Variable Frequency Drives in Nuclear Power Plants

Abstract

Variable Frequency Drives (VFDs) are used to drive electrical motors at different, adjustable speeds in industrial applications. So on the one hand, energy can be saved which leads to an economic benefit and on the other hand the behavior of the system can be controlled easier and more efficient.

VFDs have many parameters which can be customized in accordance with the system requirements. There are also existing different hardware designs of VFDs for different applications like driving pumps or fans.

To have on the one hand a high standardization in the manufacturing of VFDs and on the other hand to be flexible as much as possible, the use of software integrated in VFDs is essential. Also, in Nuclear Power Plants VFDs are used in several areas, mainly for non-safety related HVAC-applications.

For safety-related systems VFDs are not often used due to software-qualification requirements. This White Paper demonstrates a possible solution for using an industrial standard VFD in a safety-related application and what steps are to be taken for the qualification.

In addition, we would like to introduce our currently on-going qualification project of a software-free VFD solution. This opens the possibility to use the advantages of VFD’s even for safety related applications.