Protection algorithm of central relaying unit for wind farm based on directional algorithm

Abstract

Protection relay of wind farm based on directional algorithm and positive sequence fault components is proposed in the paper. This relay uses directional algorithm to detect fault in the wind farm (internal) or in the grid (external). For these faults, the relay should be stable and operatives. The magnitude of the directional angle is obtained by measuring and processing the currents and voltages using merging unit (MU) which is located at each wind turbine generator (WTG) zone, feeder cable zone and transmitted bi-directional status signal into and from the central relaying unit (CRU). The proposed relay detects the faulted feeder, Then discriminates between fault in the feeder cable or in WTG connected to this feeder. The fault in WTG requires trip signal to isolate the faulted WTG. However, the fault on the power collection feeder requires an instantaneous tripping response, but after isolation C. Bs of WTGs connected to its feeder to prevent over voltage of unfaulted phases in the feeder cable. The CRU eliminates the needing of individual relays for each (WTG). Consequently, the proposed relay requires only one setting file for the whole wind farm and eliminates the individual setting, configure, maintained, and testing the separate relays. The operating performance of the relay is verified under different fault location using MATLAB platform. The fault analyses involve different types of faults, and the faulted phases. Analyses confirm that, the relay can efficiently distinguish between faults that require an immediate, delayed or nonoperation reaction.