The graph shows how a hyrdo~~~~ . Overall, this process is divided into two stages, between the day and night. To begin with, a hydroelectric power station uses water and this process has two ways in day and night. According to the above picture, a river flows in a high-level reservoir which is in front of a dam.
(제가 해드린 것처럼, 문단을 구분할 때에는 엔터키를 두 번 쳐주셔야 합니다.)
First of all, in the daytime, the dam intakes opening therefore a river that in the high-level reservoir flows to generate electricity and go to a low-level reservoir through reversible turbines because it operates generators at this time.
On the other hand, at night, a water that in the low-level reservoir flows of water during pumping via reversible because the reversible turbines pump water into high-level reservoirs however the dam intake is closed in this period. (문장이 너무 깁니다. 바로 윗 문단도 마찬가지이고요. 현재 문법이 깔끔한 상황이 절대 아닌데 문장마저 길어질 경우 300% 손해를 보기 때문에 문장은 짧고 간결하게 끊어가주셔야 해요.)
In particular, the reversible turbines which are between the high-level reservoir and low-level reservoir connect with generators and also this is linking the power line with the national grid. (<--- 이 문장이 길이의 마지노선입니다. 사실 얘도 길긴 하지만, 그래도 이정도까지는 괜찮아요.) Accordingly in the picture, these are included in the power station.