Surge Protective Device (SPD) is a device used to limit transient overvoltage and discharge lightning current. Within the withstand voltage range, or discharge a strong lightning current into the ground to protect the protected equipment or system from impact. In order to make the surge protector operate safely and reliably in the power distribution system and prevent the occurrence of dangerous accidents. It is stipulated that the SPD must be connected in series with current protectors (such as fuses, circuit breakers). The fuse as a backup protection device has a low surge withstand capability. In order to obtain a higher surge withstand capability, the selected rated current value is relatively large, and it cannot break the low short-circuit current. Therefore, the fuse still has a great potential safety hazard as a backup protection device. Anhui Jinli independently developed a back-up integrated surge protector with a dedicated overcurrent protection function, which solves the problem of secondary serious accidents caused by the deterioration of the existing surge protection device and the occurrence of power frequency fault freewheeling and exceeding the safe range value. It can quickly realize the fuse protection, prevent the explosion of the arrester, and realize the secondary safety protection of the arrester. It solves the problem that fuses and circuit breakers have poor resistance to surge and impact, are easily damaged, and cannot break power frequency fault currents. At the same time, two separate devices, SPD and SCB, are combined to form an integrated product, which not only solves the above problems, but also greatly reduces the installation space, reduces the installation process, and reduces the effective voltage protection level. It is more convenient to replace after the failure, and the system can be restored to normal work faster. Anhui Jinli adheres to the original technology as the basis, constantly develops new products and improves the market awareness of the company's focus on the industry, and makes unremitting efforts to become a well-known lightning protection brand that is respected by the society.

Due to the exposure characteristics of the installation location of photovoltaic array, the risk of direct lightning strike is high, such as: ① Direct lightning strike (direct strike on photovoltaic panels); ② indirect impact (surge impact of photovoltaic modules, combiner boxes, inverters, etc.); ③ impact on other lines (direct impact on signal lines or surge) We must consider accidental operational losses such as downtime caused by lightning strikes, especially in high-power power generation applications. In addition, the risk of operating overvoltages must also be considered when PV systems are located in industrial field applications. At the same time, the risk level is directly related to the ground flash density and the exposure of local lines. 1. For low-voltage photovoltaic application systems, taking small residential buildings and office building rooftop power stations as examples, surge protection device must be performed on the DC side of the inverter connected to the photovoltaic array and the AC side of the inverter connected to the grid system. If the distance between the protective equipment (inverter or PV array) and the upstream spd is more than 10m, it is recommended to install an additional surge protector nearby to improve the protection capability. 2. Medium to large scale photovoltaic power generation systems can be installed on industrial test and service facilities. In order to avoid downtime and production losses due to direct or indirect lightning strikes, it is critical to install surge protectors at critical locations on equipment critical power and communication networks. 3. If the building does not have an air-termination system installed, it must be mandatory to install type 2 surge protectors on the AC and DC incoming lines of the inverter. On the photovoltaic side, for cables longer than 10m, a surge protector must be added at each end of the working cable. 4. If an air-termination system is installed, type 1 surge protection device must be installed on the AC input. On the DC side as well, Type 1 surge protectors are necessary in case the air-terminations are not installed to maintain an effective safe distance.

Lightning early warning system technical indicators and early warning classification A. Technical indicators 1. The advance time of lightning warning is not less than 10 minutes. 2. The average effective alarm rate of lightning is not less than 80%. 3. The detection radius is not less than 10 kilometers. 4. The detection accuracy of atmospheric electric field is better than ±5%. 5. With three-level lightning warning function. 6. The storage time of historical lightning warning data is not less than 3 years. 7. The lightning detection module installed on site should meet the electrical explosion-proof requirements of large oil and gas storage bases. The protection level is not lower than IP65. 8. The life of the lightning detection module is not less than 3 years. B. Early warning classification Lightning warning information is divided into three levels: 1. First-class early warning: there may be lightning activities, the atmospheric electric field in the coverage area is increasing, the electric field is fluctuating, and the location of the ground flashback strike is located in a nearby area 10 kilometers away from the large oil and gas storage base, which may cause lightning accidents. 2. Secondary early warning: the possibility of lightning occurrence is high, the atmospheric electric field in the coverage area increases rapidly, the fluctuation of the electric field intensifies, and the location of the ground flashback strike point is 5-10 kilometers away from the large oil and gas storage base, which may increase the possibility of lightning strike accidents . 3. Three-level early warning: lightning is about to occur, the atmospheric electric field in the coverage area fluctuates violently, and the location of the ground flashback strike point is 0-5 kilometers away from the large oil and gas storage base, which is likely to cause a lightning strike accident. C. Operation and maintenance 1. Before the rainy season every year, the hardware equipment, network interface, software platform and surrounding environment should be checked in time to ensure that the lightning early warning system is in normal operation, including sensors (probes), host, temperature and humidity conditions in the chassis, solar module panels , battery, etc. 2. When the data of the lightning detection module cannot be received normally, the operating status and communication of the equipment should be checked immediately.

