Modeling method, system and storage medium for lightning transient model of wind turbine generator

Abstract

The present invention relates to the field of generator set modeling, and in particular to a modeling method, system, and storage medium for a lightning transient model of a wind turbine. This modeling method first obtains the multi-conductor system of each component of the wind turbine, and the multi-conductor system of each component is composed of multiple conductor segments. Then, the quasi-static PEEC models of all the conductor segments are assembled to form a PEEC equivalent circuit model of the wind turbine. The present invention uses the PEEC method to perform electromagnetic transient analysis on the wind turbine multi-conductor system. By dividing the conductor segments, when modeling, the spatial medium is not discretized, and only the conductors are discretized. Compared with the general electromagnetic field method, the present invention simplifies the model, shortens the calculation time, and accurately considers the magnetic coupling effect between conductors compared to the equivalent circuit method.

Description

Technical Field

[0001] The present invention relates to the field of wind turbine modeling, and in particular to a modeling method, system and storage medium for a lightning transient model of a wind turbine. Background Art

[0002] Wind energy is a clean, renewable energy source that has been widely used. In recent years, as wind turbine capacity has continued to increase and blade heights have risen, the probability of wind turbines being struck by lightning has also increased. Numerous wind turbines are damaged by lightning strikes each year. Lightning strikes can cause significant damage to wind turbines. On the one hand, lightning damage can force the turbines to shut down, resulting in reduced power generation and direct economic losses for wind turbine operators. On the other hand, lightning damage to equipment and components can lead to significant repair costs.

[0003] To reduce the above risks, it is necessary to establish a wind turbine lightning transient model and evaluate the wind turbine lightning overvoltage. The wind turbine body is composed of blades, towers, and grounding systems. The existing wind turbine lightning transient modeling process does not take into account the actual structure of the wind turbine. Currently, the equivalent circuit method or electromagnetic field method is mostly used to establish the wind turbine transient model. Among them, the circuit method only represents the conductor as a circuit branch and does not consider the magnetic coupling between conductors. The electromagnetic field method requires the discretization of the spatial medium and the calculation time is long. That is, the following problems still exist in the field of wind turbine lightning protection:

[0004] (1) The wind turbine model consists of blades, towers, and grounding systems. Existing model studies have greatly simplified the wind turbine and ignored the actual structure of the turbine.

[0005] (2) The currently commonly used equivalent circuit modeling method only represents the conductor as a circuit branch, and the electrical parameters of the conductor are expressed using analytical formulas, without considering the magnetic coupling between the conductors;

[0006] (3) The currently commonly used electromagnetic field modeling method requires discretization of the spatial medium, which makes the model too complex and the calculation time is long. Summary of the Invention

[0007] In order to solve the defect of the above-mentioned prior art that wind turbine modeling is difficult, the present invention proposes a modeling method for a lightning transient model of a wind turbine, which adopts the PEEC (partial element equivalent circuit) method to construct the equivalent circuit of the wind turbine, taking into account the actual structure of the wind turbine and the magnetic coupling between the conductors. The model has high accuracy and short calculation time.

[0008] The present invention proposes a method for modeling a lightning transient model of a wind turbine generator system, comprising the following steps:

[0009] S1. Construct a multi-conductor system corresponding to each component of the wind turbine generator set. The method for constructing a multi-conductor system for a single component is: divide the component into multiple conductor segments, and the length of each conductor segment is less than or equal to λ min / 10,λ min is the wavelength corresponding to the highest frequency in the lightning current spectrum; all conductor segments divided from a component constitute a multi-conductor system of the component;

[0010] S2. Establish a quasi-static PEEC model for each conductor segment of each component;

[0011] S3. All quasi-static PEEC models are combined to form the PEEC equivalent circuit model of the wind turbine.

