Transient voltage and current calculation method and device for suspended conductor in direct current ion flow field

Abstract

The invention discloses a transient voltage and current calculation method and device for a suspended conductor in a direct current ion flow field. The method comprises the following steps: according to a relative position relationship between an overhead line and a suspended conductor in a direct-current transmission line, establishing a mathematical model of the direct-current transmission line and the suspended conductor and a field equation and boundary conditions of the direct-current transmission line and the suspended conductor; solving the mathematical model according to the field domain equation and the boundary condition, and determining self-capacitance, mutual capacitance, self-conductance and mutual conductance between the power transmission line per unit length and the suspended conductor; calculating a capacitance parameter and a conductivity parameter according to the self-capacitance, the mutual capacitance, the self-conductance, the mutual conductance and the length of the power transmission line; assigning the capacitance parameter and the conductivity parameter to a pre-established ion flow field equivalent circuit model between the power transmission line and the suspended conductor, and determining an assignment equivalent circuit model of the DC line and the suspended conductor; and according to the switching operation of the suspended conductor, solving by using the assignment equivalent circuit model, and determining the transient voltage and the transient current under the switching operation.

Description

Technical Field

[0001] The present invention relates to the technical field of transient voltage and current calculation of direct current transmission lines, and more specifically, to a method and device for calculating transient voltage and current of a suspended conductor in a direct current ion flow field. Background Art

[0002] In order to achieve carbon peak and carbon neutrality, my country is accelerating the construction of ultra-high voltage transmission projects. The country has planned and built 24 ultra-high voltage lines and 14 direct lines to effectively solve the problem of high-proportion renewable energy grid connection and large-scale cross-provincial and cross-regional deployment in my country, and fully support energy transformation.

[0003] The problem of induced voltage near DC transmission lines has always been the focus of attention of the power sector and the environmental protection department. Affected by the induced voltage, the suspended conductors near the transmission lines may have transient electric shock problems, affecting the work and life of residents. On the other hand, natural disasters such as cold waves and freezing rain are showing an explosive upward trend. Both the transmission line conductors and the ground wires will suffer from ice disasters. The transmission conductors can resist the icing of some lines due to the heat energy generated by the current flow, while the ice coverage of the ground wires without current flow will exceed that of the conductors. In addition, the ground wire has a lower breaking force than the transmission wire, and is more likely to break when it is damaged by ice. Therefore, the research on ice melting technology for ground wires is more urgent. At present, the ground wire is usually melted by power outage to ensure safety during the ice melting process. However, power outages will cause insufficient load supply and cause certain economic losses. In order to ensure power supply while melting ice, the method of melting ice without power outage can be adopted, but this will generate induced voltage and induced current on the ground wire and the ice melting device, affecting the switch operation during the ice melting process.

[0004] Due to the influence of space charge, the difficulty of calculating the induced voltage and induced current of the suspended conductor increases significantly. The existing method can only calculate the induced voltage problem after steady state, but cannot calculate the transient induced voltage and induced current. As a result, the parameters of the transient electric shock induced voltage and ice melting device mentioned above are mostly derived from experience, and the design lacks theoretical basis. Therefore, it is necessary to propose a calculation method for the transient voltage and current of the suspended conductor near the DC transmission line taking into account the ion flow field to provide technical support for solving the above problems. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a method and device for calculating the transient voltage and current of a suspended conductor in a DC ion flow field.

[0006] According to one aspect of the present invention, a method for calculating transient voltage and current of a suspended conductor in a DC ion flow field is provided, comprising:

[0007] According to the relative position relationship between overhead line and suspended conductor in DC transmission line, the mathematical model of DC line and suspended conductor as well as its field equations and boundary conditions are established;

[0008] The mathematical model is solved according to the field equations and boundary conditions to determine the self-capacitance, mutual capacitance, self-conductance and mutual conductance between the transmission line and the suspended conductor per unit length;

[0009] Calculate capacitance parameters and conductance parameters based on self-capacitance, mutual capacitance, self-conductance, mutual conductance and transmission line length;

[0010] Assign capacitance parameters and conductance parameters to the pre-established ion flow field equivalent circuit model between the transmission line and the suspended conductor, and determine the assigned equivalent circuit model of the DC line and the suspended conductor;

[0011] According to the switching operation of the suspended conductor, the assignment equivalent circuit model is used to solve and determine the transient voltage and transient current under the switching operation.

[0012] Optionally, a mathematical model is solved according to field equations and boundary conditions to determine the self-capacitance, mutual capacitance, self-conductance and mutual conductance between the transmission line and the suspended conductor per unit length, including:

[0013] According to the field equations and boundary conditions, the mathematical model is solved based on the partial capacitance solution method to determine the potential coefficient matrix between the transmission line and the suspended conductor. Based on the potential coefficient matrix, the self-capacitance and mutual capacitance between the transmission line and the suspended conductor per unit length are calculated.

