etc.

[0036] Step 103: In response to an external fault occurring on a double-circuit transmission line on the same tower, obtain the corresponding electrical quantity data for the double-circuit transmission line on the same tower.

[0037] In some embodiments, an external fault can refer to a fault that occurs outside the protection zone, such as an external grounding fault, which is not within the line segment currently being monitored or protected. Specifically, for the main protection (such as longitudinal protection or distance protection) of a double-circuit transmission line on the same tower, an internal fault can refer to a fault point located between the current transformers (CTs) at both ends of the line, while an external fault can refer to a fault point located outside either end of the line, such as a short circuit at the outlet of an adjacent line, a bus fault, or a transformer outlet fault.

[0038] In specific application scenarios, external grounding faults can induce significant zero-sequence currents in non-faulty circuits. If the influence of mutual parameters is not considered, this may lead to maloperation of zero-sequence protection. Measured electrical quantity data can be used to verify the accuracy of the model and optimize protection settings. Correspondingly, during external faults, electrical quantity data of double-circuit transmission lines on the same tower can be collected through fault recording devices, synchronous phasor measurement units (PMUs), or supervisory control and data acquisition and monitoring systems (SCADA). For example, fault recording data files can be exported from the substation's fault recorder, using the Common Format for Transient Data Exchange (COMTRADE), and records involving this double-circuit line can be filtered. Optionally, an electrical quantity database can be established to periodically analyze such events, facilitating smart grid operation and maintenance, ensuring correct relay protection operation, optimizing setting values, and improving system security.

[0039] Step 104: Based on the objective function and electrical quantity data corresponding to the parameter set, estimate the line parameter values ​​corresponding to the line parameters.

[0040] Among them, the estimated line parameters can be used for line maintenance of double-circuit transmission lines on the same tower, and the objective function can be used to solve for the zero-sequence parameters of the newly built second circuit in the double-circuit transmission line on the same tower based on the zero-sequence parameters of the first circuit in the double-circuit transmission line that has been put into operation.

[0041] In some embodiments, the line parameter estimates may be the electrical parameter estimates of the transmission line fitted based on actual operation or fault data; the objective function may be constructed based on the residual between the measured parameter values ​​and the parameter estimates; the first circuit may be a completed and long-term operating circuit, whose parameters can be calibrated through historical data and can be regarded as known parameters; the second circuit may be a newly built circuit on the same tower as the first circuit, which has not yet undergone sufficient fault analysis or measurement, and whose line parameters are unknown or only depend on design values, and need to be estimated through the coupling relationship with the first circuit. Accordingly, the line parameter estimates include the line parameter estimates of the second circuit.

[0042] For example, when a ground fault occurs in the first circuit, a large zero-sequence current is generated. Due to electromagnetic coupling with the second circuit, even if the second circuit is not in operation (unloaded or out of service), a zero-sequence voltage will be induced at its two ends. Based on the tower structure characteristics of the corresponding towers of the first and second circuits, the equivalent self-parameters and equivalent mutual parameters of the first and second circuits are determined, and corresponding parameter sets are constructed. By using the electrical quantity data measured during operation and the objective function corresponding to the parameter set, combined with the known zero-sequence parameters and measured current of the first circuit, the zero-sequence parameters of the second circuit are estimated for line maintenance. Specifically, the estimated line parameters can be used for line maintenance of double-circuit transmission lines on the same tower, such as relay protection: zero-sequence directional protection needs to consider the mutual inductance effect, otherwise it may malfunction; fault location: the double-ended electrical quantity algorithm needs to include mutual parameters to improve accuracy; electromagnetic interference assessment: during power outage maintenance, the energized circuit will induce voltage in the out-of-service circuit, which needs to be calculated using mutual parameters; dynamic simulation: an accurate model is established in the Power Systems Computer Aided Design (PSCAD) platform to predict system stability.

