Light-triggered thyristor type controllable lightning arrester

Abstract

The invention is suitable for the technical field of overvoltage protection devices of ultra-high voltage and extra-high voltage power transmission systems, and provides a light-triggered thyristor type controllable lightning arrester, which comprises a triggering device and a bipolar controllable switch connected in parallel with a controllable part of the lightning arrester, wherein the bipolar controllable switch comprises a plurality of first light-triggered thyristors and a plurality of second light-triggered thyristors; the plurality of first light-triggered thyristors are used for forward conduction of the bipolar controllable switch, and the plurality of second light-triggered thyristors are used for reverse conduction of the bipolar controllable switch; the triggering device is used for generating an optical signal when receiving the overvoltage signal; and the optical signal is used for triggering the first light-triggered thyristor or the second light-triggered thyristor to be conducted, so that the bipolar controllable switch bypasses the controllable part of the lightning arrester. The controllable switch of the controllable lightning arrester is subjected to forward and reverse simultaneous control by adopting light triggering, complicated control logic and equipment are not needed, the reliability is high, and the energy consumption is low.

Description

Technical Field

[0001] The 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 light-triggered thyristor type controllable lightning arrester. 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 itself is subject to large electrical stress when working under ultra-high voltage electric fields, and the structure is complex. There are major 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 switch, controllable arresters are 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, while gap switch type has a certain degree of dispersion, and each discharge will cause certain damage to the electrode. Summary of the invention

[0005] The embodiment of the present invention provides a light-triggered thyristor type controllable lightning arrester to simplify the control system of the controllable lightning arrester, reduce power consumption, and improve the reliability of the controllable lightning arrester.

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

[0007] In the first aspect, an embodiment of the present invention provides a light-triggered thyristor type controllable lightning arrester, comprising: a lightning arrester fixed part, a lightning arrester controllable part, a bipolar controllable switch and a trigger device; wherein the lightning arrester fixed part is grounded through the lightning arrester controllable part, and the bipolar controllable switch is connected in parallel with the lightning arrester controllable part; the bipolar controllable switch comprises a plurality of first light-triggered thyristors and a plurality of second light-triggered thyristors; the plurality of first light-triggered thyristors are used for forward conduction of the bipolar controllable switch, and the plurality of second light-triggered thyristors are used for reverse conduction of the bipolar controllable switch; the trigger device is used to generate an optical signal when an overvoltage signal is received; the optical signal is used to trigger the first light-triggered thyristor or the second light-triggered thyristor to turn on, so that the bipolar controllable switch bypasses the controllable part of the lightning arrester.

[0008] In combination with the first aspect, in some embodiments, the bipolar controllable switch includes a forward switch stack, a reverse switch stack, and a resistor stack;

[0009] The forward switch stack includes a plurality of stages of the first light-triggered thyristors connected in series;

[0010] The reverse switch stack includes a plurality of stages of the second light-triggered thyristors connected in series;

[0011] The resistor stack includes multiple stages of voltage-equalizing resistors connected in series;

[0012] The number of the first light-triggered thyristors, the second light-triggered thyristors and the voltage-equalizing resistors is the same; the first light-triggered thyristors, the second light-triggered thyristors and the voltage-equalizing resistors of each stage are connected in parallel.

[0013] In combination with the first aspect, in some embodiments, a voltage detection device is further included; the voltage detection device includes a capacitive voltage divider and a Schmitt trigger connected in sequence;

[0014] The input of the capacitive voltage divider is the target voltage, and the output end of the Schmitt trigger is connected to the input end of the trigger device; the capacitive voltage divider is provided with a preset threshold, and the capacitive voltage divider triggers the Schmitt trigger when the target voltage is greater than or equal to the preset threshold, and the Schmitt trigger sends the overvoltage signal to the trigger device when it is triggered;

[0015] Among them, the target voltage is the voltage of the first light-triggered thyristor or the second light-triggered thyristor at the ground terminal of the bipolar controllable switch; the preset threshold is determined based on the preset rated voltage ratio, the number of the voltage-equalizing resistors and the preset overvoltage protection threshold; the preset rated voltage ratio is the ratio of the rated voltage of the controllable part of the lightning arrester to the sum of the rated voltages of the fixed part of the lightning arrester and the controllable part of the lightning arrester.

