Power or load flow studies are probably the most common of all power system analysis calculations. They are used in planning studies to determine if and when specific elements will become overloaded. Major investment decisions begin with reinforcement strategies based on load-flow analysis. In operating studies, load-flow analysis is used to ensure that each generator runs at the optimum operating point; demand will be met without overloading facilities; and maintenance plans can proceed without undermining the security of the system.

The objective of any load-flow program is to produce the following information:

• Voltage magnitude and phase angle at each bus.

• Real and reactive power flowing in each element.

• Reactive power loading on each generator.