Relay protection settings calculation for the 110 kV switchyard and incident transmission lines in HPP Zakucac
Abstract
The paper presents the theoretical foundations and calculations on which the selection of the parameters of the relay protection system of the 110 kV plant and the 110 kV incident transmission lines in the Zakucac HPP is based. The relay protection system is implemented using numerical relay devices type 7SD522 (longitudinal differential and distance protection of incident lines) and 7SS52 (differential protection of busbars) from Siemens. The following basic concept of the relay protection system is applied: longitudinal differential protection, distance protection, APU line function, directional earth fault protection, backup overcurrent protection, circuit breaker failure. Distance and directional earth fault protection also use appropriate communication schemes of operation. The plant buses are protected by dedicated busbar differential protection. The paper presents the necessary analyses and the calculation and selection of parameters of all the mentioned protection functions of the numerical relay devices that make up the mentioned relay protection system.
