Cosine Similarity Based Line Protection for Large Scale Wind Farms Part II—The Industrial Application

With the integration of the large-scale wind farms, the conventional pilot protection is facing new challenges. It suffers from the performance degradation can even refuse operation for some extreme fault scenarios. To address this problem, this article continues the research of the novel pilot protection based on cosine similarity. The protection pickup setting and industrial application testing is investigated. The functional structure is described and the logic of the cosine similarity based protection is evaluated under different fault scenarios. Compared with the conventional differential protection, application of the proposed protection can greatly improve the relay performance. The proposed protection is embedded into an industry relay device, and the standard hardware-in-loop tests are carried out using the real time digital simulator before the industrial application. Now, the protection device based on cosine similarity is installed in the wind farms and put into operation in Inner Mongolia.