Lightning protection system

Abstract

The lightning protection system comprises a switch assembly connected between a protected cable and a ground wire and a control assembly used for controlling the switch assembly to be switched between a first protection circuit and a second protection circuit, and the input end of the switch assembly is connected with the protected cable; the first output end of the switch assembly is connected with a ground wire through a first protection circuit, and the second output end of the switch assembly is connected with the ground wire through a second protection circuit. The output end of the control assembly is connected with the control end of the switch assembly. According to the invention, the electric appliance can be recovered to a normal working condition in time after excessive lightning stroke occurs in an unattended state.

Description

Technical Field

[0001] The invention belongs to the technical field of lightning protection, and in particular relates to a lightning protection system. Background Art

[0002] In the field of power supply and communication, natural lightning often generates surges on the lines, which affects the working state of electrical appliances and causes damage to the appliances. In order to reduce the impact of lightning on power supply and communication lines, lightning arresters or surge protectors are usually used to guide lightning strikes or excessive surges into the ground.

[0003] Traditional lightning arresters or surge protectors are composed of gas discharge tubes or varistors. When lightning strikes or the surge exceeds the circuit carrying limit, the gas discharge tube or varistor is broken down to make the front-end circuit of the electrical appliance conductive to the ground, and the lightning current and surge current are introduced into the ground, thereby achieving the purpose of protecting the electrical appliance.

[0004] However, the main circuit of such traditional lightning arresters or surge protectors can only withstand one excessive lightning current or surge. When the circuit is broken down, a new lightning arrester or surge protector needs to be replaced so that the electrical appliances can work normally. Manual replacement of lightning arresters or surge protectors requires operators to be on duty for a long time, which cannot meet the requirements of timely power restoration and causes labor waste.

[0005] Therefore, there is a need for a lightning protection system that can intelligently switch working states, so that electrical appliances can be restored to normal working conditions in a timely manner after excessive lightning strikes occur in an unattended state. Summary of the invention

[0006] In order to solve the deficiencies in the prior art, the present invention provides a lightning protection system, which can restore electrical appliances to normal working conditions in a timely manner after excessive lightning strikes occur in an unattended state.

[0007] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a lightning protection system, comprising: a switch component connected between a protected cable and a ground wire, the input end of the switch component being connected to the protected cable; an output end one of the switch component being connected to the ground wire through a protection circuit one, and an output end two of the switch component being connected to the ground wire through a protection circuit two; a control component for controlling the switch component to switch between protection circuit one and protection circuit two, the output end of the control component being connected to the control end of the switch component.

[0008] Furthermore, the control component includes a single-chip microcomputer, the output end of the single-chip microcomputer is connected to the control end of the switch component; the input end 1 of the single-chip microcomputer is interconnected with the public information network and / or the lightning warning instrument through a network interface; the input end 2 of the single-chip microcomputer is connected to the protected cable through a voltage sampling circuit.

[0009] Furthermore, the output end of the protected cable is connected to the electrical appliance, the connection point between the switch component and the protected cable is between the input end of the protected cable and the electrical appliance, and the connection point between the voltage sampling circuit and the protected cable is located before the electrical appliance and after the connection point between the switch component and the protected cable.

[0010] Furthermore, the model of the single chip microcomputer is: Xillinx Zynq-7000.

[0011] Further, the voltage sampling circuit includes a sampling point Vin connected to the protected cable, the sampling point Vin is connected to one end of the resistor R1, the other end of the resistor R1 is respectively connected to one end of the resistor R2, one end of the capacitor C1, one end of the resistor R3, one end of the resistor R4, and one end of the resistor R5; the other end of the resistor R4 is connected to a +5V power supply, the other end of the resistor R5 is respectively connected to one end of the resistor R7 and a positive input end of the differential operational amplifier A, and the inverting input end of the differential operational amplifier A is respectively connected to one end of the resistor R6 and one end of the resistor R9; the other end of the resistor R9 is respectively connected to the output end of the differential operational amplifier A and one end of the resistor R8; the other end of the resistor R8 is respectively connected to one end of the capacitor C2 and an output end Vout connected to an AD sampling interface of the single-chip computer MCU; the other end of the resistor R2, the other end of the capacitor C1, the other end of the resistor R3, the other end of the resistor R6, the other end of the resistor R7, and the other end of the capacitor C2 are respectively grounded.

