auxiliary power supply

White standby power supply is generally diesel generator set or EPS power supply.

Article 3.0.3 of the above specification points out that "except for the particularly important load in the first-class load, the design should not be carried out according to the situation that one power supply system is overhauled or fails and the other power supply fails". That is, for the first-class load, two power supplies (when one power supply fails, the other power supply cannot be damaged at the same time) can supply power, and there is no need to set up a third power supply. At present, according to the requirements of the power supply department, diesel generator sets are often set in the case of two high-voltage trunk lines, because considering that the two high-voltage trunk lines are not two "independent" (can not be damaged at the same time) power supplies, the reliability of power supply for first-class load users is improved.

In the explanation of Article 2.0.6 of the above specification, it is pointed out that "for the secondary load, the loss caused by power failure is greater, and its coverage is wider than that of the primary load". In engineering design, it is necessary to comprehensively consider various factors such as power outage probability, loss caused by power outage, power supply conditions and investment required for various schemes of power supply system. There are many options for power supply of secondary load equipment, and engineering designers should try their best to choose safe, reliable, economical and reasonable options. "Dual power supply when possible".

Although the three-stage load does not require high reliability of power supply, it only needs one power supply. However, in engineering design, the power supply system should be as simple as possible, with few distribution stages and easy management and maintenance.