[0016] In combination with the first aspect, in some embodiments, the trigger device includes a plurality of sub-trigger circuits, the sub-trigger circuits include a first field effect transistor, and a plurality of laser diodes connected in series to a source of the first field effect transistor, the source of the first field effect transistor is connected to an anode of the laser diode connected thereto; the plurality of laser diodes in the plurality of sub-trigger circuits are used to generate the optical signal; the number of the sub-trigger circuits is determined based on the light emitting capability of the laser diodes;

[0017] The output terminal of the Schmitt trigger is connected to the gate of the first field effect transistor in the plurality of sub-trigger circuits.

[0018] In combination with the first aspect, in some embodiments, the light-triggered thyristor type controllable lightning arrester further includes a self-power-taking device; the self-power-taking device is installed at the grounding point of the bipolar controllable switch, and is used to supply power to the multiple sub-trigger circuits;

[0019] The self-energy extraction device comprises an energy extraction coil, a protection circuit, a rectifier bridge, an energy release circuit, a DC conversion module and an energy storage battery connected in sequence, and an action protection switch arranged between the energy extraction coil and the protection circuit;

[0020] Among them, the energy extraction coil is used to sense the magnetic field generated by the leakage current flowing when the bipolar controllable switch is turned off, so as to generate AC power; the protection circuit is used to protect the circuit at its rear end; the rectifier bridge is used to convert the AC power into DC power; the energy release circuit is used to stabilize the output voltage of the rectifier bridge at a preset voltage regulation value; the AC / DC conversion module is used to convert the voltage at its input end to the rated voltage of the energy storage battery; the action protection switch is used to short-circuit the circuit after the energy extraction coil when the bipolar controllable switch is actuated.

[0021] In combination with the first aspect, in some embodiments, the energy extraction coil adopts a Permalloy closed magnetic core, and the number of coil turns is 300; the protection circuit includes a transient voltage suppressor, a protection reactor and a gas discharge tube; the rectifier bridge includes four Schottky diodes; the energy release circuit includes a first capacitor, a first resistor, a second field effect transistor, a second resistor and a second capacitor;

[0022] Among them, the positive end of the energy extraction coil is connected to the anode of the transient voltage suppressor and one end of the protection inductor, the other end of the protection inductor is connected to one end of the gas discharge tube, and the negative end of the energy extraction coil is connected to the cathode of the transient voltage suppressor and the other end of the gas discharge tube; the two ends of the gas discharge tube are respectively connected to the AC input end of the rectifier bridge; the positive electrode of the rectifier bridge is respectively connected to one end of the first capacitor, one end of the second resistor and one end of the second capacitor, and the negative electrode of the rectifier bridge is respectively connected to the other end of the first capacitor, one end of the first resistor, the source of the second field effect transistor and the other end of the second capacitor; the other end of the first resistor is connected to the gate of the second field effect transistor, and the other end of the second resistor is connected to the drain of the second field effect transistor; the two ends of the second capacitor are respectively connected to the two ends of the DC conversion module, the positive end of the DC conversion module is connected to the positive end of the energy storage battery, and the negative end of the DC conversion module is connected to the negative end of the energy storage battery.

[0023] In combination with the first aspect, in some embodiments, the self-energy extraction device further includes a control module;

[0024] The control module is used to control the energy release circuit to stabilize the output voltage of the rectifier bridge at a preset voltage regulation value, and to control the action protection switch to act when the bipolar controllable switch acts.

[0025] In combination with the first aspect, in some embodiments, the rated voltage proportion of the controllable part of the arrester is in the range of 15% to 20%; the rated voltage proportion of the controllable part of the arrester is the percentage of the rated voltage of the controllable part of the arrester to the total rated voltage, and the total rated voltage is the sum of the rated voltages of the controllable part of the arrester and the fixed part of the arrester.

[0026] In combination with the first aspect, in some embodiments, the end of the fixed part of the arrester that is not connected to the controllable part of the arrester is used to connect to a power transmission line;

[0027] When the length of the transmission line is less than or equal to a first length, the rated voltage of the controllable part of the lightning arrester accounts for a first percentage; when the length of the transmission line is greater than the first length and less than or equal to a second length, the rated voltage of the controllable part of the lightning arrester accounts for a second percentage; when the length of the transmission line is greater than the second length and less than or equal to a third length, the rated voltage of the controllable part of the lightning arrester accounts for a third percentage.

[0028] 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.

