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Analysis and diagnostics of vibration in industrial systems play a significant rule to prevent severe damages. This paper proposes a non-linear model to simulate the torsional vibration in the reactor core cooling system. Simulation results of an operating reactor core cooling system set with the actual parameters are presented to validate the accuracy and reliability of the proposed analytical method...
In this paper, a protection system using a Multi-Agent concept for power distribution networks is proposed. Every digital over current relay (OCR) is developed as an agent by adding its own intelligence, self-tuning and communication ability. In order to cope with frequent changes in the network operation condition and faults, an OCR agent, suggested in this paper, is able to detect a fault or a change...
It is known that the protection system is one of the important parts of the power system. So one can say that it is the most important one. The protection system can be accepted if and only if it is efficient one and realize some requirements. The protection system must have high reliability, high selectivity, high speed and low cost. During the calculation of operation setting for different protection...
This paper presents a new expert system for fault diagnosis in power system. For this expert system, expertise is represented by propositional logic and it is converted into one Boolean function. By applying Quine-McCluskey tabular method, all Prim Implicants (PIs) of the function can be obtained automatically. The method estimates faulty sections using current state of protective relays by just checking...
This paper proposes a particle swarm optimization (PSO) method for solving the economic dispatch (ED) problem in power systems. Many nonlinear characteristics of the generator are considered for practical generator operation, such as ramp rates, prohibited operating zones, and non-smooth cost functions. The feasibility of the proposed method is demonstrated for two different systems, and is Compared...
This paper presents a new switching strategy controlling a new three-level voltage source inverter, resulting in different 25 space voltage-vectors. The new inverter combines some desirable features of two and three-level inverters. The proposed open-leg switching strategy (OLSS) intentionally opens one of the three inverter-legs per-time, in a pre-planned sequence. Thus, the number of allowed states...
A new scheme is used for applying FACTS controller in the distribution system to handle three-phase unbalanced loads is introduced. With back-propagation based Artificial Neural Network (ANN), FACTS controller in the form of Fixed Capacitor -Thyristor Controlled Reactor (FC-TCR) type is introduced to cancel negative and zero sequence line currents caused by the load to restore balanced operation....
A method is proposed in this paper for designing a series active harmonic filter which can eliminate voltage harmonic present in the busbar voltage by producing of a PWM controlled harmonic voltage. According to this method the active filter produces PWM voltage that cancels completely the existing harmonic voltage due to any harmonic voltage source up to any order. The proposed method is valid for...
Average-current-mode control allow better input current waveform; the inductor current is sensed and filtered by a current error amplifier whose output drives a Pulse-Width-Modulation (PWM) modulator. In this way the inner current loop tends to force the inductor current to follow the created reference current which is composed from the feedback voltage and the Root-Mean-Square (RMS) value of the...
Voltage sag may represent one of the major power quality problems. The abnormal operating conditions (such as heavily loading conditions, frequently starting of large induction motors and transmission system faults...) in electric system utility are considered the main reasons of voltage sag problem. In this paper, the various main reasons of voltage sag problem are studied on 4 bus system and 14...
The control of voltage and frequency of Diesel Generator (DG) is a challenging task. Fast control actions are required to tackle this problem. This paper presents a proposed technique to choose the best variable to control the whole system since the whole system is multi-input multi-output. A complete non linear model of DG system is developed for simulation study. The system performance of the open...
Using doubly fed induction generator (DFIG) for variable speed wind turbines has many advantages compared to other variable speed approaches. However, turbines with DFIG have complex operation principles and control. This paper describes the different steps for modeling and simulating the turbine behavior. Then simulation examples for studying the operation of controllers at different wind speeds...
Today's society depends heavily upon a high level of power system reliability. Accordingly, it is very important not only to avoid power failures, but also to restore power systems quickly and safely if these failures happen. In that sense, utilities arc becoming increasingly interested in developing computer aided restoration systems. This paper presents an intelligent techniques using artificial...
A detailed analysis of potential profile at a surface above energized unequally spaced grounding grid has been carried out, for soils with multiple layers. Exact and approximated algorithms are used to obtain the voltage profile and then to calculate the step and touch voltages. The analysis shows that the voltage distribution is highly dependent on soil structure type and characteristics and also...
A study and analysis of water tree phenomena in insulating materials was carried out on samples of XLPE. A model was prepared and simulation program was developed using the finite element technique to investigate the effect of different parameters. Alternating voltage was applied at room temperature, different needle tip angles were tried at different voltage levels. The relative permititivity of...
A lightning air terminal (LAT) tip can be damaged under prolonged period of service due to harsh environmental conditions among those is the impact of acid rain. The altered LAT tip profile will ultimately produce different corona discharge pattern which can influence the performance of the LAT itself. This paper presents a new closed loop mathematical modelling which can simulate the magnitude of...
This paper presents an advanced technique for current transformer saturation detection and compensation. The technique is based on the pre-fault current signal and the saturated-free portion after fault occurrence in order to calculate the effective unknown parameters of the transient secondary current. The proposed technique has attractive features include a high accuracy to determine power system...
This paper introduces a comparative study between conventional speed controllers of DC motor and an artificial intelligent speed controller showing the advantages of artificial intelligent controller over the conventional ones. All conventional controllers are implemented practically using a data acquisition card. Practical results are compared with simulation results for conventional controllers...
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