Controllable lightning arrester based on autonomous triggering air gap switch

Abstract

The invention is applicable to the technical field of overvoltage protection devices of ultra-high-voltage and extra-high-voltage power transmission systems, and provides a controllable lightning arrester based on an autonomous triggering air gap switch, which comprises a lightning arrester fixed part, a lightning arrester controllable part, a bypass capacitor high-voltage part, a bypass capacitor low-voltage part, an air gap switch and an intermediate bridge valve plate group, the lightning arrester fixed part, the lightning arrester controllable part, the bypass capacitor high-voltage part, the bypass capacitor low-voltage part and the intermediate bridge valve plate group form a bridge structure; the air gap switch is connected with the bypass low-voltage part in parallel; and the capacitance ratio of the bypass capacitor low-voltage part to the bypass capacitor high-voltage part is smaller than the rated voltage ratio of the lightning arrester fixed part to the lightning arrester controllable part. According to the invention, the short circuit of the controllable part of the lightning arrester is realized through the cooperation of electrical parameters, the overvoltage can be protected in time, the influence caused by the dispersivity of the action of the air gap switch is avoided, a complicated control system is not needed, the number of devices is small, and the structure is simple.

Description

Technical Field

[0001] The present invention belongs to the technical field of overvoltage protection devices for ultra-high and extra-high voltage power transmission systems, and in particular relates to a controllable lightning arrester based on an autonomously triggered air gap switch. Background Art

[0002] Lightning arresters are important overvoltage protection devices in power systems. In the early days, lightning arresters used gaps to limit overvoltage. Later, with the development of material science, valve-type lightning arresters made of metal resistors made of silicon carbide have been widely used. Today, the resistors of lightning arresters are mainly made of zinc oxide (ZnO).

[0003] The voltage level of the UHV substation system is high, the transmission line is long, and the switching overvoltage plays a decisive role in the insulation level of the power transmission and transformation equipment. Under the condition of fixed loaded lines, the ratio of the switching overvoltage to the operating voltage is fixed. As the system voltage increases, the impact of the switching overvoltage level on the insulation design of the power transmission and transformation equipment becomes more and more severe. Limiting the switching overvoltage multiple is an important role of the arrester. However, in the UHV system, the arrester using only high-performance resistors is still unable to limit the switching overvoltage level to the specified level.

[0004] At present, for ultra-high voltage systems with long lines, there are two main methods to limit the operating overvoltage. One is to use metal oxide (ZnO) arresters in conjunction with circuit breakers to add closing resistors, and the other is to use controllable arresters. The solution of using metal oxide arresters in conjunction with closing resistors is the most widely used, but the closing resistor as a whole works under ultra-high voltage electric fields and is subject to large electrical stresses, and has a complex structure. It has great deficiencies in terms of economy and reliability. Circuit breakers using closing resistors are one of the sources of hidden dangers for important equipment in substations. Controllable arresters connect some valve plates in parallel with controllable switches, and short-circuit some valve plates before operation to further reduce the operating overvoltage. According to the type of controllable switches, controllable arresters can be divided into mechanical switch type, power electronic switch type and gap switch type. Among them, mechanical switch type and power electronic switch type require the introduction of relatively complex control systems, and gap switch type has a certain degree of dispersion. At the same time, in addition to primary equipment such as valve plates and controllable switches, existing controllable arresters need to have complete secondary equipment such as measurement, control and triggering, which significantly increases the complexity of the equipment and increases the failure rate of the equipment. Summary of the invention

[0005] The embodiment of the present invention provides a controllable lightning arrester based on an autonomously triggered air gap switch to solve the problems of complex equipment and control system of the existing controllable lightning arrester.

