E.E. Abou Elzahab

Closure to “Optimal Protection Coordination for Meshed Distribution Systems With DG Using Dual Setting Directional Over-Current Relays”

In the presence of distributed generation (DG), it is important to assure a fast and reliable protection system for the distribution network to avoid unintentional DG disconnection during fault conditions. In this paper, dual setting directional over-current relays are proposed for protecting meshed distribution systems with DG. Dual setting relays are equipped with two inverse time-current characteristics whose settings will depend on the fault direction. The protection coordination problem for the dual setting directional relay is formulated as a nonlinear programming problem where the objective is to minimize the overall time of operation of relays during primary and backup operation. The proposed protection coordination scheme using dual setting relays is compared against the conventional approach, which relies on the conventional one setting directional relay. The proposed scheme is applied to the power distribution network of the IEEE 30-bus system equipped with synchronous and inverter-based DG. The results show that the proposed protection coordination scheme with dual setting relay can significantly reduce the overall relay operating time, making it an attractive option for distribution systems with DG.

A novel method for PID tuning using a modified biogeography-based optimization algorithm

Proportional integral derivative (PID) controller tuning is an area of interest for researchers. This paper presents a novel method for PID controller tuning using a modified biogeography-based optimization(MBBO) algorithm. Biogeography-based optimization (BBO) is a novel evolutionary algorithm that is based on the mathematical models of biogeography. Biogeography is the study of the geographical distribution of biological organisms. In the BBO model, problem solutions are represented as islands, and the sharing of features between solutions is represented as immigration and emigration between the islands. In this paper, a modified version of the BBO is proposed to improve its convergence. The MBBO algorithm is compared with the BBO using benchmarks functions. The proposed algorithm is applied to the problem of PID controller tuning and is compared with conventional biogeography-based optimization (BBO), and Particle swarm optimization (PSO).

On the Economic Selection of Capacitive Compensator Sizes in Nonsinusoidal Conditions

The selection of the optimal capacitor is a multiobjective op- timization problem. An approach to solving a multiobjective optimization problem is to transform it into a single objective problem. In this letter the use of the power factor and the efficiency as constraints is proposed be- cause power factor in distributions systems may be allowed within certain limits such as 0.85 and 1.0 and similarly for the efficiency. Keywords: Harmonics, power factor, power quality. Introduction: Reference (1) discussed the different criteria for the design of the compensating capacitor for the system shown in Figure 1, taking into consideration the skin effect (a) Maximizing the power factor,

Power factor and your electrical utility bill in Egypt

Beside being a good neighbor and not causing harmonic voltage for others that are connected to your electrical distribution circuit, complying with the legal requirements of IEEE standards 519, and maintaining safe and economical operating environments for electrical equipment within your physical load, there is another very good reason to maintain a good power factor: saving money on your electrical utility bill. Utilities often encourage consumers to maintain a high PF by applying tariff clauses, which penalize consumers for low PF. This letter discusses the topic.

Skin effect on optimal power factor

Optimization criteria are presented which allow proper calculation of optimal power factor. Optimization minimizes the line loss, maximizes the power factor and maximizes the efficiency, taking into consideration the skin effect. The performance of the obtained capacitor is discussed by means of a numerical example.

A novel method for type-2 fuzzy logic controller design using a modified biogeography-based optimization

In this paper we apply the modified biogeography-based Optimization (MBBO) to design type-2 fuzzy logic controller (T2FLC) to improve the performance of the plant control system. Biogeography-based optimization (BBO) is a novel evolutionary algorithm that is based on the mathematical models of biogeography. Biogeography is the study of the geographical distribution of biological organisms. In the BBO model, problem solutions are represented as islands, and the sharing of features between solutions is represented as immigration and emigration between the islands. A modified version of the BBO is applied to design the T2FLC to get the optimal parameters of the membership functions of the controller. We test the optimal T2FLC obtained by modified biogeography-based Optimization (MBBO) using benchmark plants and is compared with Particle swarm optimization (PSO).

Sizing of capacitors to optimize the power factor at non-sinusoidal frequencies

Abstract Optimization criteria are presented which allows proper calculation of optimal power factor. Optimization minimizes the line loss, maximizes the power factor and maximizes the efficiency taking into consideration the skin effect. The performance of the obtained capacitor is discussed by means of numerical example.

LC Compensation for Nonlinear Loads Taking Into Account Cost Constraints

An optimization method for the proper selection of the LC compensator values taking into account cost constraints is described for nonlinear loads. The solution will be obtained with an optimization algorithm based on the reduced gradient technique, which will locate maximum power factors by searching along the constant–cost power factor ridges for the point where the gradient of the transmission loss is zero. It is assumed that both the equivalent source and load are considered to generate harmonics. Also, it is assumed that the load harmonics are not sufficiently serious to suggest tuned filters, but when combined with source harmonics, the use of a pure capacitive compensator would degrade power factor and overload equipment. Consequently, a LC compensator is selected.

Effect of terminal capacitance on the supply current distortion factor

Abstract The effect of capacitance compensation of non-linear loads is considered on the displacement factor (DIPF), distortion factor (DISF), and power factor. Optimization of the DIPF is found to result in reduction of the DISF to a minimum value.