A multi-pulse surge protector with main and standby lightning protection chips

Abstract

The invention discloses a multi-pulse surge protector with a main and standby lightning protection chip, which includes two discharge bodies, namely a main discharge body and a standby discharge body, wherein the response time of the main discharge body is at the ns level, and the response time of the standby discharge body is at the μs level, and the time difference between the two is about 1000 times, and when the main discharge body discharges, the standby discharge body does not work, and when the main discharge body is damaged and fails, the standby discharge body starts to work; the discharge body is composed of a zinc oxide varistor, wherein the main discharge body adopts a 5-layer structure, and the standby discharge body adopts a 9-layer structure, and the main discharge body and the standby discharge body are installed in the left and right cavities of the lower cover. The invention can significantly reduce lightning strike accidents, and compared with the traditional surge protector protection with standby lightning protection measures, it provides an additional protection barrier for the protection equipment.

Description

Technical Field

[0001] The present invention relates to lightning protection for low-voltage power distribution systems, in particular to a multi-pulse surge protector with a primary and standby lightning protection chip, belonging to the category of surge protectors, and in particular to the field of protection of electromechanical systems. Background Art

[0002] At present, lightning high-voltage test laboratories around the world use a single waveform to test surge protectors (SPDs) in accordance with the IEC 61643-2011 (GB / T 18802.11-2020) surge protector test standard, and the impact of a single waveform does not conform to the physical characteristics of natural lightning (90% of natural lightning is negative flash discharge, a multi-pulse discharge process). Products that have passed the test according to this standard still have problems with fire and combustion during online operation, causing huge losses to electricity, communications, and personal safety. The international IEC SPD standard mainly solves the design requirements of SPDs in different application scenarios and safety issues such as single impulse tolerance, short-circuit tolerance, and TOV tolerance in lightning and non-lightning situations.

[0003] The problem of single lightning discharge and multiple impacts has always been an important topic in the field of lightning protection research in the world. Based on this, TÜV Rheinland of Germany released the test standard 2PFG 2634 / 08.17 "Requirements and Test Methods for Multi-pulse Surge Protectors Connected to Low-voltage Power Systems". This standard adds multi-pulse surge protection device testing on the basis of the original international standard test. Its test technology is closer to the simulation of the physical characteristics of natural lightning, providing a new high-level research platform for understanding and defending against lightning, facilitating the targeted development of lightning protection products adapted to different application fields, providing technical support for the rectification of hundreds of millions of SPDs in online operation, and promoting the technological upgrading of global SPD research and development and production.

[0004] Up to now, surge protectors are only fragile and consumable products. They do not work when the power grid is normal, but start working once the power grid is struck by lightning: clamp the grid voltage and discharge the lightning current safely to the earth. In actual applications, lightning current is often random. Once there is an excess lightning surge invasion (excess means: exceeding the maximum discharge current value and the number of pulses claimed by the surge protector. The maximum discharge current value can only be tolerated once, and the pulses also have a fixed number), the surge protector immediately enters a failure state due to its own overload (that is, disconnects itself from the power grid). At this time, a problem will arise: once the number of pulses exceeds the limit, the subsequent return lightning current will be applied to the equipment, and the equipment will act as a lightning current discharge path, causing damage.

[0005] The power surge protector products of the low-voltage distribution system are divided into: single-pulse surge protector and multi-pulse surge protector. The single-pulse surge protector refers to a "one-time discharge" (within 1 second) to discharge a pulse of lightning current, using a varistor; the multi-pulse surge protector refers to a "one-time discharge" (within 1 second) to discharge multiple pulses of lightning current, using multiple varistors of the same specification in parallel.

