Short circuit study of fixed speed wind turbines with STATCOM in distribution networks

The increased penetration of wind farm in distribution networks has brought changes in the performance of the whole system. Such disadvantages when connecting one of these distributed generation sources is reduced voltage and power stability of the AC network. This phenomena can cause the connected electricity consumers to suffer from disturbances. This paper investigates the use of a static synchronous compensator (STATCOM) to improve the short circuit current contribution in the network which will include balanced and unbalanced faults. The wind farm is equipped with fixed-speed wind turbines driving squirrel-cage induction generators. The IEEE 30-bus distribution test system is used to see the performance of the system under distribution level. Simulation studies are carried out in the DIgSILENT software

Improved BPSO for optimal PMU placement

Optimal phasor measurement unit (PMU) placement involves the process of minimizing the number of PMU needed while ensuring entire power system network completely observable. This paper presents the improved binary particle swarm (IBPSO) method that converges faster and also manage to maximize the measurement redundancy compared to the existing BPSO method. This method is applied to IEEE-30 bus system for the case of considering zero-injection bus and its effectiveness is verified by the simulation results done by using MATLAB software

Optimal allocation of FACTS devices in distribution networks using Imperialist Competitive Algorithm

Copyright © 2005-2015 Praise Worthy Prize. The publisher granted a permission to the author to archive this article in BURA.FACTS devices are used for controlling the voltage, stability, power flow and security of transmission lines. Imperialist Competitive is a recently developed optimization technique, used widely in power systems. This paper presents an approach to finding the optimal location and size of FACTS devices in a distribution network using the Imperialist Competitive technique. IEEE 30-bus system is used as a case study. The results show the advantages of the Imperialist Competitive technique over the conventional approaches. © 2013 Praise Worthy Prize S.r.l. - All rights reserved

Monitoring of power factor for induction machines using estimation techniques

Power factor is a significant element in power systems which is defined as the angle difference between voltages and currents that produces power fluctuation between sources and loads. Since, 40-50% of consumption of electrical power in industry is induction machines which are inductive loads, monitoring of the power factor is necessary in order to protect systems. To monitor the power factor on induction machines, it would require both voltage and current waveforms measurement in order to apply the displacement method which require equipments. In this paper, we present a mathematical method using Kriging to determine the operating power factor for an induction machine. Estimation of the operating power factor would be effectively implemented for under load detection and compensation for improving the power quality. Experimental results will be indicated to substantiate the feasibility of the proposed methods

Estimating power factor of induction motors using regression technique

Induction motors are one of the largest power consumption in electrical systems. Since induction motors are inductive loads, they produce a lot of power quality issue in the electrical systems. Solving the power quality problem, monitoring power factor of induction motors is important because at no load or light load condition power factor is low and consequently low power factor not only provide a penalty charge, but also generates a huge current and losses in the grid systems. To measure the power factor, zero crossing and instantaneous power methods can be used. Both methods require motor voltage and current waveforms at operating times. Those methods may have a huge cost in terms of requiring the motor to be out of service for connecting devices. In this research, regression analysis will be applied to estimate the power factor of induction motor at any loading condition. The results of the proposed method will be compared with the measured power factor of induction motor in order to substantiate the feasibility of the proposed method

Modelling of reduced GB transmission system in PSCAD/EMTDC

Energy and environmental issues are two of the greatest challenges facing the world today. In response to energy needs and environmental concerns, renewable energy technologies are now considered the future technologies of choice. Renewable energy is produced from natural sources that are clean and free; however, it is widely accepted that renewable energy is not a solution without challenges. An example of this can be seen in the UK, where there is much interest amongst generation developers in the construction of new large scale onshore and offshore wind farms, especially in Scotland. The stability of electric power systems is also an important issue. It is important to have full knowledge of the system and to be able to predict the behaviour under different situations is an important objective. As a result, several industrial grade power system simulator tools have been developed in order to estimate the behaviour of the electric power system under certain conditions. This paper presents a reduced Great Britain (GB) system model for stability analysis using PSCAD/EMTDC. The reduced model is based upon a future GB transmission system model and, hence, contains different types and mix of generation, HVDC transmission lines and additional interconnection. The model is based on the reduced DIgSILENT PowerFactory model developed by National Grid

A goal programming methodology for multiobjective optimization of distributed energy hubs operation

This paper addresses the problem of optimal energy flow management in multicarrier energy networks in the presence of interconnected energy hubs. The overall problem is here formalized by a nonlinear constrained multiobjective optimization problem and solved by a goal attainment based methodology. The application of this solution approach allows the analyst to identify the optimal operation state of the distributed energy hubs which ensures an effective and reliable operation of the multicarrier energy network in spite of large variations of load demands and energy prices. Simulation results obtained on the 30 bus IEEE test network are presented and discussed in order to demonstrate the significance and the validity of the proposed method

Electrical performance study of a large area multicrystalline silicon solar cell using a current shunt and a micropotentiometer

In this paper, a new technique using a Current Shunt and a Micropotentiometer has been used to study the electrical performance of a large area multicrystalline silicon solar cell at outdoor conditions. The electrical performance is mainly described by measuring both cell short circuit current and open circuit voltage. The measurements of this cell by using multimeters suffer from some problems because the cell has high current intensity with low output voltage. So, the solar cell short circuit current values are obtained by measuring the voltage developed across a known resistance Current Shunt. Samples of the obtained current values are accurately calibrated by using a Micropotentiometer (μpot) thermal element (TE) to validate this new measuring technique. Moreover, the solar cell open circuit voltage has been measured. Besides, the cell output power has been calculated and can be correlated with the measured incident radiation

Investigation of multi-phase tubular permanent magnet linear generator for wave energy converters

In this article, an investigation into different magnetization topologies for a long stator tubular permanent magnet linear generator is performed through a comparison based on the cogging force disturbance, the power output, and the cost of the raw materials of the machines. The results obtained from finite element analysis simulation are compared with an existing linear generator described in [1]. To ensure accurate results, the generator developed in [1] is built with 3D CAD and simulated using the finite-element method, and the obtained results are verified with the source.The PRIMaRE project

Vulnerability analysis of satellite-based synchronized smart grids monitoring systems

The large-scale deployment of wide-area monitoring systems could play a strategic role in supporting the evolution of traditional power systems toward smarter and self-healing grids. The correct operation of these synchronized monitoring systems requires a common and accurate timing reference usually provided by a satellite-based global positioning system. Although these satellites signals provide timing accuracy that easily exceeds the needs of the power industry, they are extremely vulnerable to radio frequency interference. Consequently, a comprehensive analysis aimed at identifying their potential vulnerabilities is of paramount importance for correct and safe wide-area monitoring system operation. Armed with such a vision, this article presents and discusses the results of an experimental analysis aimed at characterizing the vulnerability of global positioning system based wide-area monitoring systems to external interferences. The article outlines the potential strategies that could be adopted to protect global positioning system receivers from external cyber-attacks and proposes decentralized defense strategies based on self-organizing sensor networks aimed at assuring correct time synchronization in the presence of external attacks