Lightning protection power supply system

Abstract

The utility model relates to a lightning protection power supply system, which belongs to the technical field of power supply protection and comprises an alternating current constant current source, a current main loop and a plurality of power conversion devices. The input end of the alternating-current constant-current source is connected with alternating-current voltage, and the output end of the alternating-current constant-current source is connected with the current main loop; the current main loop comprises a plurality of anti-disconnection switches and current transmission and distribution lines for connecting the anti-disconnection switches in series; the anti-disconnection switch comprises a first terminal, a second terminal, a third terminal and a fourth terminal; the first terminal and the fourth terminal are connected to a current main loop; the second terminal and the third terminal are respectively connected with the first input end and the first output end of the power conversion device; when the first terminal is connected with the second terminal and the third terminal is connected with the fourth terminal, the power conversion device is connected with the current main loop; aC or DC voltage is output between the second input end and the second output end of the power conversion device. The lightning protection device has the effect of reducing the possibility of damage to electric equipment caused by lightning stroke.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power supply protection, in particular to a lightning-proof power supply system. BACKGROUND

[0002] With the development of economy, the power users have higher and higher requirements for the reliability of power supply system. At present, a low-voltage power supply system with constant alternating voltage, such as a 220V power supply system, is generally used. When the power transmission line or the power utilization equipment is subjected to lightning in the outdoor, the lightning current will generate a large lightning overvoltage, which enters the power utilization equipment in the form of common mode or differential mode, resulting in damage to the power utilization equipment.

[0003] In order to reduce the damage of lightning overvoltage formed by lightning current to the power utilization equipment, a lightning arrester is usually used in the current low-voltage power supply system. Although the lightning arrester can greatly reduce the amplitude of overvoltage when lightning occurs, it still cannot fundamentally solve the contradiction between the excessively high lightning residual voltage and the extremely low voltage tolerance of the outdoor low-voltage power utilization equipment. With the popularization of the Internet of Things, more and more intelligent power utilization equipment is installed outdoors, and the frequency of damage to the low-voltage outdoor intelligent power utilization equipment caused by lightning is still high. CONTENT OF THE UTILITY MODEL

[0004] In order to reduce the possibility of damage to the power utilization equipment caused by lightning, the present application provides a lightning-proof power supply system.

[0005] The lightning-proof power supply system provided by the present application adopts the following technical scheme:

[0006] The lightning-proof power supply system comprises an alternating constant current source, a current main circuit and a plurality of power conversion devices.

[0007] The input end of the alternating constant current source is connected to an alternating voltage, and the output end of the alternating constant current source is connected to the current main circuit to provide alternating current to the current main circuit.

[0008] The current main circuit comprises a plurality of anti-break switches and a current transmission and distribution line connected in series with the anti-break switches.

[0009] The anti-break switch comprises a first terminal, a second terminal, a third terminal and a fourth terminal. The first terminal and the fourth terminal are connected to the current main circuit. The second terminal is connected to the first input end of the power conversion device, and the third terminal is connected to the first output end of the power conversion device. When the first terminal is connected to the second terminal and the third terminal is connected to the fourth terminal, the power conversion device is connected to the current main circuit.

[0010] The second input end and the second output end of the power conversion device output alternating or direct current voltage.

[0011] By adopting the technical scheme, when a lightning strikes at any position of the current main circuit, a lightning strike voltage is formed on the current main circuit to the ground, if the lightning strike voltage is too high to cause a weak link of the current main circuit to the ground to be broken down, a lightning current to the ground is formed, since the resistance of the current main circuit is very low, even if the lightning current locally passes through the current main circuit, the lightning current cannot form an overvoltage on the current main circuit, and the normal work of the current main circuit is not affected; if the lightning strike voltage is not enough to break down the weak link of the current main circuit to the ground, the lightning current is not generated, and the work of the current main circuit is not affected, thereby reducing the possibility that the electric equipment is damaged by lightning.

[0012] Optionally, the current output by the output end of the alternating constant current source is an alternating sine wave current with a preset frequency and a preset amplitude.

[0013] Optionally, the frequency of the alternating sine wave current is a base frequency or an intermediate frequency, the base frequency is 50Hz or 60Hz, and the intermediate frequency is 50Hz-500Hz.

