Analysis of starting element for transmission line to wind farm integration

To improve the reliability of microcomputer‐based protection, the starting element is commonly applied in the exiting protection device and its starting is a premise for the protection action. Therefore, it is crucial for protection that the starting element must be more sensitive, rapidly and reliable. However, owning to the great differences of fault characteristics between the wind power source and the conventional one, it is a necessity to study whether the starting element in conventional AC power system can be adapted to the wind power. First, the principles and criterion of starting element applied in conventional AC power system are investigated. Then, combined with the fault characteristics of wind sources, the adaptabilities of the starting elements are analysed. Last, the results of the theoretical analysis are verified by the data form simulation. Based on these analyses and results, some conclusions can be drawn: there are more risks to refuse action for the main starting criterion based on fault component of current on the wind power side, especially for permanent magnet synchronous direct‐driven generator; the zero‐sequence network of wind power system is not affected by the wind sources, so the auxiliary starting element based on zero‐sequence current has no adaptability problem, but it can only discriminate the grounding faults. Thus, it needs to modify or study the main starting criterion to improve the performance of starting element on the wind source.