1 main load
Class I load means that power supply interruption will cause casualties; Interrupting power supply will cause great political influence and great economic loss; Power supply interruption will cause serious disorder of power load in public places. Such as particularly important transportation hubs, national large-scale sports centers, radio stations, TV stations, news centers, real-time computer network systems, etc. According to clause 2.0. 1 of GB 50052-95 and clause 3. 1 of JJ/T1692, among the first-class loads, some "special buildings" and "uninterrupted power supply" loads are classified as particularly important. The first-class load requires two independent power supplies, that is, two power supplies are drawn from different substations (switching stations) of the power system. When one power supply fails, the other is responsible for power supply to ensure uninterrupted power supply of the first-class load. Emergency power supply must be added to the particularly important load in the first-class load. In order to ensure the power supply to particularly important loads, it is forbidden to connect other loads to the emergency power supply system. When the primary load capacity is large or there is high-voltage electrical equipment, two high-voltage power supplies should be used for power supply.
2 secondary load
The secondary load means that the interruption of power supply will have a greater political impact; Interrupting power supply will cause huge economic losses; The interruption of power supply will lead to the confusion of power load in public places. The secondary load is powered by two power supplies. When the load is small or the regional power supply conditions are difficult, it can be composed of one circuit.
6kV and above dedicated overhead line power supply.
Three-stage load
The third-level load refers to the electric load that does not belong to the first-level load and the second-level load. Class III load has no special requirements for power supply.
Question 2: What are the requirements for secondary load power supply? In principle, sharing more secondary load power supply requires that the power supply should not be interrupted (or recovered quickly after interruption) when the power transformer fails or the common power line fails. When the load is small or the regional power supply conditions are difficult, the secondary load can be supplied by a dedicated overhead line above 6kV. 1. The interruption of power supply will cause huge political and economic losses. For example, major equipment is damaged, a large number of products are scrapped, the continuous production process is disrupted and the recovery time is long, and key enterprises reduce production in large quantities. Two, power supply interruption will affect the normal work of important power users. For example, the important power consumption load of power consumption units such as railway hubs and communication hubs, and the disorder caused by power supply interruption in important public places where a large number of people are concentrated, such as large theaters and shopping malls. Three, when the regional power supply conditions permit and the investment is not high, the secondary load should be powered by two power supplies. When the regional power supply conditions are difficult or the load is small, the secondary load can be supplied by a dedicated line above 6- 10kV. If cables are used, spare cables should be laid and kept running.
Question 3: What is a three-stage load power supply? What about level one and level two? Classification of 30-minute power load
According to the different requirements of electrical equipment for power supply reliability, the power supply load is divided into three grades.
1. Main load
The load that will cause great political and economic losses or casualties due to power supply interruption is called Class I load. Such as important railway hubs, communication hubs, important international venues, important hotels, operating rooms in hospitals, and important biological laboratories.
In addition to two independent grid power supplies, the power supply mode of primary load should also be equipped with standby power supply. The standby power supply is generally a diesel generator set or a DC battery set.
2. Secondary load
The load that power supply interruption will cause great political and economic losses or cause disorder in public places is called secondary load. For example, office buildings, three-star hotels, first-class cinemas, major libraries, museums, local and municipal cultural relics.
Except for two independent lines, the secondary load should provide standby power supply according to the actual situation.
3. Tertiary load
Except for the primary load and the secondary load, the rest belong to the tertiary load. The third-class load has no special requirements for power supply mode, and generally adopts single-loop power supply.
With the development of China's economy, the first-class load power supply mode can no longer meet the needs of some particularly important places, such as local telephone offices, telecommunications hubs, satellite ground stations, civil airports, Yinchuan stock exchange center and so on. These loads are particularly important first-class loads, which are generally called special first-class loads. At the same time, due to the development of economy and the increase of primary load and secondary load, the power supply mode of tertiary load will be gradually reduced or cancelled.
Question 4: What are the primary and secondary load power supplies and how many an loads are there? Short-term power failure may affect personal safety or equipment safety, forcing production activities to stop.
Generally, the power supply mode of automatic switching of dual power supplies is adopted.
Class II load, short-term power failure is allowed, but long-term power failure will damage the equipment or affect the production load.
Generally, the power supply mode of manual switching of dual power supplies is adopted.
Three types of load, long-term power failure has no effect on the load.
A single power supply is enough.