[0014] According to the field equations and boundary conditions, the upflow finite element method is used to solve the electric field and ion distribution of the mathematical model, and the ion distribution characteristics of the suspended conductor after the field is stable are calculated by combining the estimation verification method;

[0015] Based on the ion distribution characteristics, the electrostatic analogy method is used to solve the conductivity matrix between the transmission line and the suspended conductor. According to the conductivity matrix, the self-conductance and mutual conductance between the transmission line and the suspended conductor per unit length are calculated.

[0016] Optionally, according to the field equations and boundary conditions, the mathematical model is solved based on the partial capacitance solution method to determine the potential coefficient matrix between the transmission line and the suspended conductor, and the self-capacitance and mutual capacitance between the transmission line per unit length and the suspended conductor are calculated based on the potential coefficient matrix, including:

[0017] According to the relative position relationship and permittivity of the transmission line and the suspended conductor, the potential value is established. The coefficient relationship with charge [q] Where [α] is the first potential coefficient matrix;

[0018] The first potential coefficient matrix [α] is inverted to obtain the capacitance coefficient matrix [β] = [α] -1 ;

[0019] According to the capacitance coefficient matrix, determine the unit length capacitance matrix [C];

[0020] The self-capacitance and mutual capacitance between the unit length transmission line and the suspended conductor are calculated based on the unit length capacitance matrix [C].

[0021] Alternatively, the expression for self capacitance is:

[0022]

[0023] The expression for mutual capacitance is:

[0024] C ij =-β ij

[0025] Where n is the number of transmission line poles and the total number of suspended conductors; the [α], [β], and [C] matrices are all n×n.

[0026] Optionally, according to the field equations and boundary conditions, the upstream finite element method is used to solve the electric field and ion distribution of the mathematical model, and the ion distribution characteristics of the suspended conductor after the field is stable are calculated in combination with the estimation verification method, including:

[0027] Step 1: Estimate the potential value U0 of the suspended conductor, and use the upstream finite element method to solve the electric field and ion distribution of the mathematical model according to the field equation and boundary conditions to obtain the electric field intensity on the surface of the suspended conductor;

[0028] Step 2: Based on the electric field strength on the surface of the suspended conductor, the relationship between ion flow and electric field strength is J = (ρ + k + +ρ - k - )E, solve the current density distribution on the surface of the suspended conductor, and integrate the current density along the boundary of the suspended conductor to solve the net current value I0 injected into the suspended conductor; if I0>10 -11 A, then proceed to step 3, otherwise go to step 4;

[0029] Step 3: According to the current value I0 injected into the suspended conductor, use the formula U0'=U0+I0×10 11 Update the potential value of the suspended conductor and return to step 1;

[0030] Step 4: Record the potential value of the suspended conductor and the ion distribution characteristics in the field.

[0031] Where J is the ion current density vector; E is the electric field strength vector; ρ + ,- are the positive and negative space charge densities, respectively; k + , k - are the mobility of positive and negative ions, respectively.

[0032] Optionally, based on the ion distribution characteristics, an electrostatic analogy method is used to solve the conductivity matrix between the transmission line and the suspended conductor, and the self-conductance and mutual conductance between the transmission line per unit length and the suspended conductor are calculated according to the conductivity matrix, including:

[0033] Based on the ion distribution characteristics, the equivalent conductivity of the ion flow field γ = ρ is solved + k + +ρ - k - The distribution characteristics of

[0034] Using the electrostatic analogy method, the permittivity is set to the equivalent conductivity γ of the ion flow field in the finite element software;

[0035] According to the relative position relationship between the transmission line and the suspended conductor and the permittivity set as the equivalent conductivity of the ion flow field, the second potential coefficient matrix [α'] is solved by the finite element method.

[0036] The second potential coefficient matrix [α'] is inverted to obtain the conductivity coefficient matrix [β'] = [α'] -1 ;

[0037] According to the conductivity matrix [β'], calculate the unit length capacitance matrix [σ];

[0038] According to the unit length capacitance matrix [σ], the self-conductance and mutual conductance between the unit length transmission line and the suspended conductor are determined.

[0039] Alternatively, the expression for the autoconductance is:

[0040]

[0041] The expression of mutual conductance is:

[0042] σ ij =-β' ij

[0043] According to another aspect of the present invention, there is provided a transient voltage and current calculation device for a suspended conductor in a DC ion flow field, comprising:

[0044] Establishing a module for establishing a mathematical model of a DC line and a suspended conductor and its field equations and boundary conditions according to the relative position relationship between the overhead line and the suspended conductor in the DC transmission line;

[0045] The first solving module is used to solve the mathematical model according to the field equations and boundary conditions to determine the self-capacitance, mutual capacitance, self-conductance and mutual conductance between the transmission line per unit length and the suspended conductor;

[0046] A calculation module, used for calculating capacitance parameters and conductance parameters according to self-capacitance, mutual capacitance, self-conductance, mutual conductance and transmission line length;

[0047] An assignment module is used to assign capacitance parameters and conductance parameters to a pre-established ion flow field equivalent circuit model between a transmission line and a suspended conductor, and determine an assignment equivalent circuit model of a DC line and a suspended conductor;

[0048] The second solution module is used to solve the switching operation of the suspended conductor by using the assigned equivalent circuit model to determine the transient voltage and transient current under the switching operation.