[0043] By applying the technical solution of this application embodiment, this embodiment combines the tower structure characteristics of double-circuit transmission lines on the same tower, uses equivalent mutual parameters and equivalent self-parameters to simplify the line parameters and select the parameter set, and uses the electrical quantity data measured during operation and the objective function corresponding to the parameter set to estimate the line parameter estimates. The objective function is used to solve for the zero-sequence parameters of the newly built second circuit in the double-circuit transmission line on the same tower based on the zero-sequence parameters of the first circuit put into operation. In this way, this embodiment can effectively overcome the limitations of traditional reliance on power outage tests and manual measurements, improve the accuracy of parameter estimation, provide support for the safe and stable operation of the smart grid, and reduce the significant safety hazards of manual measurements in high-voltage or ultra-high-voltage environments.

[0044] Furthermore, as a refinement and extension of the specific implementation of the above embodiments, and to fully illustrate the implementation of this embodiment, step 102 may optionally include: determining the parameter equivalence conditions within the double-circuit transmission line on the same tower and the parameter equivalence conditions between double-circuit transmission lines on the same tower based on the tower structure characteristics of the double-circuit transmission line on the same tower. The parameter equivalence conditions within the double-circuit transmission line on the same tower include equal self-parameters and equal mutual parameters within the same circuit. The parameter equivalence conditions between double-circuit transmission lines on the same tower include equal mutual parameters and unequal self-parameters between double-circuit transmission lines on the same tower. Based on the parameter equivalence conditions within the double-circuit transmission line on the same tower and the parameter equivalence conditions between double-circuit transmission lines on the same tower, determining the equivalent self-parameters and equivalent mutual parameters corresponding to the line parameters.

[0045] For example, such as Figure 2 The diagram shows the tower conductor arrangement of a double-circuit transmission line on the same tower. It is used to visually present the spatial positional relationship of different circuits and different phase conductors on the tower. It shows the spatial layout of two three-phase AC lines on the same tower. The first circuit may include the phase conductors marked with points 1, 2 and 3 respectively, and the second circuit may include the phase conductors marked with points 4, 5 and 6 respectively.

[0046] For example, an initial parameter matrix corresponding to a double-circuit transmission line on the same tower is constructed based on this marker point. It can be represented as:

[0047] ;

[0048] In the formula, It can be an impedance matrix ( or admittance matrix ( The initial parameter matrix can contain 15 off-diagonal parameters between each conductor 1, 2, 3, 4, 5, and 6 (e.g., ...). , , , ) and 6 diagonal parameters (such as , There are a total of 21 parameters.

[0049] Optionally, the parameter equivalence conditions between double-circuit transmission lines on the same tower may include unequal self-parameters between the double-circuit transmission lines on the same tower.

[0050] Specifically, due to design errors between the two circuits of a double-circuit transmission line on the same tower, the self-parameters of the two circuits are not entirely the same. For example, the relationship expression between the self-parameters of the two circuits can be:

[0051] ;

[0052] In the formula, , These can be the self-parameters of the first circuit. , It can be a parameter of the second circuit.

[0053] Optionally, the parameter equivalence conditions within a double-circuit transmission line on the same tower may include the equality of self-parameters within the same circuit and the equality of mutual parameters within the same circuit.

[0054] Specifically, for the internal parameters of the same circuit on a tower, the asymmetry can be approximated as symmetry based on the tower structure of a double-circuit transmission line on the same tower. In some embodiments, it can be determined that the self-parameters and mutual parameters within the same circuit are equal. Based on this parameter equivalence condition, the equivalent self-parameters and equivalent mutual parameters corresponding to the self-parameters and mutual parameters within the double-circuit transmission line on the same tower can be obtained, which can be expressed as:

[0055] ;

[0056] In the formula, This can be the self-parameter of the first circuit. The equivalent self-parameter; Mutual parameters for the first circuit Equivalent cross parameters; This can be a self-parameter of the second circuit. The equivalent self-parameter; Mutual parameters for the second circuit The equivalent cross parameters.

[0057] Optionally, the parameter equivalence conditions between double-circuit transmission lines on the same tower may include that the mutual parameters between the double-circuit transmission lines on the same tower are equal.

[0058] Specifically, the mutual parameters between two-circuit transmission lines on the same tower can be approximated as equal. Based on this parameter equivalence condition, the equivalent mutual parameters corresponding to the mutual parameters between two-circuit transmission lines on the same tower can be obtained, which can be expressed as:

[0059] ;

[0060] In the formula, It can be the cross-parameter between the first and second circuits. , , The corresponding equivalent cross parameters.