1. Introduction of distributed lightning protection ——"Centralized monitoring and decentralized installation" Principle: The integrated intelligent lightning protection module (SPD+SCB+intelligent acquisition unit) is scattered in each panel cabinet to be protected, and the communication signal is sent to the monitoring background through the 485 port of the intelligent acquisition terminal to realize the centralized monitoring of the traction substation , SPD distributed installation of intelligent lightning protection. 2. Introduction of centralized combined screen lightning protection Principle: The lightning protection devices required in each panel cabinet are centrally installed to form an independent lightning protection panel cabinet, and a monitoring background is set in the lightning protection panel cabinet to realize the intelligent lightning protection of centralized installation and centralized monitoring of the traction substation. 3. Performance comparison of distributed lightning protection and centralized combined screen lightning protection 1) Common point: all of them can realize intelligent monitoring of SPD, and can centrally display and store SPD in each panel cabinet status information of the operation. 2) Differences: The installation method of the distributed type is scattered in each panel cabinet, while the centralized combination panel type is an independent group panel. 3) Comparison of advantages and disadvantages: a. The centralized and distributed installation method SPD can be close to the protected equipment to achieve the best protection effect on the circuit; the SPD of the centralized independent group screen will be far away from the protected equipment, which does not meet the "proximity principle" of equipment lightning protection. When the SPD is too far away from the protected equipment, due to the existence of line inductance, the lightning overvoltage wave (electromagnetic wave) will appear wave reflection under the action of electromagnetic oscillation, and the amplitude will further increase, making it difficult to protect the equipment. b. The lightning protection branch connection line of the distributed installation method will be slightly longer than that of the centralized combined screen, but the centralized independent grouped screen needs to occupy the space of the inner disk, and the loop cable is in and out of the "lightning protection screen". In the process of lightning, a large loop will be formed, and in the electromagnetic field of lightning, a high loop voltage will be further induced; c. For the renovation of existing projects, after the SPD circuit is installed in the distributed installation method, the panel cabinet is For crowding; and the centralized independent panel grouping method, because the loop cable laying method of the existing project has been fixed, it is necessary to Re-laying the cables is a huge amount of work. Railway is the focus industry of Anhui Jinli. From the...

Classification of Wind Power Systems - By Power Regulation Fixed pitch fan: The blade is fixedly connected to the hub, and the windward angle of the blade does not change with the wind speed. It automatically stalls by relying on the aerodynamic characteristics of the blades, that is, when the wind speed is greater than the rated wind speed, the input power is kept basically constant by relying on the stall characteristics of the blades. Pitch pitch adjustment: When the wind speed is lower than the rated wind speed, ensure that the blades are in the best angle of attack state to obtain the maximum wind energy; when the wind speed exceeds the rated wind speed, the pitch system reduces the blade attack angle to ensure that the output power is within the rated range. Active stall adjustment: when the wind speed is lower than the rated wind speed, the control system controls the wind speed in several stages, and the control accuracy is lower than the pitch control; when the wind speed exceeds the rated wind speed, the pitch system increases the blade angle of attack to make the blades "stall" , limiting the increase in the absorbed power of the wind rotor. Classification of wind power generation systems - by transmission form Gearbox type with high transmission ratio: the rotational speed of the wind rotor is low, which usually cannot meet the requirements of the generator for power generation. Direct drive type: The application of multi-pole synchronous wind turbine can remove the common gearbox in the wind power generation system, so that the wind turbine can directly drive the generator rotor to run at a low speed, which eliminates the noise and fault caused by the gearbox. The problems of high rate and high maintenance cost have improved the operational reliability. Medium transmission ratio gearbox (semi-direct drive) type: The working principle of this fan is a combination of the above two forms. The medium transmission ratio wind turbine reduces the transmission ratio of the traditional gearbox, and also reduces the number of poles of the multi-pole synchronous wind turbine accordingly, thereby reducing the volume of the generator.

