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)

A properly designed air-termination device will significantly reduce the possibility of lightning strikes requiring lightning protection spaces. Only when the design of the lightning protection device and the structural design of the building are carried out at the same time, the optimal combination of technology and economy can be obtained. Especially when designing buildings, the metal objects of buildings should be fully utilized as parts of lightning protection devices. IEC1024-1:1990 The air-termination arrangement is suitable when the requirements in the table below are met. Arrange the air-terminations according to the protection level. Protection angle method: the positions of the lightning conductor, lightning rod, lightning protection tower and lightning protection line should be such that each part of the protected building is in the shape formed by the points on the conductor of the lightning protection device with the "angle projected to the ground in all directions". within the track surface. The protective angle method has geometric limitations. Rolling ball method: For buildings with complex geometric shapes, or when the protective angle method is excluded from Table 1 of IEC1024-1, the rolling ball method shall be used to determine the area of the building and the protective space of each part. The radius of the "rolling ball" should be in accordance with the selected level of protection of the lightning protection system. The rolling ball method is to use a ball of radius "R" on a building to roll around the building until it hits the ground level, or any permanent structure or object that is in contact with the ground level and can be used as a lightning conductor until. It is possible to be struck by lightning in places where rolling contact with buildings. At such points and locations, lightning protection by lightning conductors is required. The protected space of a lightning protection system is the volume of space that the "rolling ball" does not pass through when it contacts the conductor and acts on the building. The level of protection and the installation cost of the lightning protection system increases with the size of the ball selected. Mesh method: Air-termination conductors or roof conductors shall form a closed polygon with the perimeter laid close to the edge of the roof. This polygonal air-termination device shall be completed by the addition of interconnected transverse air-termination conductors to form a grid complying with the requirements of Table 1 of IEC 1024-1.

In recent years, the technology of the photovoltaic industry has developed faster and faster, the power of a single module has become larger and larger, and the current of the string has become larger and larger, and the current of high-power modules has reached more than 17A. In terms of system design, the use of high-power components and reasonable over-provisioning can reduce the initial investment cost and kWh cost of the system. DC cables are installed outdoors. It is generally recommended to select photovoltaic special cables that have been cross-linked by irradiation. After high-energy electron beam irradiation, the molecular structure of the insulating layer material of the cable changes from linear to three-dimensional network molecular structure, which is resistant to temperature. The grade is increased from non-cross-linked 70°C to 90°C, 105°C, 125°C, 135°C, and even 150°C, which is 15-50% higher than the current carrying capacity of cables of the same specification, and can withstand severe temperature changes and chemical erosion. Used outdoors for over 25 years. When selecting the DC cable, it is necessary to select products with relevant certifications from regular manufacturers to ensure the needs of long-term outdoor use. The AC cable can be selected according to the maximum output current of the inverter. Because no matter how much the components are over-configured, the AC input current of the inverter will never exceed the maximum output current of the inverter. The circuit of the photovoltaic system is divided into a DC part and an AC part. The two parts of the circuit need to be wired separately. The DC part is connected to the components, and the AC part is connected to the grid. There are many DC cables in medium and large power stations. In order to facilitate future maintenance, the wire number of each cable should be firmly attached. Separate strong and weak wires. If there are signal wires, such as 485 communication, they should be routed separately to avoid interference. When routing the cables, prepare conduits and bridges, and try not to expose the cables. It will look better when the cables are routed horizontally and vertically. Try not to have cable joints in the threading pipes and bridges, because maintenance is inconvenient. If aluminum wires are used instead of copper wires, reliable copper-aluminum transfer terminals must be used.

The replacement of products is the law of industry development. People usually pay attention to the performance quality of products, but often ignore the time quality of products, that is, reliability. The introduction of any new product should provide users with the performance quality, time quality and economic indicators of the product. The main methods to improve SPD reliability include a. Manufacturers have improved MOV chip designs, using new materials and improved processes, to produce products with low failure rates and improved inherent reliability. b. Provide a good environment such as suitable temperature, humidity and air pressure to maintain environmental reliability. c. Screen and age the SPD to shorten the early failure period. d. Replace deteriorating SPDs as appropriate or periodically. e. Select an intelligent SPD and monitoring system capable of life early warning. f. Derating design is the main method to improve SPD reliability. The derating design is to reduce the electrical stress (surge) of the SPD, and a reasonable derating can greatly reduce the failure rate of the SPD