[0006] The present invention is achieved through the following technical solutions:

[0007] In a first aspect, an embodiment of the present invention provides a controllable lightning arrester based on an autonomously triggered air gap switch, comprising: a lightning arrester fixed part, a lightning arrester controllable part, a bypass capacitor high voltage part, a bypass capacitor low voltage part, an air gap switch and an intermediate bridge valve plate group; wherein the intermediate bridge valve plate group is a lightning arrester;

[0008] One end of the fixed part of the lightning arrester is connected to one end of the high-voltage part of the bypass capacitor, and the other end of the fixed part of the lightning arrester is respectively connected to one end of the controllable part of the lightning arrester and one end of the intermediate bridge valve plate group; the other end of the intermediate bridge valve plate group is respectively connected to the other end of the high-voltage part of the bypass capacitor and one end of the low-voltage part of the bypass capacitor; the other end of the controllable part of the lightning arrester is connected to the other end of the low-voltage part of the bypass capacitor and is grounded; the air gap switch is connected in parallel with the low-voltage part of the bypass capacitor; wherein the ratio of the capacitance of the low-voltage part of the bypass capacitor to the high-voltage part of the bypass capacitor is less than the ratio of the rated voltage of the fixed part of the lightning arrester to the controllable part of the lightning arrester.

[0009] In combination with the first aspect, in some embodiments, one end of the fixed part of the arrester connected to the high-voltage part of the bypass capacitor is used to connect a transmission line; when the length of the transmission line is greater than a first preset length and less than or equal to a second preset length, the rated voltage proportion of the controllable part of the arrester increases as the length of the transmission line increases;

[0010] Among them, the rated voltage proportion of the controllable part of the lightning arrester is the percentage of the rated voltage of the controllable part of the lightning arrester to the total rated voltage of the controllable lightning arrester; the total rated voltage of the controllable lightning arrester is the sum of the rated voltage of the fixed part of the lightning arrester and the rated voltage of the controllable part of the lightning arrester.

[0011] In combination with the first aspect, in some embodiments, the rated voltage of the controllable part of the arrester accounts for 20% to 25%.

[0012] In combination with the first aspect, in some embodiments, when the length of the transmission line is less than or equal to a first preset length, the rated voltage of the controllable part of the arrester accounts for a first preset percentage;

[0013] When the length of the transmission line is greater than the first preset length and less than or equal to the third preset length, the rated voltage of the controllable part of the arrester accounts for a second preset percentage;

[0014] When the length of the transmission line is greater than the third preset length and less than or equal to the second preset length, the rated voltage of the controllable part of the arrester accounts for a third preset percentage;

[0015] Among them, the rated voltage proportion of the controllable part of the lightning arrester is the percentage of the rated voltage of the controllable part of the lightning arrester to the total rated voltage of the controllable lightning arrester; the total rated voltage of the controllable lightning arrester is the sum of the rated voltage of the fixed part of the lightning arrester and the rated voltage of the controllable part of the lightning arrester.

[0016] In combination with the first aspect, in some embodiments, the first preset length is 250 km, the third preset length is 300 km, and the second preset length is 350 km;

[0017] The first preset percentage is 20%, the second preset percentage is 22%, and the third preset percentage is 25%.

[0018] In combination with the first aspect, in some embodiments, a ratio of the capacitance of the bypass capacitor low voltage part to the capacitance of the bypass capacitor high voltage part is 0.5 times the first ratio;

[0019] The first ratio is the ratio of the rated voltages of the fixed part of the arrester to the rated voltage of the controllable part of the arrester.

[0020] In combination with the first aspect, in some embodiments, the action voltage of the air gap switch is a preset multiple of the rated voltage of the controllable part of the arrester; the preset multiple is greater than 1 and less than 2.

[0021] In combination with the first aspect, in some embodiments, the rated voltage of the intermediate bridge valve plate group is 5% of the sum of the rated voltages of the fixed part of the arrester and the controllable part of the arrester.

[0022] In combination with the first aspect, in some embodiments, the fixed part of the arrester and the controllable part of the arrester are both metal oxide arrester resistors.

[0023] In combination with the first aspect, in some embodiments, the transmission line is an extra-high voltage transmission line or an ultra-high voltage transmission line.

