An investigation on AC loss reduction for permanent-magnet wind power generator with superconducting windings

High temperature superconducting (HTS) tapes could be introduced into large scale wind power generators in order to improve the power density. However, the alternating current (AC) loss of HTS tapes will cause the reduction of efficiency. On the basis of analytical and numerical model calculations, this paper presents an optimal design of the HTS armature winding aiming at lower AC loss. The main contribution of this work is that the relationship between the installation parameters and the AC loss of such HTS armature windings has been figured out based on the analysis of the shape feature of the HTS tape and the external magnetic field. When the tape is placed along a particular direction where the perpendicular component of external magnetic field has the lowest amplitude, the AC loss is the smallest. The modified installation location and angle are found based on the proposed generator. These results are verified using finite element method (FEM).

A multi-agent-based for fault location in distribution networks with wind power generator

The integration of distributed generation (DG) units such as wind power into the distribution network are one of the most viable technique to meet the energy demand increases. But, the integration of these DG units into power systems can change the dynamic performances of the systems and create new challenges that are necessary to be taken care of in the operation of the network. The fault location and diagnosis are the most significant technical challenges that can improve power systems’ reliability and stability. In this paper, a Multi-Agent System (MAS) based on current amplitude and current direction measured proposed for fault location, isolation, and power restoration in a smart distribution system with the presence of a wind power generator. The agents can communicate and collaborate to locate the faulted line, then send trips signal to corresponding circuit breakers accordingly. The simulation results show the performance of the proposed techniques.

An Equivalent Rotor Speed Compensation Control of PMSG-Based Wind Turbines for Frequency Support in Islanded Microgrids

Frequency regulation is a critical issue in the islanded microgrids, especially the integration of high penetration of the wind power generator. In order to provide inertial and primary frequency support to the wind power system, this article proposes an equivalent rotor speed compensation control scheme of PMSG for frequency support in the islanded microgrids. A new variable combining pitch angle and rotor speed is defined as the equivalent rotor speed. The equivalent rotor speed versus de-loaded power curve is designed to preserve a part of active power among the whole wind speed area. And the inertia control scheme is optimized by adding a virtual compensation variable to the equivalent rotor speed to obtain the reference of the machine-side converter control loop. Adopting the proposed scheme, the PMSG-based wind turbine can achieve a similar frequency regulation performance to synchronous generators. Simulation results demonstrate the feasibility and effectiveness of the proposed control scheme.