Ghaeth Fandi

Comparative review of reactive power compensation technologies

The quality of electrical power in a network is a major concern which has to be examined with caution in order to achieve a reliable electrical power system network. Reactive power compensation is a means for realising the goal of a qualitative and reliable electrical power system. This paper made a comparative review of reactive power compensation technologies; the devices reviewed include Synchronous Condenser, Static Var Compensator (SVC) and Static Synchronous Compensator (STATCOM). These technologies were defined, critically examined and compared, the most promising technology is recommended for the realisation of an effective, efficient, sustainable, qualitative and reliable electrical power network.

FACTS devices influence on power losses in transmission systems

Since there are still higher efforts for transmission systems equipment utilization, more control mechanisms and devices are integrated to the systems and their dispatch centers and these will be also in future. FACTS devices purpose is preferably to maintain voltage levels and to control active and reactive power flows. Their implementation in the grid can result from the necessity to improve the system capabilities in a long-term period or to solve some extraordinary states. The paper deals with the implementation of shunt and series FACTS devices into electrical transmission systems and their influence on active power losses. There are provided comparison analyses of how different FACTS types have a potential to changes power losses in the system either in a negative or in a positive way. There are explained basic principles and the results are presented on the IEEE/CIGRE transmission system model.

Using renewable MV wind energy resource to supply reactive power in MV distribution network

This paper deals with the use of Medium Voltage (MV) renewable wind energy source to optimize reactive power in a distribution network, it describes the increase of power factor when the reactive power is controlled at a wind farm increase in power factor allows improvement in the stability of distribution networks, and the increase in power factor is used as new methodology to reduce power losses, Matlab/Simulink program is used to show the results of the analysis.

Advantageous positioning of wind turbine generating system in MV distribution network

This paper presents a new method for achieving voltage stability and reduction of power losses with renewable wind turbine generating system (WTGS) installed at different position on a Medium Voltage (MV) distribution system. The proposed network is a three-phase system consisting of 0.4 kV low voltage (LV) feeder with an active power (P) of 8 MW and a negative VAR (Qc) of 0.5 MV AR. And a 20 kV MV feeder with an active power (P) of 22 MW and a negative VAR (Qc) of 1.5 MV AR. The 0.4 kV and 20 kV feeders has varying positive VAR values of 2, 2.25, 2.5 and 6, 6.5, 7 MVARs respectively. Three sets of datas were observed; data 1, 2, and 3, the feeders are connected to a 20 kV MV distribution network, which is then linked to a 20 kV substation. Thereafter, a 20 kV MV renewable WTGS energy source with IGBT converters is integrated to the network for effective reactive power compensation. Three different Cases have been analyzed; First is the case with the proposed power system network analyzed without any WTGS attached to the network, in other words when the WTGS is switched off (this is designated as Case 1). Second is the situation with the WTGS positioned at the terminal end of the 20 kV MV distribution network (point 1, which is designated as Case 2) and Third is the situation when the position of the wind energy source is changed and stationed at the beginning of the terminal of the 20 kV MV power line (point 2, which is designated as Case 3). Matlab/Simulink software is used for the simulation of the system model. Simulation results for each of the case studies is analyzed and it is observed that research findings for Case 2 is more efficient in achieving improved voltage stability and power losses reduction in medium voltage electric-power distribution network.

Voltage regulation and power losses reduction in a wind farm integrated MV distribution network

Abstract A medium-voltage (MV) wind production system is proposed in this paper. The system applies a medium-voltage permanent magnet synchronous generator (PMSG) as well as MV interconnection and distribution networks. The simulation scheme of an existing commercial electric-power system (Case A) and a proposed wind farm with a gearless PMSG insulated gate bipolar transistor (IGBT) power electronics converter scheme (Case B) is compared. The analyses carried out in MATLAB/Simulink environment shows an enhanced voltage profile and reduced power losses, thus, efficiency in installed IGBT power electronics devices in the wind farm. The resulting wind energy transformation scheme is a simple and controllable medium voltage application since it is not restrained by the IGBT power electronics voltage source converter (VSC) arrangement. Active and reactive power control is made possible with the aid of the gearless PMSG IGBT power converters.

Optimal location of the synchronous condenser in electric-power system networks

In this paper, authors focus on the use of the synchronous condenser device for voltage stability and power flow control on a three-phase 33 kV Medium Voltage (MV) electric-power system network. Matlab/Simulink is used for the simulation of the proposed system model. To test the validity of the system, measured and calculated power factor values were obtained. Two scenarios were studied; Firstly, is the scenario with the synchronous condenser located at the terminal end of the 33 kV MV network (position 1). And secondly, is the scenario with the synchronous condenser placed at the beginning of the 33 kV MV power Line (position 2). Simulation results obtained from the study are compared in order to determine the most appropriate location for situating the synchronous condenser device. It is observed that the locations of the synchronous condenser equipment have different impacts on the electric-power system network. However, the proposed study of the simulation model base on the location of the synchronous condenser at the terminal end of the 33 kV MV electric-power system network (position 1) demonstrate a more effective and suitable scheme of the electric-power network concerning issues of voltage stability and power flow control.

Contribution to control strategies for converter connected to unbalanced grid

The paper deals with developed and experimentally tested effective synchronization and power control techniques for grid-connected converter. A new FLL (Frequency Locked Loop) technique is developed that incorporates advantages of both the cascaded delayed signal cancellation and dual second order generalized integrator schemes. Experimental results are evaluated in terms of quality of the positive voltage sequence, frequency and phase angle identification for the grid voltage disturbed by harmonic, subharmonic, and negative sequence components as well as for amplitude, frequency, and phase angle jumps in the voltage. A novel power control technique for grid-connected converter under unbalanced voltage conditions is referred as well. The current positive and negative sequences during grid voltage sags are controlled to assure a proper exchange of active and reactive powers without substantial power ripples, and especially, without current harmonics.

Cost implication and reactive power generating potential of the synchronous condenser

The objective of this study is to examine the cost implication and reactive power generating potential of the synchronous condenser. Universally, increase in electricity demand constitutes new issues for power generation, transmission and distribution. Synchronous condenser solutions are being initiated globally to be instrumental in the best usage of power resources and offer grid systems support for todays and future sustainable, stable and reliable electrical grid network. This research x-rays the cost implication of the synchronous condenser in todays challenging environment. A vivid description of the reactive power generating potential of the synchronous condenser is shown with Matlab/Simulink environment simulation of a medium voltage (MV) power system network. It is observed that the synchronous condenser is cost-effective as compared to other reactive power generating equipments and sources. Furthermore, Matlab/Simulink simulation results of the MV electric-power network shows an effective scheme for reactive power generation.

Distance protection based on Artificial Neural Networks

In this paper we present a new approach to determine the presence of fault in near-real time conditions and to determine the fault existence in the given line length based on the implementation of Artificial Neural Networks (ANNs) in the transmission lines, of an electrical power system.