[0014] By adopting the technical scheme, since a high-frequency current is beneficial to the efficiency of power conversion, but the higher the frequency is, the greater the line impedance is, so the frequency of the current is an intermediate frequency, and the line impedance is reduced while the efficiency of power conversion is ensured.

[0015] Optionally, the shell of the power conversion device is grounded.

[0016] By adopting the technical scheme, the shell of the power conversion device is grounded, the lightning current is directly introduced into the ground, and the residual voltage on the shell is very low, so the safety of the equipment and personnel is not endangered.

[0017] Optionally, the shell of the alternating constant current source is grounded.

[0018] By adopting the technical scheme, the shell of the alternating constant current source is grounded, the lightning strike current is introduced into the ground, and the residual voltage on the shell is very low, so the safety of the equipment and personnel is not endangered.

[0019] Optionally, the current transmission and distribution line is directly grounded.

[0020] By adopting the technical scheme, when the current transmission and distribution line is directly grounded, the lightning current is directly introduced into the ground through the current transmission and distribution line, since the resistance of the current main circuit is very low, no high voltage or small high voltage is generated, and the safety of the electric equipment and the personnel around the equipment is not endangered.

[0021] Optionally, the current transmission and distribution line is indirectly grounded.

[0022] By adopting the above technical scheme, when the current transmission and distribution line is indirectly grounded, the lightning current is indirectly introduced into the ground through the current transmission and distribution line, and since the main circuit resistance is very low, no high voltage or small high voltage is generated, which does not endanger the safety of the electrical equipment and the personnel around the equipment.

[0023] Optionally, the second input end and the second output end of the power conversion device are connected with the low-voltage electrical equipment.

[0024] In summary, the present application has at least one of the following beneficial technical effects:

[0025] 1. When lightning directly strikes at any position of the main circuit, lightning strike voltage is formed on the main circuit, and if the lightning strike voltage is too high to cause the weak ground insulation part of the main circuit to break down, the lightning current is discharged to the ground. Since the resistance of the main circuit is very low, even if the lightning current partially passes through the main circuit, the lightning current cannot form an overvoltage on the main circuit, which does not affect the normal operation of the main circuit. If the lightning strike voltage is not high enough to break down the weak ground insulation part of the main circuit, no lightning current will be generated, and the operation of the main circuit will not be affected, thereby reducing the possibility of damage to the electrical equipment caused by lightning strike;

[0026] 2. When the current transmission and distribution line is directly grounded or indirectly grounded, the lightning current is introduced into the ground through the current transmission and distribution line, directly or indirectly through the voltage-sensitive device, and the loop resistance is very low, no high voltage or small high voltage is generated, which does not endanger the safety of the equipment and the personnel around the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a circuit schematic diagram of a lightning protection power supply system in embodiment 1.

[0028] Figure 2 is a circuit schematic diagram of the grounding of the current distribution line in a lightning protection power supply system in embodiment 2.

[0029] Reference signs: 1, AC constant current source; 2, current transmission and distribution line; 3, first terminal; 4, second terminal; 5, third terminal; 6, fourth terminal; 7, power conversion device. DETAILED DESCRIPTION

[0030] The following will be described in detail in combination with the accompanying Figures 1-2 The present application will be further described in detail.

[0031] Lightning rod and lightning wire can only prevent lightning to high-voltage transmission line, iron tower or large regional building to some extent, reduce the probability of lightning strike to the area, but cannot absolutely prevent lightning strike (i.e. still have the probability of side flash and induction lightning), and cannot block lightning strike to the conductor outside the area and conduct to the protected area. Since the highest lightning protection standard for current low-voltage electrical equipment is 4kV, even the overvoltage formed by side flash and induction lightning can reach tens of kV, so the conventional scheme is basically ineffective.

[0032] The embodiment of the application discloses a lightning-proof power supply system.

[0033] Embodiment 1:

[0034] With reference to Figure 1 The lightning-proof power supply system comprises an alternating current constant current source 1, a current main circuit and a plurality of power conversion devices 7. The input end of the alternating current constant current source 1 is connected to an alternating voltage, and the output end of the alternating current constant current source 1 is connected to the current main circuit to provide alternating current to the current main circuit. The current main circuit comprises a plurality of anti-break switches and a current distribution line 2 connected in series with the anti-break switches.