[0024] The embodiment of the present invention provides a controllable lightning arrester based on an autonomously triggered air gap switch, wherein the fixed part of the lightning arrester, the controllable part of the lightning arrester, the high-voltage part of the bypass capacitor, the low-voltage part of the bypass capacitor and the intermediate bridge valve plate group form a bridge structure, and the air gap switch is connected in parallel with the low-voltage part of the bypass capacitor; and the capacitance ratio between the low-voltage part of the bypass capacitor and the high-voltage part of the bypass capacitor is less than the ratio of the rated voltage of the fixed part of the lightning arrester to the controllable part of the lightning arrester, so that the voltage division ratio of the low-voltage part of the bypass capacitor is greater than the voltage division ratio of the controllable part of the lightning arrester. In this way, when an operating overvoltage or a lightning overvoltage occurs, under a high-frequency voltage, the voltage rise speed of the low-voltage part of the bypass capacitor will be significantly faster than that of the controllable part of the lightning arrester. When the voltage value of the low-voltage part of the bypass capacitor reaches the value set by the parallel air gap switch, the air gap switch breaks down, and the controllable part of the lightning arrester is replaced by the intermediate bridge valve plate group to be grounded, and the overvoltage flows into the earth through the fixed part of the lightning arrester, the intermediate bridge valve plate group and the air gap switch. That is, the present invention adopts passive devices and realizes the short circuit of the controllable part of the arrester through the coordination of electrical parameters, can timely perform overvoltage protection action, avoids the influence caused by the dispersion of air gap switch action, ensures that ultra-high and extra-high voltage operations and lightning overvoltage are within a safe range, does not require a complex control system, has few devices and a simple structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0026] Figure 1 It is a structural schematic diagram of a controllable lightning arrester based on an autonomously triggered air gap switch provided by an embodiment of the present invention;

[0027] Figure 2 is an equivalent circuit diagram of a controllable lightning arrester based on an autonomously triggered air gap switch provided by an embodiment of the present invention;

[0028] Figure 3 It is a schematic diagram of the voltage direction of a controllable lightning arrester based on autonomously triggered air gap switch provided by an embodiment of the present invention when the air gap switch is not actuated;

[0029] Figure 4 It is a schematic diagram of an overvoltage discharge path of a controllable lightning arrester based on autonomously triggered air gap switches after the air gap switch is actuated, provided by an embodiment of the present invention;

[0030] Figure 5 1 is a schematic diagram of a waveform of the voltage across an air gap switch during an overvoltage process provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0032] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0033] In addition, in the description of the present specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0034] References to "one embodiment" or "some embodiments" etc. described in the present specification mean that one or more embodiments of the present invention include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0035] The dispersion of the action of the air-gap switch means that the actual action voltage of the air-gap switch may fluctuate greatly around the set action voltage. For example, the action voltage of an air-gap switch is set to 100kV, that is, the air-gap switch breaks down when the voltage reaches 100kV. After 100 breakdown tests are performed on it, during the test, the actual breakdown voltage of the air-gap switch may be 90kV, 100kV, or 110kV, etc., that is, the action of the air-gap switch is dispersed.

[0036] The embodiment of the present invention provides a controllable lightning arrester based on an autonomously triggered air gap switch. A bypass capacitor is introduced into the air gap switch type controllable lightning arrester. By utilizing the characteristics of the capacitor, when an overvoltage occurs, the voltage of the capacitor in parallel with the air gap switch reaches the action voltage of the air gap switch before the controllable part of the lightning arrester, so as to suppress the overvoltage in time and avoid the influence caused by the dispersion of the air gap switch action.

[0037] The controllable lightning arrester based on the autonomous triggering air gap switch provided by the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments of the specification:

[0038] See also Figure 1 The controllable lightning arrester based on the autonomous triggering air gap switch provided in the embodiment of the present invention comprises: a fixed part R of the lightning arrester 1 , controllable part of the arrester R 2 , bypass capacitor high voltage part C 1 , bypass capacitor low voltage part C 2 , air gap switch S and intermediate bridge valve plate group R 3 .

