Wind power plant outgoing line classification fault distance measurement method, device, equipment, medium and product

Abstract

The invention discloses a wind power plant outgoing line classification fault distance measurement method, device and equipment, a medium and a product. The method comprises the steps that when it is monitored that the real-time current break variable of a wind power plant is larger than a preset threshold value, a fault type factor is acquired, and a fault type is determined according to the fault type factor; establishing a three-phase fault voltage equation under the target model according to the outgoing line target model; according to the three-phase fault voltage equation under the target model, respectively establishing a sending line fault distance measurement equation corresponding to each fault; and based on a least square optimization algorithm, solving the outgoing line fault distance measurement equation corresponding to each fault to obtain a fault distance corresponding to each fault. Through the technical scheme of the invention, the problem that the fault location is difficult to accurately measure when the new energy electric field outgoing line has a fault in the existing fault location can be solved, and the effect of accurate fault location of the wind power plant outgoing line is achieved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of power system fault location, and in particular, to a method, device, equipment, medium and product for classifying fault location of wind farm outgoing lines. Background Art

[0002] Clean energy has become an important direction for future energy development. New energy power plants have become a research hotspot due to their advantages such as mature technology and high conversion rate. Therefore, it is of great significance to study the impact of new energy grid connection on the power system.

[0003] The fault transient characteristics of new energy power plants are very different from those of traditional power plants. When the voltage drops deeply, a strategy of putting into the crowbar circuit (a protection circuit used to quickly cut off the current in case of a power system fault to protect equipment and personnel safety) is adopted to protect the rotor side converter. At this time, the frequency of the short-circuit current will shift, and the shift range is 35 - 65 Hz. The extraction of vectors based on power frequency quantities is no longer accurate. At this stage, the performance of direction elements and phase selection elements based on power frequency vectors deteriorates, resulting in fault current in the outgoing line. At the same time, the weak power source characteristics of new energy power plants make their positive and negative sequence impedances much larger than the zero sequence impedance. Therefore, when a ground fault occurs, the proportion of zero sequence current is very large, and the proportion of positive and negative sequence components is very small. And with the increase of the distance of the outgoing line, its distributed capacitance cannot be ignored, and traditional fault location methods will produce large errors when used for outgoing lines.

[0004] The unique fault characteristics of new energy power plants have various impacts on traditional fault location methods. However, at present, the fault location configurations of many high-voltage outgoing lines in new energy power plants do not consider the different fault characteristics of their grid-connected systems, and still adopt traditional fault location schemes, resulting in the inability to accurately determine the fault location when a fault occurs. Therefore, it is very necessary to construct a new fault location method for outgoing lines. Summary of the Invention

[0005] The embodiments of the present invention provide a method, device, equipment, medium and product for classifying fault location of wind farm outgoing lines, so as to solve the problem that it is difficult to accurately measure the fault location in the case of a fault in the outgoing line of a new energy power plant in the existing fault location.

[0006] According to one aspect of the present invention, a method for classifying fault location of wind farm outgoing lines is provided, including:

[0007] When it is monitored that the real-time current mutation amount of the wind farm is greater than a preset threshold, obtain a fault type factor, and determine the fault type according to the fault type factor;

[0008] Establish a three-phase fault voltage equation under the target model according to the target model of the outgoing line;

[0009] According to the three-phase fault voltage equation under the target model, establish an outgoing line fault location equation corresponding to each type of fault respectively;

[0010] Based on the least squares optimization algorithm, solve the outgoing line fault location equation corresponding to each type of fault to obtain the fault distance corresponding to each type of fault.

[0011] According to another aspect of the present invention, there is provided a device for classifying and locating faults in the outgoing lines of a wind farm, and the device includes:

[0012] An acquisition and determination module, configured to obtain a fault type factor when it is monitored that the real-time current mutation amount of the wind farm is greater than a preset threshold, and determine the fault type according to the fault type factor;

[0013] A first establishment module, configured to establish a three-phase fault voltage equation under the target model according to the target model of the outgoing line;

[0014] A second establishment module, configured to establish an outgoing line fault location equation corresponding to each type of fault respectively according to the three-phase fault voltage equation under the target model;

[0015] A solution module, configured to solve the outgoing line fault location equation corresponding to each type of fault based on the least squares optimization algorithm to obtain the fault distance corresponding to each type of fault.

[0016] According to another aspect of the present invention, there is provided an electronic device, and the electronic device includes:

[0017] At least one processor; and

[0018] A memory communicatively connected to the at least one processor; wherein,

[0019] The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the method for classifying and locating faults in the outgoing lines of a wind farm according to any embodiment of the present invention.

[0020] According to another aspect of the present invention, there is provided a computer-readable storage medium, and the computer-readable storage medium stores computer instructions, and the computer instructions are used to cause a processor to execute the method for classifying and locating faults in the outgoing lines of a wind farm according to any embodiment of the present invention when executed.

[0021] According to another aspect of the present invention, an embodiment of the present invention further provides a computer program product, which includes a computer program. When the computer program is executed by a processor, it implements the method for classifying and fault locating of the outgoing line of a wind farm described in any embodiment of the present invention.

