Q. Explain Power-System Loads?

Figure represents a one-line (single-line) diagram of a part of a typical three-phase power system. Notice the symbols that are used for generators, transformers, buses, lines, and loads.

Let us now consider the addition of a load bus to the operating power system. Service classifications assigned by the electric utilities include residential, commercial, light industrial, and heavy industrial loads, as well as municipal electric company loads. Let us prepare a load- bus specification, which is a summary of the service requirements that must be provided by the electric utility. Referring to the simple model of Figure, as an example, let the total new load connected to the system be 220 MVA at 0.8 power factor lagging; let the service be provided at the subtransmission level from a radial 115-kV circuit; let the 115-kV transmission line have a per-phase series impedance of 3 + j8.