[0039] Figure 2 The equivalent circuit diagram of a controllable lightning arrester based on an autonomously triggered air gap switch provided by an embodiment of the present invention is shown in FIG. Figure 2 As shown, the arrester fixed part R 1 One end of the bypass capacitor is connected to the high voltage part C 1 One end of the arrester is connected to the fixed part R 1 The other end is connected to the controllable part R of the arrester 2 One end and the middle bridge valve plate group R 3 One end; the middle bridge valve group R 3 The other end is connected to the high voltage part of the bypass capacitor C 1 The other end and the low voltage part of the bypass capacitor C 2 One end of the arrester; the controllable part R 2 The other end of the bypass capacitor is connected to the low voltage part C 2 The other end of the air gap switch S and the low voltage part of the bypass capacitor C 2 In parallel, the low voltage part of the bypass capacitor C 2 The bypass capacitor C 1 The capacitance ratio Cn2:Cn 1 , which is smaller than the fixed part R of the arrester 1 and the controllable part R of the arrester 2 The ratio of rated voltages Un1:Un2.

[0040] In the embodiment of the present invention, the arrester fixed part R 1 , controllable part of the arrester R 2 , bypass capacitor high voltage part C 1 , bypass capacitor low voltage part C 2 , air gap switch S and intermediate bridge valve plate group R 3 It should be understood that the fixed part R 1 The bypass capacitor C 1 One end of the connection is used to connect the transmission line.

[0041] Under power frequency conditions, the impedance of the bypass capacitor is much greater than that of the arrester. 1 With the controllable part R of the arrester 2 The voltage distribution depends on the ratio of the rated voltage of the arrester Un1:Un2. At this time, the high voltage part of the bypass capacitor C 1 , bypass capacitor low voltage part C 2 And the middle bridge valve group R 3 When the air gap switch S does not operate, the voltage direction in the controllable lightning arrester is as follows: Figure 3 shown.

[0042] When an operating overvoltage or lightning overvoltage occurs, under high-frequency voltage (the frequency of the overvoltage is usually much higher than the 50Hz power frequency), the low-voltage part of the bypass capacitor C 2 The voltage rise speed will be significantly faster than the controllable part R of the arrester. 2 That is to say, the voltage divider ratio in the controllable arrester is mainly determined by the high voltage part of the bypass capacitor C 1 and the low voltage part of the bypass capacitor C 2 When the bypass capacitor low voltage part C 2 When the voltage divider value reaches the action voltage value set by the parallel air gap switch S, the air gap switch breaks down and the controllable part R of the arrester 2 The middle bridge valve group R 3 Instead of grounding, the overvoltage is fixed through the arrester R 1 、Intermediate bridge valve plate group R 3 The overvoltage discharge path after the air gap switch S is actuated is as follows: Figure 4 shown.

[0043] For series capacitors, the voltage ratio is equal to the inverse ratio of the capacitance. 2 The bypass capacitor C 1 The capacitance ratio Cn2:Cn1 is less than the fixed part R of the arrester 1 and the controllable part R of the arrester 2 The rated voltage ratio of Un1:Un2, so the high voltage part of the bypass capacitor C 1 The low voltage part of the bypass capacitor C 2 The voltage division ratio UCn1:UCn2 is less than the fixed part R of the arrester 1 and the controllable part R of the arrester 2 The ratio of the rated voltages of Un1:Un2. Continuing the derivation, it can be seen that when the bypass capacitor divides the voltage, the low-voltage part of the bypass capacitor C 2 When the voltage division ratio is greater than the voltage division ratio of the arrester, the controllable part R of the arrester 2Therefore, under high-frequency voltage, the low-voltage part of the bypass capacitor C 2 The voltage divider value can be greater than the controllable part R of the arrester 2 The voltage division value reaches the action voltage of the air gap switch S earlier, thus the controllable part R of the arrester is switched off in advance. 2 resection.

[0044] In the embodiment of the present invention, the arrester fixed part R 1 and the controllable part R of the arrester 2 All of them are metal oxide arrester resistors. Depending on the installation location and the length of the loaded line, the controllable part of the arrester R 2 The percentage k of the rated voltage Un2 to the total rated voltage (Un1+Un2) of the arrester may be between 20% and 25%. The loaded line may be an extra-high voltage transmission line or a UHV transmission line.

[0045] In a possible implementation, when the length of the transmission line is greater than the first preset length and less than or equal to the second preset length, the controllable portion R of the arrester 2 The proportion k of the rated voltage increases with the length of the transmission line. That is, the longer the loaded line is, the greater the proportion of the controllable part.

