Impact traveling wave withstand voltage test device and test method for long-distance GIL

Abstract

The invention provides a long-distance GIL impact traveling wave withstand voltage test device and method, the device comprises an impact voltage generator, a high-voltage connection mechanism and a tail end integration mechanism, the impact voltage generator is connected with one end of a gas insulated transmission line GIL with the kilometer-level length through the high-voltage connection mechanism, and the other end of the gas insulated transmission line GIL is connected with the tail end integration mechanism through the high-voltage connection mechanism. The other end of the GIL is connected with the tail end integration mechanism, and the impulse voltage generator comprises a first capacitor, a switch and a second capacitor which are connected in sequence; the high-voltage connecting mechanism comprises a first high-voltage busbar or a direct-insertion type contact finger; and the tail end integration mechanism comprises a resistance-capacitance network which is connected in series and is used for realizing frequency-variable impedance. According to the invention, the impact voltage assessment of the long-distance GIL is realized, the effectiveness of a field voltage withstand test is improved, and the insulation reliability of the long-distance GIL is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of electric power equipment, and in particular relates to an impulse traveling wave withstand voltage test device and a test method for a long-distance GIL. Background Art

[0002] With the development of power systems, long-distance, large-capacity gas-insulated transmission lines (GIL) have been widely used in power transmission. The transmission capacity of GIL is extremely large. Once discharge occurs, the impact on the power grid is extremely large. Therefore, GIL has extremely high requirements for insulation reliability. However, GIL will inevitably cause some defects such as bumps, scratches, and foreign matter mixing during transportation and on-site installation, which directly threaten the insulation reliability of GIL. At present, on-site withstand voltage test is the key link to inspect and assess the aforementioned insulation defects. Efficient and reliable on-site withstand voltage test is the prerequisite for ensuring the insulation reliability of GIL.

[0003] For the insulation assessment of GIL, power frequency withstand voltage and impulse withstand voltage are the two most common and mature test assessment methods. The two test methods have different specificities. Among them, power frequency withstand voltage is more effective in detecting defects such as suspended defects and insulating component cavities, but its effectiveness in detecting defects such as busbar spikes and foreign objects along the surface is poor. Impact withstand voltage is more sensitive to the detection of defects such as busbar spikes and foreign objects along the surface. Therefore, the above two types of test assessment methods complement each other and are indispensable.

[0004] For long-distance GIL, its capacity is very large, and the requirements for the test system are extremely high. It is still feasible to carry out power frequency withstand voltage test on site, but it is very difficult to carry out impulse withstand voltage test, especially when the length of GIL exceeds the kilometer level. The equivalent capacitance of GIL is as high as hundreds of nF, which has obviously exceeded the existing domestic and foreign technical level (the inductance of the existing impulse voltage test device exceeds the requirement, which is 100μH), and it cannot be achieved yet. This will lead to insufficient on-site testing of long-distance GIL, which will significantly affect the reliability of long-distance GIL.

[0005] Therefore, it is necessary to design an impact traveling wave withstand voltage test device and test method for a long-distance GIL to solve the above-mentioned technical problems. Summary of the invention

[0006] In view of the above problems, the present invention provides an impulse traveling wave withstand voltage test device for a long-distance GIL, characterized in that the device comprises an impulse voltage generator, a high-voltage connection mechanism and a terminal integration mechanism, wherein the impulse voltage generator is connected to one end of a gas-insulated transmission line GIL of a kilometer-level length through the high-voltage connection mechanism, and the other end of the GIL is connected to the terminal integration mechanism, wherein:

[0007] The impulse voltage generator comprises a first capacitor, a switch and a second capacitor connected in sequence;

[0008] The high-voltage connection mechanism comprises a first high-voltage busbar or a direct-insertion contact finger;

[0009] The terminal integrated mechanism includes a series-connected resistor-capacitor network for realizing frequency-variable impedance.

[0010] Furthermore, the impulse voltage generator is vertical or horizontal.

[0011] Furthermore, when the impulse voltage generator is vertical, the high-voltage connection mechanism includes a first high-voltage busbar, and the impulse voltage generator is connected to the GIL via the first high-voltage busbar. Specifically:

[0012] The GIL includes bushings at both ends and a GIL pipe gallery between the two bushings. The bushing includes an outer shell and a hollow conductor rod inside the outer shell. The top of the hollow conductor rod is connected to the outer shell. The top of the bushing is electrically connected to the impulse voltage generator through the first high-voltage busbar. The bottom of the bushing is also electrically connected to the impulse voltage generator through another first high-voltage busbar for grounding. The bottom of the hollow conductor rod is also electrically connected to the GIL pipe gallery. The steep impulse traveling wave voltage is directly injected from the bushing into the GIL pipe gallery. The inductance of the first high-voltage busbar connection can be estimated using the following formula:

[0013] L1=10 -6 *1

[0014] Where L1 is the inductance of the first high-voltage busbar, unit: H / m.

