Relay protection settings calculation for the 220 kV switchyard and incident transmission lines in HPP Zakucac
Abstract
The paper presents theoretical foundations and calculations on which the selection of parameters of the relay protection system of the 220 kV plant and the 220 kV incident transmission lines in the Zakucac HPP is based. The concept of the relay protection system is based on the application of two numerical relay devices on each of the incident lines, with the implementation of the following protection functions: longitudinal differential protection, distance protection with polygonal operating characteristic and communication scheme of operation, directional earth fault protection with communication scheme of operation, backup overcurrent protection, protection against switching on to a fault. Automatic reconnection of the lines is envisaged. The relay protection of the 220 kV plant’s busbars is based on the differential principle and also includes the function of protection against circuit breaker failure. Additional backup overcurrent protection is located in the connection field of the 220 kV plant in the Zakucac HPP. The paper presents the necessary analyses and the calculation and selection of parameters of all the mentioned protection functions of all the numerical relay devices that make up the described relay protection system.