[0046] Among them, the controllable part R of the arrester 2 The rated voltage ratio k is the controllable part R of the arrester. 2 The percentage of the rated voltage of the controllable arrester to the total rated voltage of the controllable arrester; the total rated voltage of the controllable arrester is the fixed part R of the arrester 1 The rated voltage of the controllable part of the arrester R 2 The sum of the rated voltages.

[0047] In another possible implementation, when the length of the transmission line is less than or equal to the first preset length, the controllable portion R of the arrester 2 The rated voltage of the arrester accounts for a first preset percentage; when the length of the transmission line is greater than the first preset length and less than or equal to the third preset length, the controllable part R of the arrester 2 The rated voltage of the arrester accounts for a second preset percentage; when the length of the transmission line is greater than the third preset length and less than or equal to the second preset length, the controllable part R of the arrester 2 The rated voltage accounts for a third preset percentage.

[0048] Optionally, the first preset length is 250 km, the third preset length is 300 km, and the second preset length is 350 km; the first preset percentage is 20%, the second preset percentage is 22%, and the third preset percentage is 25%.

[0049] In the above implementation, when the length of the UHV transmission line is less than or equal to 250 km, the controllable part R 2 The rated voltage ratio is set to 20%; when the length of the UHV transmission line is greater than 250km and less than or equal to 300km, the rated voltage ratio is set to 22%; when the length of the UHV transmission line is greater than 300km and less than or equal to 350km, the rated voltage ratio is set to 25%.

[0050] In some embodiments, the bypass capacitor low voltage portion C 2 and bypass capacitor high voltage part C 1 The ratio of the capacitance of the arrester to the fixed part R 1 and the controllable part R of the arrester 2 The ratio of the rated voltage is 0.5 times.

[0051] In this embodiment, the voltage ratio of the series capacitors is inversely proportional to the capacitance, so the low-voltage part of the bypass capacitor C 2 The bypass capacitor C 1 The voltage ratio UCn2:UCn1 is the controllable part R of the arrester 2 With the arrester fixed part R 1 The rated voltage ratio of Un2 is twice that of Un1.

[0052] In some embodiments, the intermediate bridge valve plate group R 3 The arrester valve plate has a rated voltage of R 1 and the controllable part R of the arrester 2 5% of the sum of the rated voltages.

[0053] In this embodiment, the intermediate bridge valve plate group R with a smaller rated voltage is set 3 After the air gap switch S is broken down and turned on, it can smoothly pass through the fixed part R of the arrester 1 、Intermediate bridge valve plate group R 3 The air gap switch S smoothly introduces the overvoltage into the ground. When the air gap switch S is turned on, the fixed part R 1 And the middle bridge valve group R 3 The total rated voltage of the new arrester is only the fixed part R of the arrester. 1 and the controllable part R of the arrester 2 The total rated voltage of the lightning arrester is 80% to 85%, so the overvoltage can be effectively suppressed.

[0054] In some embodiments, the operating voltage of the air gap switch S is the controllable part R of the arrester. 2 A preset multiple of the rated voltage; wherein the preset multiple is greater than 1 and less than 2.

[0055] In a possible implementation, the preset multiple is 1.2. In this implementation, when the controllable lightning arrester is impacted by an overvoltage, the low-voltage part of the bypass capacitor C 2 The maximum withstand voltage may reach the controllable part R of the arrester 2 The rated voltage Un2 may be 1.2 times or even higher, depending on the dispersion of the air gap switch action. For example, if the action voltage of the air gap switch S is set to 1.2Un2, the actual action voltage of the air gap switch S may fluctuate around 1.2Un2; if the actual action voltage of the air gap switch is 1.25Un2, the low voltage part of the bypass capacitor C 2 The highest withstand voltage can reach 1.25Un2.

[0056] Next, the embodiment of the present invention provides a specific embodiment to illustrate the controllable lightning arrester based on the autonomously triggered air gap switch.