[0029] An embodiment of the present invention provides a light-triggered thyristor type controllable lightning arrester, including a bipolar controllable switch connected in parallel with a controllable part of the lightning arrester, the bipolar controllable switch including a plurality of first light-triggered thyristors and a plurality of second light-triggered thyristors; wherein, the plurality of first light-triggered thyristors are used for forward conduction of the bipolar controllable switch, and the plurality of second light-triggered thyristors are used for reverse conduction of the bipolar controllable switch, so that no matter whether a positive overvoltage or a negative overvoltage occurs, the bipolar controllable switch can be turned on to bypass the controllable part of the lightning arrester without the need for complex judgment logic and control system. In addition, the controllable lightning arrester of the present invention also includes a trigger device, which generates an optical signal when receiving an overvoltage signal to trigger the first light-triggered thyristor or the second light-triggered thyristor to turn on, thereby turning on the bipolar controllable switch, thereby realizing light-triggered control of the controllable lightning arrester. The light-triggered control method is simple and has high reliability. It does not require the use of electromagnetically isolated power supply equipment, and has low requirements for power supply equipment. Moreover, it only needs to be powered on instantly when triggered, that is, the trigger device does not need to consume power for a long time. Therefore, the controllable lightning arrester of the present invention is simple to control, has low energy consumption, and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] 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.

[0031] Figure 1 It is a structural schematic diagram of a light-triggered thyristor type controllable lightning arrester provided in one embodiment of the present invention;

[0032] Figure 2 is a schematic diagram of a bipolar controllable switch provided by an embodiment of the present invention;

[0033] Figure 3 is an equivalent circuit diagram of a bipolar controllable switch provided by an embodiment of the present invention;

[0034] Figure 4 is a schematic diagram of a sub-trigger circuit provided by an embodiment of the present invention;

[0035] Figure 5 It is a schematic structural diagram of a self-energy extraction device provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0036] 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.

[0037] In the description of the present specification and the appended claims, the terms "first", "second", "third" and the like are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0038] 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, "in some embodiments", "in other embodiments", etc. appearing 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.

[0039] At present, controllable lightning arresters are mainly divided into mechanical switch type, power electronic switch type and gap switch type. However, mechanical switch type and power electronic switch type require the introduction of more complex control systems. For example, when controlling these two switches, it is necessary to set the forward overvoltage control path and the reverse overvoltage control path in advance. When judging overvoltage, it is necessary to first judge the direction of the overvoltage and then select the corresponding control path for control. The gap switch type has a certain degree of dispersion and the control is not precise.

[0040] Based on the above problems, an embodiment of the present invention provides a light-triggered thyristor type controllable lightning arrester, which realizes bypass of the controllable part of the lightning arrester through a light-triggered bipolar controllable switch, with simple control method, low energy consumption and high reliability.

[0041] The light-triggered thyristor type controllable lightning arrester provided by the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments of the specification:

[0042] See also Figure 1 The light-triggered thyristor type controllable lightning arrester provided in the embodiment of the present invention comprises a lightning arrester fixed part 11, a lightning arrester controllable part 12, a bipolar controllable switch 13 and a trigger device 14. The lightning arrester fixed part 11 is grounded through the lightning arrester controllable part 12, and the bipolar controllable switch 13 is connected in parallel with the lightning arrester controllable part 12.

[0043] See also Figure 2 The bipolar controllable switch 13 includes a plurality of first light-triggered thyristors VT1 and a plurality of second light-triggered thyristors VT2. The plurality of first light-triggered thyristors VT1 are used for forward conduction of the bipolar controllable switch 13, and the plurality of second light-triggered thyristors VT2 are used for reverse conduction of the bipolar controllable switch 13.

[0044] The trigger device 14 is used to generate an optical signal when receiving an overvoltage signal; the optical signal is used to trigger the first optically triggered thyristor VT1 or the second optically triggered thyristor VT2 to turn on, so that the bipolar controllable switch 13 bypasses the controllable part 12 of the arrester.

[0045] In the embodiment of the present invention, the upper end of the arrester fixed part 11 (the end not connected to the arrester controllable part 12) is connected to the extra-high voltage or ultra-high voltage transmission line. When the voltage of the above-mentioned light-triggered thyristor type controllable arrester exceeds the preset voltage protection threshold, the bipolar controllable switch 13 is actuated to bypass the arrester controllable part 12, and only the arrester fixed part 11 is subjected to the overvoltage.