[0015] Furthermore, the diameter of the hollow conductor rod is not less than 5 cm and the length is not more than 5 m.

[0016] Furthermore, when the impulse voltage generator is horizontal, the high-voltage connection mechanism includes direct-plug contacts and two second high-voltage busbars, and the impulse voltage generator is connected to the GIL through the direct-plug contacts and the two second high-voltage busbars. Specifically:

[0017] The GIL includes bushings at both ends and a GIL pipe gallery between the two bushings. The bushing includes an outer shell and a hollow conductor rod inside the outer shell. The top of the hollow conductor rod is connected to the outer shell. The bottom of the hollow conductor rod is connected to one end of one of the second high-voltage busbars. The busbar at the other end of the second high-voltage busbar is connected to the female head of the plug-in contact finger. The impulse voltage generator is connected to one end of another second high-voltage busbar. The busbar at the other end of the second high-voltage busbar is connected to the male head of the plug-in contact finger. The male head and the female head of the plug-in contact finger are connected. The inductance of the second high-voltage busbar connected to the plug-in contact finger can be estimated by the following formula:

[0018]

[0019] In the formula, L2 is the inductance of the second high-voltage busbar, in H / m; D is the inner diameter of the outer layer of the second high-voltage busbar, in m; d is the outer diameter of the inner layer of the second high-voltage busbar, in m; f is the frequency, in Hz.

[0020] Furthermore, the outer layer of the direct-insertion contact finger has the same diameter as the GIL shell, and the inner layer has the same diameter as the busbar of the GIL.

[0021] On the other hand, the present invention also provides a test method for a long-distance GIL impulse traveling wave withstand voltage test device, wherein the test device adopts the test device as described above, and the test method comprises:

[0022] Step S102: obtaining design parameters of the GIL;

[0023] Step S104: constructing a GIL impulse traveling wave simulation circuit model and simulating the propagation characteristics of the impulse voltage traveling wave in the GIL;

[0024] Step S106: Simulate and calculate the electromagnetic transient process of the impulse voltage and evaluate its risk.

[0025] Furthermore, step S102 specifically includes:

[0026] Obtain the size parameters, rated voltage and insulation level of the GIL;

[0027] Formulate field test equipment selection, test technology plan and experimental procedures.

[0028] Furthermore, step S104 specifically includes:

[0029] Establish the circuit model of GIL according to its design parameters and combined with the distributed parameter characteristics;

[0030] Construct an electromagnetic transient simulation model for the GIL corridor impact traveling wave withstand test;

[0031] Set the waveform parameters of the impulse voltage and run the propagation process of the impulse voltage traveling wave in the GIL;

[0032] The propagation speed and attenuation characteristics of the impulse voltage traveling wave are obtained based on the simulation results.

[0033] Furthermore, step S106 specifically includes:

[0034] Calculate the electromagnetic field distribution of GIL under the impact voltage and obtain the electromagnetic transient process of GIL under the impact voltage, and evaluate its risk;

[0035] Analyze the impact of impulse voltage on GIL insulation performance and assess the possibility of insulation damage;

[0036] Consider the thermal and mechanical effects of the GIL and its related components under the impact of voltage surges and assess the risk of equipment damage;

[0037] Comprehensively analyze the impact of impulse voltage on the overall power system and assess the risks of system stability and reliability.

[0038] The beneficial effects of the present invention are:

[0039] The present invention discloses an impulse traveling wave withstand voltage test device and test method for a long-distance GIL. The device utilizes the wave impedance characteristics of the long-distance GIL and injects a traveling wave impulse voltage into the long-distance GIL through an impulse voltage generator. The impulse voltage assessment of the long-distance GIL is achieved through the propagation of the traveling wave impulse voltage in the long-distance GIL, thereby improving the effectiveness of the on-site withstand voltage test and the insulation reliability of the long-distance GIL.