[0012] Preferably, the component of the wind turbine generator set includes a tower, and the method for dividing the conductor segments of the tower includes the following steps:

[0013] SA1. Equivalently represent the tower as a cylindrical frustum, where the top surface of the cylindrical frustum is the inscribed polygon of the tower top, and the bottom surface of the cylindrical frustum is the inscribed polygon of the tower bottom;

[0014] SA2. Set the conductor segments of the tower. The sum of the lengths of all the conductor segments of the tower is equal to the sum of the edge lengths of the cylindrical frustum. The cross-sectional area of ​​the conductor segment is a circular surface with the tower thickness as the diameter.

[0015] Preferably, in SA1, the top surface of the cylindrical frustum has a side length equal to Δl h1 The bottom surface of the cylindrical frustum is an equilateral polygon with a side length equal to Δl h2 an equilateral polygon;

[0016]

[0017]

[0018] Among them, R1 is the radius of the tower top, that is, the average of the radius of the circle where the inner wall of the tower top is located and the radius of the circle where the outer wall of the tower top is located; R2 is the radius of the tower bottom, that is, the average of the radius of the circle where the inner wall of the tower bottom is located and the radius of the circle where the outer wall of the tower bottom is located; t is the number of sides of the equilateral polygons of the top and bottom surfaces of the frustum.

[0019] Preferably, t is determined according to the following steps:

[0020] SB1. Set target impact impedance Z t0 The target impulse impedance is the impulse impedance of the tower, or the impulse impedance of the equivalent column frustum of the tower when t is set to t0; t0 is the set value;

[0021] SB2, traverse the value of t through the set {1, 2, 3, ..., t1}, t1 is the set value, and t1 is less than t0; calculate the impact impedance Z corresponding to each t t ;

[0022] SB3, from satisfaction | Z t -Z t0 | / Z t0 The minimum value among the t values ​​≤ m is selected as the final t value; m is the set floating difference ratio, m≤10%.

[0023] Preferably, t0=2πR1 / d, where d is the thickness of the tower.

[0024] Preferably, the components of the wind turbine generator set include an impeller and a grounding system;

[0025] The method for dividing the conductor segments of the impeller is as follows: the drainage long conductor of each blade in the impeller of the wind turbine is divided into a plurality of conductor segments along the length direction;

[0026] The method for dividing the conductor segments of the grounding system is as follows: determine the artificial grounding body and the natural grounding body in the grounding system, and divide the artificial grounding body and the natural grounding body into multiple conductor segments along their extension directions.

[0027] Preferably, the quasi-static PEEC model of the conductor segment includes: a first node, a second node, a resistance, an inductance, a mutual capacitance controlled source, a first capacitor, a first mutual capacitance controlled source, a second capacitor, and a second mutual capacitance controlled source;

[0028] The resistor and the inductor are connected in series between the positive electrode of the mutual capacitance controlled source and the first node, and the negative electrode of the mutual capacitance controlled source is connected to the second node; the first node is grounded via a first capacitor, and the second node is grounded via a second capacitor; the first mutual capacitance controlled source is connected in parallel with the first capacitor, and the second mutual capacitance controlled source is connected in parallel with the second capacitor;

[0029] Let the total number of conductor segments contained in the wind turbine be k; in the quasi-static PEEC model of the i-th conductor segment, the resistance value is recorded as R i , the inductance of the inductor is recorded as L ii , the voltage value of the mutual inductance controlled source is recorded as V(i,l), the voltage value of the first mutual capacitance controlled source is recorded as V(i,p1), the voltage value of the second mutual capacitance controlled source is recorded as V(i,p2), the capacitance value of the first capacitor is recorded as C(i,1), and the capacitance value of the second capacitor is recorded as C(i,2);

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038] Among them, l i is the length of the i-th conductor segment, σ i is the resistivity of the i-th conductor segment, a i is the cross-sectional area of ​​the i-th conductor segment, a i+1 is the cross-sectional area of ​​the i+1th conductor segment; μ0 is the vacuum magnetic permeability, π is the circumference; I j is the current on the jth conductor segment, P ij and P i+1，j are all potential coefficients, ε0 is the vacuum dielectric constant; i and j are both ordinal numbers, 1≦i≦k, 1≦j≦k.

