Since the construction of the world's first intelligent building in the United States in 1984, intelligent buildings have continuously evolved to meet the needs of modern society's informatization and economic globalization, and to advance with the development and mutual penetration of computer technology, communication technology, and control technology. The International Society for Intelligent Engineering believes that a building should be designed to provide the necessary functions and flexibility to adapt to changes in user requirements for building use and information technology, thereby meeting users' needs for high efficiency. Generally, modern intelligent buildings consist of three main systems: Building Automation System (BAS), Office Automation System (OAS), and Information and Communication System (CAS). These systems are integrated into an intelligent building management system that utilizes computer network and communication technologies. Finally, a Structured Cabling System (SCS) integrates the cabling of different signals such as voice, data, video, and monitoring into a standardized cabling system as the transmission network within the building or building complex. Intelligent buildings are characterized by dense cabling, numerous system devices, complex microelectronic equipment, and limited protection capabilities. To ensure the safe and normal operation of these systems and equipment, specialized and unique protection measures are essential. Lightning protection, grounding, and interference suppression are crucial, necessary, and effective protective measures. The following analysis focuses on these three aspects. 1. Lightning Protection for Intelligent Buildings: For intelligent systems, besides direct lightning strikes, the most destructive factors are the secondary, high-current, and instantaneous nature of lightning. Powerful lightning generates electrostatic fields, alternating electromagnetic fields and electromagnetic radiation, lightning wave intrusion, ground potential backflash, and the effects of lightning electromagnetic pulses (LEMP). Due to the large gradient of lightning current changes, it can generate a powerful changing electromagnetic field, inducing electromotive force and current in surrounding metal objects. On the one hand, this severely interferes with wireless and wired communications; on the other hand, once it intrudes into the signal input of microelectronic devices, it will cause device breakdown and burnout, leading to network paralysis and equipment failure. The International Electrotechnical Commission (IEC) states that lightning is the nemesis of high technology. As electronic equipment has weak protection capabilities, sensitive electronic equipment can only withstand energy up to the millijoule level, while the energy released by lightning strikes can reach hundreds of megajoules. The energy difference is quite large, so measures must be taken to protect it. (1) According to the importance, function, probability of lightning strike accidents and consequences of buildings, lightning protection of buildings is divided into three categories according to lightning protection requirements. For lightning protection measures of the second category of buildings, the lightning protection code GB50057-94 has specified the corresponding requirements; (2) Antenna lightning protection facilities: The antenna is installed on the roof of the building and is connected to the lightning protection grounding device on the roof, and the connection points shall not be less than two. If the protruding part of the antenna exceeds the lightning protection range of the building, an independent lightning rod shall be installed and shall be reliably connected to the antenna lightning protection grounding device. For comprehensive lightning protection, the antenna should be equipped with a high antenna feeder system lightning arrester; (3) Lightning protection for pipes, lines and cables entering and exiting the building: all kinds of metal pipes, cables and lead lines entering and exiting the building should be connected to the building's lightning protection grounding device at the entry and exit points; the power supply metal sheath, steel sleeve and other materials should be connected to the grounding of electrical equipment at the entry and exit points. If the cable is converted to an overhead line, a lightning arrester should be installed at the conversion device; (4) Protection of information systems: graded protection should be provided, and different parts of the electronic equipment should be treated separately and properly handled; (5) Protection of power supply systems: graded protection should be carried out using electronic lightning arresters, with high voltage cabinets, low voltage cabinets, main distribution boxes and distribution boxes protected step by step to reduce lightning overvoltage to a level that the equipment can withstand; (6) Protection of electronic equipment: corresponding comprehensive prevention and control measures should be taken based on the analysis of different paths of lightning pulse LEMP attack on electronic equipment. Lightning energy acts on the conductors connected to electronic equipment, forming lightning waves and induced overvoltages that enter the electronic equipment along the conductors, including distribution lines, signal lines, and antenna feeders. Lightning energy directly couples onto electronic components, causing damage due to malfunctions. Ground potential rise damages equipment components and the insulation materials of conductors and devices. Measures that can be taken include: implementing equipotential bonding for system equipment; using metal-lined wiring to enhance shielding and reduce induced effects; implementing equipment shielding, computer room shielding, and building shielding; and installing electronic surge arresters to limit the amplitude of lightning overvoltages entering electronic equipment. According to historical statistical analysis, over 70% of lightning-damaged equipment incidents originate from power supply lines. Therefore, implementing multi-level lightning protection for power supply lines is a crucial aspect of lightning protection for electronic equipment and the entire system. Currently, surge arresters primarily use varistor lightning protection. 