[0057] In this embodiment, the arrester fixed part R 1 , controllable part of the arrester R 2 And the middle bridge valve group R 3 They are all composed of ordinary zinc oxide resistors in series. 1 The rated voltage is 1000kV, the controllable part R of the arrester 2 The rated voltage is 250kV, the intermediate bridge valve group R 3 The rated voltage of the arrester is 62.5kV. 2 The rated voltage of the air gap switch S is 300kV, which is the controllable part of the arrester R. 2 1.2 times the rated voltage of the bypass capacitor. 2 The ratio of the capacitance to the high voltage part of the bypass capacitor is 2.5.

[0058] When the lightning overvoltage and the operating overvoltage are applied to the controllable arrester, the voltage across the air gap switch S is:

[0059]

[0060] Among them, U p (t) is the overvoltage signal, C 2 / C 1 The value of is k / 2.

[0061] When U S (t) When the action voltage of the air gap switch S is reached, the air gap switch S is broken down and turned on. The schematic diagram of its voltage waveform is shown in Figure 5 As shown. Due to the intermediate bridge valve group R 3 The rated voltage is only the controllable part R of the arrester 2One fifth to one quarter of the rated voltage, the controllable part R of the arrester 2 At this time, it is in a failed state, and the switching and lightning overvoltages can be fixed by the arrester R 1 、Intermediate bridge valve plate group R 3 The path formed by the air gap switch S flows into the ground. Figure 5 It can be seen that the air gap switch S can act quickly when overvoltage comes, so as to timely switch the controllable part R of the arrester. 2 Cut off and effectively suppress overvoltage.

[0062] In this embodiment, when U S (t) is the operating voltage of the air gap switch S at 300kV, the high voltage part of the bypass capacitor C 1 The voltage at both ends is 750kV, that is, when there is an operating overvoltage of 750kV, the air gap switch S can be operated. In this way, even if the action of the air gap switch S is dispersed, when an overvoltage of more than 1000kV occurs, the controllable lightning arrester can be turned on anyway. It should be noted that, under normal circumstances, as long as an overvoltage (operating overvoltage or lightning overvoltage) occurs in UHV equipment, the overvoltage can definitely reach more than 1000kV.

[0063] If the controllable arrester does not have a bypass capacitor (and the intermediate bridge valve plate group does not need to be set), that is to say, the air gap switch is directly connected in parallel with the controllable part of the arrester. In this case, if the rated voltages of the fixed part of the arrester and the controllable part of the arrester are the same as those in the above embodiment, i.e., 1000kV and 250kV respectively, the action voltage of the air gap switch is set to 250kV (if it is still 300kV, the controllable part of the arrester will be turned on at 250kV, and the switch will not work). In this way, the air gap switch can only be turned on when the voltage of the entire controllable arrester reaches 1250kV. If the dispersion of the air gap switch action is considered, the air gap switch may be turned on when the voltage reaches 1260kV. In this way, the controllable arrester cannot effectively suppress overvoltages below 1260kV. Therefore, compared with this design, the controllable lightning arrester based on the autonomously triggered air gap switch provided in the embodiment of the present invention can enable the air gap switch S to act in advance, prepare for the overvoltage, and ensure that the overvoltage is effectively suppressed.

[0064] The controllable lightning arrester based on the self-triggering air gap switch in the above embodiment is composed entirely of passive components. The short circuit of the controllable part of the lightning arrester is achieved through the coordination of electrical parameters, and the overvoltage protection action can be performed in time, avoiding the influence of the dispersion of the air gap switch action, and ensuring that the ultra-high and extra-high voltage operations and lightning overvoltages are within a safe range. The controllable lightning arrester does not require a complex control system, has few components and a simple structure. Compared with the existing controllable lightning arrester, it avoids the use of a large number of secondary devices such as measurement, control and triggering, and the reliability of the lightning arrester is significantly improved.