[0039] Preferably, in step S3, the method of collecting all quasi-static PEEC models to form a PEEC equivalent circuit model of a wind turbine is as follows: let the first node in the quasi-static PEEC model of the i-th conductor segment be N(i) and the second node be M(i), then N(i) and M(i-1) are connected to the same potential, M(i) and N(i+1) are connected to the same potential, 1≦i-1≦k, 1≦i+1≦k, M(i-1) is the second node in the quasi-static PEEC model of the i-1-th conductor segment, and N(i+1) is the first node in the quasi-static PEEC model of the i+1-th conductor segment.

[0040] The present invention also proposes a modeling system and storage medium for a wind turbine lightning transient model, which are used to carry the above-mentioned modeling method for a wind turbine lightning transient model, so as to promote the application of the method.

[0041] The present invention proposes a modeling system for a lightning transient model of a wind turbine generator set, comprising a memory and a processor. The memory stores a computer program, and the processor is used to execute the computer program to implement the modeling method for the lightning transient model of the wind turbine generator set.

[0042] The present invention provides a storage medium storing a computer program, which is used to implement the modeling method of the lightning transient model of a wind turbine generator set when the computer program is executed.

[0043] The advantages of the present invention are:

[0044] (1) In the present invention, the multi-conductor system of each component of the wind turbine is first obtained, and the multi-conductor system of each component is constructed by multiple conductor segments. Then, the quasi-static PEEC models of all the conductor segments are combined to form the PEEC equivalent circuit model of the wind turbine. The present invention uses the PEEC method to perform electromagnetic transient analysis on the wind turbine multi-conductor system. By dividing the conductor segments, when modeling, the spatial medium is not discretized, and only the conductors are discretized. Compared with general electromagnetic field methods, the present invention simplifies the model and shortens the calculation time.

[0045] (2) The present invention adopts the PEEC method to establish a lightning transient calculation model of the wind turbine generator set body including blades, tower, and grounding system, namely, a quasi-static PEEC model, which takes into account the actual structure of the wind turbine generator set and can realize the accurate calculation of the lightning transient characteristics of the wind turbine generator set body.

[0046] (3) The present invention selects the partial element equivalent circuit (PEEC) method to construct an equivalent circuit, which is derived from the mixed potential integral equation and converts the electromagnetic problem into the circuit domain. Although the model is represented by lumped circuit elements, all electromagnetic effects are retained and the magnetic coupling between conductors can be accurately considered.

[0047] (4) In the present invention, the number of edges of the tower is selected according to the impact impedance, which is beneficial to reducing the number of edges as much as possible while ensuring the accuracy of equivalent circuit construction, reducing calculation complexity and improving calculation efficiency.

[0048] (5) In the present invention, t0 is calculated based on the ratio of the tower top circumference to the tower thickness, and then the target impact impedance is calculated. Field experience and simulations have shown that this t0 can achieve a high-precision equivalent circuit model for a wind turbine. Thus, the present invention provides a reliable method for obtaining t0, further simplifying the construction of the tower's multi-conductor system and improving the overall modeling efficiency and accuracy of the wind turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 Schematic diagram of the quasi-static PEEC model;

[0050] Figure 2 A schematic diagram of the process of the modeling method of the present invention;

[0051] Figure 3(a) is a partial schematic diagram of the PEEC equivalent circuit model of a wind turbine;

[0052] Figure 3(b) is a schematic diagram of the connection of the PEEC equivalent circuit model of the wind turbine;

[0053] Figure 4 Schematic diagram of the multi-conductor system of the impeller;

[0054] Figure 5This is a schematic diagram of the multi-conductor system of the tower;

[0055] Figure 6 Schematic diagram of a multi-conductor system for a grounding system. DETAILED DESCRIPTION

[0056] A quasi-static PEEC model

[0057] In this embodiment, a quasi-static PEEC model of a cylindrical conductor with known length and cross-sectional area is proposed, which includes: a first node N, a second node M, a resistor R, an inductor L, a mutual capacitance controlled source UP, a first capacitor C1, a first mutual capacitance controlled source UP1, a second capacitor C2, and a second mutual capacitance controlled source UP2.