Question 5: What is the difference between primary load and secondary load? (1) Both primary and secondary loads are powered by two power sources, but the difference lies in the power source:
A unipolar load power supply that meets one of the following conditions:
① Power supply comes from two different power plants; ② Power supply comes from two regional substations (voltage is generally 35kV and above).
Secondary load:
(1) When the load is small or the regional power supply conditions are difficult, the secondary load can be supplied by dedicated overhead lines or cables of 6KV or above.
(2) When using overhead lines, it can supply power for one overhead line; When cables are used, two cables should be used for power supply, and each cable should be able to bear the secondary load of 100%.
(2) The standby power supply only specifies the first-class load: for the particularly important load in the first-class load, in addition to the two power supplies, an emergency power supply should be added, which can be a generator set, a storage battery or a dry battery. In a building with primary load power supply, when self-contained power generation equipment is used as backup power supply, the self-contained power generation equipment should be equipped with automatic and manual starting devices, and the automatic starting mode should be able to supply power within 30s.
(3) According to the time allowed to interrupt power supply, the following emergency power supplies can be selected respectively:
(1) It is allowed to interrupt the power supply for more than 15s, and a quick self-starting generator set can be selected.
(2) If the action time of automatic switching device can meet the allowable interruption time of power supply, a dedicated feeder with automatic switching device independent of normal power supply can be selected.
(3) Millisecond interruption of power supply is allowed, and battery static uninterrupted power supply device, battery mechanical energy storage motor uninterrupted power supply device or diesel engine uninterrupted power supply device can be selected.
(4) The working time of emergency power supply should be considered according to the downtime required by the production process. When used in conjunction with an automatically started generator set, it should not be less than 10 minute.
(d) The sensitivity requirement of dual power switch is independent of primary and secondary loads.
Question 6: What is the difference between secondary load and tertiary load? According to different fields, the load classification standards are slightly different.
But the guiding ideology should be similar.
Short-term power failure may affect personal safety or equipment safety and force production activities to stop. This kind of load adopts the power supply mode of automatic switching of dual power supplies.
Class II load, short-term power failure is allowed, but long-term power failure will damage the equipment or affect the production load. This kind of load generally adopts the power supply mode of manual switching of dual power supplies.
Three types of load, long-term power failure has no effect on the load. This load can be powered by a single power supply.
If there are two sets of standby equipment, there can be different power outages on the same power bus at the same time.
Question 7: What are primary and secondary loads? According to the requirements of power users for power supply reliability, it is usually divided into three levels. The first level refers to those who, if the power is suddenly cut off, will cause personal injury, major equipment damage, a large number of waste products of important products, resulting in production confusion, obstruction of important transportation hubs and trunk lines, interruption of water supply, communication and broadcasting in important cities, etc. , thus causing huge economic losses or significant political impact. In the first-class load, it will cause poisoning, explosion, fire and other loads. When power supply is interrupted, loads that are not allowed to interrupt power supply in particularly important places should be regarded as particularly important loads. Secondary load refers to the situation that sudden power failure will cause serious production reduction, shutdown, local damage, traffic congestion in some areas and interruption of the normal life of most urban residents. Those that do not belong to Class I and Class II loads are Class III loads.
Question 8: What is the main difference between primary load and secondary load? The significance of load classification is to objectively reflect the power supply reliability boundary required by power load, which is convenient for designers to design power supply and distribution schemes economically and reasonably, meet the needs of users in various industries and improve investment benefits. According to the reliability of power supply and the degree of political and economic loss, influence and disorder of power supply interruption, power load is generally divided into three levels, namely, primary load, secondary load and tertiary load. Particularly important loads and fire fighting loads are also within this classification. The description of 1 particularly important load in Code for Electrical Design of Civil Buildings (hereinafter referred to as "Civil Code") should be classified as 1. 1. For some special buildings, such as transportation hubs, communication hubs, state-level hotels undertaking major national activities, halls, etc.
Question 9: The power supply should not be lower than the secondary load requirements. What does the secondary load requirement mean? According to the reliability of power supply and the political and economic losses caused by power failure, the power load can be divided into grade one, grade one, grade two and grade three.
Level 1: power supply interruption will cause casualties;
Level 1: national special buildings, important transportation hubs, national hotels, great halls, sports centers and places where important international activities are often held;
Grade II: great economic and political losses are caused after the interruption;
Grade III: All the above power loads are Grade III.