[0040] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 A circuit diagram of an impulse voltage generator according to an embodiment of the present invention is shown;

[0043] Figure 2 It shows a structural diagram of a test device using a vertical impulse voltage generator according to an embodiment of the present invention;

[0044] Figure 3 It shows a structural diagram of a test device using a horizontal impulse voltage generator according to an embodiment of the present invention;

[0045] Figure 4 The structure diagram of the test device using a horizontal impulse voltage generator according to an embodiment of the present invention is shown.

[0046] Figure 5 A flow chart of a test method according to an embodiment of the present invention is shown;

[0047] Figure 6The equivalent circuit of a uniform lossless single-conductor line unit according to an embodiment of the present invention is shown;

[0048] Figure 7 A schematic diagram of refraction and reflection of waves according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] like Figure 1 As shown, the present invention provides an impulse traveling wave withstand voltage test device for a long-distance GIL, the device comprising an impulse voltage generator 1, a high-voltage connection mechanism and a terminal integration mechanism, wherein the impulse voltage generator 1 is connected to one end of a gas-insulated transmission line GIL 3 with a length of kilometers through the high-voltage connection mechanism, and the other end of the GIL 3 is connected to the terminal integration mechanism.

[0051] Among them, the impulse voltage generator 1 is vertical or horizontal, and adopts a "capacitor + switch + capacitor" unit module with extremely low inductance, that is, it includes a first switch 5, a first capacitor 3, a resistor 1, a second capacitor 2 and a third switch 4 connected in sequence, wherein the first switch and the second switch are two non-contacting metal balls, and the two capacitors are charged to accumulate positive and negative charges on the metal balls respectively, and after accumulating to a certain extent, a breakdown occurs between the two metal balls. The first capacitor 3, the switch 5 and the second capacitor 2 are arranged in a linear manner, so as to achieve an extremely low total inductance of the device, providing a basis for the application of steep impulse traveling waves of ultra-large capacity and ultra-long distance GIL3; the high-voltage (rated impulse withstand voltage value of 550kV equipment is 1675kV) connection mechanism includes a first high-voltage busbar or a plug-in contact finger; the terminal integration mechanism includes a series-connected resistor-capacitor network (resistance-capacitor oscillation circuit) for realizing frequency-variable impedance, which can not only meet the voltage division measurement under steep traveling wave voltage, but also realize the terminal impedance matching of long-distance GIL 3.

[0052] The test device of the present invention is described in detail below.

[0053] Example 1

[0054] like Figure 2As shown, when the impulse voltage generator 1 is vertical, the high-voltage connection mechanism includes a first high-voltage busbar. Specifically, the GIL includes bushings at both ends and a GIL pipe gallery between the two bushings. The inner layer of the bushing 2 includes an outer shell and a hollow conductor rod inside the outer shell (the top of the hollow conductor rod is connected to the outer shell). The top and the middle are both grading rings, and the bottom is a base. The top of the bushing 2 is electrically connected to the impulse voltage generator 1 through the first high-voltage busbar 6, and the bottom of the bushing 2 is also electrically connected to the impulse voltage generator 1 through another first high-voltage busbar 6 for grounding. The bottom of the hollow conductor rod is also connected to the GIL 3 pipe gallery. The steep impulse traveling wave voltage can eventually be injected into the GIL 3 pipe gallery through the bushing 2. The diameter of the hollow conductor rod is not less than 5 cm, the length does not exceed 5 m, and should be as short as possible, so as to further reduce the inductance of the steep impulse traveling wave application loop and reduce the rise time of the steep impulse traveling wave.

[0055] In the present invention, the first high-voltage busbar 6 is used for connection in order to meet the requirements of its compact structure, current transmission capacity, heat dissipation performance, installation and maintenance, etc., wherein the inductance of the first high-voltage busbar 6 connection can be estimated by the following formula:

[0056] L1=10 -6 *1

[0057] Wherein, L1 is the inductance of the first high-voltage busbar 6, in H / m.

