I am actually quite confused on how a generator is supposed to be modeled... To add more power to a bus, we put more generators in parallel at the same voltage (which is the bus voltage). Therefore, I would say generators are current sources as more generator are put in parallel, more current is produced at the bus voltage allowing more P = VI to be produced. However, my more experienced co-workers say generators are voltage sources, but didn't explain why. I would think putting multiple voltage sources in parallel do not increase the power put into the bus, so this model would not work. Can you guys on PF help me clear my confusion? Thanks!