Effects of dependent and common mode outages on the reliability of bulk electric system — Part I: Basic concepts

This paper is the first part of a two-part paper based on the ongoing activity carried out by the Task Force (TF) of the Working Group (WG) on Probability Applications for Common Mode Events (PACME) in electric power systems under the Reliability, Risk and Probability Applications (RRPA) Subcommittee. The primary objectives of this work are to (1) review and discuss the basic definitions of dependent, common-mode and cascading outage events, (2) identify the major causes of common-mode, dependent and cascading outages, (3) recognize the effects of protection system failures and misoperations on the Bulk Electric System (BES), and (4) assess the impact of weather related outages and extreme events on the performance of the BES. The scope of Part I is limited to the basic concepts on common-mode and dependent outages. The overall goal of the two papers is to assist the wider efforts within the industry in practically assessing the effects of dependent and common-mode outages on the reliability of BES.