[0022] In an embodiment of the present invention, when it is monitored that the real-time current mutation amount of a wind farm is greater than a preset threshold, a fault type factor is obtained, and the fault type is determined according to the fault type factor. A three-phase fault voltage equation under the target model is established according to the target model of the outgoing line, and for each type of fault, an outgoing line fault location equation is established respectively according to the three-phase fault voltage equation under the target model. Based on the least squares optimization algorithm, the outgoing line fault location equations corresponding to each type of fault are solved to obtain the fault distance corresponding to each type of fault. Through the technical solution of the present invention, the problem that it is difficult to accurately measure the fault location in the outgoing line fault of a new energy power plant in the existing fault location can be solved, and the effect of accurate fault location of the outgoing line of a wind farm can be achieved.

[0023] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 is a flowchart of a method for classifying and fault locating of the outgoing line of a wind farm in an embodiment of the present invention;

[0026] Figure 2 is a simulation model of a new energy outgoing line in an embodiment of the present invention;

[0027] Figure 3 is a schematic structural diagram of a device for classifying and fault locating of the outgoing line of a wind farm in an embodiment of the present invention;

[0028] Figure 4 is a schematic structural diagram of an electronic device for implementing the method for classifying and fault locating of the outgoing line of a wind farm in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] To enable those skilled in the art to better understand the solution of the present invention, the following will clearly and completely describe the technical solution in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0030] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned accompanying drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and their derivatives are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily need to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0031] It can be understood that before using the technical solutions disclosed in the embodiments of the present disclosure, the types, usage scopes, usage scenarios, etc. of the personal information involved in the present disclosure should be informed to users and the authorization of users should be obtained in an appropriate manner in accordance with relevant laws and regulations.

[0032] Embodiment 1

[0033] Figure 1 is a flowchart of a method for classifying and locating faults in the outgoing lines of a wind farm in an embodiment of the present invention. This embodiment is applicable to the situation of classifying and locating faults in the outgoing lines of a wind farm based on a π model with transition resistance correction. This method can be executed by a device for classifying and locating faults in the outgoing lines of a wind farm in an embodiment of the present invention. This device can be implemented in a software and / or hardware manner, such as Figure 1 shown, and the method specifically includes the following steps:

[0034] S101. When the real-time current mutation amount of the wind farm is detected to be greater than a preset threshold, obtain a fault type factor and determine the fault type according to the fault type factor.

[0035] In this embodiment, collect the parameters of the wind farm and the outgoing line: record the self-resistance per unit length of the outgoing line as r s , and the self-inductance as l s ; the mutual resistance per unit length of the line is r m , and the mutual inductance is l m ; the capacitance to the ground per unit length of the line is c 0。Monitor the voltage and current at the wind farm terminal in real time. Denote the three-phase voltage as u mj , and the current as i mj , where j = a, b, c, representing the three phases a, b, c respectively. Subsequently, A, B, C can also be used to represent the three phases respectively.

[0036] Among them, the real-time current mutation can be the change in current when the current in the wind farm mutates. Specifically, the real-time current mutation can be determined by calculating the difference between the current value at the current moment and the current value one power frequency cycle ago. In this embodiment, the preset threshold can be a threshold preset according to actual requirements or empirical values, and is used to judge when to start the fault location of the outgoing line. In the actual operation process, the specific value of the preset threshold in this embodiment is not limited.

[0037] Among them, the fault type factor can be a factor used to determine the fault type, and can be represented by α in this embodiment. In this embodiment, specifically, the fault types can include: single-phase ground fault, two-phase short-circuit ground fault, two-phase short-circuit fault, and three-phase short-circuit fault.

[0038] Specifically, collect the parameters of the wind farm and the outgoing line, such as line resistance, inductance, and line capacitance, etc., and monitor the voltage and current at the wind farm terminal in real time. Use the real-time current mutation at the wind farm terminal as the fault location starting element. When it is monitored that the real-time current mutation at the wind farm is greater than the preset threshold, that is, when a fault occurs, obtain the fault type factor, and determine the fault type according to the fault type factor.

[0039] S102. Establish a three-phase fault voltage equation under the target model according to the target model of the outgoing line.

[0040] In this embodiment, the target model of the outgoing line can be the π model of the outgoing line.

[0041] Specifically, based on the π model of the outgoing line, establish the voltage equation from the protection installation point to the fault point:

[0042]

[0043] Among them, u ma , u mb , u mc are the three-phase voltages; i ma , i mb , i mc are the three-phase currents; r m is the mutual resistance per unit length of the line, l m is the mutual inductance per unit length of the line; r s is the self-resistance per unit length of the outgoing line, l s is the self-inductance per unit length of the outgoing line; u fa , u fb, u fc is the fault point voltage; c s = 1 / 2c 0 , where c 0 is the capacitance to ground per unit length of the line; d is the length of the faulty line.

[0044] S103. Based on the three-phase fault voltage equations under the target model, establish the fault location ranging equations for the outgoing lines corresponding to each type of fault respectively.

[0045] In this embodiment, the fault location ranging equations for the outgoing lines can be equations used to calculate the corresponding fault distances respectively when each type of fault occurs.

[0046] During the actual operation process, establish the three-phase fault voltage equations and perform transition resistance correction to form the fault location ranging equations for the outgoing lines corresponding to each type of fault.

[0047] S104. Based on the least squares optimization algorithm, solve the fault location ranging equations for the outgoing lines corresponding to each type of fault to obtain the fault distances corresponding to each type of fault.