[0061] Accordingly, based on the equivalent independent parameters and equivalent cross parameters within the first circuit, the equivalent independent parameters and equivalent cross parameters within the second circuit, and the equivalent independent parameters between the first and second circuits, the initial parameters in the initial parameter matrix can be processed to obtain a simplified parameter matrix. It can be represented as:

[0062] ;

[0063] This method reduces the number of parameters to be solved in the parameter matrix, thereby improving the efficiency of parameter solving.

[0064] Optionally, before step 102, the method of this embodiment may further include: establishing a single-segment π-type lumped parameter model for the double-circuit transmission line on the same tower; acquiring electrical quantity data using the double-end measuring device of the double-circuit transmission line on the same tower during operation; and establishing a set of parametric equations corresponding to the second circuit when an external fault occurs based on the electrical quantity data and the known parameters of the first circuit, using the single-segment π-type lumped parameter model.

[0065] For example, if the total length of a double-circuit transmission line on the same tower is 80km, which is considered a medium length, each circuit can be equivalent to a π-type circuit. Considering phase-to-phase and phase-to-circuit coupling, a single-segment π-type lumped parameter model of the line can be established. Correspondingly, the dual-end measurement device can include measurement devices deployed at the transmitting and receiving ends of the double-circuit transmission line on the same tower to measure the electrical quantity data of the double-circuit transmission line during operation. The electrical quantity data may include, but is not limited to, positive-sequence parameters, phasor domain zero-sequence voltage measurements, and phasor domain zero-sequence current measurements. For example, the positive-sequence parameters of the double-circuit transmission line on the same tower can be obtained through dual-end measurements of the line during normal operation.

[0066] In some embodiments, an external fault refers to a fault occurring outside the line protection zone. Although the fault is outside the zone, it generates a significant zero-sequence current on the line through electromagnetic coupling, which can be used for parameter estimation. Specifically, based on the electrical quantity data measured during normal operation of the first line and the known parameters of the first line, a set of parametric equations corresponding to the second line when an external fault occurs can be established based on a single-segment π-type lumped parameter model and Kirchhoff's voltage and current laws. The set of parametric equations corresponding to the second line may include the zero-sequence impedance matrix, zero-sequence admittance matrix, etc., for solving for the zero-sequence parameters in the second line and the zero-sequence mutual parameters between the two lines. In this way, given the self-parameters of one line, the zero-sequence impedance and zero-sequence admittance of the other AC transmission line on the same tower, as well as the zero-sequence mutual impedance and mutual admittance between the two lines, can be determined using electrical quantity data recording, facilitating line maintenance.

[0067] Optionally, step 104 may specifically include: constructing an objective function by using the residual between the actual measured values ​​of the double-circuit transmission line on the same tower in the phasor domain and the predicted values ​​of the parametric equations; and using the set of solution parameters corresponding to the minimum value of the objective function as the estimated values ​​of the line parameters.

[0068] In some embodiments, the zero-sequence parameters in the second circuit and the zero-sequence cross-parameters between the two circuits can be established using Kirchhoff's voltage and current laws to create a set of parametric equations. An objective function is constructed using the residuals between the actual measured values ​​in the phasor domain and the set of parametric equations obtained through a single-segment π-type lumped parameter model. J It can be represented as:

[0069] ;

[0070] In the formula, for , For a diagonal matrix, its diagonal elements These are normalization parameters; for This can represent the zero-sequence impedance of the second circuit and the zero-sequence mutual impedance between the two circuits. for , can represent the zero-sequence admittance of the second circuit and the zero-sequence cross-admittance between the two circuits; , , and These are the phasor domain zero-sequence voltage measurements at the transmitting end of the two lines, the phasor domain zero-sequence current measurements at the transmitting end of the two lines, the phasor domain zero-sequence voltage measurements at the receiving end of the two lines, and the phasor domain zero-sequence current measurements at the receiving end of the two lines, respectively. and These represent the zero-sequence impedance and zero-sequence admittance, respectively. for , for ,in and The zero-sequence impedance and zero-sequence admittance of the first circuit that has been put into operation are both known quantities; Denotes the zero-sequence impedance matrix of unit length, where This represents a zero-sequence resistance matrix of unit length. Represents the zero-sequence inductance matrix per unit length; Let represent a unit-length zero-order admittance matrix, where This represents the zero-sequence conductance matrix per unit length. Represents a zero-sequence capacitance matrix of unit length; This is the total length of the line.

