Abstract
This paper presents a first comprehensive statistical study of transmission inventory and outage data of overhead AC circuits in the Kazakhstan Electricity Grid Operating Company (KEGOC). The analysis is based on the data collected and reported to the KEGOC centralized outage data collection system during the years 2013 to 2018. The outage-data statistics of KEGOC have been analyzed to demonstrate the leading cause-code and seasonal contributions to the automatic outages of overhead transmission lines of 200 kV and above voltage classes. The KEGOC's 6-year collected outage data are used to estimate basic reliability indices (frequency of automatic and sustained automatic outages per circuit and per hundred kilometers, outage duration, and an element unavailability) that are needed to perform any type of probabilistic reliability studies. Also, these 6-year collected outage data are used to assess and benchmark the reliability performance of a system's zones. The importance of these kinds of data and analysis for reliability applications is stressed.