[0048] Specifically, in this embodiment, based on the least squares optimization algorithm, solving the fault location ranging equations for the outgoing lines corresponding to each type of fault to obtain the fault distances corresponding to each type of fault can be divided into two types: solving the fault location ranging equations for the outgoing lines under single-phase grounding fault and two-phase short-circuit grounding fault based on the least squares optimization algorithm to obtain the fault distances; solving the fault location ranging equations for the outgoing lines under two-phase interphase fault (i.e., two-phase short-circuit fault) and three-phase short-circuit fault based on the least squares optimization algorithm to obtain the fault distances.

[0049] In the embodiment of the present invention, when it is monitored that the real-time current mutation amount of the wind farm is greater than the preset threshold, obtain the fault type factor, determine the fault type according to the fault type factor, establish the three-phase fault voltage equations under the target model according to the target model of the outgoing line, based on the three-phase fault voltage equations under the target model, establish the fault location ranging equations for the outgoing lines corresponding to each type of fault respectively, and based on the least squares optimization algorithm, solve the fault location ranging equations for the outgoing lines corresponding to each type of fault to obtain the fault distances corresponding to each type of fault. Through the technical solution of the present invention, the problem that it is difficult to accurately measure the fault location in the outgoing line fault of the new energy power plant in the existing fault location ranging can be solved, and the effect of accurate fault location ranging for the outgoing line of the wind farm can be achieved.

[0050] Optionally, before obtaining the fault type factor and determining the fault type when it is monitored that the real-time current mutation amount of the wind farm is greater than the preset threshold, it further includes:

[0051] Real-time monitor the current value of the wind farm, and use the difference between the current value monitored at the current moment and the current value one power frequency cycle ago as the real-time current mutation amount of the wind farm.

[0052] In this embodiment, the real-time current mutation at the wind farm side is used as the fault location starting element. When the current mutation exceeds the preset threshold, the fault location of the outgoing line is started, and the fault time is recorded.

[0053] Specifically, the calculation method of the real-time current mutation of the wind farm can be expressed as:

[0054] i mj·k -i mj·(k-M) >i Δ·zd ;

[0055] In the formula, i mj·k is the current value at the current moment; i mj·(k-M) is the current value one power frequency cycle ago; i Δ·zd is the protection starting setting value, that is, the preset threshold; M is the number of sampling points in one power frequency cycle, which is not limited in this embodiment.

[0056] Optionally, obtain the fault type factor and determine the fault type according to the fault type factor, including:

[0057] Obtain the corrected current mutation corresponding to each phase in the three phases.

[0058] In this embodiment, the corrected current mutation corresponding to each phase in the three phases can be represented by Δi mA·comp , Δi mB·comp , Δi mC·comp .

[0059] Exemplarily, taking phase A as the reference, the following corrected current mutation is constructed (the same applies to the other two phases, which will not be elaborated one by one in this embodiment):

[0060]

[0061] Among them, Δi mA·comp , Δi mB·comp , Δi mC·comp are the corrected current mutations corresponding to each phase in the three phases respectively; C 1 is the positive sequence current distribution coefficient; θ is the rotation factor.

[0062] Determine the amplitude ratio corresponding to each phase according to the corrected current mutation corresponding to each phase.

[0063] It should be noted that the amplitude ratio corresponding to each phase can be the ratio of the corrected current mutation of each phase to the inter-phase corrected current mutation of the other two phases. Among them, the inter-phase corrected current mutation can be obtained by taking the difference between the corrected current mutations of two phases.

[0064] Specifically, construct the following amplitude ratio according to the sudden change of the corrective current of each phase and the amplitude of the sudden change of the corrective current between the other two phases:

[0065]

[0066] Wherein, is the sudden change of the corrective current of a certain phase in the three phases; is the sudden change of the corrective current between the other two phases (the sudden change of the corrective current between phases can be obtained by taking the difference between the sudden changes of the corrective currents of the two phases).

[0067] Determine the fault type factor according to the corresponding amplitude ratio of each phase.

[0068] Specifically, sort the three amplitude ratios corresponding to the three phases from largest to smallest, and construct the fault type judgment factor α:

[0069]

[0070] Wherein, K max is the maximum value among the three amplitude ratios corresponding to the three phases, K min is the minimum value among the three amplitude ratios corresponding to the three phases, K mid is the intermediate value among the three amplitude ratios corresponding to the three phases. At this time, the phase corresponding to K max is the fault phase.

[0071] Determine the fault type according to the fault type factor.

[0072] In the actual operation process, combine the value range of the fault type factor α and the magnitude of the zero-sequence current under different faults to construct the following fault type criterion:

[0073]

[0074] Wherein, i 0·zd is the setting value of the zero-sequence current, generally one-eighth of the rated current.

[0075] Optionally, the fault types include: single-phase ground fault.

[0076] According to the three-phase fault voltage equation under the target model, establish the fault distance measurement equation corresponding to each fault respectively, including:

[0077] According to the three-phase fault voltage equation under the target model, establish the fault voltage equation for each phase when a single-phase ground fault occurs.

[0078] Exemplarily, in this embodiment, taking the A-phase ground fault as an example, establish the fault voltage equation when a single-phase ground fault occurs, and perform transition resistance correction to form the fault distance measurement equation when a single-phase ground fault occurs. The same applies to the other two phases, and this embodiment will not elaborate here one by one.

[0079] Specifically, the fault voltage equation is:

[0080]

[0081] In the formula, r 1 and r 0 are the zero-sequence resistance and positive-sequence resistance per unit length of the line; l 1 and l 0 are the zero-sequence positive-sequence inductance and zero-sequence inductance per unit length of the line.

