Q. Use of Computers in Power Systems?

The control and stability of any electric power system is indeed extremely important, in particular when a system is expected to maintain uninterrupted continuity of service within set limits of frequency and voltage, and to guarantee reliability of the system. Digital computers and microprocessors, along with highly developed software programs, have made their way into planning, designing, operating, and maintaining complex interconnected power systems. A large volume of network data must also be acquired and accurately processed. Digital computer programs in power-system engineering include power-flow, stability, short-circuit, and transients programs.

For a network under steady-state operating conditions, power-flow programs compute the voltage magnitudes, phase angles, and transmission-line power flows. Today's computers are capable of handling networks with more than 2000 buses (nodes) and 2500 transmission lines in less than 1 minute power-flow solutions. Interactive power-flow programs have also been developed along with CRT displays.

Stability programs are used to analyze power systems under various disturbances. Short- circuit programs compute fault currents and voltages under various fault conditions. These, inturn, will help in circuit-breaker selection, relay coordination, and overall system protection.

Transients programs yield the magnitudes and shapes of transient overvoltages and currents that may result from lightning strikes and other surges on the system. Based on the results of such studies, insulation coordination and surge-arrester selection are configured.