[0049] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the storage medium stores a computer program, and the computer program is used to execute the method described in any one of the above aspects of the present invention.

[0050] According to another aspect of the present invention, an electronic device is provided, comprising: a processor; a memory for storing instructions executable by the processor; the processor is configured to read the executable instructions from the memory and execute the instructions to implement the method described in any one of the above aspects of the present invention.

[0051] Therefore, the present invention provides a method for calculating transient voltage and current of a suspended conductor near a DC transmission line based on a field-circuit coupling model, which meets the requirements of parameter design of ice melting devices in the process of induced electricity and ground wire ice melting. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0053] Figure 1 It is a flow chart of a method for calculating transient voltage and current of a suspended conductor in a DC ion flow field provided by an exemplary embodiment of the present invention;

[0054] Figure 2 It is a schematic diagram of a flow chart of calculating the induced voltage and ion distribution characteristics of a suspended conductor after the field is in steady state provided by an exemplary embodiment of the present invention;

[0055] Figure 3 is a schematic diagram of an example computing object provided by an exemplary embodiment of the present invention;

[0056] Figure 4is a diagram of iterative calculation results of net injected current and suspension voltage of a suspended conductor provided by an exemplary embodiment of the present invention;

[0057] Figure 5 is an equivalent conductivity distribution diagram in a field provided by an exemplary embodiment of the present invention;

[0058] Figure 6 is a diagram of transient current and transient voltage calculation results provided by an exemplary embodiment of the present invention;

[0059] Figure 7 It is a schematic structural diagram of a transient voltage and current calculation device for a suspended conductor in a DC ion flow field provided by an exemplary embodiment of the present invention;

[0060] Figure 8 This is a structure of an electronic device provided by an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0061] Below, the exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments of the present invention, and it should be understood that the present invention is not limited to the exemplary embodiments described here.

[0062] It should be noted that the relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

[0063] Those skilled in the art can understand that the terms "first" and "second" in the embodiments of the present invention are only used to distinguish different steps, devices or modules, etc., and neither represent any specific technical meaning nor indicate the necessary logical order between them.

[0064] It should also be understood that, in the embodiments of the present invention, “plurality” may refer to two or more than two, and “at least one” may refer to one, two or more than two.

[0065] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more, unless explicitly limited or otherwise indicated in the context.

[0066] In addition, the term "and / or" in the present invention is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects before and after are in an "or" relationship.

[0067] It should also be understood that the description of the various embodiments of the present invention focuses on the differences between the various embodiments, and the same or similar aspects thereof can be referenced to each other, and for the sake of brevity, they will not be described one by one.

[0068] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0069] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0070] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0071] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0072] Embodiments of the present invention can be applied to electronic devices such as terminal devices, computer systems, servers, etc., which can operate with many other general or special computing system environments or configurations. Examples of well-known terminal devices, computing systems, environments and / or configurations suitable for use with electronic devices such as terminal devices, computer systems, servers, etc. include, but are not limited to: personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, network personal computers, small computer systems, large computer systems, and distributed cloud computing technology environments including any of the above systems, etc.

[0073] Electronic devices such as terminal devices, computer systems, servers, etc. can be described in the general context of computer system executable instructions (such as program modules) executed by computer systems. Generally, program modules can include routines, programs, object programs, components, logic, data structures, etc., which perform specific tasks or implement specific abstract data types. Computer systems / servers can be implemented in a distributed cloud computing environment, where tasks are performed by remote processing devices linked through a communication network. In a distributed cloud computing environment, program modules can be located on local or remote computing system storage media including storage devices.

[0074] Exemplary Methods

[0075] Figure 1FIG. 1 is a flow chart of a method for calculating transient voltage and current of a suspended conductor in a DC ion flow field provided by an exemplary embodiment of the present invention. This embodiment can be applied to electronic devices, such as Figure 1 As shown, the method 100 for calculating transient voltage and current of a suspended conductor in a DC ion flow field includes the following steps:

[0076] Step 101, establishing a mathematical model of the DC line and the suspended conductor and its field equations and boundary conditions according to the relative position relationship between the overhead line and the suspended conductor in the DC transmission line;

[0077] Step 102, solving the mathematical model according to the field equations and boundary conditions to determine the self-capacitance, mutual capacitance, self-conductance and mutual conductance between the transmission line per unit length and the suspended conductor;

[0078] Step 103, calculating capacitance parameters and conductance parameters according to self-capacitance, mutual capacitance, self-conductance, mutual conductance and transmission line length;

[0079] Step 104, assigning capacitance parameters and conductance parameters to a pre-established ion flow field equivalent circuit model between the transmission line and the suspended conductor, and determining an assigned equivalent circuit model of the DC line and the suspended conductor;

[0080] Step 105 , according to the switching operation of the suspended conductor, the assignment equivalent circuit model is used to solve and determine the transient voltage and transient current under the switching operation.