[0082] The fault voltage equation for single-phase grounding corresponding to each phase is corrected for the transition resistance to obtain the fault location equation for single-phase grounding corresponding to each phase.

[0083] Specifically, when correcting for the transition resistance, the relationship between the fault point voltage and the transition resistance is:

[0084] u fa = i fa R f = 3(i ma0 - i Cm0 - i Cf0 )NR f ;

[0085] where R f is the transition resistance; N is the zero-sequence current coefficient. Since there is a phase difference in the zero-sequence currents on both sides of the fault point, N can be regarded as a complex number, i.e., N = N 1 + jN 2 , then:

[0086] NR f = (N 1 + jN 2 )R f = (R' f + jωL');

[0087] where R' f and L' f are the corrected transition resistance and transition inductance.

[0088] Combining the above formula, the fault location equation is as follows:

[0089] u ma = A x1 d + A x2 d 2 + A x3 R' f + A x4 dR' f + A x5 d 2 R'f +A x6 L' f +A x7 dL' f +A x8 d 2 L' f ;

[0090] Among them, A xi is a coefficient composed of line parameters and monitored quantities, and the specific expression is as follows:

[0091]

[0092] Optionally, the fault types include: two-phase short-circuit grounding fault.

[0093] According to the three-phase fault voltage equation under the target model, establish the fault location equations for the outgoing lines corresponding to each fault respectively, including:

[0094] According to the three-phase fault voltage equation under the target model, establish the fault voltage equations for two-phase short-circuit grounding corresponding to each pair of phases respectively.

[0095] Exemplarily, taking the BC-phase short-circuit grounding fault as an example, establish the fault voltage equation for two-phase short-circuit grounding, and perform transition resistance correction to form the fault location equation for two-phase short-circuit grounding. The same applies to the other two combination methods, which will not be elaborated here one by one in this embodiment.

[0096] Specifically, the fault voltage equation is:

[0097]

[0098] Perform transition resistance correction on the fault voltage equations for two-phase short-circuit grounding corresponding to each pair of phases to obtain the fault location equations for two-phase short-circuit grounding corresponding to each pair of phases.

[0099] Specifically, the transition resistance is corrected as follows:

[0100]

[0101] Among them, N is the zero-sequence current coefficient. Since there is a phase difference in the zero-sequence current on both sides of the fault point, N can be regarded as a complex number, that is, N = N 1 +jN 2 , then there is:

[0102] 2NR f = 2(N 1 +jN 2 )R f =(R' f +jωL');

[0103] Based on the above equations, the fault location equation is as follows:

[0104] u mb +u mc =A y1 d+A y2 d 2 +A y3 R' f +A y4 dR' f +A y5 d 2 R' f +A y6 L' f +A y7 dL' f +A y8 d 2 L' f ;

[0105] In the formula, A yi is a coefficient composed of line parameters and monitored quantities, and the specific expression is as follows:

[0106]

[0107] Optionally, the fault types include: two-phase short-circuit fault.

[0108] According to the three-phase fault voltage equation under the target model, the fault location equations for the outgoing lines corresponding to each fault are established, including:

[0109] According to the three-phase fault voltage equation under the target model, the fault voltage equations for two-phase short circuits corresponding to each pair of phases are established.

[0110] Exemplarily, taking the short-circuit fault of phase BC as an example, the fault voltage equation for two-phase short circuit is established and the transition resistance is corrected to form the fault location equation for two-phase short circuit. The same applies to the other two combination methods, which will not be elaborated here in this embodiment.

[0111] Specifically, the fault voltage equation for two-phase short circuit is:

[0112]

[0113] The fault voltage equations for two-phase short circuits corresponding to each pair of phases are corrected for the transition resistance to obtain the fault location equations for two-phase short circuits corresponding to each pair of phases.

[0114] Specifically, the transition resistance is corrected:

[0115]

[0116] Based on the above equations, the fault location equation is as follows:

[0117] u mb -u mc = B x1 d + B x2 d 2 + B x3 R' f + B x4 dR' f + B x5 d 2 R' f ;

[0118] Wherein, B xi is a coefficient composed of line parameters and monitored quantities, and the specific expression is as follows:

[0119]

[0120] Optionally, the fault types include: three-phase short-circuit fault.

[0121] According to the three-phase fault voltage equation under the target model, the fault location equations for the outgoing lines corresponding to each fault are established, including:

[0122] According to the three-phase fault voltage equation under the target model, the fault voltage equation during three-phase short circuit is established.

[0123] In this embodiment, the fault voltage equation during three-phase short circuit is established and the transition resistance is corrected to form the fault location equation during three-phase short circuit.

[0124] Specifically, the fault voltage equation during three-phase short circuit fault is:

[0125]

[0126] The fault voltage equation during three-phase short circuit is corrected for the transition resistance to obtain the fault location equation during three-phase short circuit.

[0127] Specifically, the transition resistance is corrected:

[0128]

[0129] Combining the above equations, the fault location equation is as follows:

[0130] u ma = B y1 d + B y2 d 2 + B y3 R' f + B y4 dR' f + B y5 d 2 R'f ;

[0131] In the formula, B yi is a coefficient composed of line parameters and monitored quantities, and the specific expression is as follows:

[0132]

[0133] In this embodiment, based on the least squares optimization algorithm, the fault location equations of the outgoing lines corresponding to each type of fault are solved, and the fault distances corresponding to each type of fault can be divided into two types: solving the fault location equations of the outgoing lines under single-phase ground fault and two-phase short-circuit ground fault based on the least squares optimization algorithm to obtain the fault distance; solving the fault location equations of the outgoing lines under two-phase interphase fault and three-phase short-circuit fault based on the least squares optimization algorithm to obtain the fault distance.

