Analysis of distribution and protection characteri

Analysis of distribution and protection characteristics of computer system

Abstract: at the beginning of the 21st century, science and technology have achieved rapid development, and the society characterized by the wide application of computers has begun to enter a new era of intelligence and networking. Various types of computer systems have been installed in all walks of life, such as energy, transportation, construction, culture, education and health, finance, posts and telecommunications, tourism and so on, as well as in people's daily life. They rely on advanced science and technology to improve production efficiency and management level, and enrich people's cultural life. All these are inseparable from the reliable, safe and stable operation of computer system equipment. The characteristics of different electric loads in different industries also put forward different requirements for its power supply

key words: computer system distribution protection power supply Untitled Document when mankind enters the 21st century, science and technology have achieved rapid development, and the society characterized by the wide application of computers has begun to enter a new era of intelligence and networking. Various types of computer systems led display are installed in all walks of life, such as energy, transportation, construction, culture, education and health, finance, post and telecommunications, tourism and so on, as well as people's daily life. Relying on advanced science and technology to improve production efficiency and management level, we can enrich people's experimental life of end sliding friction on this machine. All these are inseparable from the reliable, safe and stable operation of computer system equipment. The characteristics of different electric loads in different industries also put forward different requirements for its power supply. 1、 Load classification and power quality the classification of computer system power supply in the current relevant design codes and standards in China has only made clear provisions for the computer system power supply of important buildings (such as provincial and ministerial office buildings, international conference centers, securities trading centers, radio and television stations, large department stores, etc.) due to the limitation of the scope of computer application at the time of compilation, which stipulates that it is a particularly important load, In addition, other important buildings and electrical appliance manufacturers that produce and sell in the global market can simplify their supply chain, and the computer power supply in the buildings has not been explained accordingly. Due to the rapid development of computer technology and the increasing popularity of computer applications, the author believes that it is necessary to briefly explain the power levels of this part of the computer system in the first and second level loads, so as to meet the power needs of computer systems in various buildings, and avoid exceeding the standard design and configuration, causing unnecessary investment waste. With the popularization and application of network technology, computer system has become the central link in the use of various building functions. Therefore, the load level of system power supply should be divided into the highest level or increased by one level in the building. In buildings with primary load as the main load, the system power load can generally be classified as particularly important load; In buildings with secondary load as the main load and a small part of primary load, the system power load can generally be classified as primary load; In buildings with class III load as the main load, the system power load can generally be classified as class II load. Of course, the sudden power loss of computer equipment will cause program interruption and data loss. In each load scheme, UPS should be set to ensure the stability and safety of the system power supply. Power quality mainly refers to the quality of voltage, frequency and waveform. The technical indicators representing power quality mainly include voltage fluctuation, frequency fluctuation and waveform distortion rate. Code for design of computer room gb50174-93 divides the power quality into three levels The power quality is different from the general product quality, and has the following remarkable characteristics: (1) it does not completely depend on the power production department. Some indicators such as harmonic, voltage fluctuation and flicker, three-phase imbalance, etc. are often determined by user interference. (2) For different power supply (consumption) points, power quality indicators are often different at different power supply (consumption) times. In other words, power quality is in dynamic changes in space and time. For electrical designers, in the power distribution design, we should pay more attention to the characteristics of different loads, adopt corresponding measures to reduce the interference of electrical equipment on electricity and purify the power quality, which is beneficial to both electricity and electrical equipment. 2、 The main factor affecting the quality of power supply by the common distribution mode of computer system is that the electrical load capacity of electronic computer system in the building only accounts for a small part of the total electrical load of the whole building, which is generally dozens of kW. In most cases, the power and lighting loads in civil buildings share the same low-voltage side bus of the transformer or the same low-voltage distribution trunk line. Therefore, the power market wait-and-see mood of other loads in the low-voltage distribution where the computer system is located directly affects the power quality of the power supply of the computer system. (1) Start and stop of high-capacity load when there is a large change in the electrical load, that is, when the nearby high-capacity equipment starts or stops suddenly, it will cause the fluctuation of bus power supply voltage and produce a transient low voltage or high voltage. (2) The application of a large number of nonlinear loads, high-power silicon controlled rectifier devices, various voltage regulation and speed regulation devices, various gas discharge light sources, electronic ballasts, etc. will make the power supply voltage waveform supplied to the computer system change and produce a large number of harmonic currents. (3) Switching overvoltage and transient overvoltage operation overvoltage will be caused by the internal inductive load of distribution system, the input and removal of compensation capacitor, and the opening and closing of circuit breaker. When lightning strikes, lightning waves propagate transient overvoltage through transmission lines, causing transient pulses and damaging computer data equipment. According to statistics, in the whole transient pulse accident, Internal Overvoltage accounts for 80%, and lightning overvoltage accounts for about 15%. (4) Instant power loss if low-voltage power loss occurs, it will directly affect the normal operation of the computer. For most computers, interrupting the power supply for more than 10ms may cause the internal 5vp-g signal of the computer to disappear, resulting in the destruction of the running program and data loss. 3、 Protective measures to ensure the quality of computer system power supply common protective measures include the following: isolation transformer, voltage regulator, filter, overvoltage protection device, uninterruptible power supply, etc. (1) Isolation transformer isolation transformer is through the electromagnetic coupling between primary and secondary windings to achieve the purpose of transmitting power frequency energy. At the beginning, there is an electrostatic shielding layer between the secondary windings, which effectively isolates the signal interference such as transient pulses in electricity. (2) Voltage stabilizer the purpose of setting the voltage stabilizer is to input electricity when power is supplied