[0071] Correspondingly, we can look for ways to make the objective function Minimum parameter and The most suitable parameters are used as the estimated values ​​of the line parameters.

[0072] Optionally, the solution parameter set corresponding to the minimum value of the objective function can be used as the estimated value of the line parameters. Specifically, this may include: constructing a particle swarm corresponding to the parameter set based on the preset particle swarm optimization algorithm corresponding to the objective function and the parameters to be identified in the parameter set, where the positions of the particles in the particle swarm correspond to the parameters to be identified in the parameter set; updating the positions of the particles according to the fitness of the particle positions and the preset update rules of the particles, obtaining the global optimal position corresponding to the parameter set, and using it as the solution parameter set corresponding to the minimum value of the objective function.

[0073] In some embodiments, the preset particle swarm optimization algorithm can be an improved particle swarm optimization algorithm, which adapts the velocity and position of particles through nonlinear weights and combines Gaussian variation to solve for the global optimal position corresponding to the parameter set, thereby optimizing the solution process of the parameter set corresponding to the minimum value of the objective function.

[0074] Optionally, based on the fitness of the particle's position and a preset update rule, the particle's position is updated to obtain the globally optimal position corresponding to the parameter set, which serves as the solution parameter set for the minimum objective function. Specifically, this may include: during the particle's position update process, determining the nonlinear inertia weight corresponding to the particle based on the particle's iteration count; determining a preset update rule based on the nonlinear inertia weight and the particle's average fitness; obtaining the updated position of the particle based on the preset update rule; and determining the globally optimal position corresponding to the parameter set based on the fitness of the updated position of the particle, which serves as the solution parameter set for the minimum objective function.

[0075] The number of iterations for a particle can include the maximum number of iterations, the current number of iterations, etc. For example, the nonlinear inertia weight can be calculated iteratively in each iteration to update the particle position.

[0076] Optionally, the global optimal position is subjected to mutation processing based on a preset Gaussian mutation probability, and the solution parameter set is determined based on the fitness of the global optimal position after mutation and the fitness of the global optimal position before mutation.

[0077] For example, such as Figure 3The diagram shows the flowchart of the improved particle swarm optimization algorithm. First, the current particle fitness corresponding to the current iteration number is obtained, and the ratio of the current particle fitness to the average particle fitness is calculated. This ratio is then compared with the average particle fitness. If the ratio is equal, the particle's position and velocity are updated according to a preset particle adaptive algorithm. If not, the position and velocity are updated according to the traditional particle algorithm. After updating, the particle fitness is calculated, and the particle's optimal position and global optimal position are updated. Then, with a preset Gaussian mutation probability, a Gaussian mutation is performed on the global optimal position. It is determined whether the global optimal position is better after the Gaussian mutation. If it is better, the global optimal position is updated. If not, the iteration continues until the maximum number of iterations or the global optimum is reached.

[0078] Specifically, we can first set the particle swarm size to M, and the maximum number of iterations to... , Represents particles Location, , to Here are the parameters that need to be solved in the parameter set. D represents the number of parameters that need to be identified. Each particle's position corresponds to a set of parameters that need to be identified. The quality of particle position i is determined by the particle's position. fitness corresponding to location To evaluate;

[0079] At the initial moment, generate the positions and velocities of M particles within a given boundary, and calculate the fitness of each particle. Set the initial optimal position for each particle. This yields the global optimal position of the particle swarm. ;

[0080] In each iteration, the nonlinear inertia weight corresponding to the particle is first calculated. The formula for calculating nonlinear inertia weight is as follows:

[0081] ;

[0082] In the formula, r ( t +1) is the definition of the Logistic mapping. w ( t +1) represents the inertia weight. Iterative, and These are the preset maximum and minimum inertia weight values, respectively. The maximum number of iterations, t This represents the current iteration number.

