M.M. Aman

Optimum Simultaneous DG and Capacitor Placement on the Basis of Minimization of Power Losses

and the results will also be discussed in detail.

Economic dispatch with valve point effect using iteration particle swarm optimization

Economic dispatch (ED) is one of the optimization problems in power system operation and planning. The practical ED problems have non-smooth cost functions with equality and inequality constraints. It becomes more complicated problem when valve point effects of generator are considered and results multiple local minima. This makes the ED problems are difficult to find global optimum solution when using any mathematical approach due to non-convex cost function. The Classical particle swarm optimization (PSO) has ability to reach near global optimum solution by tuning some parameters but always stuck at local minima. In this paper, an iteration particle swarm optimization (IPSO) is proposed to solve ED problems with valve point effects. The proposed algorithm is introduced a new parameter in the original velocity equation of PSO in order to enrich searching behaviour, solution quality and avoid being trapped at local minima. The proposed IPSO algorithm has been implemented on two test power systems (consisting 3 and 13 generating units) to validate its effectiveness. The simulation results confirmed that IPSO algorithm has better convergence characteristic and more robust compared to PSO and some published results.

Optimum multi DG units placement and sizing based on voltage stability index and PSO

Optimum DG placement and sizing is one of the current topics in restructured power system. Most of the authors have worked out on their optimum placement base on the power losses reduction concept. However, the improvement on power losses value in the network will not guarantee to the planner to have lower voltage stability index (VSI) for the system. This paper proposes a new approached for multi DG placement and sizing for distribution systems which is based on a voltage stability index. The most optimum DG size will be found out using several types of PSO optimization algorithm. The output results will also compared with EPSO, REPSO, and IPSO. The proposed algorithm is tested on 12-bus, modified 12-bus and 69-bus radial distribution networks.

Gravitational Search Algorithm and Selection Approach for Optimal Distribution Network Configuration Based on Daily Photovoltaic and Loading Variation

Network reconfiguration is an effective approach to reduce the power losses in distribution system. Recent studies have shown that the reconfiguration problem considering load profiles can give a significant improvement on the distribution network performance. This work proposes a novel method to determine the optimal daily configuration based on variable photovoltaic (PV) generation output and the load profile data. A good combination and coordination between these two varying data may give the lowest power loss in the system. Gravitational Search Algorithm (GSA) is applied to determine the optimum tie switches positions for 33-Bus distribution system. GSA based proposed method is also compared with Evolutionary Programming (EP) to examine the effectiveness of GSA algorithm. Obtained results show that the proposed optimal daily configuration method is able to improve the distribution network performance in term of its power loss reduction, number of switching minimization and voltage profile improvement.

Modeling and simulation of digital negative sequence relay for unbalanced protection of generator

Modeling tools are useful for educational and industrial use. Such tools help the new engineers to simulate the power system under normal and faulty conditions. This paper presents the design and various data conversion steps of a digital negative sequence relay. The digital relay has a superiority over electromechanical relay in terms of accuracy and speed. The detection of negative sequence current and appropriate action is useful for protection of power system components. The operation of relay should be fast and reliable for minimum outage of power system in case of abnormality or electrical fault. In this paper, the relay performance under different system dynamics is also visualized on MATLAB / SIMULINK® considering a 400V power system.

Modeling and simulation of reverse power relay for generator protection

Modeling tools are useful for basic understanding of power system, particularly for new engineers. Such tools help the new engineers to modulate the system under normal and faulty conditions. This paper presents the modeling and simulation of digital reverse power relay on MATLAB/Simulink®. Various data conversion steps in digitization of a signal are also discussed. In the past, electromechanical relays were commonly used, now such relays have been replaced with high accuracy and high speed digital relays. Fast operation of relay is desirable, particularly for such type of faults which could lead to system blackout. Digital relays offer other advantages also, in term of multiple variable settings and compact size. In this paper, the relay performance is tested on 11kV synchronous generator, connected with 220kV through a step up transformer.

High impedance fault localization in a distribution network using the discrete wavelet transform

Basic guidelines for the preparation of a technical work for the Locating the faulty section for High Impedance Fault (HIF) in a power system is a major challenge especially for a radial distribution network. This is due to the effect of the complexity of the distribution network such as branches; non-homogenous lines and high impedance fault that results in a variation of fault location. In this paper, analysis of fault location using the discrete wavelet transform based Multi-Resolution Analysis (MRA) and database approach is proposed. The three-phase voltage signal at the main substation to be analyzed was measured. The 1st, 2nd and 3rd level of detail coefficients were extracted for each phase and were used for the identification of faulty section using the proposed method. The simulation on a 38 nodes distribution network system in a national grid in Malaysia using PSCAD software was simulated. The proposed method has successfully determined the faulty section.

Optimal Daily Configuration of a Distribution Network Based on Photovoltaic Generation and System Loading Using Imperialist Competitive Algorithm and Selection Approach

This paper presents a new method to determine the best configuration for a distribution system for a day considering Photovoltaic (PV) generation and load profile. In the first part, the hourly optimal configuration for a day is obtained by using Imperialist Competitive Algorithm (ICA) and in second part; a selective approach based on minimum total daily power loss is used to select the optimal daily configuration. The proposed method is validated on IEEE 33 bus test system.

Combination of adaptive and intelligent load shedding techniques for distribution network

One of the challenge in islanding operation is to maintain frequency stability when generation is less than demand. This paper presents a new Under-Frequency Load shedding scheme for an islanded distribution network. The scheme is based on an adaptive and intelligent load shedding techniques. This proposed scheme is able to conserve power system collapse even for large disturbance and events in the system. The proposed scheme is evaluated through simulation in PSCAD/EMTDC software. A distribution network connected with mini-hydro generation in Malaysia is chosen for the test. Various test scenarios show the effectiveness of the proposed load shedding scheme to shed optimum load.

Fast stability achievement through fuzzy logic based non-linear excitation control of synchronous generator

Power System Controllers are most commonly used for stabilized operation of power system under different operating conditions. Different conventional controller exists for excitation control to maintain power system voltages, for synchronism and stability. Many controllers work satisfactorily under steady state conditions, but needed their fast action under transient conditions. In this paper the impact of fuzzy logic controller on system performance observed through non-linear excitation control of synchronous generator under transient condition. The results of fuzzy logic controller are also compared with the conventional controller (PID).