[0006] Multi-pulse surge protectors are usually installed in main incoming cabinets of low-voltage power distribution systems in areas with extremely high risk of lightning strikes, and in fully exposed open areas and places with high lightning strike frequencies. Lightning is a violent discharge phenomenon in nature. When a cloud layer carrying an electric charge approaches a tall building on the ground, a collision of positive and negative charges will occur, and the leading charge will fall into the grounding point, forming a first return stroke lightning current and multiple subsequent return stroke lightning currents. According to the 2013 International Conference on Large Power Grids CIGRE Final Report 2013 "LIGHTNING PARAMETERS FOR ENGINEERING APPLICATIONS", the average current peak of the first return stroke is 2-3 times the peak current of the subsequent return stroke. However, about one-third of ground lightning contains at least one subsequent return stroke with a large electric field peak, such as Figure 8 (Quoted from TÜV's 2PFG 2634 / 08.17 "Requirements and test methods for multi-pulse surge protectors connected to low-voltage power systems"), the last subsequent strikeback current peak is greater than or equal to the first strikeback, which poses a serious threat to power supply lines and other systems.

[0007] For a multi-pulse surge protector with a single discharge body, after releasing the first return stroke lightning current, the discharge body is at risk of being damaged by the first return stroke lightning current. Once damaged, the surge protector will lose its lightning protection function, and the subsequent return stroke lightning current cannot be released. A large amount of subsequent return stroke lightning current will directly rush into the power supply line, posing a serious threat to the electromechanical equipment of the power supply line. Summary of the invention

[0008] The object of the present invention is to provide a multi-pulse surge protector with a main and standby lightning protection chip. The multi-pulse surge protector has two discharge bodies, and the two discharge bodies discharge in sequence and will not discharge at the same time. When the main discharge body releases the first return stroke lightning current, the standby discharge body is in a dormant state. Only when the main discharge body is damaged by the lightning current, the standby discharge body starts to release the subsequent subsequent return stroke lightning current, thereby introducing the multiple pulse lightning currents on the power supply line into the earth, ensuring that the electrical equipment is in a safe environment.

[0009] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a multi-pulse surge protector with a main and standby lightning protection chip, including two discharge bodies, namely a main discharge body and a standby discharge body, the response time of the main discharge body to the lightning current is in the nanosecond (ns) level, and the response time of the standby discharge body is in the microsecond (μs) level, and the response time difference between the two is about 1000 times; when the main discharge body discharges, the standby discharge body does not work, and when the main discharge body is damaged and fails, the standby discharge body starts to work.

[0010] Furthermore, the main discharge body and the backup discharge body are lightning protection chips made of any one of the following materials: gas discharge tube, spark gap discharger, zinc oxide varistor, and graphite gap.

[0011] Furthermore, the discharge body is composed of a zinc oxide varistor, wherein the main discharge body adopts a 5-layer structure and the backup discharge body adopts a 9-layer structure. The main discharge body and the backup discharge body are installed in the left and right cavities of the lower cover, and a buffer space is arranged around the cavity.

[0012] Furthermore, the five-layer structure of the main discharge body is as follows: a main discharge body central tripping electrode is used in the center, two main discharge body zinc oxide ceramic sheets are superimposed on both sides of the main discharge body central tripping electrode, and main discharge body welding electrodes are located on the left and right sides; the lightning current enters through the main discharge body central tripping electrode, enters the main discharge body zinc oxide ceramic sheets on the left and right sides, and the main discharge body zinc oxide ceramic sheets are quickly turned on and reduce impedance, so that the lightning current flows out and is discharged through the main discharge body welding electrodes on both sides.

[0013] Furthermore, the 9-layer structure of the backup discharge body is combined as follows: the center adopts the backup discharge body center tripping electrode, the backup discharge body center tripping electrode adopts the electrode grooving method, the entire electrode groove is wound from the outside to the inside to reach the center point, forming an inductance characteristic, and the rapidly rising surge current is suppressed and the discharge is delayed by increasing the inductance, and the two sides of the backup discharge body center tripping electrode are two glass fiber isolation plates, the center of the glass fiber isolation plate is hollowed out and corresponds to the center of the backup discharge body center tripping electrode, and on the outside of the glass fiber isolation plate are two backup discharge body electrodes with bosses, the bosses of the backup discharge body electrodes are buckled into the hollow of the glass fiber isolation plate, and on the outside of the two backup discharge body electrodes are the backup discharge body zinc oxide ceramic sheets and the backup discharge body welding electrodes in turn.

