Abdelaziz Chaghi

Considering the series compensation in optimal coordination of directional overcurrent protections using PSO technique

This paper presents an optimal coordination of inverse definite minimum time (IDMT) direction overcurrent relays (DOCR) in electrical networks considering the impact of the line series compensation (SC). The coordination problem is formulated as a non-linear constrained mono-objective optimization problem. The objective function of this optimization problem is the minimization of the total operation time of the associated relays in the power system, and the decision variables are: the time dial setting (TDS) and the pickup current setting (Ip) of each relay. To solve this complex non linear optimization problem, the Particle Swarm Optimization (PSO) is used. The original PSO algorithm is improved in order to handle the inequality constraints violation considering a penalty function. The proposed method is validated on 8-bus power transmission systems test systems considering various scenarios. The obtained results show a high efficiency of the proposed method to solve such complex optimization problem, in such a way the relays coordination is guaranteed for all simulation scenarios with minimum total operating time.

A Comparative Study of Ground Fault Analysis for a Practical Case of a Transmission Line Equipped with Different Series FACTS Devices

Due to the rising power demand and increasing population worldwide, electrical power networks have been extensively growing and striving to satisfy the escalating loads. This necessitates the need for using Flexible AC Transmission System (FACTS) devices which have become indispensable during normal and abnormal operating conditions. This paper investigates the impact of using series FACTS devices, namely Thyristor Controlled Series Capacitor (TCSC), GTO Controlled Series Capacitor (GCSC) and Thyristor Controlled Series Reactor (TCSR), on the impedance and power flow of a practical 400 kV transmission line in the Algerian power network. It also investigates the effect of varying the fault resistance on short-circuit calculations in the case of a phase to ground fault that occurs at the end of the compensated line. Analytical formulas of the employed FACTS devices, the system model under fault and short-circuit calculations are deduced and presented in the paper. Simulations results obtained using MATLAB are demonstrated for the compensated line and without compensation. These simulations are compared to show the effect of using these devices for the studied cases. It is concluded that GCSC provides better performance in the active and reactive power flow of the line under normal operating conditions and in reducing the fault current during abnormal operating conditions when the fault resistance increases. On the other hand, TCSR shows a better performance in maintaining higher voltages under fault with the increase of fault resistance.

Impact of Series FACTS Devices (GCSC, TCSC and TCSR) on Distance Protection Setting Zones in 400 kV Transmission Line

© 2013 Zellagui and Chaghi, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Impact of Series FACTS Devices (GCSC, TCSC and TCSR) on Distance Protection Setting Zones in 400 kV Transmission Line