[0134] In one case, the specific process of solving the fault location equations of the outgoing lines under single-phase ground fault and two-phase short-circuit ground fault based on the least squares optimization algorithm to obtain the fault distance can be described as follows:

[0135] Optionally, based on the least squares optimization algorithm, solving the fault location equations of the outgoing lines corresponding to each type of fault to obtain the fault distance corresponding to each type of fault includes:

[0136] Constructing a matrix differential equation according to the fault location equations of the outgoing lines corresponding to each type of fault.

[0137] Specifically, when a single-phase ground fault and a two-phase short-circuit ground fault occur, multiple groups of data sampling form multiple fault location equations and constitute the following matrix differential equation:

[0138] M u = A 1 d + A 2 d 2 + A 3 R' f + A 4 dR' f + A 5 d 2 R' f + A 6 L' f + A 7 dL' f + A 8 d 2 L' f ;

[0139] Among them, M u is the voltage matrix; A i is a coefficient matrix composed of A xi or A yi .

[0140] The objective function is determined based on the matrix differential equation.

[0141] Specifically, the following objective function is constructed using matrix differential equations:

[0142] J=(M u -(A 1 d+A 2 d 2 +A 3 R' f +A 4 dR f +A 5 d 2 R' f +A 6 L' f +A 7 dL' f +A 8 d 2 L' f )) 2 .

[0143] The fault distance corresponding to each fault is obtained by solving the objective function.

[0144] Specifically, the three partial derivative equations of the objective function are combined to calculate the fault distance d:

[0145]

[0146] In another case, the specific process of solving the fault distance equation of the outgoing line under two-phase phase-to-phase fault and three-phase short circuit fault based on the least squares optimization algorithm and obtaining the fault distance can be described as follows:

[0147] Optionally, based on the least squares optimization algorithm, the transmission line fault distance equation corresponding to each fault is solved to obtain the fault distance corresponding to each fault, including:

[0148] A matrix differential equation is constructed based on the fault location equation of the transmission line corresponding to each fault.

[0149] Specifically, when a two-phase phase-to-phase fault or a three-phase short circuit fault occurs, multiple sets of data sampling form multiple fault distance measurement equations and constitute the following matrix differential equation:

[0150] M u =B 1 d+B 2 d 2 +B 3 R' f +B 4 dR f +B 5 d 2R' f ;

[0151] Among them, M u is the voltage matrix; B i For B xi or B yi The coefficient matrix composed of .

[0152] The objective function is determined based on the matrix differential equation.

[0153] Specifically, the following objective function is constructed using matrix differential equations:

[0154] J=(M u -(B 1 d+B 2 d 2 +B 3 R' f +B 4 dR f +B 5 d 2 R' f )) 2 .

[0155] The fault distance corresponding to each fault is obtained by solving the objective function.

[0156] Specifically, the three partial derivative equations of the objective function are combined to calculate the fault distance d:

[0157]

[0158] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects: the embodiment of the present invention improves the fault distance measurement method of the renewable energy transmission line so that it can adapt to the fault characteristics of the renewable energy transmission line. In terms of fault phase selection, the phase selection factor (i.e., the fault type factor) is constructed by compensating for the current mutation amount to eliminate the failure of fault phase selection caused by the unequal positive and negative sequence impedances of renewable energy. In terms of fault distance calculation, the π model is used to establish the fault distance measurement equation to weaken the influence of distributed capacitance on the measurement distance, and the transition resistance is corrected by taking into account the current phase difference on both sides of the fault point, so as to achieve accurate fault distance measurement of the wind farm transmission line.

[0159] As an exemplary description of an embodiment of the present invention, a simulation model of a new energy transmission line is built on a simulation platform. Figure 2 It is a simulation model of a new energy transmission line in an embodiment of the present invention. Figure 2As shown, the simulation sampling frequency is 4 kHz. The N side is the system side, and the M side is the new energy power field side. Bus M is the outlet bus of the new energy power field after the collection line converges. The length of the outgoing line is 100 km. The positive sequence resistance per unit length of the line is 0.0472 (Ω / km), the positive sequence inductance is 0.3955 (mH / km), the grounding capacitance is 0.1186 (uF / km), the zero sequence resistance is 0.1042 (Ω / km), the zero sequence inductance is 0.1671 (mH / km), the main transformer turns ratio is 110 kV / 35 kV, and the system side voltage is 110 kV. Now, taking the fault location measurement at the M end as an example, the F point is the fault location, and d is the fault distance.

[0160] (1) When an A-phase ground fault occurs at 21 km from the M side of the outgoing line: The sudden change in the real-time current of the wind farm detected at the M side is greater than the preset threshold. The fault type factor α = 31.2 > 10, and K AφBC is the maximum amplitude ratio. It is judged as an A-phase ground fault. The ranging equation corresponding to the single-phase ground fault is used, and the system parameters and the monitored quantities of phase A are substituted to calculate the fault distance d as 21.04 km.