[0046] In the embodiment of the present invention, the arrester fixed part 11 and the arrester controllable part 12 are both metal oxide arrester resistors. According to the length of the loaded line at the installation location, the percentage of the rated voltage of the arrester controllable part 12 to the total rated voltage of the controllable arrester is between 15% and 20%. The longer the loaded line, the greater the proportion of the controllable part. Here, the total rated voltage of the controllable arrester is the sum of the rated voltages of the arrester fixed part 11 and the arrester controllable part 12.

[0047] In some embodiments, when the length of the transmission line is less than or equal to a first length, the rated voltage of the controllable part 12 of the lightning arrester accounts for a first percentage; when the length of the transmission line is greater than the first length and less than or equal to a second length, the rated voltage of the controllable part 12 of the lightning arrester accounts for a second percentage; when the length of the transmission line is greater than the second length and less than or equal to a third length, the rated voltage of the controllable part 12 of the lightning arrester accounts for a third percentage.

[0048] Optionally, the first length is 250km, the second length is 300km, and the third length is 350km; the first percentage is 15%, the second percentage is 17%, and the third percentage is 20%. When the length of the UHV line is less than or equal to 250km, the proportion of the rated voltage of the controllable part of the controllable arrester is set to 15%; when the line length is greater than 250km and less than or equal to 300km, the proportion is set to 17%; when the line length is greater than 300km and less than or equal to 350km, the proportion is set to 20%.

[0049] See also Figure 3The bipolar controllable switch 13 includes a forward switch stack 31, a reverse switch stack 32 and a resistor stack 33. The forward switch stack 31 includes a first light-triggered thyristor VT1 connected in series in multiple stages; the reverse switch stack 32 includes a second light-triggered thyristor VT2 connected in series in multiple stages; and the resistor stack 33 includes a voltage-equalizing resistor R connected in series in multiple stages. The number of the first light-triggered thyristor VT1, the second light-triggered thyristor VT2 and the voltage-equalizing resistor R is the same. The first light-triggered thyristor VT1, the second light-triggered thyristor VT2 and the voltage-equalizing resistor R of each stage are connected in parallel.

[0050] In this embodiment, each level of the resistor stack 33 is connected in parallel with each level of the forward switch stack 31 and the reverse switch stack 32. The forward switch stack 31, the reverse switch stack 32 and the resistor stack 33 are arranged in a triangle. The existence of the voltage balancing resistor R ensures that the voltage on each level of the light-triggered thyristor in the switch stack is the same.

[0051] In some embodiments, the first light-triggered thyristor VT1 and the second light-triggered thyristor VT2 can be light-triggered thyristor switches with a withstand voltage of 7.5 kV. The voltage-equalizing resistor R is a cylindrical resistor with a withstand voltage of 7.5 kV and a resistance of 2 MΩ. That is to say, the forward switch stack 31 and the reverse switch stack 32 are respectively composed of light-triggered thyristor switches with a withstand voltage of 7.5 kV in series, and the resistor stack 33 is composed of cylindrical resistors with a withstand voltage of 7.5 kV and a resistance of 2 MΩ in series. The number of the first light-triggered thyristor VT1, the second light-triggered thyristor VT2 and the voltage-equalizing resistor R can be determined according to the rated voltage of the controllable part 12 of the arrester. For example, if the rated voltage of the controllable part 12 of the arrester is 300 kV, the number of the first light-triggered thyristor VT1, the second light-triggered thyristor VT2 and the voltage-equalizing resistor R can be set to 40.

[0052] In a possible implementation, the forward thyristor (first light-triggered thyristor VT1), the reverse thyristor (second light-triggered thyristor VT2) and the voltage-equalizing resistor R of each stage are pressed and connected by triangle connectors of upper and lower layers, such as Figure 3 shown.

[0053] In some embodiments, the above-mentioned light-triggered thyristor type controllable lightning arrester may further include a voltage detection device. The voltage detection device includes a capacitive voltage divider and a Schmitt trigger connected in sequence. The input of the capacitive voltage divider is the target voltage, and the output of the Schmitt trigger is connected to the input of the trigger device 14; the capacitive voltage divider is provided with a preset threshold value, and the capacitive voltage divider triggers the Schmitt trigger when the target voltage is greater than or equal to the preset threshold value, and the Schmitt trigger sends an overvoltage signal to the trigger device 14 when it is triggered.

