Assessment of Various Unit Control Architectures

Traditionally, generating stations have depended upon a number of unique systems and devices for the protection and control of both the Prime Mover and Generator. Some examples of auxiliary systems are excitation, voltage regulators, synchronizers, governors, and generator protection. Over years of experience, each of these specialties have progressively advanced into, very unique and individual, complex fields of expertise. Initially, having separate controllers required very costly and complex intercommunication schemes. But today, the advanced digital communications among controllers and supervisory control systems dramatically simplify the 'connectivity' design.

Since the arrival of digital control systems, now around twenty years ago, industry has experimented with amalgamating some or all of these discrete systems. These completely integrated systems have only been successfully utilized in a very limited number of applications, typically in very small facilities. For major generating stations, most system designers have returned to using dedicated pieces of equipment for each specialty.

The following examples describe actual projects, and will illustrate several points to consider before selecting a 'style' of control integration. Although the problems encountered focus on the Speed Governor, the point of this paper is to illustrate there can be serious deficiencies in every specialty system, when they are administered without proper application experience.