[0081] Specifically, for the induced voltage problem of suspended conductors near DC transmission lines, the existing methods can only calculate the steady-state situation, but cannot calculate the transient induced voltage and induced current. The present invention provides a method for calculating the transient voltage and current of suspended conductors near DC transmission lines based on a field-circuit coupling model to meet the requirements of parameter design of ice melting devices during induced electricity and ground wire ice melting. The implementation process of the technical solution of the present invention is as follows:

[0082] A method for calculating transient voltage and current of a suspended conductor in a DC ion flow field, in particular a method for calculating transient voltage and current of a suspended conductor near a DC transmission line based on a field-circuit coupling model, comprising the following steps:

[0083] Step 1: According to the relative position relationship between the overhead line and the suspended conductor, a mathematical model of the DC overhead line and the suspended conductor is established, and the field equations and boundary conditions are given.

[0084] Step 2: Use the upstream finite element method to solve the electric field and ion distribution, and combine it with the prediction verification method to calculate the induced voltage and ion distribution characteristics of the suspended conductor after the field is stable.

[0085] Step 3: Based on the partial capacitance solution method, the potential coefficient matrix between the transmission line and the suspended conductor is solved, and the self-capacitance and mutual capacitance between the transmission line and the suspended conductor per unit length are calculated based on the potential coefficient matrix.

[0086] Step 4: Based on the ion distribution characteristics of step 2, the electrostatic analogy method is used to solve the conductivity matrix between the transmission line and the suspended conductor, and based on the conductivity matrix, the self-conductance and mutual conductance between the transmission line per unit length and the suspended conductor are calculated.

[0087] Step 5: Establish an equivalent circuit model of the ion flow field between the transmission line and the suspended conductor, calculate the capacitance and conductance parameters according to the length of the transmission line, and assign the capacitance and conductance in the equivalent circuit model. According to the circuit model when the suspended conductor is switched or contacts other objects, solve the transient voltage and current of the suspended conductor in this process.

[0088] Preferably, reference Figure 2 As shown, in step 2, the induced voltage and ion distribution characteristics of the suspended conductor after the field steady state are calculated by using the upstream finite element method combined with the estimation verification method, including:

[0089] Step 21: Estimate the potential value U0 of the suspended conductor, solve the electric field and ion distribution according to the upstream finite element method, and obtain the electric field intensity on the surface of the suspended conductor.

[0090] Step 22: Based on the electric field strength on the surface of the suspended conductor, the relationship between ion flow and electric field strength is J = (ρ + k + +ρ - k - )E, solve the current density distribution on the surface of the suspended conductor, and integrate the current density along the boundary of the suspended conductor to solve the net current value I0 injected into the suspended conductor. If I0>10 -11 A, then proceed to step 23, otherwise go to step 24.

[0091] Where J is the ion current density vector; E is the electric field strength vector; ρ + , - are the positive and negative space charge densities, respectively; k + , k - are the mobility of positive and negative ions, respectively.

[0092] Step 23: According to the current value I0 injected into the suspended conductor, use the formula U0'=U0+I0×10 11 Update the potential value of the suspended conductor and return to step 21.

[0093] Step 24: Record the potential value of the suspended conductor and the ion distribution characteristics in the field, and solve the equivalent conductivity of the ion flow field γ = ρ + k+ +ρ - k - distribution characteristics.

[0094] Preferably, the method for solving the self-capacitance and mutual capacitance between the transmission line and the suspended conductor in step 3 includes:

[0095] Step 31: Establish the potential value based on the relative position relationship and permittivity of the transmission line and the suspended conductor The coefficient relationship with charge [q] The potential coefficient matrix [α] can be solved using the simulated charge method or the finite element method.

[0096] Step 32: Invert the potential coefficient matrix to obtain the capacitance coefficient matrix [β] = [α] -1 , then the self-capacitance in the capacitance matrix [C] The mutual capacitance C ij =-β ij , the unit length capacitance matrix [C] is calculated.

[0097] Where n is the number of transmission line poles and the total number of suspended conductors; the [α], [β], and [C] matrices are all n×n.

[0098] Preferably, the method for solving the self-conductance and mutual conductance between the transmission line and the suspended conductor in step 4 includes:

[0099] Step 41: Using the electrostatic analogy method, the permittivity is set to the equivalent conductivity γ of the ion flow field in step 2 in the finite element software.

[0100] Step 42: According to the relative position relationship between the transmission line and the suspended conductor and the permittivity set as the equivalent conductivity of the ion flow field, the potential coefficient matrix [α'] is solved by using the finite element method.

[0101] Step 43: Invert the potential coefficient matrix to obtain the conductivity coefficient matrix [β'] = [α'] -1 , then the self-conductance in the conductivity matrix [σ] The mutual capacitance σ ij =-β' ij , the unit length capacitance matrix [σ] is calculated.