[0083] Then, the preset update rules for particle velocity and position can be expressed as:

[0084] ;

[0085] In the formula, Where is the particle's velocity, and w is the coefficient of inertia. and As a learning factor, and A random number between 0 and 1. This is the ratio of the current particle fitness to the average particle fitness. The average fitness of the particles.

[0086] Next, the fitness of the particle's new position is calculated, and the particle's historical best position is updated. and global optimal position Finally, for the global optimum generated in each iteration, The probability of performing a Gaussian mutation, Given a pre-defined Gaussian mutation probability, the globally optimal position after the mutation can be represented as:

[0087] ;

[0088] In the formula, This is the current globally optimal position. This represents the globally optimal position after the mutation. The coefficient of variation; and The boundary condition for the particle's position has a dimension of D; The symbol represents the element-wise multiplication of two matrices along their dimensions; Let be a matrix of random variables of dimension D that follows a normal distribution. If the fitness of the global optimum position after the mutation is better than that of the global optimum position before the mutation, then the new global optimum position is the position after the mutation, and the solution parameter set corresponding to the minimum value of the objective function is determined based on this position; otherwise, the position before the mutation is kept unchanged.

[0089] As one possible implementation method, such as Figure 4As shown, firstly, a suitable parameter set can be selected, then the physical laws of the single-segment π-lumped parameter model can be established, an optimization objective function can be constructed, and then the optimal parameters can be estimated by solving the improved particle swarm optimization (PSO) algorithm. For example, the single-segment π-lumped parameter model can be used to model and estimate the parameters of a double-circuit AC transmission line on the same tower. This system is a 500kV system with a total transmission line length of 80km. A single-phase ground fault occurs 30km away from this line, and the fault occurs at 0.5 seconds. Solving for the parameter set (such as...) ... , , , , The corresponding units, measured values, estimated values, and relative errors are shown in Table 1.

[0090] Table 1

[0091]

[0092] Compared with related technologies, this embodiment can combine the tower structure characteristics of the double-circuit transmission line on the same tower to determine the equivalent mutual parameters and equivalent self-parameters of the line parameters corresponding to the double-circuit transmission line on the same tower, construct a parameter set, realize the simplification of line parameters and selection of parameter set, and when an external fault occurs, use the double-end measuring device of the double-circuit transmission line on the same tower to collect electrical quantity data during line operation, and combine the electrical quantity data and the known parameters of the first circuit to establish a set of parametric equations based on a single-segment π-type lumped parameter model. By constructing an objective function and introducing an improved pre-defined particle swarm optimization algorithm, the global optimal position corresponding to the parameter set is obtained based on the fitness of the particle's position and the pre-defined update rule of the particle. This position serves as the estimated value of the line parameters. During the particle position update process, the nonlinear inertial weight corresponding to the particle is determined based on the number of iterations. The global optimal position is then subjected to variation processing based on a pre-defined Gaussian variation probability, realizing nonlinear weight adaptation and Gaussian variation mechanism. The optimal parameter set is iteratively solved, thereby achieving parameter estimation of key parameters such as zero-sequence impedance and zero-sequence admittance of the line. This effectively overcomes the limitations of traditional reliance on power outage tests and manual measurements, improves the accuracy of parameter estimation, and provides support for the safe and stable operation of the smart grid.

[0093] Furthermore, embodiments of this application provide a parameter estimation device for a double-circuit transmission line on the same tower based on parameter set selection, such as... Figure 5 As shown, the device includes: an acquisition module 31, a determination module 32, and an estimation module 33.

[0094] The acquisition module 31 is configured to acquire the line parameters corresponding to the double-circuit transmission line on the same tower;

[0095] The determination module 32 is configured to determine the equivalent independent parameters and equivalent mutual parameters corresponding to the line parameters based on the tower structure characteristics of the double-circuit transmission line on the same tower, and obtain the parameter set corresponding to the equivalent independent parameters and equivalent mutual parameters;

[0096] The acquisition module 31 is configured to acquire electrical quantity data corresponding to the double-circuit transmission line on the same tower in response to an external fault occurring on the double-circuit transmission line on the same tower.

