This paper presents the results of a comprehensive investigation of five blackouts that occurred on 28 August to 8 September 2011 due to bushing failures of the 132/33 kV, 125 MVA transformers at JBB Ali Grid station. The investigation aims to explore the root causes of the bushing failures and come up with recommendations that help in rectifying the problem and avoiding the reoccurrence of sim...

Power transformers being the major apparatus in a power system, thus the assessment of transformer operating condition and lifespan have obtained crucial significance in latest years. Dissolved gas analysis (DGA) is a sensitive and reliable technique for the detection of incipient fault condition within oil-immersed transformers, which provides the basis of diagnostic evaluation of equipment he...

Voltage stability (VS) has recently become a challenging issue in many distribution networks, especially in industrial areas. The distribution networks are generally reconfigured with a view of reducing the real power loss and offering a better voltage profile for the utilities. This paper presents a new reconfiguration algorithm that aims to enhance VS of distribution networks using biogeograp...

optimal reactive power dispatch (orpd) is a multi-variable problem with nonlinear constraints and continuous/discrete decision variables. due to the stochastic behavior of loads, the orpd requires a probabilistic mathematical model. in this paper, monte carlo simulation (mcs) is used for modeling of load uncertainties in the orpd problem. the problem is formulated as a nonlinear constrained mul...

Voltage stability has recently become a challenging issue in many power systems. The distribution systems are reconfigured with a view to reduce the system losses and offer a better voltage profile for the utilities. This paper presents a new fuzzy based reconfiguration algorithm that enhances voltage stability and improves the voltage profile besides minimising losses, without incurring any ad...

This paper presents solution of optimal power flow (OPF) problem of a power system via an Ant Colony Optimization Meta-heuristic method. The objective is to minimize the total fuel cost of thermal generating units and also conserve an acceptable system performance in terms of limits on generator real and reactive power outputs, bus voltages, shunt capacitors/reactors, transformers tap-setting a...

• A new OLTC transformer modeling technique is proposed. Taps are modelled as equivalent current sources. Power flow analysis significantly accelerated. Applicable to 3-wire medium voltage and 4-wire multigrounded low networks. This short communication presents a comprehensive model of on-load tap-changer (OLTC) transformers that connects (MV) with (LV) The proposed enables the inclusion MV net...

As an integral part of the Smart Grid, smart transformers both work independently to constantly regulate voltage and maintain contact with the smart grid in order to allow remote administration if needed and to provide information and feedback about the power supply and the transformers themselves. Through a process known as voltage optimization, a smart transformer provides the exact amount of...

Stray magnetic field is one of the main issues in design of transformers, since it causes non-ideal behavior of transformers. One of the techniques is usually adopted to mitigate the unwanted stray magnetic field is the use of auxiliary windings creating a magnetic field opposite to the incident one giving rise to the reduction of the total magnetic fields. This paper presents a new mathematica...