1 - System Studies

Abstract

This chapter describes three main areas of transmission and distribution network analysis; namely, load flow, system stability, and short circuit analysis. Such system studies necessitate a thorough understanding of network parameters and production of plant characteristics for the correct input of system data and interpretation of results. Harmonic analysis is recognized as a major system study tool. A load flow analysis allows identification of real and reactive power flows, voltage profiles, power factor, and any overloads in the network. Once the network parameters have been entered into the computer database, the analysis allows the engineer to investigate the performance of the network under a variety of outage conditions. Different programs use a variety of different mathematical methods to solve the load flow equations associated with the network. Some programs ask the user to specify the method they would wish to use from a menu of choices. The problem of stability in a network concerns energy balance and the ability to generate sufficient restoring forces to counter system disturbances. Minor disturbances to the system result in a mutual interchange of power among the machines in the system acting to keep them in step with each other and to maintain a single universal frequency.