[0058] The resistor R and the inductor L are connected in series between the positive electrode of the mutual inductance controlled source UP and the first node N, and the negative electrode of the mutual inductance controlled source UP is connected to the second node M; the first node N is grounded through the first capacitor C1, and the second node M is grounded through the second capacitor C2; the first mutual capacitance controlled source UP1 is connected in parallel with the first capacitor C1, and the second mutual capacitance controlled source UP2 is connected in parallel with the second capacitor C2.

[0059] When constructing a circuit, the first node N and the second node M are equivalent to the two ends of the cylindrical conductor.

[0060] PEEC equivalent circuit model of wind turbine

[0061] In this embodiment, each component of the wind turbine is first equivalent to a collection of multiple cylindrical conductor segments, and the length and cross-sectional area of ​​each conductor segment are calculated; then, the quasi-static PEEC model of each conductor segment is obtained, and the quasi-static PEEC models of all conductor segments are connected in series to form a PEEC equivalent circuit model of the wind turbine.

[0062] In this embodiment, the quasi-static PEEC model for the conductor segment is as described above. Let the first node in the quasi-static PEEC model of the i-th conductor segment be N(i) and the second node be M(i). Then, N(i) and M(i-1) are connected to each other at the same potential, and M(i) and N(i+1) are connected to each other at the same potential. M(i-1) is the second node in the quasi-static PEEC model of the i-1-th conductor segment, and N(i+1) is the first node in the quasi-static PEEC model of the i+1-th conductor segment. 1≦i≦k, 1≦i-1≦k, 1≦i+1≦k; k is the total number of conductor segments included in the wind turbine, that is, the sum of the number of conductor segments corresponding to each component of the wind turbine.

[0063] In the quasi-static PEEC model of the i-th conductor segment of the PEEC equivalent circuit model, the resistance value of the resistor R is denoted as R i , the inductance value of the inductor L is recorded as L ii, the voltage value of the mutual inductance controlled source UP is recorded as V(i,l), the voltage value of the first mutual capacitance controlled source UP1 is recorded as V(i,p1), the voltage value of the second mutual capacitance controlled source UP2 is recorded as V(i,p2), the capacitance value of the first capacitor C1 is recorded as C(i,1), and the capacitance value of the second capacitor C2 is recorded as C(i,2);

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] Among them, l i is the length of the i-th conductor segment, σ i is the resistivity of the i-th conductor segment, a i is the cross-sectional area of ​​the i-th conductor segment, a i+1 is the cross-sectional area of ​​the i+1th conductor segment; μ0 is the vacuum magnetic permeability, π is the circumference; I j is the current on the jth conductor segment, P ij and P i+1，j are all potential coefficients, ε0 is the vacuum dielectric constant; i and j are both ordinal numbers, 1≦i≦k, 1≦j≦k.

[0072] It can be seen that in this embodiment, the values ​​of the resistance R, the inductor L, the first capacitor C1 and the second capacitor C2 are determined by the material and size parameters of the conductor segment itself, and the values ​​of the mutual inductance controlled source UP, the first mutual capacitance controlled source UP1 and the second mutual capacitance controlled source UP2 take into account the electrical parameters of other conductor segments in the equivalent circuit, thereby ensuring the accuracy of the PEEC equivalent circuit model of the wind turbine generator set.

[0073] When designing the conductor segments of components of a wind turbine, the smaller the length of the conductor segments, the higher the accuracy of the wind turbine PEEC equivalent circuit model, but the greater the difficulty of calculation. In this embodiment, the length of the conductor segments is limited to be less than or equal to λ min / 10, to balance model accuracy and computational difficulty, λ min It is the wavelength corresponding to the highest frequency in the lightning current spectrum.

