Smart compact secondary substations — Method for evaluation of functionality for utilities

Smart Grid technology manifests itself within all levels of electric energy supply. One of the levels where the benefits can be of greatest value is within Medium Voltage (MV) distribution level. The Compact Secondary Substation (CSS) will be a key node here. The MV distribution network consists of a large number of components over a wide area from various manufacturers. For a typical Utility, the present situation is that the control and monitoring of faults and operating conditions on the distribution network are very scarce and far from what is available on higher voltage levels. For instance, fault localization is often based on reports from customers and manual supervision. A manufacturer of Smart CSS focuses on the technological aspects and functionality which can be provided based on assumed customer benefits. Such assumptions will not always match the expectations coming from the Utilities. A Utility must evaluate all investments in new technology in relation to a wide range of criteria which will have different level of importance for the individual Utility. This paper will discuss such criteria definition and show how it has been applied by Skagerak Nett AS, the second largest Utility in Norway, when evaluating investments in Smart CSS. Such functionality mapping for a Utility gives valuable information and guidance for the Utility when classifying the CSSs in their network, as well as to the supplier industry to secure correct products and solutions fitting the Smart CSS applications.