Regarding the electricity load classification

The power supply load is determined when applying for electricity use. I. A load is considered a Class 1 load under one of the following conditions: 1. When a power outage would result in casualties. 2. Power supply will be interrupted when it causes significant ** and economic losses. For example: severe damage to major equipment, significant scrapping of products, large-scale rejection of products manufactured from key raw materials, and disruptions to the continuous production processes of key enterprises in the national economy that take a long time to recover. 3. A power outage will disrupt the normal operations of electrical users of significant ** and economic importance. For example: important electrical loads in facilities such as key transportation hubs, important communication centers, major hotels, large sports venues, and public places where large numbers of people gather and are used for international events. Among primary loads, those for which a power outage could lead to poisoning, explosions, fires, etc., as well as those in particularly important locations where a power outage is not permitted, should be considered as especially important loads. II. A load shall be classified as a Class II load under one of the following conditions: 1. When a power outage will cause significant losses in terms of ** and economics. For example: damage to key equipment, large quantities of products being scrapped, disruptions in the continuous production process that take a long time to resolve, and significant reductions in production volume for key enterprises. 2. A power outage will affect the normal operation of important electrical users. For example, important electrical loads in facilities such as transportation hubs and communication centers, as well as important public places with large crowds like large theaters and shopping malls, where a power outage would lead to chaos. III. Those that do not fall under category 1 or category 2 loads should be classified as category 3 loads. The classification of load levels is determined based on design considerations; generally, important equipment uses UPS as an uninterruptible power supply, which corresponds to a level 2 load. Even more critical equipment makes use of two UPS units connected in parallel to ensure power continuity.

Class I loads require two or more power supply inputs. For level 2, a backup power source such as EPS can be used in addition to the main power supply; for level 3, only a single power supply is used

The answer upstairs was good; I was exactly looking to learn about this, but unfortunately it took too long so I couldn’t give a rating :(

I believe load classification involves determining the category of each electrical device within a plant based on the nature of its load; in other words, within one plant, some devices have first-class loads, some have second-class loads, and the majority have third-class loads.

I think the people upstairs have a misunderstanding regarding load levels; they are talking about power supply load levels, while what the original poster is asking about is equipment load levels. If a factory has two different power supply inputs, it can be said that the factory’s power load level meets the requirements of category 2; however, the specific electrical equipment within the factory may not necessarily meet the requirements of category 2 loads. Because secondary loads not only have requirements for power supplies, but also for transformers and wiring. This problem has troubled me for a very long time; I only understood it after discussing it with many senior engineers. To give a simple example, a substation in a rural area has two power supply lines, but does that mean the electricity consumption level of every household reaches level two? Obviously not.

This post was last edited by js*aoyuyao on 2014-2-27 at 12:57. Reply from Ou Lai Xue Xue: I originally wanted to start a new thread for everyone to discuss and learn together, but then I thought there wasn’t much to write about, so I’ll just write it here briefly. For example, a chemical plant has a 10kV substation equipped with two 10/0.4kV transformers. The substation has two 10kV feeders, which meets the requirements for secondary power loads. The following discusses how to ensure that the entire plant meets the requirements for class II and class I load levels: 1. If the electrical equipment in the entire plant is to meet the requirements of class II load, then the load capacity of the two transformers must not exceed 0.6; otherwise, in the event of a failure in one transformer, the electrical equipment connected to that transformer cannot be switched over to the other transformer (why is it 0.6? Because when both loads are around 0.6, switching to one transformer results in a load rate of around 1.3 for that transformer, which allows for short-term overloading). If the coefficient exceeds 0.6, it is certain that not all the equipment in the entire plant meets the requirements for class II load. 2. If all the electrical equipment in the entire plant is to meet the requirements of Class 1 load, this is basically impossible. Since first-class loads require two completely independent power sources, which means that a factory needs to draw electricity from two different power grids; the difficulty of this can be imagined. The common approach is to draw electricity from two substations that are as far apart as possible. Then, for particularly important loads such as fire pumps and foam systems, diesel generators are also required. Therefore, two incoming lines only indicate that the power load level reaches grade 2; if the load rate on the transformers is too high, or if the two transformers do not have a device for mutual switching, the requirements for grade 2 load cannot be met. It is even more difficult to meet the requirements of Class I load.