What is everyone’s understanding of the descriptions provided in the drawings issued by the design institute?

Questions regarding the drawings can be raised for clarification during the professional review of the construction drawings; if there are indeed errors, they can be addressed through a \"design change order\" to update the drawings.

It’s indeed a bit hard to understand; maybe they forgot before the modification was completed. . . . .

Share your understanding of the literal interpretation of the drawings

So, I hope I can get your help in explaining what it might mean. Haha

So, I hope I can get your help in explaining what it might mean. Haha

Electricity is not my field of expertise, so I won’t click things randomly.

It would be much easier to understand this diagram if the upper-level busbars and transformers were shown. In my opinion, when load changes occur due to seasonal variations (for example, when the load decreases to within the capacity of a single transformer), it is possible to operate only one of the two transformers that were previously used for power supply. However, in order to prevent the transformers from operating at full capacity for extended periods, some less frequently used loads can be disconnected (and the load can be adjusted again when they are needed).

Actually, what I want to say is that if two transformers are operated in parallel, not all three circuit breakers need to be engaged; it’s hard to understand why it’s stated that this must not happen at any time

Actually, what I want to say is that if two transformers are operated in parallel, not all three circuit breakers need to be engaged; it’s hard to understand why it’s stated that this must not happen at any time

The existing theory is based on the principle of “three openings and two closures”. My personal understanding: when two transformers are operating simultaneously, if 1–3QF are not opened, it should be what you refer to as parallel operation. However, it is said that the prerequisite for this is that the two transformers are exactly identical; it is reported that this is how parallel operation is carried out in most power utility systems. As power-consuming enterprises located at the end of the power grid, the biggest problem with such an operation is that when a short circuit occurs in the load on a certain bus (assuming that the protection devices at that level do not trip), the inrush current will affect both transformers simultaneously. If one of the incoming line switches trips, it is possible that the other incoming line switch will also trip, or even both switches may trip at once. Therefore, operating in a mode of “three open and two closed” is relatively safe. Of course, the above problem can be prevented from causing both bus sections to trip by setting a limited current value on the 3QF.