[0097] The estimation module 33 is configured to estimate the line parameter estimates corresponding to the line parameters based on the objective function and electrical quantity data corresponding to the parameter set. The line parameter estimates are used for line maintenance of double-circuit transmission lines on the same tower. The objective function is used to solve for the zero-sequence parameters of the newly built second circuit in the double-circuit transmission line on the same tower based on the zero-sequence parameters of the first circuit in the double-circuit transmission line that is put into operation.

[0098] In some embodiments, the acquisition module 31 is further configured to establish a single-segment π-type lumped parameter model for the double-circuit transmission line on the same tower; acquire electrical quantity data using the double-end measuring device of the double-circuit transmission line on the same tower during operation; and establish a set of parametric equations corresponding to the second circuit when an external fault occurs based on the electrical quantity data and the known parameters of the first circuit, using the single-segment π-type lumped parameter model.

[0099] In some embodiments, the estimation module 33 is specifically configured to construct an objective function by using the residual between the actual measured values ​​of the double-circuit transmission line on the same tower in the phasor domain and the predicted values ​​of the parametric equation set; and to use the set of solution parameters corresponding to the minimum value of the objective function as the estimated values ​​of the line parameters.

[0100] In some embodiments, the estimation module 33 is specifically configured to construct a particle swarm corresponding to the parameter set based on a preset particle swarm optimization algorithm corresponding to the objective function and the parameters to be identified in the parameter set, wherein the positions of the particles in the particle swarm correspond to the parameters to be identified in the parameter set; update the positions of the particles according to the fitness of the particle positions and the preset update rules of the particles, and obtain the global optimal position corresponding to the parameter set as the solution parameter set corresponding to the minimum value of the objective function.

[0101] In some embodiments, the estimation module 33 is specifically configured to, during the update process of the particle's position, determine the nonlinear inertia weight corresponding to the particle based on the number of iterations of the particle; determine a preset update rule based on the nonlinear inertia weight and the average fitness of the particle; obtain the updated position of the particle based on the preset update rule; and determine the global optimal position corresponding to the parameter set based on the fitness corresponding to the updated position of the particle, as the solution parameter set corresponding to the minimum value of the objective function.

[0102] In some embodiments, the estimation module 33 is further configured to perform mutation processing on the global optimal position based on a preset Gaussian mutation probability, and determine the solution parameter set based on the fitness of the global optimal position after mutation and the fitness of the global optimal position before mutation.

[0103] In some embodiments, the determining module 32 is specifically configured to determine, based on the tower structure characteristics of the double-circuit transmission line on the same tower, the parameter equivalence conditions within the double-circuit transmission line on the same tower and the parameter equivalence conditions between double-circuit transmission lines on the same tower. The parameter equivalence conditions within the double-circuit transmission line on the same tower include the equality of self-parameters and the equality of mutual parameters within the same circuit. The parameter equivalence conditions between double-circuit transmission lines on the same tower include the equality of mutual parameters and the inequality of self-parameters between double-circuit transmission lines on the same tower. Based on the parameter equivalence conditions within the double-circuit transmission line on the same tower and the parameter equivalence conditions between double-circuit transmission lines on the same tower, the equivalent self-parameters and equivalent mutual parameters corresponding to the line parameters are determined.

[0104] It should be noted that other corresponding descriptions of the functional units involved in the parameter estimation device for a double-circuit transmission line on the same tower based on parameter set selection provided in this application embodiment can be found in the following references. Figure 1 The corresponding description in [the document] will not be repeated here.

[0105] Based on the above, Figure 1 As illustrated in the example, correspondingly, embodiments of this application also provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described... Figure 1 The example method shown.

[0106] Based on the above, Figure 1 As illustrated, correspondingly, embodiments of this application also provide a computer program product, including a computer program that, when executed by a processor, implements the above-described... Figure 1 The example method shown.

[0107] Based on this understanding, the technical solutions of the embodiments of this application can be embodied in the form of a software product. The software product can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, mobile hard drive, etc.) and includes several instructions to cause a computer device (such as a personal computer, server, or network device, etc.) to execute the methods of various implementation scenarios of this application.