[0065] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0066] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A controllable lightning arrester based on autonomously triggered air gap switch, characterized in that: include: The arrester fixed part, the arrester controllable part, the bypass capacitor high voltage part, the bypass capacitor low voltage part, the air gap switch and the intermediate bridge valve plate group; wherein the intermediate bridge valve plate group is the arrester; One end of the fixed part of the lightning arrester is connected to one end of the high-voltage part of the bypass capacitor, and the other end of the fixed part of the lightning arrester is respectively connected to one end of the controllable part of the lightning arrester and one end of the intermediate bridge valve plate group; the other end of the intermediate bridge valve plate group is respectively connected to the other end of the high-voltage part of the bypass capacitor and one end of the low-voltage part of the bypass capacitor; the other end of the controllable part of the lightning arrester is connected to the other end of the low-voltage part of the bypass capacitor and is grounded; the air gap switch is connected in parallel with the low-voltage part of the bypass capacitor; wherein the ratio of the capacitance of the low-voltage part of the bypass capacitor to the high-voltage part of the bypass capacitor is less than the ratio of the rated voltage of the fixed part of the lightning arrester to the controllable part of the lightning arrester.

2. The controllable lightning arrester based on autonomously triggered air gap switch according to claim 1, characterized in that: One end of the fixed part of the arrester connected to the high-voltage part of the bypass capacitor is used to connect a transmission line, and when the length of the transmission line is greater than a first preset length and less than or equal to a second preset length, the rated voltage proportion of the controllable part of the arrester increases as the length of the transmission line increases; Among them, the rated voltage proportion of the controllable part of the lightning arrester is the percentage of the rated voltage of the controllable part of the lightning arrester to the total rated voltage of the controllable lightning arrester; the total rated voltage of the controllable lightning arrester is the sum of the rated voltage of the fixed part of the lightning arrester and the rated voltage of the controllable part of the lightning arrester.

3. The controllable lightning arrester based on autonomously triggered air gap switch according to claim 2, characterized in that: The rated voltage of the controllable part of the arrester accounts for 20% to 25%.

4. The controllable lightning arrester based on autonomously triggered air gap switch according to claim 1, characterized in that: One end of the fixed part of the arrester connected to the high-voltage part of the bypass capacitor is used to connect a power transmission line, and when the length of the transmission line is less than or equal to a first preset length, the rated voltage of the controllable part of the arrester accounts for a first preset percentage; When the length of the transmission line is greater than the first preset length and less than or equal to the third preset length, the rated voltage of the controllable part of the arrester accounts for a second preset percentage; When the length of the transmission line is greater than the third preset length and less than or equal to the second preset length, the rated voltage of the controllable part of the arrester accounts for a third preset percentage; Among them, the rated voltage proportion of the controllable part of the lightning arrester is the percentage of the rated voltage of the controllable part of the lightning arrester to the total rated voltage of the controllable lightning arrester; the total rated voltage of the controllable lightning arrester is the sum of the rated voltage of the fixed part of the lightning arrester and the rated voltage of the controllable part of the lightning arrester.

5. The controllable lightning arrester based on autonomously triggered air gap switch according to claim 4, characterized in that: The first preset length is 250 km, the third preset length is 300 km, and the second preset length is 350 km; The first preset percentage is 20%, the second preset percentage is 22%, and the third preset percentage is 25%.

6. The controllable lightning arrester based on autonomously triggered air gap switch according to any one of claims 2 to 5, characterized in that: The transmission line is an extra-high voltage transmission line or a UHV transmission line.

7. The controllable lightning arrester based on autonomously triggered air gap switch according to any one of claims 1 to 5, characterized in that: The ratio of the capacitance of the bypass capacitor low voltage part to the capacitance of the bypass capacitor high voltage part is 0.5 times the first ratio; The first ratio is the ratio of the rated voltages of the fixed part of the arrester to the rated voltage of the controllable part of the arrester.

8. The controllable lightning arrester based on autonomously triggered air gap switch according to any one of claims 1 to 5, characterized in that: The action voltage of the air gap switch is a preset multiple of the rated voltage of the controllable part of the arrester; the preset multiple is greater than 1 and less than 2.

9. The controllable lightning arrester based on autonomously triggered air gap switch according to any one of claims 1 to 5, characterized in that: The rated voltage of the intermediate bridge valve plate group is 5% of the sum of the rated voltages of the fixed part of the arrester and the controllable part of the arrester.

10. The controllable lightning arrester based on autonomously triggered air gap switch according to claim 1, characterized in that: The arrester fixed part and the arrester controllable part are both arrester resistors made of metal oxide.

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