[0012] Furthermore, the switch assembly comprises: a third contact connected to the protected cable, a first contact connected to the protection circuit 1, and a second contact connected to the protection circuit 2; the third contact is electrically connected to the first contact or the second contact.

[0013] Further, the first contact is connected to the input point Vin1 of the protection circuit 1; the second contact is connected to the input point Vin2 of the protection circuit 2; the input point Vin1 of the protection circuit 1 is respectively connected to one end of the three-terminal gas discharge tube G1 and one end of the inductor L1; the other end of the inductor L1 is respectively connected to one end of the varistor RV1, one end of the capacitor C3, one end of the capacitor C4, and the output end Vout1; the input point Vin2 of the protection circuit 2 is respectively connected to the other end of the three-terminal gas discharge tube G1 and one end of the inductor L2; The other end of L2 is connected to one end of the varistor RV2, the other end of the capacitor C3, one end of the capacitor C5, and the output end Vout2 respectively; the third end of the three-terminal gas discharge tube G1 is grounded, and the other end of the varistor RV1 and the other end of the varistor RV2 are grounded through the two-terminal gas discharge tube G2; the other end of the capacitor C4 and the other end of the capacitor C5 are grounded respectively; the breakdown voltage of the three-terminal gas discharge tube G1 is V2; the two-terminal gas discharge tube G2 is a ceramic gas discharge tube, and the breakdown voltage of the two-terminal gas discharge tube G2 is V1, wherein, .

[0014] Furthermore, when the input end of the single chip microcomputer receives a set first signal, the third contact is electrically connected to the second contact; the first signal includes thunderstorm weather warning information.

[0015] Furthermore, when the voltage sampling value received by the input terminal 2 of the single-chip microcomputer meets the set conditions and the input terminal 1 of the single-chip microcomputer receives the set second signal, the third contact is electrically connected to the first contact; the second signal includes thunderstorm weather warning cancellation information.

[0016] Furthermore, the voltage sampling circuit inputs the voltage sampling value to the AD sampling interface of the single chip microcomputer through the SMA interface.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: the present invention connects the input end of the switch component to the protected cable; the output end one of the switch component is connected to the ground wire through the protection circuit one, and the output end two of the switch component is connected to the ground wire through the protection circuit two; the output end of the control component is connected to the control end of the switch component, which is used to control the switch component to switch between the protection circuit one and the protection circuit two, and can restore the electrical appliances to normal working conditions in time after excessive lightning strikes occur in an unattended state. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of a circuit principle of a lightning protection system provided by an embodiment of the present invention; Figure 2 yes Figure 1 A schematic diagram of the circuit principle of the medium voltage sampling circuit; Figure 3 yes Figure 1 Schematic diagram of the circuit principles of protection circuit 1 and protection circuit 2. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0020] like Figure 1 As shown, a useful electrical appliance EA is connected between the input end Sin and the output end Sout of the protected cable, and the lightning protection system includes: a switch component SP2T and a control component.

[0021] The switch component SP2T is connected between the protected cable and the ground wire GND, and the input end of the switch component SP2T is connected to the protected cable; the output end 1 of the switch component SP2T is connected to the ground wire GND through the protection circuit 1 MOV1, and the output end 2 of the switch component SP2T is connected to the ground wire through the protection circuit 2 MOV2. When the protected cable is overcurrent, the protection circuit 1 MOV1 or the protection circuit 2 MOV2 is broken down, so that the switch component SP2T is short-circuited with the ground wire GND.

[0022] The control component is used to control the switch component SP2T to switch between the protection circuit 1 MOV1 and the protection circuit 2 MOV2, and the output end of the control component is connected to the control end of the switch component SP2T.