[0108] Based on the above, Figure 1 The method shown, and Figure 5To achieve the above objectives, the present application also provides an electronic device, comprising a storage medium and a processor; the storage medium for storing a computer program; and the processor for executing the computer program to implement the above-described virtual device embodiments. Figure 1 The method shown.

[0109] Optionally, the aforementioned electronic device may also include a user interface, a network interface, a camera, radio frequency (RF) circuitry, sensors, audio circuitry, a Wi-Fi module, etc. The user interface may include a display screen, an input unit, etc.

[0110] Those skilled in the art will understand that the physical device structure provided in this embodiment does not constitute a limitation on the physical device, and may include more or fewer components, or combine certain components, or have different component arrangements.

[0111] The storage medium may also include an operating system and a network communication module. The operating system is a program that manages the hardware and software resources of the aforementioned physical device, supporting the operation of information processing programs and other software and / or programs. The network communication module is used to enable communication between the various components within the storage medium, as well as communication with other hardware and software in the information processing physical device.

[0112] Through the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware platforms, or it can be implemented by hardware. Compared with related technologies, this application can combine the tower structural characteristics of the double-circuit transmission line on the same tower to determine the equivalent mutual parameters and equivalent self-parameters of the line parameters corresponding to the double-circuit transmission line on the same tower, construct a parameter set, realize the simplification of line parameters and the selection of parameter set, and when an external fault occurs, use the double-end measuring device of the double-circuit transmission line on the same tower to collect electrical quantity data during line operation, and combine the electrical quantity data and the known parameters of the first circuit to establish a set of parametric equations based on a single-segment π-type lumped parameter model. By constructing an objective function and introducing an improved pre-defined particle swarm optimization algorithm, the global optimal position corresponding to the parameter set is obtained based on the fitness of the particle's position and the pre-defined update rule of the particle. This position serves as the estimated value of the line parameters. During the particle position update process, the nonlinear inertial weight corresponding to the particle is determined based on the number of iterations. The global optimal position is then subjected to variation processing based on a pre-defined Gaussian variation probability, realizing nonlinear weight adaptation and Gaussian variation mechanism. The optimal parameter set is iteratively solved, thereby achieving parameter estimation of key parameters such as zero-sequence impedance and zero-sequence admittance of the line. This effectively overcomes the limitations of traditional reliance on power outage tests and manual measurements, improves the accuracy of parameter estimation, and provides support for the safe and stable operation of the smart grid.

[0113] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variations thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0114] The above are merely specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to these embodiments, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A parameter estimation method for a double-circuit transmission line on the same tower based on parameter set selection, characterized in that, include: Obtain the line parameters corresponding to a double-circuit transmission line on the same tower; Based on the tower structure characteristics of the double-circuit transmission line on the same tower, determine the equivalent independent parameters and equivalent mutual parameters corresponding to the line parameters, and obtain the parameter set corresponding to the equivalent independent parameters and equivalent mutual parameters; In response to an external fault occurring on the double-circuit transmission line on the same tower, electrical quantity data during the operation of the double-circuit transmission line on the same tower are acquired; Based on the objective function corresponding to the parameter set and the electrical quantity data, the estimated values ​​of the line parameters are estimated. The estimated values ​​of the line parameters are used for line maintenance of the double-circuit transmission line on the same tower. The objective function is used to solve for the zero-sequence parameters of the newly built second circuit in the double-circuit transmission line on the same tower based on the zero-sequence parameters of the first circuit in operation of the double-circuit transmission line on the same tower.

2. The method according to claim 1, characterized in that, Before estimating the estimated line parameters corresponding to the line parameters based on the objective function corresponding to the parameter set and the electrical quantity data, the method further includes: A single-segment π-type lumped parameter model is established for the aforementioned double-circuit transmission line on the same tower; During the operation of the double-circuit transmission line on the same tower, the electrical quantity data are obtained using the double-ended measuring device of the double-circuit transmission line on the same tower; Based on the electrical quantity data and the known parameters of the first circuit, a set of parametric equations corresponding to the second circuit when the external fault occurs is established based on the single-segment π-type lumped parameter model.

