While "crazy russian" gave you an intelligible response, the real answer is (a) have a vagina; or (b) admit that you let yourself get sodomized.

When you have multiple power plants and loads connected to single grid you have to balance total power production and consumption. If you are out of balance, f.e. plants produce more power than consumed you are in great trouble with barely predictable outcome. Also, large changes in load could destabilise grid too. So you need some centralised entity to watch after that balance and command plants to increase or decrease production. That entity named "grid operator". It's like air traffic control for electricity.

If a grid have bad balance, f.e. it's only citizens and power plants, then you have problems every evening and night, when all citizens turn on light at evening and turn off it going to sleep. You need to nearly stop power plants at night and run them in full power at evening. You could eaily fall to that thing even without any consumtion grow, f.e. if factories who are constant load are bankrupted or moved out from your area you stay with population who consume electricity in very ragged way.