[0014] Furthermore, the tripping welding points of the main discharge body and the backup discharge body are connected to the first terminal through the tripping protection metal spring, and the main discharge body and the backup discharge body are also connected to the second terminal through the current protection device. In the same surge protector, the main and backup discharge bodies have a conduction voltage difference of 100V in the static test, and the temperature difference is >20°C in the impulse current 10kA (8 / 20us) test.

[0015] Furthermore, the discharge body selection comprises the following steps:

[0016] Step 1: Use the instrument to test the varistor voltage, make the voltage difference between the main and standby lightning protection chips within 100V, and the leakage current of both is <5uA, and then perform the main and standby pairing;

[0017] Step 2: After applying a 10kA (8 / 20us) lightning current shock to the same group of active and standby lightning protection chips in step 1, if the temperature difference between the active and standby lightning protection chips is above 20°C within 1 minute, they are grouped together if the condition is met.

[0018] Furthermore, for products produced in the same batch, 5% or 3 units are randomly tested, and the test process is: single pulse action load test of main chip module → multi-pulse voltage protection level test + multi-pulse combination wave action load test → simulated failure mode test of main chip module → single pulse action load test of spare chip module → multi-pulse voltage protection level test + multi-pulse combination wave action load test → test result determination.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] Traditional surge protectors without primary and standby lightning protection chips (including single-pulse and multi-pulse surge protectors) have fixed lightning current tolerance values ​​and the number of pulses they can withstand. The core parameters are the maximum impact lightning current (Imax value) and the number of lightning pulses. Once these two parameters are exceeded, the surge protector will enter self-protection failure (disconnection from the power grid), and the electrical lines that lose the protection of the surge protector will be at risk of being invaded by lightning. When the subsequent return current of this lightning strike occurs continuously, the electrical equipment is a conductor and will inevitably be directly damaged by lightning. At the same time, the traditional multi-pulse surge protector, the surge protector connected to the power supply circuit, has only one discharge body. Regardless of whether this discharge body is composed of a single piece or multiple pieces of discharge materials of the same specifications or discharge materials of different specifications, it can only release a fixed maximum lightning current value and number of lightning pulses.

[0021] The multi-pulse surge protector with main and standby lightning protection chips of the present invention is a surge protector with two discharge bodies connected to a power supply circuit. When the main discharge body is working, the standby discharge body is in a dormant state. When the main discharge body fails, the standby discharge body starts to work and continues to release multiple pulse lightning currents of multiple lightning strikes.

[0022] The surge protector with main and backup dischargers of the present invention is compared with the above ones with the same lightning current bearing value and pulse number. When lightning strikes, the main discharger starts to discharge the lightning current, and the backup discharger is on standby. Once the main discharger is overloaded and damaged, the backup discharger is activated, so that the lightning safety protection effect of the electrical grid is twice that of the traditional surge protector, and the failure rate of lightning accidents is reduced by half.

[0023] In summary, the "multi-pulse surge protector with main and standby lightning protection chips" of the present invention solves the event of a lightning current with a random pulse of discharge. On the basis of the same specifications (specifications refer to: the maximum lightning discharge current value claimed by the product and the number of pulses to be borne), it has single-pulse lightning current protection and multi-pulse lightning current protection, and also has the ability to protect the equipment again after excess failure. That is, when the main discharge body is damaged, the standby discharge body starts to work; the two are misaligned in the start-up time, and there is a sequence in the energy discharge, which is equivalent to installing two sets of surge protectors that can be replaced. Once the lightning current overload damages the main discharge body, the standby discharge body automatically replaces it, solving the problem of multiple lightning current discharges and causing damage to the user's electrical equipment (the first time damages the surge protector, and the second time invades the user's equipment); the lightning safety protection effect is improved by 2 times. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is the overall structure diagram of the present invention after assembly;