3. The method according to claim 2, characterized in that, The step of estimating the estimated line parameters corresponding to the line parameters based on the objective function corresponding to the parameter set and the electrical quantity data includes: The objective function is constructed by the residual between the actual measured values ​​of the double-circuit transmission line on the same tower in the phasor domain and the predicted values ​​of the parametric equations. The set of parameters corresponding to the minimum value of the objective function is used as the estimated value of the line parameters.

4. The method according to claim 3, characterized in that, The step of using the set of parameters corresponding to the minimum value of the objective function as the estimated values ​​of the line parameters includes: Based on the preset particle swarm optimization algorithm corresponding to the objective function and the parameters that need to be identified in the parameter set, a particle swarm corresponding to the parameter set is constructed, and the positions of the particles in the particle swarm correspond to the parameters that need to be identified in the parameter set. Based on the fitness of the particle's position and the preset update rule of the particle, the position of the particle is updated, and the global optimal position corresponding to the parameter set is obtained as the solution parameter set corresponding to the minimum value of the objective function.

5. The method according to claim 4, characterized in that, The step of updating the particle's position based on its fitness and a preset update rule, and obtaining the globally optimal position corresponding to the parameter set, as the solution parameter set corresponding to the minimum value of the objective function, includes: During the update of the particle's position, the nonlinear inertial weight corresponding to the particle is determined based on the number of iterations of the particle; The preset update rule is determined based on the nonlinear inertia weight and the average fitness of the particles; The updated position of the particle is obtained based on the preset update rule, and the global optimal position corresponding to the parameter set is determined according to the fitness of the updated position of the particle, which is used as the solution parameter set corresponding to the minimum value of the objective function.

6. The method according to claim 5, characterized in that, The method further includes: The global optimal position is subjected to mutation processing based on a preset Gaussian mutation probability. The solution parameter set is determined based on the fitness of the global optimal position after mutation and the fitness of the global optimal position before mutation.

7. The method according to claim 1, characterized in that, The step of determining the equivalent independent parameters and equivalent mutual parameters corresponding to the line parameters based on the tower structural characteristics of the double-circuit transmission line on the same tower includes: Based on the tower structure characteristics of the double-circuit transmission line on the same tower, the parameter equivalence conditions within the double-circuit transmission line on the same tower and the parameter equivalence conditions between the double-circuit transmission lines on the same tower are determined. The parameter equivalence conditions within the double-circuit transmission line on the same tower include the equality of self-parameters and the equality of mutual parameters within the same circuit. The parameter equivalence conditions between the double-circuit transmission lines on the same tower include the equality of mutual parameters and the inequality of self-parameters between the double-circuit transmission lines on the same tower. Based on the parameter equivalence conditions within the double-circuit transmission line on the same tower and the parameter equivalence conditions between the double-circuit transmission lines on the same tower, the equivalent self-parameters and equivalent mutual parameters corresponding to the line parameters are determined.

8. A parameter estimation device for a double-circuit transmission line on the same tower based on parameter set selection, characterized in that, include: The acquisition module is configured to acquire the line parameters corresponding to the double-circuit transmission line on the same tower. The determination module is configured to determine the equivalent independent parameters and equivalent mutual parameters corresponding to the line parameters based on the tower structure characteristics of the double-circuit transmission line on the same tower, and obtain the parameter set corresponding to the equivalent independent parameters and equivalent mutual parameters; The acquisition module is configured to acquire electrical quantity data of the double-circuit transmission line on the same tower during operation in response to an external fault occurring on the double-circuit transmission line on the same tower. The estimation module is configured to estimate the line parameter estimates corresponding to the line parameters based on the objective function corresponding to the parameter set and the electrical quantity data. The line parameter estimates are used for line maintenance of the double-circuit transmission line on the same tower. The objective function is used to solve for the zero-sequence parameters of the newly built second circuit in the double-circuit transmission line on the same tower based on the zero-sequence parameters of the first circuit in operation of the double-circuit transmission line on the same tower.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1 to 7.

10. An electronic device comprising a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method of any one of claims 1 to 7.

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