The New Adaptive Protection Method for the Compensated Transmission Lines with the Series Capacitor in a High Share of Wind Energy Resources by Using PMU Data

摘要

Nowadays, using renewable energy sources ignited plays an essential role in the power system grid. Although using wind energy as a renewable energy source has some benefits, such as higher performance over other renewable energy sources, it has opened new field power system protection for this power grid type. Wind power plants in a contingency situation such as short circuit fault in the power grid may disconnect from the power grid and make the situation worse for the dynamic stability of the power system.Low Voltage Ride-Through (LVRT) has proposed by Wind Energy Conversion Systems (WECS). A mismatch will be acquired during a voltage drop across the grid between the wind generator's active power and those delivered to the power grid. Constant speed wind generators are highly dependent on reactive power, so they require much reactive power in a short circuit failure; otherwise, they become unstable and must be disconnected from the power system. On the other hand, some proposed method to provide reactive power to wind generators might negatively affect distance protection, especially in the lines equipped by series capacitors. Besides, Proper protection of high voltage transmission lines equipped with series compensation has ignited some challenges for distance power system protection; these challenges are caused due to some factors such as the influence of the series capacitor on the fault ring and the variation of the impedance, the failure to detect the direction of the fault due to changes of angle and the measurement of phase voltage, transient fluctuations caused by low current errors as well as switching.On the other hand, the fault location in a transformer compensated transmission line is complicated by the series capacitor due to the MOV and complex transient conditions. Therefore, it is necessary to investigate methods to improve transmission lines' distance protection (as the most common conservation in lines), and research has been done in this regard. In this paper, a proposed scheme based on phasor measurement data from PMU on both sides of the line this method calculate the percentage of compensation in real-time mode, and the setting of second and third relay zones will be minimized depending on the conditions for recovery and improper performance of distance protection. To assess the accuracy of the proposed method, IEEE 39-BUS is employed. Proper performance of protection areas obtained in fault conditions using this scheme indicates the accuracy of the proposed method all of the numeric calculation has been done in Digsilent Power factory software