[0102] Preferably, the calculation of transient voltage and current of the suspended conductor in step 5 includes:

[0103] Step 51: Establish an equivalent circuit model of the ion flow field between the transmission line and the suspended conductor, calculate the capacitance and conductance parameters according to the length of the transmission line, and assign capacitance and conductance in the equivalent circuit model.

[0104] Step 52: According to the circuit model when the suspended conductor is switched or contacts other objects, the transient voltage and current of the suspended conductor in the process are solved.

[0105] The transient voltage and current calculation method of a suspended conductor in a DC ion flow field provided by the present invention is calculated according to a specific embodiment: a ±500kV double-circuit transmission line on the same tower uses 4 split conductors with a split spacing of 550mm, the conductor model is JL / G1A-900 / 75, the conductor outer diameter is 40.6mm, the single-circuit conductors are arranged up and down, the upper conductor spacing is 18.2m, the lower conductor spacing is 14.5m, the arc sag heights are 35.1m and 20.5m respectively, the DC resistance is 0.03216Ω / km (20℃), the ground wire height is 48.5m, the spacing is 28.4m, the left conductor is in operation, the right conductor is out of service, the No. 6 ground wire is de-iced, No. 2, No. 4 and No. 6 are all suspended conductors, such as Figure 3 The specific steps are:

[0106] 1. Establish the DC overhead line and suspended conductor model, and give the field equations and boundary conditions.

[0107] Field and suspended conductor models such as Figure 3 As shown. The equations satisfied in the field are as follows:

[0108]

[0109] The boundary equation conditions are as follows: the surface potential values ​​of the operating conductors are 500kV and -500kV respectively, the ground potential value is zero, the potential value of the No. 5 ground wire is zero, the No. 2, No. 4 conductors and the No. 6 ground wire are all at floating potential, and the net inflow current is 0.

[0110] 2. Solve the induced voltage and ion distribution characteristics of the suspended conductor after the field stabilizes.

[0111] The initial values ​​of the floating potentials of conductor No. 2, conductor No. 4 and the ground wire are set to -20kV, 20kV and -40kV respectively, and are calculated as the first type of boundary conditions in the upstream finite element method.

[0112] Solve the upstream finite element method to obtain the net injection current of conductor No. 2, conductor No. 4 and ground wire, and correct the suspension potential according to the calculation results. The iterative calculation results of current and suspension voltage are as follows: Figure 4 shown.

[0113] Finally, after meeting the iterative convergence conditions, the steady-state suspension voltages were approximately -53.11 kV (wire No. 2), 55.79 kV (wire No. 4) and -80.59 kV (ground wire No. 6) and ion distribution characteristics; based on the ion distribution characteristics, the equivalent conductivity distribution law in the field was obtained.

[0114] 3. Solution of self-capacitance and mutual capacitance between transmission line and suspended conductor

[0115] According to the relative position relationship between the transmission line and the suspended conductor and the permittivity (air permittivity), the potential value is established The coefficient relationship with charge [q] The potential coefficient matrix [α] is solved using the simulated charge method. There are 6 conductors in total, and the matrices are all 6×6.

[0116] Invert the potential coefficient matrix to obtain the capacitance coefficient matrix [β] = [α] -1 , and then calculate the unit length capacitance matrix [C], the capacitance matrix calculation results are as follows:

[0117]

[0118] 4. Solution of self-conductance and mutual conductance between transmission line and suspended conductor

[0119] Using the electrostatic analogy method, the permittivity is set to the equivalent conductivity γ of the ion flow field in step 2 in the finite element software.

[0120] According to the relative position relationship between the transmission line and the suspended conductor and the permittivity set as the equivalent conductivity of the ion flow field, the potential coefficient matrix [α'] is solved by the finite element method.

[0121] Invert the potential coefficient matrix to obtain the conductivity coefficient matrix [β'] = [α'] -1 , and then calculate the unit length conductivity matrix [σ], the conductivity matrix calculation results are as follows:

[0122]

[0123] 5. Calculation of transient voltage and current of suspended conductor

[0124] First, according to the capacitance matrix and the conductance matrix, the capacitance and resistance of 1000km length are calculated as follows:

[0125]

[0126]

[0127] Then, based on the above results, a circuit model is established in the circuit calculation software.

[0128] During the ice melting process, first connect the No. 2 conductor to the ground wire, and then connect the No. 4 conductor to the ground wire. Use the circuit model to calculate the transient voltage and current during the closing process, such as Figure 6 shown.

[0129] Therefore, the present invention provides a method for calculating transient voltage and current of a suspended conductor near a DC transmission line based on a field-circuit coupling model, which meets the requirements of parameter design of ice melting devices in the process of induced electricity and ground wire ice melting.