[0023] The control component includes a single-chip microcomputer MCU, the output end of the single-chip microcomputer MCU is connected to the control end of the switch component SP2T; the input end 1 of the single-chip microcomputer is interconnected with the public information network and the lightning warning instrument through the network interface RJ45; the input end 2 of the single-chip microcomputer MCU is connected to the protected cable through the voltage sampling circuit VSC. The model of the single-chip microcomputer MCU is: Xillinx Zynq-7000. The switch component SP2T short-circuits one end of the protection circuit 1 MOV1 or the protection circuit 2 MOV2 with the protected cable according to the instruction of the single-chip microcomputer MCU.

[0024] The principle of the voltage sampling circuit VSC is as follows Figure 2 As shown, A is a LTC2051 differential operational amplifier, Vin is a sampling point, connected to the protected cable; Vout is the output end, connected to the single-chip microcomputer MCU. The voltage sampling circuit VSC uses resistor voltage division and filters the sine wave, and finally inputs the AD sampling interface of the single-chip microcomputer MCU. Among them, R1~R9 are resistors, and the resistance values ​​are 390kΩ, 2kΩ, 10kΩ, 4.7kΩ, 10kΩ, 10kΩ, 10kΩ, 2kΩ, and 10kΩ respectively; C1 and C2 are capacitors, and the capacitance values ​​are both 1nF.

[0025] The sampling point Vin connected to the protected cable is connected to one end of the resistor R1, and the other end of the resistor R1 is respectively connected to one end of the resistor R2, one end of the capacitor C1, one end of the resistor R3, one end of the resistor R4, and one end of the resistor R5; the other end of the resistor R4 is connected to a +5V power supply, the other end of the resistor R5 is respectively connected to one end of the resistor R7 and the non-inverting input end of the differential operational amplifier A, and the inverting input end of the differential operational amplifier A is respectively connected to one end of the resistor R6 and one end of the resistor R9; the other end of the resistor R9 is respectively connected to the output end of the differential operational amplifier A and one end of the resistor R8; the other end of the resistor R8 is respectively connected to one end of the capacitor C2 and the output end Vout connected to the AD sampling interface of the single-chip computer MCU.

[0026] The other ends of resistor R2, the other end of capacitor C1, the other end of resistor R3, the other end of resistor R6, the other end of resistor R7, and the other end of capacitor C2 are respectively grounded.

[0027] The connection point of the voltage sampling circuit VSC and the protected cable is located before the electrical appliance EA and after the connection point of the switch assembly SP2T and the protected cable. The voltage sampling point of the voltage sampling circuit VSC is set before the electrical appliance EA and as close as possible to the air switch or other protection switches; the voltage sampling point of the voltage sampling circuit VSC is set after the switch assembly SP2T and as far as possible from the electrical appliance EA.

[0028] The switch assembly SP2T includes: a third contact connected to the protected cable, a first contact Port1 connected to the protection circuit MOV1, and a second contact Port2 connected to the protection circuit MOV2; the third contact is electrically connected to the first contact Port1 or the second contact Port2.

[0029] As Figure 3 shown, where RV1 and RV2 are varistors, mainly used to suppress high-voltage common-mode and differential-mode surge signals; G1 is a three-terminal gas discharge tube, mainly used to suppress high-voltage common-mode surge signals, and its breakdown voltage is V2; G2 is a two-terminal ceramic gas discharge tube, and its breakdown voltage V1 << V2. The protection circuits MOV1 and MOV2 are selected with high and low withstand voltage values, and the withstand voltage values should differ by more than 2 times (i.e., 2V1 < V2), which can further prevent the protection circuit with a high withstand voltage value from being inductively broken down. The first contact is connected to the input point Vin1 of the protection circuit MOV1; the second contact is connected to the input point Vin2 of the protection circuit MOV2; the input point Vin1 of the protection circuit MOV1 is respectively connected to one end of the three-terminal gas discharge tube G1 and one end of the inductor L1; the other end of the inductor L1 is respectively connected to one end of the varistor RV1, one end of the capacitor C3, one end of the capacitor C4, and the output terminal Vout1; the input point Vin2 of the protection circuit MOV2 is respectively connected to the other end of the three-terminal gas discharge tube G1 and one end of the inductor L2; the other end of the inductor L2 is respectively connected to one end of the varistor RV2, the other end of the capacitor C3, one end of the capacitor C5, and the output terminal Vout2; the ground wire (the third terminal) of the three-terminal gas discharge tube G1 is grounded, and the other ends of the varistors RV1 and RV2 are both grounded through the two-terminal gas discharge tube G2; the other ends of the capacitors C4 and C5 are respectively grounded.