[0074] The components of a wind turbine include rotors, towers and grounding systems.

[0075] Impeller conductor segment division method

[0076] The impeller includes multiple blades, each of which is provided with a conductor serving as a drain conductor. The equivalent circuit of the impeller can be regarded as a multi-chain circuit consisting of drain conductors connected at the roots of the blades. A multi-chain circuit consisting of three drain conductors is shown in FIG. Figure 4 In specific implementation, the nth drainage long conductor in the blade can be divided into pieces with a length of Δl bn Multiple conductor segments are obtained to obtain the conductor segments corresponding to the impeller. Figure 4 As shown, the impeller includes three blades, and its three drainage long conductors are respectively b1 , Δl b2 and Δl b3 Split conductor segments.

[0077] The tower of the wind turbine generator set is a conical structure. In this embodiment, two methods for dividing the conductor segments of the tower are provided.

[0078] Tower conductor segment division method

[0079] In this embodiment, the method for dividing the conductor segments of the tower includes the following steps:

[0080] SA1. The tower is equivalent to a cylindrical frustum, where the top surface of the cylindrical frustum is the inscribed polygon at the top of the tower, and the bottom surface of the cylindrical frustum is the inscribed polygon at the bottom of the tower. In specific implementation, the top of the tower can be equivalent to a polygon with a side length equal to Δl. h1 The bottom of the tower is equivalent to an equilateral polygon with a side length equal to Δl h2 The two equilateral polygons have the same number of sides; the corresponding vertices of the two equilateral polygons are connected to form the edges of the cylindrical frustum, as shown in the following example: Figure 5 shown.

[0081] SA2. Set the conductor segments of the tower. The sum of the lengths of all the conductor segments of the tower is equal to the sum of the edge lengths of the cylindrical frustum. The cross-sectional area of ​​the conductor segment is a circular surface with the tower thickness as the diameter.

[0082] In specific implementation, each side of the equilateral polygon at the top of the column frustum, i.e., the top edge, can be regarded as a length of Δl. h1 The conductor segment is considered as each side of the equilateral polygon at the bottom of the cone, i.e. the bottom edge, with a length of Δl h2 conductor segment, divide each side edge of the cylindrical frustum into equal parts of length Δl v conductor segment.

[0083]

[0084]

[0085] Among them, R1 is the radius of the tower top, that is, the average of the radius of the circle where the inner wall of the tower top is located and the radius of the circle where the outer wall of the tower top is located; R2 is the radius of the tower bottom, that is, the average of the radius of the circle where the inner wall of the tower bottom is located and the radius of the circle where the outer wall of the tower bottom is located; t is the number of sides of the equilateral polygons of the top and bottom surfaces of the frustum.

[0086] In this embodiment, the t value may be determined according to the equivalent impact impedance of the tower.

[0087] When the value of t is known, the impact impedance Z of the column cone corresponding to the tower when t takes any value can be obtained by combining formulas (8) and (9) through software simulation and other means. t In this embodiment, the impact impedance Z t With the set target impact impedance Z t0 The floating difference determines whether the t value meets the requirements.

[0088] In specific implementation, multiple t values ​​can be traversed, and the minimum value among the t values ​​that meet the impact impedance requirements can be selected to construct a cylindrical cone equivalent to the tower, so as to reduce the amount of calculation as much as possible and improve the calculation efficiency in the subsequent construction of the equivalent circuit model of the wind turbine.

[0089] Method for dividing conductor segments of grounding system

[0090] In this embodiment, the artificial grounding body and the natural grounding body in the grounding system are first identified, and then the artificial grounding body and the natural grounding body are respectively divided to obtain multiple conductor segments. In specific implementation, the artificial grounding body is cut along its extension direction, that is, the cross-sectional area of ​​the conductor segments into which the artificial grounding body is divided is the cross-sectional area of ​​the artificial grounding body; the natural grounding body is cut along its extension direction, that is, the cross-sectional area of ​​the conductor segments into which the natural grounding body is divided is the cross-sectional area of ​​the natural grounding body. This facilitates the confirmation of the size parameters of the conductor segments, fully takes into account the shape differences between the artificial and natural grounding bodies, and further reduces the difficulty of grounding system analysis.