[0054] Among them, the target voltage is the voltage across the equalizing resistor R at the ground end of the bipolar controllable switch 13; the preset threshold can be determined based on the preset rated voltage ratio, the number of equalizing resistors R and the preset overvoltage protection threshold; the preset rated voltage ratio is the ratio of the rated voltage of the controllable part 12 of the lightning arrester to the sum of the rated voltages of the fixed part 11 of the lightning arrester and the controllable part 12 of the lightning arrester.

[0055] In this embodiment, the function of the trigger device 14 is to determine the current voltage of the entire arrester by collecting the voltage of the lowest-level light-triggered thyristor and to send out a trigger signal of the light-triggered thyristor, i.e., the above-mentioned light signal. The voltage of the lowest-level light-triggered thyristor is collected by a capacitive voltage divider. When the instantaneous voltage of the low-voltage arm of the capacitive voltage divider reaches a preset threshold, the Schmitt trigger of the subsequent stage is triggered, and the Schmitt trigger inputs its high-level output signal to the input end of the trigger device 14. The above-mentioned overvoltage signal is the high-level output signal of the Schmitt trigger.

[0056] In some embodiments, the trigger device 14 may include a plurality of sub-trigger circuits. Figure 4 Each sub-trigger circuit includes a first field effect transistor M1, and a plurality of laser diodes D connected in series to the source of the first field effect transistor M1, the source of the first field effect transistor M1 is connected to the anode of the laser diode D connected thereto; the plurality of laser diodes D in the plurality of sub-trigger circuits are used to generate optical signals; the number of sub-trigger circuits is determined based on the light emitting capability of the laser diode D. The gates of the first field effect transistors M1 in the respective sub-trigger circuits are respectively connected to the output terminals of the above-mentioned Schmitt triggers.

[0057] Optionally, the first field effect transistor M2 is a metal-oxide-semiconductor field-effect transistor (MOSFET).

[0058] In this embodiment, the sub-trigger circuit adopts a pulse signal trigger mechanism. When the bipolar controllable switch needs to be actuated, the first field effect transistor M1 of each sub-trigger circuit is triggered at the same time, generating a pulse signal on the series-connected laser diode D, and generating a pulse light signal, which is connected to the first light-triggered thyristor VT1 and the second light-triggered thyristor VT2 of the bipolar controllable switch 13 through optical fiber to complete the triggering.

[0059] In a possible implementation, each sub-trigger circuit can trigger eight light-triggered thyristors. The number of sub-trigger circuits is set according to the number of first light-triggered thyristors VT1 and second light-triggered thyristors in the bipolar controllable switch 13 .

[0060] In the above embodiments, the overvoltage signal is judged by the voltage of the light-triggered thyristor at the bottom of the bipolar controllable switch. The voltage is relatively small, and the overvoltage is judged by a capacitive voltage divider, which can avoid the high energy consumption caused by complex detection devices. Moreover, the light-triggered control method only needs to pass electricity for a moment when triggered, and the energy consumption is also very low. For example, if the power supply voltage of the sub-trigger circuit is 24V, when no action is required, the energy consumed by each sub-trigger circuit is less than 0.5mW. Therefore, the light-triggered thyristor type controllable lightning arrester of the present application can be powered by a self-energy extraction device.

[0061] See also Figure 1 The light-triggered thyristor type controllable lightning arrester in the embodiment of the present invention may further include a self-power-taking device 15. The self-power-taking device 15 is installed at the grounding position of the bipolar controllable switch 13 and is used to supply power to multiple sub-trigger circuits.

[0062] See also Figure 5 The self-energy extraction device 15 includes an energy extraction coil 51, a protection circuit 52, a rectifier bridge 53, an energy release circuit 54, a DC conversion module 55 and an energy storage battery 56 which are connected in sequence, and an action protection switch 57 arranged between the energy extraction coil 51 and the protection circuit 52.

[0063] Among them, the energy extraction coil 51 is used to sense the magnetic field generated by the leakage current flowing when the bipolar controllable switch 13 is turned off, so as to generate AC power. The protection circuit 52 is used to protect the circuit at its rear end. The rectifier bridge 53 is used to convert AC power into DC power. The energy release circuit 54 is used to stabilize the output voltage of the rectifier bridge 53 at a preset voltage regulation value. The AC-DC conversion module 55 is used to convert the voltage at its input end to the rated voltage of the energy storage battery 56. The action protection switch 57 is used to short-circuit the circuit after the energy extraction coil 51 when the bipolar controllable switch 13 is actuated.

