Discussion: Excitation system redundancy

Today, technology continues to evolve as more functionality is placed into smaller packages with the aid of new innovative hardware and improving software in digital excitation systems. The advancement of the microprocessor has provided the means to increase the feature function capacity into less hardware and provide additional means to enhance reliability by offering redundancy of a complete full functional digital excitation channel. This paper will discuss various approaches to redundancy being accomplished today by vendors that include discussions at various levels ranging from digital controllers, firing circuits, power supplies, and power rectifier bridges. Recently, the latest version of IEEE 421.4 Guidelines for Specifying an Excitation System was released that included discussion of excitation system redundancy. This paper expands upon the various levels of redundancy offered by the manufacturers so the end user will have sufficient information to make the best choices for his application.