[0091] Example

[0092] In this embodiment, a specific wind turbine is modeled. The wind turbine parameters in this embodiment are as follows:

[0093] The number of blades included in the impeller = 3;

[0094] The cross-sectional area of ​​the drainage long conductor set on the blade is 75mm 2 ;

[0095] The grounding system adopts the Class A grounding device proposed in the international standard IEC61400-24. The grounding system includes a ring-shaped artificial grounding body and no less than two vertical grounding electrodes as natural grounding bodies. The cross-sectional area of ​​the artificial grounding body and the vertical grounding electrode is 100mm. 2 The conductor, that is, the artificial grounding body has a cross-sectional area of ​​100mm 2 The cross-sectional area of ​​the vertical grounding electrode is 100mm 2 cylindrical conductor.

[0096] In this embodiment, the Figure 2 The method shown is used to construct the PEEC equivalent circuit model of the wind turbine.

[0097] First, in this embodiment, the multi-conductor systems of the impeller, tower, and grounding system are obtained respectively.

[0098] In this embodiment, the drainage long conductors corresponding to the three blades in the impeller are divided into conductor segments with reference to the above-mentioned impeller conductor segment division method. In this embodiment, Δl b1 , Δl b2 and Δl b3 They can be equal or not. It should be noted that the first long conductor is divided into n b1 Equal parts, so that the second long conductor is divided into n b2 Equal parts, make the third drain long conductor divided into n b3 The length of the first drain conductor is Δl b1 ×n b1 , then the length of the first drain conductor is Δl b2 ×n b2 , then the length of the first drain conductor is Δl b3 ×n b3 That is, the multi-conductor system of the impeller is composed of conductor segments divided by three long drainage conductors.

[0099] In this embodiment, the multi-conductor system of the impeller includes n b1 +n b2 +n b3 The cross-sectional area of ​​each conductor segment is 75 mm 2 , where n b1 The length of the root conductor segment is Δl b1 , n b2 The length of the root conductor segment is Δl b2 , n b3 The length of the root conductor segment is Δl b3 .

[0100] In this embodiment, the tower adopts the above-mentioned tower conductor segment division method.

[0101] In this embodiment, the t value is first determined. Based on professional experience, the column frustum constructed when t = 12 can better meet the accuracy requirements of the equivalent circuit model of the wind turbine. In this embodiment, the impact impedance of the column frustum constructed when t = 12 is recorded as the target impact impedance Z t0 , and set the floating error ratio m=5%.

[0102] In this embodiment, in order to improve efficiency, the impact impedance of the cylindrical frustum constructed at t=4 and t=8 is calculated respectively, and the impact impedance of the cylindrical frustum constructed at t=4 is recorded as Z4, and the impact impedance of the cylindrical frustum constructed at t=8 is recorded as Z8.

[0103] In this embodiment, Z is obtained by software simulation t0 , Z4 and Z8, according to the calculation:

[0104] |Z4-Z t0 | / Z t0 >5%

[0105] |Z8-Z t0 | / Z t0 ≤5%

[0106] Therefore, in this embodiment, the tower is equivalent to an equilateral octagonal cylindrical cone, that is, the top and bottom are both equilateral octagons, the central axes of the equilateral octagon at the top and the equilateral octagon at the bottom are collinear, and the side edges are coplanar with the central axis.

[0107] In this embodiment, each edge of the top and bottom of the column frustum is used as a separate conductor segment, and each side edge is connected with a length of Δl v Divide into equal parts.