[0161] (2) When a BC-phase ground fault occurs at 41 km from the M side of the outgoing line: The sudden change in the real-time current of the wind farm detected at the M side is greater than the preset threshold. The fault type factor 0.5 < α = 1.5 < 10, the zero-sequence current is greater than the setting value, and K BφCA is the maximum amplitude ratio, K CφAB is the intermediate amplitude ratio. It is judged as a BC-phase ground fault. The ranging equation corresponding to the phase-to-phase ground fault is used, and the system parameters and the monitored quantities of phases BC are substituted to calculate the fault distance d as 40.97 km.

[0162] (3) When a BC-phase fault occurs at 52 km from the M side of the outgoing line: The sudden change in the real-time current of the wind farm detected at the M side is greater than the preset threshold. The fault type factor 0.5 < α = 1.8 < 10, the zero-sequence current is less than the setting value, and K CφAB is the maximum amplitude ratio, K BφCA is the intermediate amplitude ratio. It is judged as a BC-phase fault. The ranging equation corresponding to the phase-to-phase fault is used, and the system parameters and the monitored quantities of phases BC are substituted to calculate the fault distance d as 52.03 km.

[0163] (3) When a three-phase short circuit fault occurs at 75 km from the M side of the outgoing line: The sudden change in the real-time current of the wind farm detected at the M side is greater than the preset threshold. The fault type factor α = 0.19 < 0.5, and K CφAB is the maximum amplitude ratio. It is judged as a three-phase short circuit fault. The ranging equation corresponding to the three-phase short circuit fault is used, and the system parameters and the monitored quantities of phase C are substituted to calculate the fault distance d as 75.13 km.

[0164] In view of the problem that it is difficult to accurately measure the fault location when a fault occurs in the outgoing line of a new energy power plant in the existing fault location measurement, the embodiment of the present invention provides a new method for classifying fault location measurement of the outgoing line of a wind farm based on a π model corrected by a transition resistance. The technical solution of the embodiment of the present invention can eliminate the influence of fault current frequency offset, unequal positive and negative sequence impedances of the power plant, and distributed capacitance of the line on the fault location measurement of the new energy outgoing line, and realize accurate fault location measurement of the outgoing line of the wind farm.

[0165] Embodiment 2

[0166] Figure 3 It is a schematic structural diagram of a device for classifying fault location measurement of the outgoing line of a wind farm in the embodiment of the present invention. This embodiment is applicable to the case of classifying fault location measurement of the outgoing line of a wind farm based on a π model corrected by a transition resistance. The device can be implemented in software and / or hardware, and can be integrated in any device that provides the function of classifying fault location measurement of the outgoing line of a wind farm, such as Figure 3 As shown, the device for classifying fault location measurement of the outgoing line of the wind farm specifically includes: an acquisition and determination module 201, a first establishment module 202, a second establishment module 203, and a solution module 204.

[0167] Among them, the acquisition and determination module 201 is used to obtain a fault type factor when the real-time current mutation of the wind farm is detected to be greater than a preset threshold, and determine the fault type according to the fault type factor;

[0168] The first establishment module 202 is used to establish a three-phase fault voltage equation under the target model according to the target model of the outgoing line;

[0169] The second establishment module 203 is used to establish a fault location measurement equation for the outgoing line corresponding to each fault according to the three-phase fault voltage equation under the target model;

[0170] The solution module 204 is used to solve the fault location measurement equation for the outgoing line corresponding to each fault based on the least squares optimization algorithm to obtain the fault distance corresponding to each fault.

[0171] Optionally, the acquisition and determination module 201 is specifically used for:

[0172] Obtain the corrected current mutation corresponding to each phase in the three phases;

[0173] Determine the amplitude ratio corresponding to each phase according to the corrected current mutation corresponding to each phase;

[0174] Determine the fault type factor according to the amplitude ratio corresponding to each phase;

[0175] Determine the fault type according to the fault type factor.

[0176] Optionally, the fault types include: single-phase grounding fault;

[0177] The second establishing module 203 is specifically configured to:

[0178] According to the three-phase fault voltage equation under the target model, respectively establish the fault voltage equations for single-phase grounding corresponding to each phase;

[0179] Perform transition resistance correction on the fault voltage equations for single-phase grounding corresponding to each phase to obtain the fault location equations for single-phase grounding corresponding to each phase.

[0180] Optionally, the fault types include: two-phase short-circuit grounding fault;

[0181] The second establishing module 203 is specifically configured to:

[0182] According to the three-phase fault voltage equation under the target model, respectively establish the fault voltage equations for two-phase short-circuit grounding corresponding to each pair of phases;

[0183] Perform transition resistance correction on the fault voltage equations for two-phase short-circuit grounding corresponding to each pair of phases to obtain the fault location equations for two-phase short-circuit grounding corresponding to each pair of phases.

[0184] Optionally, the fault types include: two-phase short-circuit fault;

[0185] The second establishing module 203 is specifically configured to:

[0186] According to the three-phase fault voltage equation under the target model, respectively establish the fault voltage equations for two-phase short-circuit corresponding to each pair of phases;

[0187] Perform transition resistance correction on the fault voltage equations for two-phase short-circuit corresponding to each pair of phases to obtain the fault location equations for two-phase short-circuit corresponding to each pair of phases.