2. Grounding in Intelligent Buildings Grounding is a common issue for high-voltage, low-voltage, and intelligent systems. Grounding can be divided into two main categories based on its function: functional grounding and protective grounding. Functional grounding includes: system grounding, working grounding, logic grounding, and shielding grounding; protective grounding includes: protective grounding, lightning protection grounding, static grounding, and repeated grounding. Building grounding can be divided into independent grounding and combined grounding according to the connection method. (1) Independent grounding is to separate DC grounding, protective grounding, and lightning protection grounding. The purpose of doing so is to eliminate interference sources from the ground wire. This is a grounding measure taken according to the requirement of independent grounding for electronic computer equipment or separate grounding for communication systems. In order to avoid different potentials introduced by different system grounding, which may lead to personal injury and equipment accidents, according to the specifications, the distance between the backup grounding system must be greater than 20m, and their grounding electrodes and ground wires must be kept insulated, with an insulation resistance of more than 2MΩ and a grounding resistance of less than 4Ω. (2) Combined grounding is to connect various groundings to the same grounding device through grounding wires. Generally, except in special cases, a building can only have one grounding system to avoid introducing different potentials that may lead to personal injury and equipment accidents. Therefore, unless there are special requirements, the building grounding of intelligent system equipment in intelligent buildings should adopt combined grounding. 3. Interference Resistance of Intelligent Buildings There is a large amount of electromagnetic interference in the natural environment outside the building complex and in the environment of the equipment inside the building. Electromagnetic interference will cause the intelligent system equipment to generate errors, miscodes, and malfunctions; it will also pollute the signal system and generate noise. Strong pulse interference will also cause damage to electronic devices and equipment; in actual work, the phenomenon of equipment performance degradation and inability to work often occurs; therefore, it is necessary to purify the electromagnetic environment of the building, prevent stray electromagnetic wave interference, and improve the anti-interference ability of the system and equipment inside the building. Anti-interference has become an indispensable technical measure for intelligent building systems. Before adopting appropriate anti-interference measures and methods, it is necessary to first analyze the interference source, understand the cause of interference and the propagation path of interference. 3.1 Generation of Interference Sources (1) Signal spectrum of broadcasting, communication, radar, and navigation transmitting equipment. These devices have a large transmission power, and their fundamental wave can generate interference of useful signals, while harmonics can constitute interference of useless signals; (2) Radiation field strength of industrial, scientific, medical, and induction heating equipment. These devices have high power and poor shielding, resulting in large power leakage and strong high-order harmonic components; (3) Electromagnetic interference from overhead power lines and electric traction systems, mainly due to conductor corona and poor contact, as well as occasional sparks or micro-arcs generated during sliding current collection; (4) Electromagnetic interference from automotive ignition systems and fluorescent lighting equipment. The interference from automobiles mainly comes from the ignition system, generators, fans, motors, etc. When fluorescent lamps start, they generate electrical breakdown pulses, causing radio frequency interference. This interference can be radiated through the lamp tube itself and the power supply line, or injected into the shared power supply through the power supply line, forming relatively strong conducted interference; When fluorescent lamps are working, the power frequency harmonic interference generated by the ballast greatly increases the harmonic components of the power supply, resulting in a decrease in power supply quality; (5) Shared power supply, electrostatic discharge, electromagnetic pulse. Since the internal resistance of the shared power supply is not equal to "zero", the shared power supply provides useful electrical energy to the equipment, but also provides interference voltage. According to relevant statistical analysis, for computers and instruments using computing technology, the most harmful interference signals are those caused by spike pulse signals and damped vibrations. This is because they can lead to program errors, memory loss, and even system damage. 3.2 Interference Pathways Interference, whether within equipment or the system itself, causes interference through capacitive coupling, inductive coupling, electromagnetic radiation, common impedance (grounding system), and conduction via conductors (power lines, signal lines, output control lines, etc.). Therefore, methods to eliminate and suppress interference include electric field shielding, magnetic field shielding, electromagnetic shielding, grounding of electronic equipment, bridging, and filtering. 3.3 Common anti-interference measures (1) Install low-pass filters at the power supply input and output ports to eliminate high-frequency interference in the power grid; (2) To prevent sudden changes in the mains power grid or overvoltage caused by lightning strikes, it is recommended that intelligent devices use series-type regulated power supplies; (3) To suppress interference caused by grounding and common impedance, the method is to ensure that various groundings do not form loops; (4) Keep the intelligent system computer room away from high-power emission sources and elevator machine rooms; (5) Determine the effective shielding method based on the electromagnetic interference of the surrounding environment; (6) Ground the cable shielding layer; (7) Use optocouplers and optical fibers to transmit digital signals; (9) Install power line filters on the power supply lines of lighting devices and shield the power supply terminals; (10) Separate or isolate the interfered circuit from the interfering circuit. From the above analysis, it can be seen that the means of lightning protection is grounding, and the purpose of grounding is to prevent interference. The ultimate goal of lightning protection, grounding, and anti-interference is to ensure the safety of buildings and the equipment and personnel inside the buildings.