[0025] Figure 2 It is a schematic diagram of the assembly of the main and standby discharge bodies of the present invention;

[0026] Figure 3 is an exploded view of the present invention;

[0027] Figure 4 It is a circuit structure principle diagram of the present invention;

[0028] Figure 5 It is a schematic diagram of the main discharge structure of the present invention;

[0029] Figure 6 It is a schematic diagram of the structure of the standby discharge body of the present invention;

[0030] Figure 7 It is a product sampling test verification flow chart of the present invention;

[0031] Figure 8 It is the waveform diagram of the lightning current from the first return stroke to the subsequent return stroke.

[0032] Marked in the figure: 1-shell cover, 2-status indicator light, 3-micro switch, 4-tripping protection metal spring, 5-first terminal, 6-main discharge body, 61-main discharge body welding electrode, 62-main discharge body zinc oxide ceramic, 63-main discharge body center tripping electrode, 7-spare discharge body, 71-spare discharge body welding electrode, 72-spare discharge body zinc oxide ceramic, 73-spare discharge body electrode, 74-glass fiber isolation board, 75-spare discharge body center tripping electrode, 10-current protection device, 11-second terminal, 12-signal output port, 13-first PCB board, 14-second PCB board, 15-lower cover, 16-main cavity, 17-spare cavity, 18-third PCB board. DETAILED DESCRIPTION

[0033] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] like Figure 1 and 2 A multi-pulse surge protector with a main and standby lightning protection chip includes two discharge bodies, namely a main discharge body 6 and a standby discharge body 7. The response time of the main discharge body 6 is at the ns level, and the response time of the standby discharge body 7 is at the μs level. The time difference between the two is about 1000 times. When the main discharge body 6 discharges, the standby discharge body 7 does not work. When the main discharge body 6 is damaged and fails, the standby discharge body 7 starts to work. Among them, the discharge body is not limited to a lightning protection chip composed of materials such as a gas discharge tube, a spark gap discharger, a zinc oxide varistor, and a graphite gap.

[0035] like Figure 3 and 4 The multi-pulse surge protector of this embodiment includes an upper cover 1, a lower cover 15, a main cavity 16 and a spare cavity 17. The main cavity 16 is loaded with a main discharge body 6, and the spare cavity 17 is loaded with a spare discharge body 7. The main and spare discharge bodies are welded together with the first PCB board 13 and are correspondingly installed in the main and spare cavities. The trip welding point at the upper end of the main and spare discharge bodies is connected in series with the trip protection metal spring 4, and is collectively connected to the first terminal 5. The lower end is connected in series with the current protection device 10, and is collectively connected to the second terminal 11. The main circuit design of the signal acquisition part is on the third PCB board 18, which contains AC / DC circuit + AND gate logic circuit + MCU signal processing circuit. The signal is finally output through the signal output port 12.

[0036] In this embodiment, the corresponding main discharge body and backup discharge body are respectively installed in the main cavity 16 and the backup cavity 17, and then sealed with epoxy resin to resist the electric force and play a role in heat dissipation.

[0037] In this embodiment, the first wiring terminal 5 is assembled with the tripping protection metal spring 4, and is welded to the upper end of the discharge body, and is welded with 145°C low-temperature tin. Once the temperature rise is exceeded, it can be tripped and disconnected. The second wiring terminal 11 is assembled with the current protection device 10, and finally welded to the side end of the discharge body. The current protection device 10 can use a current protection fuse, which will be blown in time when the current exceeds 100A. Once the temperature of the tripping welding point exceeds the limit, the tin welded to the discharge body will melt. Once the tin melts, the corresponding spring will bend up and hold up the corresponding micro switch 3 (one each for the main and standby) above to realize the switching function; the micro switch 3 and the main and standby status indicator light 2 are installed on the second PCB14 board, and assembled in the upper cover 1, which plays the role of indicating and transmitting fault signals.