[0058] Example 2

[0059] like Figure 3 As shown, when the impulse voltage generator 1 is horizontal, the high-voltage connection mechanism includes a plug-in contact finger 7 and two second high-voltage busbars 8, wherein the impulse voltage generator is connected to the GIL 3 through the plug-in contact finger 7. Specifically, the GIL 3 includes a bushing 2 at both ends and a GIL corridor between the two bushings 2, the bushing 2 includes an outer shell and a hollow conductor rod inside the outer shell, the top of the hollow conductor rod is connected to the outer shell, the bottom of the hollow conductor rod is connected to one end of one of the second high-voltage busbars 8, the busbar 81 at the other end of the second high-voltage busbar 8 is connected to the female head 71 of the plug-in contact finger 7, the impulse voltage generator 1 is connected to one end of another second high-voltage busbar 8, the busbar 81 at the other end of the second high-voltage busbar 8 is connected to the male head 72 of the plug-in contact finger 7, the male head 72 of the plug-in contact finger is butted with the female head 71, and the plug-in contact finger 7 is used to perform a quick plug-in function with the horizontal voltage generator 1, and the outer layer of the plug-in contact finger 7 is connected to the GIL 3 shells are of equal diameter, and the inner layer is of equal diameter to the busbar of GIL 3 (located inside the GIL pipe gallery), thereby realizing the quick docking function and realizing the inductance of the steep shock traveling wave application loop, reducing the rise time of the steep shock traveling wave.

[0060] In addition, in the present invention, as shown in Figure 4, a pot-type insulator is installed on one of the second high-voltage busbars, and a groove is opened on the outer wall of the male head 72, in which an annular spring 73 is installed (the annular spring can be made of a metal material with good conductivity), so that the male head 72 can be squeezed into the groove of the female head 71.

[0061] In the present invention, the direct plug-in contact finger 7 is used for docking in order to enhance its advantages in structural robustness, high frequency characteristics, shielding effect and adaptability to application scenarios. The inductance of the second high-voltage busbar 8 docked by the direct plug-in contact finger 7 can be estimated by the following formula:

[0062]

[0063] In the formula, L2 is the inductance of the second high-voltage busbar 8, which is composed of the internal inductance of the inner and outer conductors (the inner and outer layers of the second high-voltage busbar 8) and the external inductance between the inner and outer conductors, and the unit is H / m; D is the inner diameter of the outer conductor of the second high-voltage busbar 8, and the unit is m; d is the outer diameter of the inner conductor of the second high-voltage busbar 8, and the unit is m; f is the frequency, and the unit is Hz.

[0064] like Figure 5 As shown, the present invention also provides a test method using the above test device, which is described in detail below.

[0065] The test method includes:

[0066] Step S102: obtaining the design parameters of GIL 3 to carry out the on-site shock traveling wave withstand test plan and feasibility analysis of GIL 3;

[0067] Step S104: constructing a GIL 3 impulse traveling wave simulation circuit model and simulating the propagation characteristics of the impulse voltage traveling wave in the GIL 3;

[0068] Step S106: Simulate and calculate the electromagnetic transient process of the impulse voltage and evaluate its risk.

[0069] In some embodiments of the present invention, step S102 specifically includes:

[0070] Get the dimensional parameters, rated voltage and insulation level of GIL 3;

[0071] Formulate field test equipment selection, test technical plan and test procedures;

[0072] Conduct technical feasibility analysis and safety analysis.

[0073] In some embodiments of the present invention, step S104 specifically includes:

[0074] According to the design parameters of GIL 3 and the distributed parameter characteristics, the circuit model is established. Through the simulation of this model, the overvoltage waveforms at each key component (such as the first and tail end casings, etc.) can be obtained, so as to analyze the propagation law of impulse traveling waves in the GIL3 pipe gallery.

[0075] The electromagnetic transient simulation model of the GIL corridor impulse traveling wave withstand voltage test is constructed. The model consists of an impulse voltage generator, a bushing, a GIL corridor, and a basin insulator, a three-pillar insulator (e.g. Figure 2 As shown, the pot insulator 4 can be sleeved at the end of the GIL busbar, and the three-pillar insulator 5 can be sleeved at other parts of the GIL, such as the middle part), etc., which can realize the simulation of the withstand voltage test of the GIL system;

[0076] Set the impulse voltage waveform parameters and run the impulse voltage traveling wave propagation process in GIL 3;

[0077] The propagation speed and attenuation characteristics of the impulse voltage traveling wave are obtained based on the simulation results.

[0078] In some embodiments of the present invention, step S106 specifically includes:

[0079] Calculate the electromagnetic field distribution of GIL 3 under the impulse voltage and obtain the electromagnetic transient process of GIL 3 under the impulse voltage, and evaluate its risk;

[0080] Analyze the impact of impulse voltage on the insulation performance of GIL 3 and evaluate the possibility of insulation damage (the test process is to apply a 1675kV standard lightning wave to the GIL corridor. After the test, the GIL corridor is disassembled to check whether it is damaged. Whether each component is damaged can be obtained from the on-site test results);

[0081] Consider the thermal and mechanical effects of GIL 3 and its related components under the impact voltage, and assess the risk of equipment damage;

[0082] Comprehensively analyze the impact of impulse voltage on the overall power system and assess the risks of system stability and reliability.