[0064] In some embodiments, the protection circuit 52 includes a transient voltage suppressor (TVS), a protection reactor L and a gas discharge tube G. The rectifier bridge 53 includes four Schottky diodes. The energy release circuit 54 includes a first capacitor C1, a first resistor R1, a second field effect transistor M2, a second resistor R2 and a second capacitor C2.

[0065] like Figure 5As shown, the positive end of the energy extraction coil 51 is connected to the anode of the TVS and one end of the protection reactor L, the other end of the protection reactor L is connected to one end of the gas discharge tube G, and the negative end of the energy extraction coil 51 is connected to the cathode of the TVS and the other end of the gas discharge tube G; the two ends of the gas discharge tube G are respectively connected to the AC input end of the rectifier bridge 53. The positive electrode of the rectifier bridge 53 is respectively connected to one end of the first capacitor C1, one end of the second resistor R2, and one end of the second capacitor C2, and the negative electrode of the rectifier bridge 53 is respectively connected to the other end of the first capacitor C1, one end of the first resistor R1, the source of the second field effect transistor M2, and the other end of the second capacitor C2. The other end of the first resistor R1 is connected to the gate of the second field effect transistor M2, and the other end of the second resistor R2 is connected to the drain of the second field effect transistor M2; the two ends of the second capacitor C2 are respectively connected to the two ends of the DC conversion module 55, the positive end of the DC conversion module 55 is connected to the positive end of the energy storage battery 56, and the negative end of the DC conversion module 55 is connected to the negative end of the energy storage battery 56.

[0066] Optionally, the energy storage battery 56 may be a lithium iron phosphate battery or a lead-acid battery.

[0067] Optionally, the second field effect transistor M2 is a MOSFET.

[0068] In a possible implementation, the energy taking coil 51 uses a Permalloy closed magnetic core with high magnetic induction intensity and saturation magnetic flux, and the coil is wound about 300 turns. The protection circuit 52 consists of three parts: a transient voltage suppressor, a protection inductor, and a gas discharge tube. The three devices complete the protection of the back-end circuit step by step. The rectifier bridge 53 is composed of four low-power Schottky diodes, which convert the AC power obtained by the energy taking coil 51 into DC power, and its steady-state voltage drop is less than 0.2V. The energy release circuit 54 is responsible for stabilizing the voltage output by the rectifier bridge 53 at 10V. When the voltage exceeds 10V, the MOSFET in the energy release circuit 54 is turned on, and the energy in the circuit is lost through resistance. The DC conversion module (DC / DC) 55 converts the front-end 10V voltage into a 24V voltage for charging the lead-acid battery. The rated voltage of the lead-acid battery 46 is 24V, and the capacity of the lead-acid battery can ensure continuous internal operation for 3 months. The function of the action protection switch 57 is to form a short circuit at the outlet of the energy extraction coil 51 when the bipolar controllable switch 13 is activated, so as to prevent the pulse current impact caused by the overvoltage from affecting the subsequent circuit. The control circuit of the self-energy extraction device 15 itself adopts low-power devices, and its overall power consumption is less than 3mW.

[0069] In this embodiment, the self-energy device 15 further includes a control module; the control module is used to control the energy release circuit 54 to stabilize the output voltage of the rectifier bridge 53 at a preset voltage value, and when the bipolar controllable switch 13 is actuated, control the action protection switch 57 to actuate. The control module can be implemented using a low-power ARM, which is responsible for timing control, energy management, and control of related modules in the self-energy device 15.

[0070] In the above embodiment, during the operation of the arrester, when the bipolar controllable switch 13 is actuated, a large current flows back through the ground wire, and the magnetic core of the energy extraction coil 51 will first enter a saturation state, and no linearly increasing voltage will be induced on the load side of the energy extraction coil 51. When the arrester is not actuated, the current flowing through the energy extraction coil 51 does not exceed 3mA, and the output voltage of the energy extraction coil 51 is about 10V. When the arrester is actuated, the instantaneous current flowing through the energy extraction coil 51 does not exceed 1A because the magnetic core enters a saturation state.

