An FPGA-based Cost-effective Digital Differential Relay for Wind Farm Protection

Abstract

Wind farm protection against any abnormalities such as extreme wind speed, symmetrical and unsymmetrical faults remains an engineering challenge. Commonly, inverse time-delay overcurrent relay and distance protection relays have been used for power system protection against overcurrent incidences. However, the performance of these relays is not reliable for wind farm protection due to dynamic behavior of wind farms during harsh wind speed variations. A microprocessor-based differential protection relays (MDPR) with extensive communication capability may be used to tackle the effect of wind speed variation on protective relays. Nonetheless, implementing several MDPR in a large-scale wind farm could be extremely costly and in the event of communication failure, the relay would fail to operate during fault incidence. Therefore, in this research a cost-effective and more reliable differential protection relay is designed in a field-programmable gate array (FPGA) and is proposed as an alternative protection scheme for wind farms. The performance of the proposed FPGA-based digital differential protection scheme (FPGA-DDPS) is verified in the lab environment using DE2-115 FPGA board equipped with Cyclone IV E (EP4CE115F29C7). The experimental results show that the proposed FPGA-DDPR can successfully detects fault locations, trips the internal faults and even faults with extremely high resistance, while ignores the external fault. Thus, the proposed FPGA-DDPR protection scheme would be a cost-effective alternative to MDPRs.