[0083] Among them, the electromagnetic transient propagation process of the obtained impulse traveling wave (waveform corresponding to the impulse voltage) in the long-distance GIL 3 is as follows:

[0084] In order to find the general expression of the law of traveling wave motion on a uniform lossless line, a length unit dx can be taken out for study, see Figure 6 ,but:

[0085]

[0086] After finishing, we can get:

[0087]

[0088] Taking partial derivatives of the above equation, we can get the following partial differential equations of voltage wave and current wave after sorting:

[0089]

[0090] In formula (1-3), C0, L0, u, i are the equivalent capacitance, equivalent inductance, voltage of C0 and current of C0 respectively.

[0091] The above is the wave equation describing the voltage and current at point x of the line at time t, and its solution is:

[0092] u(x,t)=u f (x-vt)+u b (x+vt)

[0093] i(x,t)=[u f (x-vt)-u b (x+vt)] / Z

[0094] =i f (x-vt)+i b (x+vt) (1-4)

[0095] In the formula, u f ,u b are the forward voltage wave component and the reflected voltage wave component that constitute the voltage wave, respectively. f ,i b They are the forward current wave component and the reflected current wave component that constitute the current wave respectively.

[0096] In formula (1-4), u f (x-vt) is a function of (x-vt). As time t increases, it moves in the direction of increasing x, which is called a forward wave. b (x+vt) is a function of (x+vt). As t increases, it moves in the direction where x decreases, which is called a reverse traveling wave. Therefore, equation (1-4) can be rewritten as:

[0097]

[0098] The following is an analysis of the physical meaning of the forward wave, such as Figure 7 As shown in the figure, assuming that the direction indicated by the arrow is the positive direction of x, the wave propagates along the positive direction of x. At time t, the instantaneous distribution of the forward wave is at the position indicated by the dotted line. After time dt, the wave reaches the position indicated by the solid line at a speed of v, and the propagation distance dx = vdt. From the distribution diagrams at two different times, u f(x-vt) moves forward, its forward speed is v, after time dt, the distance moved forward is dx. If the observer starts at any time t1, from any point x1 on the line, and moves along the x direction with speed v, then for any time t and his position x, we have:

[0099] x-vt=[x1+v(t-t1)]-vt=x1-vt1=constant(1-6)

[0100] Therefore, the u observed by the observer f (xt) value remains unchanged. b (x+vt) represents a voltage reverse traveling wave that propagates in the opposite direction of x at a speed of v. The relationship between the voltage wave and the current wave value is related through the wave impedance Z, but traveling waves of different polarities propagate in different directions, and a certain positive direction needs to be specified. The sign of the voltage wave is only determined by the sign of the corresponding charge on the capacitance of the wire to the ground, and has nothing to do with the direction of movement. The sign of the current wave is not only related to the sign of the corresponding charge, but also to the direction of movement of the charge.

[0101] In summary, four equations describing the basic law of traveling wave propagation on a uniform and lossless single wire can be obtained:

[0102] u(x,t)=u f +u b

[0103] i(x,t)=i f +i b

[0104] u f =Zi f

[0105] u b =-Zi b (1-7)

[0106] The physical meanings of the four equations are: the voltage or current at any point on the wire is equal to the sum of the forward wave and the reverse wave passing through the point; the ratio of the forward wave voltage to the current is equal to +Z; the ratio of the reverse wave voltage to the current is equal to -Z. Starting from these four equations, plus the boundary and initial conditions, various types of wave process problems can be solved.

[0107] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A long-distance GIL shock wave withstand voltage test device, characterized in that: The device comprises an impulse voltage generator, a high voltage connection mechanism and a terminal integration mechanism, wherein the impulse voltage generator is connected to one end of a gas-insulated transmission line GIL of kilometer-level length through the high voltage connection mechanism, and the other end of the GIL is connected to the terminal integration mechanism, wherein: The impulse voltage generator comprises a first capacitor, a switch and a second capacitor connected in sequence; The high-voltage connection mechanism comprises a first high-voltage busbar or a direct-insertion contact finger; The terminal integrated mechanism includes a series-connected resistor-capacitor network for realizing frequency-variable impedance.

2. The long-distance GIL shock traveling wave withstand voltage test device according to claim 1, characterized in that: The impulse voltage generator is vertical or horizontal.