[0035] In order to reduce the line impedance per unit length, the current distribution line 2 comprises a plurality of insulated wires with small skin effect and a large cross-sectional area of the conductor to reduce power supply loss. The alternating current output by the alternating current constant current source 1 is an alternating sine wave current with a preset frequency and a preset amplitude. The preset amplitude is not limited and can be set as required. The frequency of the alternating sine wave current is a base frequency or a medium frequency to improve the efficiency of power conversion. The base frequency is 50Hz or 60Hz, and the medium frequency is 50Hz-500Hz. The shell of the alternating current constant current source 1 and the shell of the power conversion device 7 are grounded. In this embodiment, the shells of the alternating current constant current source 1 and the power conversion device 7 are directly grounded to guide the current formed by lightning strike on the shells of the alternating current constant current source 1 and the power conversion device 7 to the ground, thereby reducing the possibility of damage to the alternating current constant current source 1 and the power conversion device 7 caused by lightning strike.

[0036] The anti-break switch comprises a first terminal 3, a second terminal 4, a third terminal 5 and a fourth terminal 6. The first terminal 3 and the fourth terminal 6 are connected to the current main circuit. The second terminal 4 is connected to the first input end of the power conversion device 7, and the third terminal 5 is connected to the first output end of the power conversion device 7. When the first terminal 3 is connected to the second terminal 4, and the third terminal 5 is connected to the fourth terminal 6, the power conversion device 7 is connected to the current main circuit.

[0037] The second input end and the second output end of the power conversion device 7 are further connected to a low-voltage electrical equipment.

[0038] In the embodiment, the AC constant current source 1 is installed in a power distribution station, and is used to transform the voltage from the power grid or a generator into a constant AC current to be output externally. At this time, the first terminal 3 is connected with the second terminal 4, and the third terminal 5 is connected with the fourth terminal 6. The AC current enters the power supply conversion device 7 through the current transmission line 2, and the power supply conversion device 7 converts the AC current into a power source required by the low-voltage electrical equipment to supply power to the low-voltage electrical equipment.

[0039] As an example, the power supply conversion device 7 can convert the AC current into an AC voltage, and can also convert it into a DC voltage.

[0040] When it is necessary to add a low-voltage electrical equipment in the current main circuit or to remove a low-voltage electrical equipment in the current main circuit, the first terminal 3 and the fourth terminal 6 in the anti-break switch corresponding to the low-voltage electrical equipment to be added or removed are connected to the current main circuit. At this time, the first terminal 3 is connected with the fourth terminal 6, the connection between the first terminal 3 and the second terminal 4 is disconnected, and the connection between the third terminal 5 and the fourth terminal 6 is disconnected. At this time, the AC current enters the current main circuit through the current transmission line 2, the first terminal 3 and the fourth terminal 6, and no longer enters the power supply conversion device 7 at the position where the low-voltage electrical equipment to be added or removed is located. In this way, the normal transmission of the current on the current transmission line 2 can be ensured without interruption during the installation, removal, use or expansion.

[0041] After the operation of adding or removing the low-voltage electrical equipment is completed, the first terminal 3 and the second terminal 4 in the anti-break switch corresponding to the low-voltage electrical equipment to be added or removed are connected, and the third terminal 5 and the fourth terminal 6 are connected. Then, the connection between the first terminal 3 and the fourth terminal 6 is disconnected. At this time, the AC current enters the power supply conversion device through the current transmission line 2, the first terminal 3 and the second terminal 4 to supply power.

[0042] When a lightning stroke occurs at any position of the current main circuit, a lightning stroke voltage will be formed on the current main circuit. If the lightning stroke voltage is too high to cause the weak insulation part of the current main circuit to be broken down, a lightning current will be formed. Since the resistance of the current main circuit formed by the AC constant current source 1, the current transmission line 2, the anti-break switch and the power supply conversion device 7 is very low, even if the lightning current partially passes through the current main circuit, the lightning current cannot form an overvoltage on the current main circuit, and thus the normal operation of the current main circuit will not be affected. If the lightning stroke voltage is not high enough to cause the weak insulation part of the current main circuit to be broken down, no lightning current will be generated, and the operation of the current main circuit will not be affected. Thus, the purpose of continuously and stably supplying power in a lightning stroke state is achieved.