The lightning warning system employs atmospheric electric field detecting devices, sensors, etc., using the principle of measurement environmental electrostatic fields to detect thunder clouds. At any time, the system can detect thunderstorm clouds within 15 kilometers depending on the change of the environmental electrostatic field. This means that lightning is likely to occur in the measurement area of the electric field strength. After the atmospheric electric field detection device, after the lightning electric field change data value, the atmospheric warning level is analyzed, transmitting data wirelessly to the warning control host intelligent processing unit through the communication module, and the host intelligent processing unit can transmit data to the control center, and pass the upper position Machine software displays early warning information. China Meteorological Bureau "Lightning Motorion Disaster Mitigation Management Measures" clearly requires: "Meteorological authorities at all levels should strengthen the construction of lightning prevention system, improve lightning, warning and lightning protection," "" "" Meteorological authorities at all levels should organize The relevant departments strengthen the research theory of basic theories and defense technologies such as lightning and lightning disasters, and strengthen the research and development of lightning protection and mitigation techniques and lightning monitoring, early warning systems. " After more than ten years of exploration and practice, my country's lightning early warning monitoring technology has been perfectted and has a relevant group standard. According to industry analysts, only about 1/4 of oil and gas storage companies in the country are actively equipped with a lightning monitoring warning system, and this situation is changing under the requirements of government departments. Lightning warning systems are expected to become a basic configuration of large oil and gas storage bases, but the support of relevant technical specifications is very important.

Ground Potential Counterattack Solutions A. For the system using opposite grounding, that is to say, there are more than two independent grounding grids in a computer room. For example, one grounding grid uses steel bars in the building frame as grounding grids, and the other system is independent grounding grids, then when When the distance between the two ground grids is less than the safety distance against ground potential counterattack, it is necessary to use an "equipotential connector" for equipotential connection between the two ground grids. The function of the equipotential connector is to ensure that the two grounding grids are not connected and do not interfere with each other under normal working conditions. When a grounding system is struck by lightning, the GI 1000-5 equipotential connector makes the two grounding grids instantly form an equipotential to eliminate the Damage caused by this transient high potential within the device due to line-to-line voltage differences. B. According to the requirements of Chapter VI of GB 50057-94 (2000) "Code for Design of Lightning Protection of Buildings", metal water pipes, communication cables and power cable armored sheaths or cable metal pipes and other external pipelines, all water pipes and cables should be Buried into the equipment room, the water pipe and cable armored sheath and protective metal pipe should be grounded when entering the equipment room, the cable should be armored cable or buried into the equipment room through the metal pipe. For grounding wires with long wiring distances in the building, such as power PE wires, in the equipment room with higher requirements, the "equipotential connector of the equipment room" can be used to connect the AC working ground, DC working ground, anti-static and protective grounding in the equipment room. Equipotential connection is carried out inside to ensure that the precision system equipment is not disturbed under normal working conditions, and no breakdown occurs in the equipment when there is transient overvoltage.

Highway electromechanical and intelligent traffic control systems have a large number of sensitive electronic equipment requiring surge protection. Why is surge protection necessary? High exposure: Equipment is usually installed in a high point or protruding position (LPZ0A/B), the high exposure characteristics increase the risk of lightning strike damage Multiple connections: Such as DC power + data communication combined equipment, its overvoltage tolerance and anti-interference ability are reduced Long outdoor extension distance: Weak outdoor shielding ability and long transmission lines greatly increase the risk of system failure Large indirect losses: System failure may result in high system maintenance costs such as charging and high security risks Device Sensitive: The internal components of smart devices are delicate and extremely sensitive Numerous devices: A large number of equipment installations increase the probability of system failure under overvoltage How to protect more reasonably? Risk Analysis: Thunderstorm Day (Ground Lightning Density), Line Length, Equipment Density… Analyze protected device or system sensitivity Protection of all incoming equipment (AC/DC power supplies, communication systems, etc.) Consider the situation on site: Protected power/signal network characteristics Type of surge and expected magnitude of attack Mounting Features (Indoor/Outdoor, DIN Rail)