[0130] Exemplary Devices

[0131] Figure 7 FIG. 1 is a schematic diagram of a transient voltage and current calculation device for a suspended conductor in a DC ion flow field provided by an exemplary embodiment of the present invention. Figure 7 As shown, the apparatus 700 includes:

[0132] Establishing module 710, for establishing a mathematical model of the DC line and the suspended conductor and its field equations and boundary conditions according to the relative position relationship between the overhead line and the suspended conductor in the DC transmission line;

[0133] A first solving module 720 is used to solve the mathematical model according to the field equations and boundary conditions to determine the self-capacitance, mutual capacitance, self-conductance and mutual conductance between the transmission line and the suspended conductor per unit length;

[0134] A calculation module 730, configured to calculate capacitance parameters and conductance parameters according to self-capacitance, mutual capacitance, self-conductance, mutual conductance and transmission line length;

[0135] The assignment module 740 is used to assign capacitance parameters and conductance parameters to the pre-established ion flow field equivalent circuit model between the transmission line and the suspended conductor, and determine the assigned equivalent circuit model of the DC line and the suspended conductor;

[0136] The second solution module 750 is used to solve the switching operation of the suspended conductor using the assigned equivalent circuit model to determine the transient voltage and transient current under the switching operation.

[0137] Optionally, the first solution module 810 includes:

[0138] The first calculation submodule is used to solve the mathematical model based on the partial capacitance solution method according to the field equations and boundary conditions, determine the potential coefficient matrix between the transmission line and the suspended conductor, and calculate the self-capacitance and mutual capacitance between the transmission line and the suspended conductor per unit length according to the potential coefficient matrix;

[0139] The second calculation submodule is used to solve the electric field and ion distribution of the mathematical model using the upstream finite element method according to the field equations and boundary conditions, and to calculate the ion distribution characteristics of the suspended conductor after the field is stable by combining the estimation verification method;

[0140] The third calculation submodule is used to solve the conductivity matrix between the transmission line and the suspended conductor based on the ion distribution characteristics and the electrostatic analogy method, and calculate the self-conductance and mutual conductance between the transmission line and the suspended conductor per unit length according to the conductivity matrix.

[0141] Optionally, the first computing submodule includes:

[0142] According to the relative position relationship and permittivity of the transmission line and the suspended conductor, the potential value is established. The coefficient relationship with charge [q] Where [α] is the first potential coefficient matrix;

[0143] The first potential coefficient matrix [α] is inverted to obtain the capacitance coefficient matrix [β] = [α] -1 ;

[0144] According to the capacitance coefficient matrix, determine the unit length capacitance matrix [C];

[0145] The self-capacitance and mutual capacitance between the unit length transmission line and the suspended conductor are calculated based on the unit length capacitance matrix [C].

[0146] Alternatively, the expression for self capacitance is:

[0147]

[0148] The expression for mutual capacitance is:

[0149] C ij =-β ij

[0150] Where n is the number of transmission line poles and the total number of suspended conductors; the [α], [β], and [C] matrices are all n×n.

[0151] Optionally, the second computing submodule includes:

[0152] Step 1: Estimate the potential value U0 of the suspended conductor, and use the upstream finite element method to solve the electric field and ion distribution of the mathematical model according to the field equation and boundary conditions to obtain the electric field intensity on the surface of the suspended conductor;

[0153] Step 2: Based on the electric field strength on the surface of the suspended conductor, the relationship between ion flow and electric field strength is J = (ρ + k + +ρ - k - )E, solve the current density distribution on the surface of the suspended conductor, and integrate the current density along the boundary of the suspended conductor to solve the net current value I0 injected into the suspended conductor; if I0>10 -11 A, then proceed to step 3, otherwise go to step 4;

[0154] Step 3: According to the current value I0 injected into the suspended conductor, use the formula U0'=U0+I0×10 11 Update the potential value of the suspended conductor and return to step 1;

[0155] Step 4: Record the potential value of the suspended conductor and the ion distribution characteristics in the field.

[0156] Where J is the ion current density vector; E is the electric field strength vector; ρ + , - are the positive and negative space charge densities, respectively; k + , k - are the mobility of positive and negative ions, respectively.

[0157] Optionally, the third computing submodule includes:

[0158] Based on the ion distribution characteristics, the equivalent conductivity of the ion flow field γ = ρ is solved + k + +ρ - k - The distribution characteristics of

[0159] Using the electrostatic analogy method, the permittivity is set to the equivalent conductivity γ of the ion flow field in the finite element software;

[0160] According to the relative position relationship between the transmission line and the suspended conductor and the permittivity set as the equivalent conductivity of the ion flow field, the second potential coefficient matrix [α'] is solved by the finite element method.

[0161] The second potential coefficient matrix [α'] is inverted to obtain the conductivity coefficient matrix [β'] = [α'] -1 ;

[0162] According to the conductivity matrix [β'], calculate the unit length capacitance matrix [σ];

[0163] According to the unit length capacitance matrix [σ], the self-conductance and mutual conductance between the unit length transmission line and the suspended conductor are determined.

[0164] Alternatively, the expression for the autoconductance is:

[0165]

[0166] The expression of mutual conductance is:

[0167] σ ij =-β' ij

[0168] Where n is the total number of transmission line poles and suspended conductors.

