Integrated generator protection-user benefits

Protecting a generator against faults and abnormal operating conditions requires different types of protective functions. A traditional scheme usually consists of a number of discrete protective relays, which are combined together with external auxiliary relays and wiring to produce the necessary trip logic. With modern digital techniques, all the protection functions, together with the scheme logic, can be integrated into the same relay case. The protection can share the same current transformer (CT) and voltage transformer (VT) inputs and can drive common relay outputs. This produces a reduction in both the panel space and the burdens of CTs and VTs. With the integrated scheme logic, the amount of external wiring and auxiliary relays are also minimized, thus reducing panel engineering work. Additional user benefits are also provided with digital technology, such as local and remote instrumentation, fault, event and disturbance recording, commissioning aids, remote communications and self-monitoring. These are discussed in the paper.