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FSTPI is given an increasing interest especially in many industrial applications such as aeronautics, robotics, renewable energy conversion systems and automotive as far as cost-effectiveness is concerned. Nevertheless, This reduced structure inverter is sensitive to several faults. In order to perform diagnostic speed, and to avoid false alarms caused by speed and load fast variations, an improved method to diagnose open IGBT faults in FSTPI fed IM drives is proposed. This enhanced method is based on the information yielded from the current’s slope combined with those yielded from the normalized currents. The proposed diagnostic method is simple and just requires the current’s sensors avoiding the use of another hardware or extra sensors. This means that the implementation of this method and its integration into the control system become easier and consequently, the cost of the drive systems decreases. To rely better dynamic performance, the direct RFOC strategy is applied to control the speed of the IM fed by FSTPI. Simulation results, which are presented and commented, have proved the high performance, under distinct operating conditions, of the proposed diagnostic method in terms of fast fault detection associated with a high robustness against false alarms.

The penetration of photovoltaic (PV) system into the low-voltage distribution networks (LV-DNs) has become, in the few last years, a main international trend, encouraged by the sinking prices of PVs. However, this integration may impact the normal operation of the DNs in both beneficial and detrimental ways. In this context, this paper is an attempt in order to investigate the effects of the PV integration on the LV-DNs. This study has been carried out for a portion of a real LV-DN in the region of Sfax, Tunisia. Different scenarios of demand level and PV production are presented and carefully discussed so as to assess the technical impacts occurred by the PV systems integration. For the load-flow analysis, a Backward/Forward sweep algorithm was used.

This paper presents the methodology for design Takagi-Sugeno controller to mono-machine power system in order to study transient stability under severe perturbation. The nonlinear system is modeled and transformed on linear fuzzy model. Then, the design of Takagi-Sugeno regulator is derived from optimal control. The feedback gains are determined by linear quadratic instruction. This Technique is applied on test system. Important issues of transient stability and design are remarked.

This paper dealt with the optimal distribution network planning (DNP) under loads growth condition where the Particle Swarm Optimization with Constriction Factor (PSO-CF) was considered. This paper aimed at ensuring that the consumers' load demands which always increase with time can be satisfied in an optimum way by the distribution network reconfiguration (DNR). The planning problem was addressed as a mono-criterion one with reduced power losses cost objective. The radiality, voltages limits, and power balance constraints were taken into consideration in this study. So as to evaluate the active power losses, a load flow technique was carried out. The PSO-CF was tested on IEEE-10 bus. All simulation studies and results showed the algorithm efficiency and capability to fulfill good results.

In this paper, a methodology to find the optimal topology of an electric distribution network is presented. To find the spanning tree visiting all the nodes, the study is based on the optimization of a problem using two objective functions: the implantation cost and the active losses in the network lines taking into account a set of economic and functional constraints. The proposed method, for solving this problem, is based on the Genetic Algorithm (G.A) in order for finding the spanning trees visiting all the nodes. The load-flow problem is used to determinate the active losses in the network. The application of the optimization algorithm is executed on a test network included 10 nodes and 19 branches.

Generally, the soil is considered homogeneous. Whereas, in reality, is not the case. In fact, in this paper we assume that the soil is composed of two layers which have two different resistivities. And under these conditions, we try to know the behavior (electrical and frequency comportment) of an underground cable which is in this type of soil.

The Flexible AC transmission System (FACTS) devices, such as, thyristor controlled series compensators (TCSC) may be used to enhance system performance by controlling the power flows in the network. It is important to limit the number of TCSCs and to locate optimally these devices in the power system because of their considerable costs. Firstly, we have applied optimization technique, namely, NSGA-II, to find out the optimal number of multi-devices of TCSC in order to improve the system loadabilty, to reduce the installation cost of these series FACTS and to minimize the real power losses. Secondly, we perform a contingency analysis procedure based on severity index (SIl) to identify and classify the most severe line contingencies. Then, we determine the optimal placement and parameter setting of TCSCs in stressed power system by using the above optimization approach to alleviate the line overloads. In this paper, the optimization problem consists to reduce TCSCs installation cost and to decrease total real power losses. To demonstrate the effectiveness of the proposed approach, IEEE 30-bus test system has been studied.

The rate of dissipation of transient energy is usually used as a tool to measure dynamic system damping. This paper applies and discusses the above control strategy for suppressing undesirable electromechanical oscillations in power system with a STATic synchronous COMpensator (STATCOM), static synchronous series compensator (SSSC) and unified power flow controller (UPFC). A single machine infinite bus power system was studied over a several disturbance. The obtained results show the effectiveness and robustness of these devices on power system stability.