Substation construction

How is it that GIS distribution cabinets aren’t allowed to be used?? I’m also confused. The advantage of open-type distribution devices is that it’s easy to see which switches are inside them, but GIS systems require no maintenance and offer much higher safety levels than open-type ones. How is that possible??? All I can suggest is the following: 1. Electrical design mainly involves the total load and the load factor; once these two factors are determined, the capacity of the transformer needed can generally be determined as well. 2. Total load calculation: A simple method is to add up all the loads directly, then eliminate those that are counted multiple times; for example, primary and backup devices that cannot be activated simultaneously can be considered based on their type of load. The load must be calculated in terms of capacity, not just power. 3. Estimating the likelihood that multiple loads will be activated at the same time, that is, the load factor, is generally done using a coefficient ranging from 0.5 to 0.8. Finally, account should be taken of the margin reserved for the development of substations; this is necessary for substations that are constructed in phases, and even more so for those built all at once, with a coefficient of 1.2 to 2 generally applied.