Connecting large machines to power systems

There are several methods of connecting machines to systems, each method having its advantages for particular types of machine and specific system conditions. Whereas, in the past, limitations were imposed only on the characteristics of the machine during the process of connection attempts are now made to assess the mutual effects between the system and the machine and to make allowance for these. On large and important systems involving large machines it is becoming apparent that a thorough study of the problem of connection may result in a more economic and technically superior arrangement than has been used in the past. Several factors may be involved during machine connection; these include switching surges, voltage reductions caused by starting currents, acceleration effects with possible current pulsations and synchronizing effects. The significance of any, or all of these, on the system is determined by the consequent effects on other machines or apparatus connected to the system is on the machine itself. A combined analysis of the machine and local system is the only satisfactory way to determine the limiting factors which can be improved most economically, and so enable the most satisfactory combination of apparatus and starting method to be selected for any particular installation.