[0038] In this embodiment, the signal output port 12 outputs the master / slave status and the status information of each chip, and adopts 485 signal transmission.

[0039] like Figure 5 and 6 The discharge body is composed of a zinc oxide varistor, wherein the main discharge body adopts a 5-layer structure and the backup discharge body adopts a 9-layer structure.

[0040] The five-layer structure of the main discharge body is as follows: the center uses the main discharge body center tripping electrode 63, two main discharge body zinc oxide ceramic sheets 62 are stacked on both sides of the main discharge body center tripping electrode 63, and the main discharge body welding electrodes 61 are located on the left and right sides; the lightning current enters through the main discharge body center tripping electrode 63, and enters the main discharge body zinc oxide ceramic sheets 62 on the left and right sides. The main discharge body zinc oxide ceramic sheets 62 are quickly turned on and reduce impedance, so that the lightning current flows out and discharges through the main discharge body welding electrodes 61 on both sides. After the five-layer structure is combined, it is wrapped with epoxy resin as a whole. This design method can achieve large through-current and fast reaction speed.

[0041] The 9-layer structure of the standby discharge body is as follows: the center adopts the standby discharge body center tripping electrode 75, and the standby discharge body center tripping electrode 75 adopts the electrode grooving method. The entire electrode groove is wound from the outside to the inside to reach the center point, forming an inductance characteristic. The rapidly rising surge current is suppressed and the discharge is delayed by increasing the inductance. The two sides of the standby discharge body center tripping electrode 75 are two glass fiber isolation plates 74, and the center of the glass fiber isolation plate 74 is hollowed out and corresponds to the center of the standby discharge body center tripping electrode 75. On the outside of the glass fiber isolation plate 74 are two standby discharge body electrodes 73 with bosses, and the bosses of the standby discharge body electrodes 73 are buckled into the hollow of the glass fiber isolation plate 74. On the outside of the two standby discharge body electrodes 73 are standby discharge body zinc oxide ceramic sheets 72 and standby discharge body welding electrodes 71. After the 9-layer structure is combined, it is wrapped with epoxy resin as a whole. This design method can reduce the starting speed while obtaining a large through-current.

[0042] In this embodiment, in the same surge protector, the conduction voltage difference between the main and standby dischargers in the static test is 100V, and in the impulse current 10kA (8 / 20us) test, the temperature difference is >20°C.

[0043] In this embodiment, the selection of the discharge body includes the following steps:

[0044] Step 1: Use the instrument to test the varistor voltage, make the voltage difference between the main and standby lightning protection chips within 100V, and the leakage current of both is <5uA, and then perform the main and standby pairing;

[0045] Step 2: After applying a 10kA (8 / 20us) lightning current shock to the same group of active and standby lightning protection chips in step 1, if the temperature difference between the active and standby lightning protection chips is above 20°C within 1 minute, they are grouped together if the condition is met.

[0046] like Figure 7 The finished product of the multi-pulse surge protector of the main and standby lightning protection chips of the present invention needs to be tested and certified. The sampling process is: for the products produced in the same batch, 5% or 3 units are sampled and tested, and the test process is: single pulse action load test of the main chip module → multi-pulse voltage protection level test + multi-pulse combination wave action load test → simulated failure mode test of the main chip module → single pulse action load test of the standby chip module → multi-pulse voltage protection level test + multi-pulse combination wave action load test → test result judgment: the qualified multi-pulse surge protector is the one that passes all the test results.

[0047] In summary, in the multi-pulse surge protector with main and standby lightning protection chips of the present invention, when lightning strikes, the main discharger starts to discharge lightning current and the standby discharger is on standby. Once the main discharger is overloaded and damaged, the standby discharger is activated, so that the lightning safety protection effect of the electrical grid is twice that of the traditional surge protector, thereby reducing the failure rate of lightning accidents by half.

[0048] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the protection scope of the present invention in any form, and all technical solutions obtained by equivalent replacement and the like fall within the protection scope of the present invention. The parts not involved in the present invention are the same as the prior art or can be implemented by the prior art.