[0071] It should be noted that the light-triggered thyristor type controllable lightning arrester in the embodiment of the present invention can be regarded as a passive device during operation. When used for the first time and when it has not been connected to the power system for more than 3 months, the energy storage battery 56 in the system may be in a low-power state. Since the overvoltage generated by the switch operation process involved in the commissioning of the equipment requires the intervention of the controllable part of the controllable lightning arrester, the controllable lightning arrester should be in an operable state, so the system needs to be pre-charged. The pre-charging process can be to connect a wire to the magnetic core of the energy taking coil 51 and pass an AC current of 0.2A to 0.3A. After about half an hour, the electric energy stored in the controllable lightning arrester can supply the controllable lightning arrester to operate. After the controllable lightning arrester exits the system operation, the power of the built-in energy storage battery 56 can ensure continuous internal operation for 3 months. If the lightning arrester exits the system for more than 3 months or the operation indicator light goes out, pre-charging is performed again.

[0072] The light-triggered thyristor type controllable lightning arrester provided by the embodiment of the present invention determines the current overvoltage state by collecting the voltage of the light-triggered thyristor at the bottom, and controls the bipolar controllable switch composed of the light-triggered thyristor through the optical signal emitted by the trigger device, and can switch the operating state without external signal triggering. The trigger device is simple in design, high in reliability, and low in power consumption. At the same time, a self-power-collecting device can also be provided to realize the passive design of the lightning arrester. During the installation and operation process, it does not need to lay additional power lines except for the pre-charging required for the first use.

[0073] 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 light-triggered thyristor type controllable lightning arrester, characterized in that: It includes a lightning arrester fixed part, a lightning arrester controllable part, a bipolar controllable switch and a trigger device; wherein the lightning arrester fixed part is grounded through the lightning arrester controllable part, and the bipolar controllable switch is connected in parallel with the lightning arrester controllable part; The bipolar controllable switch comprises a plurality of first light-triggered thyristors and a plurality of second light-triggered thyristors; the plurality of first light-triggered thyristors are used for forward conduction of the bipolar controllable switch, and the plurality of second light-triggered thyristors are used for reverse conduction of the bipolar controllable switch; The trigger device is used to generate an optical signal when receiving an overvoltage signal; the optical signal is used to trigger the first optically triggered thyristor or the second optically triggered thyristor to turn on, so that the bipolar controllable switch bypasses the controllable part of the arrester.

2. The light-triggered thyristor type controllable lightning arrester according to claim 1, characterized in that: The bipolar controllable switch includes a forward switch stack, a reverse switch stack and a resistor stack; The forward switch stack includes a plurality of stages of the first light-triggered thyristors connected in series; The reverse switch stack includes a plurality of stages of the second light-triggered thyristors connected in series; The resistor stack includes multiple stages of voltage-equalizing resistors connected in series; The number of the first light-triggered thyristors, the second light-triggered thyristors and the voltage-equalizing resistors is the same; the first light-triggered thyristors, the second light-triggered thyristors and the voltage-equalizing resistors of each stage are connected in parallel.

3. The light-triggered thyristor type controllable lightning arrester according to claim 2, characterized in that: It also includes a voltage detection device; the voltage detection device includes a capacitive voltage divider and a Schmitt trigger connected in sequence; The input of the capacitive voltage divider is the target voltage, and the output end of the Schmitt trigger is connected to the input end of the trigger device; the capacitive voltage divider is provided with a preset threshold, and the capacitive voltage divider triggers the Schmitt trigger when the target voltage is greater than or equal to the preset threshold, and the Schmitt trigger sends the overvoltage signal to the trigger device when it is triggered; Among them, the target voltage is the voltage of the first light-triggered thyristor or the second light-triggered thyristor at the ground terminal of the bipolar controllable switch; the preset threshold is determined based on the preset rated voltage ratio, the number of the voltage-equalizing resistors and the preset overvoltage protection threshold; the preset rated voltage ratio is the ratio of the rated voltage of the controllable part of the lightning arrester to the sum of the rated voltages of the fixed part of the lightning arrester and the controllable part of the lightning arrester.