[0030] When a thunderstorm is about to occur, the input terminal 1 of the single-chip microcomputer MCU receives the thunderstorm warning information (i.e., the set first signal) transmitted through the public information network, and controls the switch component SP2T to electrically connect the third contact with the second contact Port2, so that the protection circuit 2 MOV2 with a lower withstand voltage value is connected to the protection circuit branch, which is more conducive to conducting the lightning current into the earth and reducing the impact of the lightning strike on the electrical appliance EA.

[0031] When a thunderstorm occurs and excessive lightning current flows into the protected line, the second protection circuit MOV2 is broken down, causing the protected line to be short-circuited to the ground through the switch component SP2T, and the lightning current is introduced into the ground.

[0032] When a thunderstorm occurs, the single-chip microcomputer MCU determines the working state of the protected line according to the voltage sampling value of the voltage sampling circuit VSC, and determines whether the thunderstorm weather has ended according to the weather warning information received from the public information network and the lightning warning instrument; that is, the voltage sampling circuit VSC inputs the voltage sampling value to the input terminal 2 (AD sampling interface) of the single-chip microcomputer MCU through the SMA interface. When the voltage sampling value received by the input terminal 2 of the single-chip microcomputer MCU meets the set condition (when the protected line is protected, the voltage sampling value becomes 0V or is much lower than the voltage sampling value under normal working conditions), and the input terminal 1 of the single-chip microcomputer MCU receives the set second signal (that is, the thunderstorm weather warning cancellation information, or the thunderstorm weather cancellation notification sent back by the lightning warning instrument), the control switch component SP2T electrically connects the third contact with the first contact Port1, thereby resuming the operation of the electrical appliance EA.

[0033] When the protection circuit is triggered, the single-chip microcomputer MCU records and forms a log file. The single-chip microcomputer MCU also sends the information to the user through the input terminal in the form of a network email, prompting that the protection circuit is broken down and the damaged protection circuit should be replaced in time.

[0034] The single-chip computer MCU obtains the voltage sampling value through the voltage sampling circuit VSC and determines whether the currently connected protection circuit is broken down. It also obtains local weather information by connecting to the public information network and connects to the lightning warning instrument to obtain the change of lightning risk in this area. Therefore, when the currently connected protection circuit is broken down and the thunderstorm ends, the switch component SP2T is controlled to switch the protection circuit, so that the front end of the electrical appliance EA is no longer short-circuited to the ground wire, thereby restoring the electrical appliance to normal working conditions, reducing the manual intervention link and reducing the interval time from the shutdown of the electrical appliance due to lightning strike to the resumption of work.

[0035] The single-chip microcomputer MCU obtains local weather information by interconnecting with the public information network. When the weather forecast shows that a thunderstorm is about to occur locally, the control switch component SP2T switches the protection circuit to the protection branch where the protection circuit with a low withstand voltage value is located, which is more conducive to realizing lightning protection for the electrical appliance EA.

[0036] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A lightning protection system, characterized in that: include: A switch component connected between the protected cable and the ground wire, wherein an input end of the switch component is connected to the protected cable; The output terminal 1 of the switch assembly is connected to the ground wire through the protection circuit 1, and the output terminal 2 of the switch assembly is connected to the ground wire through the protection circuit 2; A control component for controlling the switch component to switch between protection circuit 1 and protection circuit 2, wherein the output end of the control component is connected to the control end of the switch component.

