Abstract
One of the tasks of a fundamentally unresolved problem in the energy sector is addressed: the development of a new relay protection system without using current transformers. A method and a protection device for two parallel power transmission lines are proposed. The protection is based on reed switches, eliminating the need for metal-intensive current transformers to obtain information about the currents in the line phases. The operating principle of the protection involves monitoring the time intervals between the activation of reed switches installed near the corresponding phases and the current magnitudes in these phases. It is demonstrated that to implement this principle, two reed switches must be installed near each phase: one for time measurement and the other for current measurement. A detailed description of the protection's behavior under various operating modes of the two parallel lines is provided.