4. The light-triggered thyristor type controllable lightning arrester according to claim 3, characterized in that: The trigger device comprises a plurality of sub-trigger circuits, each of which comprises a first field effect transistor and a plurality of laser diodes connected in series to a source of the first field effect transistor, wherein the source of the first field effect transistor is connected to an anode of the laser diode connected thereto; the plurality of laser diodes in the plurality of sub-trigger circuits are used to generate the optical signal; the number of the sub-trigger circuits is determined based on the light emitting capability of the laser diode; The output terminal of the Schmitt trigger is connected to the gate of the first field effect transistor in the plurality of sub-trigger circuits.

5. The light-triggered thyristor type controllable lightning arrester according to claim 4, characterized in that: The light-triggered thyristor type controllable lightning arrester also includes a self-powered device; the self-powered device is installed at the grounding point of the bipolar controllable switch and is used to supply power to the multiple sub-trigger circuits; The self-energy extraction device comprises an energy extraction coil, a protection circuit, a rectifier bridge, an energy release circuit, a DC conversion module and an energy storage battery connected in sequence, and an action protection switch arranged between the energy extraction coil and the protection circuit; Among them, the energy extraction coil is used to sense the magnetic field generated by the leakage current flowing when the bipolar controllable switch is turned off, so as to generate AC power; the protection circuit is used to protect the circuit at its rear end; the rectifier bridge is used to convert the AC power into DC power; the energy release circuit is used to stabilize the output voltage of the rectifier bridge at a preset voltage regulation value; the AC / DC conversion module is used to convert the voltage at its input end to the rated voltage of the energy storage battery; the action protection switch is used to short-circuit the circuit after the energy extraction coil when the bipolar controllable switch is actuated.

6. The light-triggered thyristor type controllable lightning arrester according to claim 5, characterized in that: The energy taking coil adopts a Permalloy closed magnetic core, and the number of coil turns is 300; the protection circuit includes a transient voltage suppressor, a protection reactor and a gas discharge tube; the rectifier bridge includes four Schottky diodes; the energy releasing circuit includes a first capacitor, a first resistor, a second field effect transistor, a second resistor and a second capacitor; Among them, the positive end of the energy extraction coil is connected to the anode of the transient voltage suppressor and one end of the protection inductor, the other end of the protection inductor is connected to one end of the gas discharge tube, and the negative end of the energy extraction coil is connected to the cathode of the transient voltage suppressor and the other end of the gas discharge tube; the two ends of the gas discharge tube are respectively connected to the AC input end of the rectifier bridge; the positive electrode of the rectifier bridge is respectively connected to one end of the first capacitor, one end of the second resistor and one end of the second capacitor, and the negative electrode of the rectifier bridge is respectively connected to the other end of the first capacitor, one end of the first resistor, the source of the second field effect transistor and the other end of the second capacitor; the other end of the first resistor is connected to the gate of the second field effect transistor, and the other end of the second resistor is connected to the drain of the second field effect transistor; the two ends of the second capacitor are respectively connected to the two ends of the DC conversion module, the positive end of the DC conversion module is connected to the positive end of the energy storage battery, and the negative end of the DC conversion module is connected to the negative end of the energy storage battery.

7. The light-triggered thyristor type controllable lightning arrester according to claim 5, characterized in that: The self-energy extraction device also includes a control module; The control module is used to control the energy release circuit to stabilize the output voltage of the rectifier bridge at a preset voltage regulation value, and to control the action protection switch to act when the bipolar controllable switch acts.

8. The light-triggered thyristor type controllable lightning arrester according to claim 1, characterized in that: The value range of the rated voltage proportion of the controllable part of the lightning arrester is 15% to 20%; 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, and the total rated voltage is the sum of the rated voltages of the controllable part of the lightning arrester and the fixed part of the lightning arrester.

9. The light-triggered thyristor type controllable lightning arrester according to claim 8, characterized in that: An end of the fixed part of the arrester that is not connected to the controllable part of the arrester is used to connect to a power transmission line; When the length of the transmission line is less than or equal to a first length, the rated voltage of the controllable part of the lightning arrester accounts for a first percentage; when the length of the transmission line is greater than the first length and less than or equal to a second length, the rated voltage of the controllable part of the lightning arrester accounts for a second percentage; when the length of the transmission line is greater than the second length and less than or equal to a third length, the rated voltage of the controllable part of the lightning arrester accounts for a third percentage.

10. The light-triggered thyristor type controllable lightning arrester according to claim 9, characterized in that: The transmission line is an extra-high voltage transmission line or a UHV transmission line.

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