Analysis of causes of failures in 10 kV electrical power distribution networks (on the example of the Southern electrical networks of the city of Irkutsk)

Disconnection of power consumers from power grids is quite a common event, with a wide range of consequences. Power supply interruptions can be caused by both casual events, and planned shutdowns. Disruptions in systems of power supply of consumers lead to a variety of adverse events (under-delivery of products, large-scale product rejection, failure of production equipment, etc.), which inflicts a significant economic damage. The retrospective analysis of the failure rate of electrical networks of the Right Bank and Left Bank districts of Irkutsk over 2013–2017 has been carried out. The analysis was based on the data from dispatching logs of observations on events of failures caused by emergency damage to the Southern electrical networks. It is established that the greatest number of failures occurs for such reasons as damage at substations, damage to consumer electrical networks, wire breakage in air and cable power lines as well as damage of switching equipment. Failures related to wind load, damage at packaged transformer substations, insulators and surge arresters are also analysed. The percentage rate of failures of electrical power networks caused by specific reasons from the total number of failures is presented. Besides, the analysis is performed of the duration of interruptions of power supply owing to damage of individual elements of power network equipment as well as the amount of electric energy undelivered for these reasons, and financial losses caused by these failures due to under-delivery of electric energy, with the average wholesale electricity prices taken into account.