2. The lightning protection system according to claim 1, characterized in that: The control component includes a single-chip microcomputer, the output end of the single-chip microcomputer is connected to the control end of the switch component; the input end 1 of the single-chip microcomputer is interconnected with the public information network and / or the lightning warning instrument through a network interface; the input end 2 of the single-chip microcomputer is connected to the protected cable through a voltage sampling circuit.

3. The lightning protection system according to claim 2, characterized in that: The output end of the protected cable is connected to the electrical appliance, the connection point between the switch component and the protected cable is between the input end of the protected cable and the electrical appliance, and the connection point between the voltage sampling circuit and the protected cable is located before the electrical appliance and after the connection point between the switch component and the protected cable.

4. The lightning protection system according to claim 2, characterized in that: The model of the single chip microcomputer is: Xillinx Zynq-7000.

5. The lightning protection system according to claim 2, characterized in that: The voltage sampling circuit includes a sampling point Vin connected to the protected cable, the sampling point Vin is connected to one end of a resistor R1, the other end of the resistor R1 is respectively connected to one end of a resistor R2, one end of a capacitor C1, one end of a resistor R3, one end of a resistor R4, and one end of a resistor R5; the other end of the resistor R4 is connected to a +5V power supply, the other end of the resistor R5 is respectively connected to one end of a resistor R7 and a positive input end of a differential operational amplifier A, the inverting input end of the differential operational amplifier A is respectively connected to one end of a resistor R6 and one end of a resistor R9; the other end of the resistor R9 is respectively connected to the output end of the differential operational amplifier A and one end of a resistor R8; the other end of the resistor R8 is respectively connected to one end of a capacitor C2 and an output end Vout connected to an AD sampling interface of a single-chip computer MCU; The other end of the resistor R2 , the other end of the capacitor C1 , the other end of the resistor R3 , the other end of the resistor R6 , the other end of the resistor R7 , and the other end of the capacitor C2 are grounded, respectively.

6. The lightning protection system according to claim 2, characterized in that: The switch assembly comprises: a third contact connected to the protected cable, a first contact connected to the first protection circuit and a second contact connected to the second protection circuit; the third contact is electrically connected to the first contact or the second contact.

7. The lightning protection system according to claim 6, characterized in that: The first contact is connected to the input point Vin1 of the protection circuit 1; the second contact is connected to the input point Vin2 of the protection circuit 2; The input point Vin1 of the protection circuit 1 is respectively connected to one end of the three-terminal gas discharge tube G1 and one end of the inductor L1; the other end of the inductor L1 is respectively connected to one end of the varistor RV1, one end of the capacitor C3, one end of the capacitor C4, and the output end Vout1; The input point Vin2 of the second protection circuit is respectively connected to the other end of the three-terminal gas discharge tube G1 and one end of the inductor L2; the other end of the inductor L2 is respectively connected to one end of the varistor RV2, the other end of the capacitor C3, one end of the capacitor C5, and the output end Vout2; The third end of the three-terminal gas discharge tube G1 is grounded, and the other end of the varistor RV1 and the other end of the varistor RV2 are both grounded through the two-terminal gas discharge tube G2; The other end of the capacitor C4 and the other end of the capacitor C5 are grounded respectively; The breakdown voltage of the three-terminal gas discharge tube G1 is V2; the two-terminal gas discharge tube G2 is a ceramic gas discharge tube, and the breakdown voltage of the two-terminal gas discharge tube G2 is V1, where: .

8. The lightning protection system according to claim 7, characterized in that: When the input terminal of the single chip microcomputer receives a set first signal, the third contact is electrically connected to the second contact; the first signal includes thunderstorm weather warning information.

9. The lightning protection system according to claim 7, characterized in that: When the voltage sampling value received by the second input terminal of the single chip microcomputer meets the set condition and the first input terminal of the single chip microcomputer receives the set second signal, the third contact is electrically connected to the first contact; the second signal includes thunderstorm weather warning cancellation information.

10. The lightning protection system according to claim 9, characterized in that: The voltage sampling circuit inputs the voltage sampling value to the AD sampling interface of the single chip microcomputer through the SMA interface.

Images