Gaëtan Didier

A novel approach to determine the optimal location of SFCL in electric power grid to improve power system stability

This paper presents a novel approach to determine the optimal location of a resistive superconducting fault current limiter (SFCL) for enhancing the transient stability of an electric power grid (EPG). To select the optimal location of the SFCL, the sensitivity analysis of the angular separation of the rotors of synchronous machines present in the power system is introduced. The optimal location of the SFCL in EPG is coordinated with the corresponding optimal resistive value to improve transient stability and low-frequency oscillation damping performance of the system. It is shown that the SFCL can have different impacts (positive and negative) in function of its location in the EPG when a fault occurs. To evaluate the effectiveness of the proposed method, the IEEE benchmarked four-machine two-area test system is used to carry out several case studies. The results show that the optimal location of SFCL combined with its optimal resistive value reduces the angular separation of the rotors that improves effectively the system stability during a fault.

The remote surveillance device in monitoring and diagnosis of induction motor by using a PDA

The main goal of this paper is to propose a novel approach about remote diagnostic of induction motor by using a Personal Digital Assistant (PDA). For the updating information, a framework acquisition system has to be used. It includes both acquisition and data processing systems. Thus, information on the PDA can be updated thanks to a wireless via Bluetooth Local Area Network (LAN) access point. Consequently, this approach will exert some leverage to put a lot of care on monitoring and diagnosis on induction machines.

Power system stability improvement with superconducting fault current limiter

This paper presents a novel approach to determine the optimal location of a resistive superconducting fault current limiter (SFCL) to improve the transient stability of an electric power grid (EPG). The presented method use the angular separation of the rotors of synchronous machines present in the power system to select the optimal location of SFCL. The selection of this optimal location is coordinated with the corresponding optimal resistive value to improve transient stability in case of short-circuit fault. To obtain a global study on the optimal placement of SFCL in case of fault, various types of short-circuits are considered. To evaluate the effectiveness of the proposed method, the IEEE benchmarked four-machine two-area test system is used to carry out several case studies.

Increase of Stability Margin in Embedded DC Electric Grid With Superconducting Stabilizer

Embedded electric grids are constantly subject to problems of stability. Some responses can be done with the help of resistive superconducting fault current limiters. In this paper, we propose a new system named superconducting stabilizer (SS) in order to stabilize the dc grid. The SS uses the losses created by the ac and dc components of the current to increase the stability margin in dc electric grid. For dc electric grid, in stable state, only the dc current component exists. If the load increases beyond a threshold limit, the dc electric grid becomes unstable, and the current contains ac + dc components. The SS has very low losses in the superconducting state, and they can be considered as negligible in comparison with other losses in dc grid. In the case of the unstable state, the ac component of the current induces losses in the SS. It will be theoretically shown that increasing of the losses in the SS can stabilize the dc grid with efficiency. In this paper, the measurements of the critical current Ic and the ac + dc losses of SS are reported. A comparison between a short length tape, and two superconducting noninductive coils has been made. The tape used in the experiments is a DI-BSCCO tape. One noninductive coil is wounded on an aluminium plate and the other one, on a wooden plate. In the latter, the turns are free to move and also, better cooled by liquid nitrogen. Similar values of losses per meter have been measured for the three samples. The only and important observed difference is the maximal current, which leads to the transition of the noninductive coils. It can be explained by the cooling efficiency of the designed coils. These experimental results are useful to design SS in the future.