The intelligent joint control technology of the inverter and the tracking bracket (SDS intelligent tracking algorithm), combined with the intelligent string inverter, aims to realize the linkage optimization of the inverter and the bracket control, and further improve the additional effect of the tracking bracket. SDS technology can realize the linkage and closed-loop control of the inverter and the tracking bracket control system, and always keep the power station system running in a state with the largest amount of light received by the components and the best power output. And it does not require additional sensing equipment, gets rid of manual and experience dependence, uses AI technology to automatically perceive occlusion and weather change information, and automatically performs tracking angle optimization and control. Currently, it has cooperated with most mainstream bracket manufacturers. At present, whether it is morning or evening, the phenomenon of blocking the front and rear rows of the power station is basically gone, and the power generation in cloudy and rainy days has increased significantly. Although SDS is only a small-scale application, it has already brought us benefits. "If it is applied to the entire 200MW power station, according to the same increase ratio, excluding subsidies, it is conservatively estimated that it can bring nearly 2 million yuan in revenue. The application value of high-efficiency modules, inverters and tracking systems has been recognized by end customers, and the application ratio will increase rapidly, but to make the photovoltaic system play a greater potential, simple patchwork is far from enough, and it is impossible to create a future-oriented smart system. The actual application case has also been verified again. Only by achieving the collaborative integration and linkage optimization between efficient equipment can maximize the efficiency of equipment and systems and enable the power station to generate electricity vigorously throughout its life cycle.

Connecting to zero and concepts related to grounding Connect to zero: The neutral point of the generator and distribution transformer is called the zero point, and the line drawn from the neutral point is called the zero line. The metal shell of the electrical equipment is connected to the zero line, which is called zero connection. Working grounding: The neutral point of the power supply system transformer is directly grounded as working grounding. Working grounding can ensure the reliable operation of electrical equipment and reduce the contact voltage of human body. Protective grounding: Under normal working conditions of all electrical equipment, good grounding of non-charged metal parts is used as protective grounding, and protective grounding mainly protects the work safety of personnel. Repeated grounding: Repeated grounding is made by connecting multiple points on the neutral line to the ground multiple times. When the neutral point is directly grounded in the system, the voltage to ground can be reduced; when the neutral line is broken, the damage of the fault can be reduced. Static grounding: When equipment moves or objects move in pipelines, static electricity is generated due to friction, which accumulates on pipelines, containers and storage tanks or processing equipment, forming a high potential that is dangerous to personal safety and equipment and buildings. Static grounding is made, and once static electricity is generated, it is introduced into the ground to eliminate the possibility of its accumulation. A piece of conductive rubber that touches the ground at the rear of the tanker and the rear of the car belongs to electrostatic grounding. DC working grounding: Most computers and all microelectronic equipment use medium and large-scale integrated circuits, which have the same "potential" reference point, and connect the "zero" potential point of all equipment to the same grounding device, so that it can stabilize the circuit. Potential to prevent external interference. This grounding is called DC working grounding.

A few days ago, the Anhui Meteorological Bureau and the Provincial Development and Reform Commission jointly issued the "Fourteenth Five-Year Development Plan for Meteorological Services in Anhui Province." The plan proposes that during the "14th Five-Year Plan" period, the province's meteorological construction will focus on four items: meteorological monitoring, forecasting and early warning, the Yangtze River Delta integrated development of meteorological support service capacity building (Anhui), comprehensive management of rural lightning disasters, and the improvement of basic capabilities of meteorological stations. Key projects to further improve the level of social development of meteorological services. The comprehensive management project of rural lightning disasters will focus on the rural revitalization strategy and the defense of rural lightning disasters, upgrade and expand the original facilities and monitoring and early warning systems, and improve the monitoring and early warning capabilities of rural lightning disasters. In conjunction with the construction of beautiful villages, carry out the construction of lightning defense demonstration projects in provincial central villages, and improve the lightning protection facilities of various public lines and buildings (structures) in the villages with multiple lightning strikes, lightning disaster prevention facilities in public areas, and lightning safety shelters. Anhui Jinli Electric Technology Co., Ltd., the best innovative enterprise in the lightning protection industry in China, is located in Hefei, Anhui Province, an ancient city of science, education and culture. , Medium and low voltage overvoltage protection products. Through the nationwide sales and technical service network, we provide users with fast and personal services and create a safe and worry-free electricity environment.