[0169] Exemplary Electronic Devices

[0170] Figure 8 This is a structure of an electronic device provided by an exemplary embodiment of the present invention. Figure 8 As shown, the electronic device 80 includes one or more processors 81 and a memory 82 .

[0171] The processor 81 may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0172] The memory 82 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory (cache), etc. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 81 may run the program instructions to implement the methods of the software programs of the various embodiments of the present invention described above and / or other desired functions. In one example, the electronic device may also include: an input device 83 and an output device 84, which are interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0173] In addition, the input device 83 may also include, for example, a keyboard, a mouse, etc.

[0174] The output device 84 can output various information to the outside, and can include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto.

[0175] Of course, to simplify, Figure 8 Only some of the components related to the present invention in the electronic device are shown, and components such as a bus, an input / output interface, etc. are omitted. In addition, the electronic device may further include any other appropriate components according to specific application conditions.

[0176] Exemplary computer program products and computer-readable storage media

[0177] In addition to the above-mentioned methods and devices, an embodiment of the present invention may also be a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to execute the steps of the method according to various embodiments of the present invention described in the above-mentioned "Exemplary Method" section of this specification.

[0178] The computer program product may be written in any combination of one or more programming languages ​​to write program code for performing the operations of the embodiments of the present invention, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0179] In addition, an embodiment of the present invention may also be a computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor, enable the processor to execute the steps of the method according to various embodiments of the present invention described in the above “Exemplary Method” section of this specification.

[0180] The computer readable storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can include, for example, but is not limited to, a system, system or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0181] The basic principle of the present invention is described above in conjunction with specific embodiments. However, it should be pointed out that the advantages, strengths, effects, etc. mentioned in the present invention are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. must be possessed by each embodiment of the present invention. In addition, the specific details disclosed above are only for the purpose of illustration and facilitation of understanding, rather than limitation, and the above details do not limit the present invention to being implemented by adopting the above specific details.

[0182] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system embodiment, since it basically corresponds to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0183] The block diagrams of the devices, systems, equipment, and systems involved in the present invention are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, systems, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The word "such as" used here refers to the phrase "such as but not limited to", and can be used interchangeably with it.

[0184] The method and system of the present invention may be implemented in many ways. For example, the method and system of the present invention may be implemented by software, hardware, firmware or any combination of software, hardware, firmware. The above order of steps for the method is only for illustration, and the steps of the method of the present invention are not limited to the order specifically described above, unless otherwise specifically stated. In addition, in some embodiments, the present invention may also be implemented as a program recorded in a recording medium, which includes machine-readable instructions for implementing the method according to the present invention. Thus, the present invention also covers a recording medium storing a program for executing the method according to the present invention.

[0185] It should also be noted that in the system, device and method of the present invention, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent schemes of the present invention. The above description of the disclosed aspects is provided to enable any technician in the field to make or use the present invention. Various modifications to these aspects are very obvious to those skilled in the art, and the general principles defined here can be applied to other aspects without departing from the scope of the present invention. Therefore, the present invention is not intended to be limited to the aspects shown here, but in accordance with the widest range consistent with the principles and novel features disclosed here.

[0186] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present invention to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A method for calculating transient voltage and current of a suspended conductor in a DC ion flow field, characterized in that: include: According to the relative position relationship between overhead line and suspended conductor in DC transmission line, the mathematical model of DC line and suspended conductor as well as its field equations and boundary conditions are established; Solving the mathematical model according to the field equations and the boundary conditions to determine the self-capacitance, mutual capacitance, self-conductance and mutual conductance between the transmission line per unit length and the suspended conductor; Calculate capacitance parameters and conductance parameters according to the self-capacitance, the mutual capacitance, the self-conductance, the mutual conductance and the length of the transmission line; Assign the capacitance parameter and the conductance parameter to a pre-established ion flow field equivalent circuit model between the transmission line and the suspended conductor, and determine the assigned equivalent circuit model of the DC line and the suspended conductor; According to the switching operation of the suspended conductor, the assignment equivalent circuit model is used to perform a solution to determine the transient voltage and the transient current under the switching operation.

2. The method according to claim 1, characterized in that The mathematical model is solved according to the field equations and the boundary conditions to determine the self-capacitance, mutual capacitance, self-conductance and mutual conductance between the transmission line per unit length and the suspended conductor, including: According to the field equations and the boundary conditions, the mathematical model is solved based on a partial capacitance solution method to determine a potential coefficient matrix between the transmission line and the suspended conductor, and based on the potential coefficient matrix, the self-capacitance and mutual capacitance between the transmission line per unit length and the suspended conductor are calculated; According to the field equation and the boundary conditions, the electric field and ion distribution of the mathematical model are solved by using the upstream finite element method, and the ion distribution characteristics of the suspended conductor after the field is stable are calculated by combining the estimation verification method; Based on the ion distribution characteristics, the electrostatic analogy method is used to solve the conductivity matrix between the transmission line and the suspended conductor, and the self-conductance and mutual conductance between the transmission line per unit length and the suspended conductor are calculated based on the conductivity matrix.