[0043] When the direct lightning strikes the shell of the power conversion device 7, the lightning strike has no effect on the current main circuit, does not affect the continuous and stable operation of the power supply system under lightning strike, and does not affect the normal power supply of the power supply system, because the shell of the power conversion device 7 is directly grounded, the lightning current will be directly introduced into the ground, so the residual voltage on the shell of the power conversion device 7 is extremely low, and the safety of the low-voltage electrical equipment will not be endangered.

[0044] When the peripheral lightning induces current on the current transmission line 2, the anti-break switch and other conductors, the induced current on the current transmission line, the anti-break switch and the power conversion device 7 can form a high voltage to the ground, and there is a certain danger for personnel to contact, but the working circuit in the power supply system is not affected, and the purpose of continuous and stable power supply under lightning strike can still be achieved.

[0045] Generally, the AC constant current source 1 is installed indoors, and lightning will not directly act on the AC constant current source 1. If the AC constant current source 1 is installed outdoors, when lightning strikes the shell of the AC constant current source 1, the lightning strike has no effect on the current main circuit, does not affect the continuous and stable operation of the power supply system under lightning strike, and does not affect the normal power supply of the power supply system, because the AC constant current source 1 is directly grounded, the lightning current will be directly introduced into the ground, the residual voltage on the shell of the AC constant current source 1 is extremely low, and the safety of the low-voltage electrical equipment and personnel will not be endangered.

[0046] Example 2:

[0047] Reference Figure 2 The difference from example 1 is that the current transmission line 2 is grounded, and the current transmission line 2 can be directly grounded or indirectly grounded. When indirect grounding is used, indirect grounding is achieved through voltage-sensitive devices, which include voltage-sensitive resistors, overvoltage protectors and discharge tubes.

[0048] When the direct lightning strikes any position of the current transmission line, the anti-break switch and the power conversion device 7, the lightning current will be directly or indirectly introduced into the ground through the current transmission line 2 and voltage-sensitive devices, because the resistance of the current main circuit is very low, so no high voltage or small high voltage is generated, which does not endanger the safety of the equipment and the personnel around the equipment.

[0049] When the peripheral lightning induces lightning current on the current transmission line, the anti-break switch and other conductors, the induced lightning current is transmitted at low resistance and is directly or indirectly introduced into the ground through voltage-sensitive devices, no high voltage is generated at the charged part, and the residual voltage at the grounding point has no effect on the power transmission circuit of the entire system, which does not affect the normal power supply of the load and does not endanger the safety of the equipment.

[0050] The above are all preferred embodiments of the present application, and do not limit the protection scope of the present application, so that: all equivalent changes made according to the structure, shape, principle of the present application should be covered in the protection scope of the present application.

Claims

1. A lightning protection power supply system, characterized in that: include: AC constant current source, main current circuit and several power conversion devices; The input terminal of the AC constant current source is connected to an AC voltage, and the output terminal of the AC constant current source is connected to the main current circuit to provide AC current to the main current circuit. The main current circuit includes several circuit breakers and current transmission lines that connect the circuit breakers in series. The circuit breaker includes a first terminal, a second terminal, a third terminal, and a fourth terminal; the first terminal and the fourth terminal are connected in the main current circuit. The second terminal is connected to the first input terminal of the power conversion device, and the third terminal is connected to the first output terminal of the power conversion device; when the first terminal is connected to the second terminal, and the third terminal and the fourth terminal are connected, the power conversion device is connected to the main current circuit; The power conversion device outputs AC or DC voltage between its second input terminal and its second output terminal.

2. The lightning protection power supply system according to claim 1, characterized in that: The current output from the output terminal of the AC constant current source is an AC sinusoidal current with a preset frequency and preset amplitude.

3. The lightning protection power supply system according to claim 2, characterized in that: The frequency of the AC sinusoidal current is either the fundamental frequency or the intermediate frequency, wherein the fundamental frequency is 50Hz or 60Hz, and the intermediate frequency is 50Hz-500Hz.

4. The lightning protection power supply system according to claim 1, characterized in that: The casing of the power conversion device is grounded.

5. A lightning protection power supply system according to claim 1, characterized in that: The casing of the AC constant current source is grounded.

6. A lightning protection power supply system according to claim 1, characterized in that: The current transmission line is directly grounded.

7. A lightning protection power supply system according to claim 1, characterized in that: The current transmission line is indirectly grounded.

8. A lightning protection power supply system according to claim 1, characterized in that: The power conversion device is connected to low-voltage electrical equipment between its second input terminal and its second output terminal.

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