3. The long-distance GIL shock traveling wave withstand voltage test device according to claim 2, characterized in that: When the impulse voltage generator is vertical, the high-voltage connection mechanism includes a first high-voltage busbar, and the impulse voltage generator is connected to the GIL through the first high-voltage busbar. Specifically: The GIL includes bushings at both ends and a GIL pipe gallery between the two bushings. The bushing includes an outer shell and a hollow conductor rod inside the outer shell. The top of the hollow conductor rod is connected to the outer shell. The top of the bushing is electrically connected to the impulse voltage generator through the first high-voltage busbar. The bottom of the bushing is also electrically connected to the impulse voltage generator through another first high-voltage busbar for grounding. The bottom of the hollow conductor rod is also electrically connected to the GIL pipe gallery. The steep impulse traveling wave voltage is directly injected from the bushing into the GIL pipe gallery. The inductance of the first high-voltage busbar connection can be estimated using the following formula: L1＝10 -6 *1 Where L1 is the inductance of the first high-voltage busbar, unit: H / m.

4. The long-distance GIL shock traveling wave withstand voltage test device according to claim 3, characterized in that: The diameter of the hollow conductor rod is not less than 5 cm and the length is not more than 5 m.

5. The long-distance GIL shock traveling wave withstand voltage test device according to claim 2, characterized in that: When the impulse voltage generator is horizontal, the high-voltage connection mechanism includes direct-plug contacts and two second high-voltage busbars, and the impulse voltage generator is connected to the GIL through the direct-plug contacts and the two second high-voltage busbars. Specifically: The GIL includes bushings at both ends and a GIL pipe gallery between the two bushings. The bushing includes an outer shell and a hollow conductor rod inside the outer shell. The top of the hollow conductor rod is connected to the outer shell. The bottom of the hollow conductor rod is connected to one end of one of the second high-voltage busbars. The busbar at the other end of the second high-voltage busbar is connected to the female head of the plug-in contact finger. The impulse voltage generator is connected to one end of another second high-voltage busbar. The busbar at the other end of the second high-voltage busbar is connected to the male head of the plug-in contact finger. The male head and the female head of the plug-in contact finger are connected. The inductance of the second high-voltage busbar connected to the plug-in contact finger can be estimated by the following formula: In the formula, L2 is the inductance of the second high-voltage busbar, in H / m; D is the inner diameter of the outer layer of the second high-voltage busbar, in m; d is the outer diameter of the inner layer of the second high-voltage busbar, in m; f is the frequency, in Hz.

6. The long-distance GIL shock traveling wave withstand voltage test device according to claim 5, characterized in that: The outer layer of the direct-insertion contact finger has the same diameter as the GIL shell, and the inner layer has the same diameter as the busbar of the GIL.

7. A test method for a long-distance GIL shock traveling wave withstand voltage test device, wherein the test device is a test device as claimed in any one of claims 1 to 6, characterized in that: The test method includes: Step S102: obtaining design parameters of the GIL; Step S104: constructing a GIL impulse traveling wave simulation circuit model and simulating the propagation characteristics of the impulse voltage traveling wave in the GIL; Step S106: Simulate and calculate the electromagnetic transient process of the impulse voltage and evaluate its risk.

8. The test method of the long-distance GIL shock traveling wave withstand voltage test device according to claim 7, characterized in that: Step S102 specifically includes: Obtain the size parameters, rated voltage and insulation level of the GIL; Formulate field test equipment selection, test technology plan and experimental procedures.

9. The test method of the long-distance GIL shock traveling wave withstand voltage test device according to claim 7, characterized in that: Step S104 specifically includes: Establish the circuit model of GIL according to its design parameters and combined with the distributed parameter characteristics; Construct an electromagnetic transient simulation model for the GIL corridor impact traveling wave withstand test; Set the waveform parameters of the impulse voltage and run the propagation process of the impulse voltage traveling wave in the GIL; The propagation speed and attenuation characteristics of the impulse voltage traveling wave are obtained based on the simulation results.

10. The test method of the long-distance GIL shock traveling wave withstand voltage test device according to claim 7, characterized in that: Step S106 specifically includes: Calculate the electromagnetic field distribution of GIL under the impact voltage and obtain the electromagnetic transient process of GIL under the impact voltage, and evaluate its risk; Analyze the impact of impulse voltage on GIL insulation performance and assess the possibility of insulation damage; Consider the thermal and mechanical effects of the GIL and its related components under the impact of voltage surges and assess the risk of equipment damage; Comprehensively analyze the impact of impulse voltage on the overall power system and assess the risks of system stability and reliability.

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