3. The method according to claim 2, characterized in that According to the field equation and the boundary conditions, the mathematical model is solved based on a partial capacitance solution method to determine a potential coefficient matrix between the transmission line and the suspended conductor, and based on the potential coefficient matrix, the self-capacitance and mutual capacitance between the transmission line per unit length and the suspended conductor are calculated, including: According to the relative position relationship and permittivity of the transmission line and the suspended conductor, the potential value is established. The coefficient relationship with charge [q] Where [α] is the first potential coefficient matrix; The first potential coefficient matrix [α] is inverted to obtain the capacitance coefficient matrix [β] = [α] -1 ; Determine a unit length capacitance matrix [C] according to the capacitance coefficient matrix; The self-capacitance and the mutual capacitance between the transmission line per unit length and the suspended conductor are calculated according to the unit length capacitance matrix [C].

4. The method according to claim 3, characterized in that The expression of the self-capacitance is: The expression of the mutual capacitance is: C ij ＝-β ij Where n is the number of transmission line poles and the total number of suspended conductors; the [α], [β], and [C] matrices are all n×n.

5. The method according to claim 2, characterized in that: According to the field equation and the boundary conditions, the electric field and ion distribution of the mathematical model are solved by the upstream finite element method, and the ion distribution characteristics of the suspended conductor after the field is stable are calculated by combining the estimation verification method, including: Step 1: Estimate the potential value U0 of the suspended conductor, and solve the electric field and ion distribution of the mathematical model using the upstream finite element method according to the field equation and the boundary conditions to obtain the electric field intensity on the surface of the suspended conductor; Step 2: Based on the electric field strength on the surface of the suspended conductor, the relationship between ion flow and electric field strength is J = (ρ + k + +ρ - k - )E, solve the current density distribution on the surface of the suspended conductor, and integrate the current density along the boundary of the suspended conductor to solve the net current value I0 injected into the suspended conductor; if I0>10 -11 A, then proceed to step 3, otherwise go to step 4; Step 3: According to the current value I0 injected into the suspended conductor, use the formula U0'=U0+I0×10 11 Update the potential value of the suspended conductor and return to step 1; Step 4: Record the potential value of the suspended conductor and the ion distribution characteristics in the field. Where J is the ion current density vector; E is the electric field strength vector; ρ + , - are the positive and negative space charge densities, respectively; k + , k - are the mobility of positive and negative ions, respectively.

6. The method according to claim 5, characterized in that Based on the ion distribution characteristics, the electrostatic analogy method is used to solve the conductivity matrix between the transmission line and the suspended conductor, and the self-conductance and mutual conductance between the transmission line and the suspended conductor per unit length are calculated according to the conductivity matrix, including: Based on the ion distribution characteristics, the equivalent conductivity of the ion flow field γ = ρ is solved + k + +ρ - k - The distribution characteristics of Using the electrostatic analogy method, the permittivity is set to the equivalent conductivity γ of the ion flow field in the finite element software; According to the relative position relationship between the transmission line and the suspended conductor and the permittivity set as the equivalent conductivity of the ion flow field, the second potential coefficient matrix [α'] is solved by using the finite element method. The second potential coefficient matrix [α'] is inverted to obtain the conductivity coefficient matrix [β'] = [α'] -1 ; Calculate the unit length capacitance matrix [σ] according to the conductivity matrix [β']; According to the unit length capacitance matrix [σ], the self-conductance and mutual conductance between the unit length transmission line and the suspended conductor are determined.

7. The method according to claim 6, characterized in that The expression of the self-conductance is: The expression of the mutual conductance is: s ij =-b' ij 8. A transient voltage and current calculation device for a suspended conductor in a DC ion flow field, characterized in that: include: Establishing a module for establishing a mathematical model of a DC line and a suspended conductor and its field equations and boundary conditions according to the relative position relationship between the overhead line and the suspended conductor in the DC transmission line; A first solving module, used for solving the mathematical model according to the field equation and the boundary conditions, and determining the self-capacitance, mutual capacitance, self-conductance and mutual conductance between the transmission line per unit length and the suspended conductor; a calculation module, configured to calculate a capacitance parameter and a conductance parameter according to the self-capacitance, the mutual capacitance, the self-conductance, the mutual conductance and the length of the transmission line; An assignment module, used for assigning the capacitance parameter and the conductance parameter to a pre-established ion flow field equivalent circuit model between the transmission line and the suspended conductor, and determining an assignment equivalent circuit model of the DC line and the suspended conductor; The second solution module is used to solve the switching operation of the suspended conductor using the assigned equivalent circuit model to determine the transient voltage and transient current under the switching operation.

9. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and the computer program is used to execute the method according to any one of claims 1 to 7.

10. An electronic device, characterized in that: The electronic device comprises: processor; a memory for storing instructions executable by the processor; The processor is used to read the executable instructions from the memory and execute the instructions to implement the method described in any one of claims 1 to 7.

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