Chuvashenergo, a branch of IDGC of Volga, JSC (a member of Rosseti Group of Companies) commenced preparations for the thunderstorm season-2015 to ensure reliable and fault-free operation of electrical networks. The company issued a number of regulatory documents on preparation for operations during the thunderstorm season-2015, assigned persons responsible for elaboration and implementation of measures ensuring safe and secure operations of business entities during the forthcoming thunderstorm season. Long before the thunderstorm period (i.e. the period from May to September), the company prepared an integrated plan of necessary measures to be taken. This plan sets procedures for employees responsible for verifying operational readiness of equipment used to detect faulty and damaged overhead transmission lines, conducting additional inspections of overhead transmission lines, equipment of 35-110 kV switchgears at substations and 6-10 kV distribution networks. Special attention is given to technical condition of lightning protection devices and overvoltage protective devices (such as arrestors and overvoltage suppressors) for all components of switchgears at substations and incoming transmission lines. Specialists of on-site response teams and line crews undergo extensive training. Staff members are thoroughly briefed in safety procedures to be followed when localizing and rectifying faults and failures on overhead transmission lines. Preparing to thunderstorm season is one of the main stages of power engineers' work necessary to ensure reliable and uninterrupted power supply to consumers, and it is one of the conditions making it possible to eliminate failures in power grids of the Chuvash Republic in the shortest time.