[0188] Optionally, the fault types include: three-phase short-circuit fault;

[0189] The second establishing module 203 is specifically configured to:

[0190] According to the three-phase fault voltage equation under the target model, establish the fault voltage equation for three-phase short-circuit;

[0191] Perform transition resistance correction on the fault voltage equation for three-phase short-circuit to obtain the fault location equation for three-phase short-circuit.

[0192] Optionally, the solving module 204 is specifically configured to:

[0193] Construct a matrix differential equation according to the fault location equations of the outgoing lines corresponding to each type of fault;

[0194] Determine an objective function according to the matrix differential equation;

[0195] Solve the objective function to obtain the fault distance corresponding to each fault.

[0196] Optionally, the device further includes:

[0197] A monitoring module, configured to monitor the current value of the wind farm in real time, and use the difference between the current value monitored at the current moment and the current value one power frequency period ago as the real-time current mutation amount of the wind farm.

[0198] The above product can execute the wind farm outgoing line classification fault ranging method provided by any embodiment of the present invention, and has the corresponding functional modules and beneficial effects for executing the method.

[0199] Embodiment III

[0200] Figure 4 FIG. shows a schematic structural diagram of an electronic device 30 that can be used to implement an embodiment of the present invention. The electronic device is intended to represent various forms of digital computers, such as, for example, a laptop computer, a desktop computer, a workbench, a personal digital assistant, a server, a blade server, a mainframe computer, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as, for example, a personal digital processor, a cellular phone, a smart phone, a wearable device (such as a helmet, glasses, a watch, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the present invention described and / or claimed herein.

[0201] As Figure 4 shown, the electronic device 30 includes at least one processor 31, and a memory communicatively connected to the at least one processor 31, such as a read-only memory (ROM) 32, a random access memory (RAM) 33, etc., wherein the memory stores a computer program executable by the at least one processor, and the processor 31 can execute various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 32 or the computer program loaded from the storage unit 38 into the random access memory (RAM) 33. In the RAM 33, various programs and data required for the operation of the electronic device 30 can also be stored. The processor 31, the ROM 32, and the RAM 33 are connected to each other through a bus 34. The input / output (I / O) interface 35 is also connected to the bus 34.

[0202] Multiple components in the electronic device 30 are connected to the I / O interface 35, including: an input unit 36, such as a keyboard, a mouse, etc.; an output unit 37, such as various types of displays, speakers, etc.; a storage unit 38, such as a magnetic disk, an optical disc, etc.; and a communication unit 39, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 39 allows the electronic device 30 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0203] The processor 31 can be various general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the processor 31 include but are not limited to a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The processor 31 executes the various methods and processes described above, such as the wind farm outgoing line classification fault location method:

[0204] When it is monitored that the real-time current mutation amount of the wind farm is greater than a preset threshold, obtain a fault type factor, and determine the fault type according to the fault type factor;

[0205] Establish a three-phase fault voltage equation under the target model according to the outgoing line target model;

[0206] According to the three-phase fault voltage equation under the target model, establish an outgoing line fault location equation corresponding to each fault respectively;

[0207] Based on the least squares optimization algorithm, solve the outgoing line fault location equation corresponding to each fault to obtain the fault distance corresponding to each fault.

[0208] In some embodiments, the wind farm outgoing line classification fault location method can be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as the storage unit 38. In some embodiments, part or all of the computer program can be loaded and / or installed onto the electronic device 30 via the ROM 32 and / or the communication unit 39. When the computer program is loaded into the RAM 33 and executed by the processor 31, one or more steps of the wind farm outgoing line classification fault location method described above can be executed. Alternatively, in other embodiments, the processor 31 can be configured to execute the wind farm outgoing line classification fault location method in any other suitable manner (for example, by means of firmware).

[0209] The various embodiments of the systems and techniques described above in this specification can be implemented in digital electronic circuitry, integrated circuit systems, field programmable gate arrays (FPGA), application specific integrated circuits (ASIC), application specific standard products (ASSP), systems-on-chip (SOC), complex programmable logic devices (CPLD), computer hardware, firmware, software, and / or combinations thereof. These various embodiments can include: being implemented in one or more computer programs that are executable and / or interpretable on a programmable system including at least one programmable processor, which can be a special-purpose or general-purpose programmable processor that receives data and instructions from, and transmits data and instructions to, a storage system, at least one input device, and at least one output device.

[0210] The computer programs for implementing the methods of the present invention can be written in any combination of one or more programming languages. These computer programs can be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the computer programs, when executed by the processor, cause the functions / operations specified in the flowchart and / or block diagram to be implemented. The computer programs can be executed entirely on the machine, partly on the machine, as a stand-alone software package partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[0211] In the context of the present invention, a computer-readable storage medium can be a tangible medium that can contain or store a computer program for use by or in connection with an instruction execution system, apparatus, or device. The computer-readable storage medium can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. Alternatively, the computer-readable storage medium can be a machine-readable signal medium. More specific examples of the machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer diskette, 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 disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0212] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the electronic device. Other kinds of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, speech input, or tactile input).

[0213] The systems and techniques described herein can be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer having a graphical user interface or a web browser through which the user can interact with an implementation of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system can be interconnected to each other by digital data communication in any form or medium (e.g., a communication network). Examples of communication networks include: local area network (LAN), wide area network (WAN), blockchain network, and the Internet.

[0214] The computing system can include a client and a server. The client and the server are generally remote from each other and typically interact through a communication network. The client-server relationship is created by computer programs running on respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or a cloud host, which is a host product in the cloud computing service system, solving the defects of difficult management and weak business scalability existing in traditional physical hosts and VPS services.