[0108] It can be seen that in this embodiment, the multi-conductor system of the tower consists of three conductor segments;

[0109] The first part consists of 8 conductor segments, each of which has a length equal to the side length Δl of the equilateral octagon at the top of the pyramid. h1 , the cross-sectional area of ​​the conductor segment is the circumferential area with the tower thickness as the diameter;

[0110] The second part consists of 8 conductor segments, each of which has a length equal to the side length Δl of the equilateral octagon at the bottom of the cone. h2 , the cross-sectional area of ​​the conductor segment is the circumferential area with the tower thickness as the diameter;

[0111] The third part contains 8×n v Root conductor segments, the length of each conductor segment is equal to Δl v , the cross-sectional area of ​​the conductor segment is the circumferential area with the tower thickness as the diameter; n vEqual to the length of the side edge and Δl v ratio.

[0112] In this embodiment, the grounding system is divided into a ring-shaped artificial grounding body and multiple vertical grounding electrodes. In this embodiment, the multi-conductor system of the grounding system includes two parts:

[0113] The first part includes the ring-shaped artificial grounding body divided along the circumferential direction. g1 conductor segments, the length of the conductor segment is Δl g1 , the cross-sectional area of ​​the conductor segment is 100mm 2 ;

[0114] The second part contains z×n g2 conductor segments, the length of the conductor segment is Δl g2 , the cross-sectional area of ​​the conductor segment is 100mm 2 ;n g2 Equal to the ratio of the length of the vertical grounding electrode to Δl g2 .

[0115] Thus, in this embodiment, the wind turbine generator system includes k=n b1 +n b2 +n b3 +16+8×n v +n g1 +n g2 The length and cross-sectional area of ​​each conductor segment are known.

[0116] In this embodiment, each conductor segment is equivalent to the above-mentioned quasi-static PEEC model, and then the quasi-static PEEC models of all conductor segments are connected in series to form the above-mentioned PEEC equivalent circuit model. Figure 1 , Figure 3(a) and Figure 3(b); the values ​​of each electrical component in the PEEC equivalent circuit model can be calculated according to formulas (1) to (7).

[0117] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A modeling method for a lightning transient model of a wind turbine generator set, characterized in that: The following steps are involved: S1. Construct a multi-conductor system corresponding to each component of the wind turbine generator set. The method for constructing a multi-conductor system for a single component is: divide the component into multiple conductor segments, and the length of each conductor segment is less than or equal to λ min / 10,λ min is the wavelength corresponding to the highest frequency in the lightning current spectrum; all conductor segments divided from a component constitute a multi-conductor system of the component; S2. Establish a quasi-static PEEC model for each conductor segment of each component; S3, combining all quasi-static PEEC models to form a PEEC equivalent circuit model of the wind turbine; The quasi-static PEEC model of the conductor segment includes: a first node, a second node, a resistance, an inductance, a mutual capacitance controlled source, a first capacitor, a first mutual capacitance controlled source, a second capacitor, and a second mutual capacitance controlled source. The resistor and the inductor are connected in series between the positive electrode of the mutual capacitance controlled source and the first node, and the negative electrode of the mutual capacitance controlled source is connected to the second node; the first node is grounded via a first capacitor, and the second node is grounded via a second capacitor; the first mutual capacitance controlled source is connected in parallel with the first capacitor, and the second mutual capacitance controlled source is connected in parallel with the second capacitor; Let the total number of conductor segments contained in the wind turbine be k; in the quasi-static PEEC model of the i-th conductor segment, the resistance value is recorded as R i , the inductance of the inductor is recorded as L ii , the voltage value of the mutual inductance controlled source is recorded as V(i,l), the voltage value of the first mutual capacitance controlled source is recorded as V(i,p1), the voltage value of the second mutual capacitance controlled source is recorded as V(i,p2), the capacitance value of the first capacitor is recorded as C(i,1), and the capacitance value of the second capacitor is recorded as C(i,2); Among them, l i is the length of the i-th conductor segment, σ i is the resistivity of the i-th conductor segment, a i is the cross-sectional area of ​​the i-th conductor segment, a i+1 is the cross-sectional area of ​​the i+1th conductor segment; μ0 is the vacuum magnetic permeability, π is the circumference; I j is the current on the jth conductor segment, P ij and P i+1，j are all potential coefficients, ε0 is the vacuum dielectric constant; i, j are both ordinal numbers, 1≦i≦k, 1≦j≦k; In step S3, the method of combining all quasi-static PEEC models to form the PEEC equivalent circuit model of the wind turbine is as follows: let the first node in the quasi-static PEEC model of the i-th conductor segment be N(i) and the second node be M(i), then N(i) and M(i-1) are connected to the same potential, M(i) and N(i+1) are connected to the same potential, 1≦i-1≦k, 1≦i+1≦k, M(i-1) is the second node in the quasi-static PEEC model of the i-1-th conductor segment, and N(i+1) is the first node in the quasi-static PEEC model of the i+1-th conductor segment.

