What is the difference between the high-voltage DC power supply system and other power supply systems?
1. The reliability of the high-voltage DC power supply system is greatly improved-the main purpose of applying the high-voltage DC power supply technology is to improve the safety of the system.
2. The high-voltage DC power supply system has greatly improved efficiency. At present, the most widely used UPS hosts are of the online double conversion type. When the load rate is greater than 50%, the conversion efficiency is similar to that of the switching power supply.
3. The input parameters of the high-voltage DC power supply system are greatly improved. Field tests have found that the current commonly used 12-pulse online double-conversion UPS mainframe, with 11 filters installed, its input power factor is usually 0.8-0.9, and the maximum 0.95, the input current harmonic content is usually around 7.5%.
4. The high-voltage DC power supply system has greatly improved load capacity-the load capacity of the UPS system is restricted by two factors. One is the power factor of the load. Taking a certain type of host of a large domestic UPS manufacturer as an example, the output power factor When it is 0.5 (capacitive), the maximum allowable load rate is only 50%; the second is the current crest factor of the load, usually the design crest factor of the UPS host is 3, if the current crest factor of the load is greater than 3, the UPS host will drop Content to use.
5. High-voltage DC power supply system with low transmission voltage drop-DC cable lines are free from the trouble of capacitive current in AC cable lines, no magnetic induction loss and dielectric loss, basically only core wire resistance loss, relatively low insulation voltage, DC transmission technology It is more suitable for long-distance transmission and meets the current national requirements for energy saving and environmental protection. It is a green and environmentally friendly power supply program.
Of course, there are also problems with DC transmission, such as high cost of converter station, poor overload capacity, large capacity of reactive power compensation equipment, converter station itself is a large harmonic source, difficulty in producing DC high voltage circuit breakers and high cost.
At present, DC is only used in the transmission link, and power generation and power supply are still AC systems.