[0215] In one embodiment, the embodiment of the present invention further includes a computer program product, which includes a computer program that, when executed by a processor, implements the wind farm outgoing line classification fault location method of any embodiment of the present invention.

[0216] In the process of implementing the computer program product, computer program code for performing the operations of the present invention can be written in one or more programming languages or combinations thereof. The programming languages include object-oriented programming languages such as Java, Smalltalk, C++, and also include conventional procedural programming languages such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, executed as an independent software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any kind of network - including a local area network (LAN) or a wide area network (WAN) - or, alternatively, can be connected to an external computer (e.g., by using an Internet service provider to connect through the Internet).

[0217] It should be understood that the various forms of the flow shown above can be used, steps can be reordered, added or deleted. For example, the steps recited in the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved, and no limitation is made herein.

[0218] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for measuring fault location of wind farm transmission lines, characterized in that: include: When the real-time current mutation amount of the wind farm is monitored to be greater than a preset threshold, a fault type factor is obtained, and the fault type is determined according to the fault type factor; According to the transmission line target model, a three-phase fault voltage equation under the target model is established; According to the three-phase fault voltage equation under the target model, a transmission line fault distance measurement equation corresponding to each fault is established respectively; Based on the least squares optimization algorithm, the fault distance measurement equation of the transmission line corresponding to each fault is solved to obtain the fault distance corresponding to each fault.

2. The method according to claim 1, characterized in that Obtaining a fault type factor, and determining a fault type according to the fault type factor, includes: Obtain the correction current mutation amount of each corresponding phase in the three phases; Determine the amplitude ratio of each corresponding portion according to the correction current mutation amount of each corresponding portion; Determine the fault type factor according to each corresponding amplitude ratio; The fault type is determined according to the fault type factor.

3. The method according to claim 1, characterized in that The fault types include: single-phase grounding fault; According to the three-phase fault voltage equation under the target model, the transmission line fault location equation corresponding to each fault is established respectively, including: According to the three-phase fault voltage equation under the target model, the fault voltage equation of each corresponding single-phase grounding is established respectively; The fault voltage equation for each corresponding single-phase grounding is corrected by transition resistance to obtain the fault distance equation for each corresponding single-phase grounding.

4. The method according to claim 1, characterized in that: The fault types include: two-phase short circuit grounding fault; According to the three-phase fault voltage equation under the target model, the transmission line fault location equation corresponding to each fault is established respectively, including: According to the three-phase fault voltage equation under the target model, respectively establish the fault voltage equation when two corresponding two phases are short-circuited to ground; The fault voltage equation when each two corresponding two-phase short circuit grounding is corrected by transition resistance, and the fault distance measurement equation when each two corresponding two-phase short circuit grounding is obtained.

5. The method according to claim 1, characterized in that The fault types include: two-phase short circuit fault; According to the three-phase fault voltage equation under the target model, the transmission line fault location equation corresponding to each fault is established respectively, including: According to the three-phase fault voltage equation under the target model, respectively establish the fault voltage equation when each two corresponding two-phase short circuit occurs; The fault voltage equation when each two corresponding two-phase short circuit is subjected to transition resistance correction, and the fault distance measurement equation when each two corresponding two-phase short circuit is obtained.

6. The method according to claim 1, characterized in that The fault types include: three-phase short circuit fault; According to the three-phase fault voltage equation under the target model, the transmission line fault location equation corresponding to each fault is established respectively, including: According to the three-phase fault voltage equation under the target model, a fault voltage equation when three-phase short circuit occurs is established; The fault voltage equation during three-phase short circuit is corrected by transition resistance to obtain the fault distance measurement equation during three-phase short circuit.

7. The method according to claim 1, characterized in that Based on the least squares optimization algorithm, the fault distance equation of the outgoing line corresponding to each fault is solved to obtain the fault distance corresponding to each fault, including: A matrix differential equation is constructed based on the outgoing line fault location equation corresponding to each fault; determining an objective function according to the matrix differential equation; The fault distance corresponding to each fault is obtained by solving the objective function.

8. The method according to claim 1, characterized in that When the real-time current mutation amount of the wind farm is monitored to be greater than a preset threshold, before obtaining a fault type factor and determining the fault type according to the fault type factor, the method further includes: The current value of the wind farm is monitored in real time, and the difference between the current value at the current moment and the current value one power frequency cycle ago is used as the real-time current mutation value of the wind farm.

9. A wind farm transmission line classification fault distance measurement device, characterized in that: include: An acquisition and determination module, used to acquire a fault type factor when the real-time current mutation amount of the wind farm is monitored to be greater than a preset threshold, and determine the fault type according to the fault type factor; The first establishing module is used to establish a three-phase fault voltage equation under the target model according to the transmission line target model; The second establishment module is used to establish the transmission line fault distance measurement equation corresponding to each fault according to the three-phase fault voltage equation under the target model; The solution module is used to solve the transmission line fault distance measurement equation corresponding to each fault based on the least squares optimization algorithm to obtain the fault distance corresponding to each fault.

10. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the wind farm transmission line classification fault location method according to any one of claims 1-8.

11. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the wind farm transmission line classification fault location method according to any one of claims 1-8 when executed.

12. A computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the method for measuring fault location of a wind farm transmission line according to any one of claims 1 to 8 is implemented.

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