2. The method for modeling a lightning transient model of a wind turbine generator set according to claim 1, wherein: The components of the wind turbine generator set include a tower, and the method for dividing the conductor segments of the tower includes the following steps: SA1. Equivalently represent the tower as a cylindrical frustum, where the top surface of the cylindrical frustum is the inscribed polygon of the tower top, and the bottom surface of the cylindrical frustum is the inscribed polygon of the tower bottom; SA2. Set the conductor segments of the tower. The sum of the lengths of all the conductor segments of the tower is equal to the sum of the edge lengths of the cylindrical frustum. The cross-sectional area of ​​the conductor segment is a circular surface with the tower thickness as the diameter.

3. The method for modeling a lightning transient model of a wind turbine generator set according to claim 2, wherein: In SA1, the top surface of the cylindrical frustum is equal to Δl h1 The bottom surface of the cylindrical frustum is an equilateral polygon with a side length equal to Δl h2 an equilateral polygon; Among them, R1 is the radius of the tower top, that is, the average of the radius of the circle where the inner wall of the tower top is located and the radius of the circle where the outer wall of the tower top is located; R2 is the radius of the tower bottom, that is, the average of the radius of the circle where the inner wall of the tower bottom is located and the radius of the circle where the outer wall of the tower bottom is located; t is the number of sides of the equilateral polygons of the top and bottom surfaces of the frustum.

4. The method for modeling a lightning transient model of a wind turbine generator set according to claim 3, wherein: t is determined according to the following steps: SB1. Set target impact impedance Z t0 The target impulse impedance is the impulse impedance of the tower, or the impulse impedance of the equivalent column frustum of the tower when t is set to t0, where t0 is the set value; SB2, traverse the value of t through the set {1, 2, 3, ..., t1}, t1 is the set value, and t1 is less than t0; calculate the impact impedance Z corresponding to each t t ; SB3, from satisfaction | Z t -Z t0 | / Z t0 The minimum value among the t values ​​≤ m is selected as the final t value; m is the set floating difference ratio, m≤10%.

5. The method for modeling a lightning transient model of a wind turbine generator set according to claim 4, wherein: t0=2πR1 / d, d is the thickness of the tower.

6. The method for modeling a lightning transient model of a wind turbine generator set according to claim 1, wherein: The components of a wind turbine include the impeller and the grounding system; The method for dividing the conductor segments of the impeller is as follows: the drainage long conductor of each blade in the impeller of the wind turbine is divided into a plurality of conductor segments along the length direction; The method for dividing the conductor segments of the grounding system is as follows: determining an artificial grounding body and a natural grounding body in the grounding system, and dividing the artificial grounding body and the natural grounding body into a plurality of conductor segments along their extension directions.

7. A modeling system for a lightning transient model of a wind turbine generator set, characterized in that: The invention comprises a memory and a processor, wherein the memory stores a computer program, and the processor is used to execute the computer program to implement the modeling method of the lightning transient model of a wind turbine generator set according to any one of claims 1 to 6.

8. A storage medium, characterized in that: A computer program is stored, and when the computer program is executed, it is used to implement the modeling method of the lightning transient model of the wind turbine generator set according to any one of claims 1 to 6.

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