Claims

1. A multi-pulse surge protector with a primary and standby lightning protection chip, characterized in that: It includes two discharge bodies, namely a main discharge body and a backup discharge body. The response time of the main discharge body to lightning current is nanoseconds, and the response time of the backup discharge body is microseconds. The difference between the response times is 1000 times. When the main discharge body is discharging, the backup discharge body does not work. When the main discharge body is damaged and fails, the backup discharge body starts to work. The discharge body is composed of a zinc oxide varistor, wherein the main discharge body adopts a 5-layer structure and the backup discharge body adopts a 9-layer structure. The main discharge body and the backup discharge body are installed in the left and right cavities of the lower cover, and a buffer space is arranged around the cavity; The 9-layer structure combination of the backup discharge body is as follows: the center adopts the backup discharge body center tripping electrode, the backup discharge body center tripping electrode adopts the electrode grooving method, the entire electrode groove is wound from the outside to the inside to reach the center point, forming an inductance characteristic, and the rapidly rising surge current is suppressed and the discharge is delayed by increasing the inductance, and the two sides of the backup discharge body center tripping electrode are two glass fiber isolation plates, the center of the glass fiber isolation plate is hollowed out and corresponds to the center of the backup discharge body center tripping electrode, and the outside of the glass fiber isolation plate is two backup discharge body electrodes with bosses, the bosses of the backup discharge body electrodes are buckled into the hollow of the glass fiber isolation plate, and the outsides of the two backup discharge body electrodes are the backup discharge body zinc oxide ceramic sheets and the backup discharge body welding electrodes in turn.

2. A multi-pulse surge protector with a primary and standby lightning protection chip according to claim 1, characterized in that: The main discharge body and the backup discharge body are lightning protection chips made of any one of the materials selected from the group consisting of a gas discharge tube, a spark gap discharger, a zinc oxide varistor and a graphite gap.

3. The multi-pulse surge protector with a primary and standby lightning protection chip according to claim 1, characterized in that: The five-layer structure of the main discharge body is as follows: a main discharge body central tripping electrode is used in the center, two main discharge body zinc oxide ceramic sheets are stacked on both sides of the main discharge body central tripping electrode, and main discharge body welding electrodes are located on the left and right sides; The lightning current enters through the central tripping electrode of the main discharge body, and enters the zinc oxide ceramics of the main discharge body to the left and right sides. The zinc oxide ceramics of the main discharge body quickly conduct and reduce the impedance, so that the lightning current flows out and is discharged through the welding electrodes of the main discharge body on both sides.

4. The multi-pulse surge protector with a primary and standby lightning protection chip according to claim 1, characterized in that: The tripping welding points of the main discharge body and the backup discharge body are connected to the first terminal through the tripping protection metal spring, and the main discharge body and the backup discharge body are also connected to the second terminal through the current protection device. In the same surge protector, the main and backup discharge bodies have a conduction voltage difference of 100V in the static test, and the temperature difference is >20°C in the impulse current 10kA test.

5. The multi-pulse surge protector with a primary and standby lightning protection chip according to claim 1, characterized in that: The discharge body selection comprises the following steps: Step 1: Use the instrument to test the varistor voltage, make the voltage difference between the main and standby lightning protection chips within 100V, and the leakage current of both is <5uA, and then perform the main and standby pairing; Step 2: After using a 10kA lightning current shock on the same group of active and standby lightning protection chips in step 1, if the temperature difference between the active and standby lightning protection chips is above 20°C within 1 minute, they are grouped together if the condition is met.

6. A multi-pulse surge protector with a primary and standby lightning protection chip according to claim 5, characterized in that: For products produced in the same batch, 5% or 3 units are randomly tested. The test process is: single pulse action load test of main chip module → multi-pulse voltage protection level test + multi-pulse combination wave action load test → simulated failure mode test of main chip module → single pulse action load test of spare chip module → multi-pulse voltage protection level test + multi-pulse combination wave action load test → test result determination.

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