Differential Protection for an Outgoing Transformer of Large-Scale Doubly Fed Induction Generator-Based Wind Farms

Energies

Bingtuan Gao²  Wei Wei²  Luoma Zhang²  Ning Chen³  Yingjun Wu¹ 

[1] School of Automation, Nanjing University of Posts and Telecommunications, No. 9, Wenyuan Road, Nanjing 210023, Jiangsu, China; E-Mail:;School of Electrical Engineering, Southeast University, No. 2, Sipailou, Nanjing 210096, Jiangsu, China; E-Mails:;China Electric Power Research Institute, No. 8, Nanrui Road, Nanjing 210003, Jiangsu, China; E-Mail:

关键词: wind farm;    differential protection;    transformer;    frequency inconsistency;   

DOI  :  10.3390/en7095566

来源: mdpi

【 摘 要 】

With the rapid development of wind energy, relay protection for large-scale wind farms has been attracting some researchers, due to the absence of standards. Based on the large-scale doubly fed induction generator (DFIG)-based wind farms located in Gansu Province, China, this paper studies the differential protection for the outgoing power transformer of large-scale DFIG-based wind farms. According to the equivalent circuit of the power grid integrated with wind farms, the main frequency components of current and voltage during faults are identified mathematically and then verified by simulations. The results show that the frequencies of current and voltage at the terminals of outgoing transmission lines are inconsistent. Following the feature of frequency inconsistency, the adaptability of differential protection is analyzed, and it is found that differential protection for an outgoing transformer in large-scale wind farms may fail once ignoring the frequency inconsistency. Simulation studies demonstrate that inconsistent frequency characteristics will deteriorate the sensitivity and reliability of differential protection. Finally, several suggestions are provided for improving the performance of relay protections for large-scale DFIG-based wind farms.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland