The power supply load is divided into three levels according to the different requirements of power equipment for the reliability of power supply.
1. First-class load
The interruption of power supply will cause significant political and economic losses or casualties of the load, called the first-class load. Such as important railroad hubs, communication hubs, important international events, important hotels, hospital operating rooms, important biological laboratories.
The primary load of power supply in addition to the use of two independent grid power supply, should also set up a backup power supply, the general backup power using diesel generator sets or DC battery packs.
2. Secondary load
Interruption of power supply will cause greater political and economic losses or cause public **** place of order and chaos of the load, called secondary load. Such as local and municipal government office buildings, three-star hotels, grade A movie theater, local and municipal libraries, museums, cultural relics and treasures library.
Two loads of power supply in addition to take two independent of each other in addition to the line, according to the actual situation, should also set up a backup power supply.
3. Tertiary load
In addition to the primary load, secondary load, the other belongs to the tertiary load, the tertiary load in the power supply method has no special requirements, generally using a single circuit power supply.
With the development of China's economy, the power supply of primary loads has been unable to meet the needs of some particularly important places, such as the municipal telephone exchange, telecommunication hubs, satellite earth stations, civil airports, banks and securities trading centers, etc., which belong to the particularly important loads of the first level, generally called the special load. At the same time, due to economic development, the primary load, the increase in the secondary load, the three loads of power supply will gradually reduce or cancel.