Availability of a SCADA/OMS/DMS system — A case study

Abstract

With the advent of the smart grid, new challenges arise for electricity distribution. In particular, reliable power distribution will become evermore dependent upon information and communication technology (ICT). With this increasing dependency comes a need for a deeper understanding of the availability of those ICT components that maintain the power grid. This paper presents a study in which all components of a supervisory control and data acquisition (SCADA), Outage Management (OMS) and Distribution Management (DMS) system at a power utility are analyzed from an availability perspective, identifying the parts of the system that contribute the most to overall system downtime. Furthermore, the case study involves a downsizing regarding the IT system architecture redundancy. This downsizing makes it very interesting to investigate how hardware redundancy relates to the overall SCADA/OMS/DMS system availability. Such knowledge is required to assess the rationality of the architectural restructuring decision, as well as for more general rational decision making when it comes to the ICT components of the power distribution grid. It is concluded that even in the new architecture, the remaining hardware redundancy level is enough. Instead, it is found that most of the downtime of the SCADA/OMS/DMS system is caused by failing software, causing all the redundant hardware to become unavailable at the same time. Since the software is a third party piece from the supplier of the system, one important source of downtime can be seen as emanating from the requirements and procurement process of the company.