Heuristic methods for solution of FACTS optimization problem in power systems

This paper presents a comprehensive review on various heuristic methods for solution of flexible AC transmission systems (FACTS) optimization problem in power systems. First, it classifies FACTS optimization methods into four main groups, then subdivides heuristic methods into different subsets and discusses thoroughly about characteristics, advantages and disadvantages of each heuristic subset. Finally, some hints for future researches on this area will be offered

Parameter selection in particle swarm optimisation: a survey

Nowadays, particle swarm optimisation (PSO) is one of the most commonly used optimisation techniques. However, PSO parameters significantly affect its computational behaviour. That is, while it exposes desirable computational behaviour with some settings, it does not behave so by some other settings, so the way for setting them is of high importance. This paper explains and discusses thoroughly about various existent strategies for setting PSO parameters, provides some hints for its parameter setting and presents some proposals for future research on this area. There exists no other paper in literature that discusses the setting process for all PSO parameters. Using the guidelines of this paper can be strongly useful for researchers in optimisation-related fields

Static power system security assessment via artificial neural network.

Maintaining system security is an important factor in the operation of a power system. The aim of this study is to evaluate the reliability using artificial neural network (ANN) in static security assessment to determine the security status of a power system. Feed Forward Back Propagation Neural Network is implemented to classify the security condition of IEEE 9 bus system. The input data of ANN are derived from offline Newton Raphson load flow analysis. The result obtained from the ANN method is compared with the Newton Raphson load flow analysis in terms of accuracy to predict the security level of IEEE 9 bus system and the computational time required by each method. The average time required by Newton- Raphson load flow analysis to evaluate security level of IEEE 9 bus system is 0.0481 seconds while the average time required by neural network is 0.0119 seconds. The accuracy of 13 hidden neurons feed forward back propagation neural network to predict the security level of IEEE 9 bus system is 98.57%. In conclusion, ANN is found to be reliable to evaluate the security level of IEEE 9 bus system

Voltage regulation of uninterrupted power supplies

Uninterrupted Power Supply (UPS) systems are used as one solution of power quality problems and to provide ultimate protection for power disturbances such as power blackouts and brownouts. Many UPS systems suffer from poor output voltage regulation especially with heavy loads. This work is aimed to design and implement the UPS hardware system capable of producing continuous and constant 230Vac, 50 Hz output supply. A feedback loop has been implemented using microcontroller to adjust the dc level supplying the UPS inverter. At the end of the hardware implementation, tests have been carried out to determine the reliability and effectiveness of the designed system, and a good results have been obtained in improving the voltage regulation

A comprehensive review on methods for solving FACTS optimization problem in power systems.

This paper presents a comprehensive review of various methods for solution of flexible AC transmission systems (FACTS) optimization problem in power systems. First, it explains the requirements of an ideal solution for FACTS optimization problem, then classifies the methods used by researchers in four main groups as classical methods, technical methods, heuristics and mixed methods, and discusses thoroughly about characteristics, advantages and disadvantages of each group of methods. Finally, according to the pros and cons of these methods, heuristic methods are determined as the most effective group of optimizers and also some hints are offered for future researches on this area

Effect of the non-standard lightning current and waveshape on lightning surge analysis

The withstand capability of the insulation system of an equipment under lightning overvoltages is measured by the international standard 1.2/50μ s waveform. Many workers and designers of the power apparatus equipment have dedicated their research tried to understand how the insulation behaves under the non-standard waveform. The fact that the lightning-caused transient voltage can have very fast components and the need for higher reliability and cost effectiveness have added the impetus in recent years to better understand the effects of a non-standard lightning voltage on the power system. As far as the lightning is concerned, much attention has been paid to the breakdown occurring at extremely fast rise times, which could be in nanosecond regime. This research provides some reviews on the non-standard waveform of the lightning and focuses on the simulation of the effect of the non-standard lightning current and waveshape on lightning surge analysis using the PSCAD/EMTDC software

Analysis of air humidity and temperature for post lightning circumstances

Lightning is a natural phenomenon that generates a high electric field during thunderstorm. It has been reported that lightning strikes amid storms can occur around 100 times per second. The atmospheric electric field is an imperative parameter during a thunderstorm. Therefore, monitoring the electric field and its parameters is the best way for local lightning forecast. The electric field monitoring data can validate the accuracy of weather prediction in a local area from meteorology department or by using equipment specially designed to measure this electric field that exists when the phenomenon of lightning occurs. In this paper, the relationship between lightning, air humidity and temperature is discussed to understand the post lightning effect on these electric parameters. Additionally, the characteristics of the parameters are observed and analysed

Top-oil temperature model for transformers based on nonlinear thermal resistance, lumped capacitance and thermal-electrical analogy

Top-Oil Temperature (TOT) is one of the basic components to estimate the Hot-Spot temperature (HST) of the transformers. This paper presents an alternative TOT model based on the heat transfer theory that utilises Nonlinear Thermal Resistance (NTR) and Lumped Capacitance (LC) approaches. It is applied in a thermal-electrical analogy and the heat transfer equivalent equation is determined. This model is tested on a measured TOT of 250 MVA ONAF and 400 MVA ONAF transformers obtained from IEC 60076-7 and previous research. A comparison of TOT is carried out with the existing models IEC 60076-7 exponential and IEEE Loading Guide clause 7 methods. It is found that the thermal model based on the NTR and LC approach could determine the measured TOT closer than the existing methods available in the standards

Investigation on the effect of moisture on AC breakdown voltage of refined, bleached, and deodorized palm oil

The effect of moisture on the AC breakdown voltage of palm oil was studied in this paper. The type of palm oil used in this study was Refined, Bleached and Deodorized Palm Oil (RBDPO) olein. RBDPO with different moisture contents were prepared by oven drying method. The AC breakdown voltage measurement was carried out based on ASTM D1816 at a gap distance of 1 mm. The AC breakdown voltage data were analyzed statistically by normal, lognormal and Weibull Cumulative Distribution Function (CDF). It is found that the AC breakdown voltage of RDBPO decreases almost exponentially as the moisture content increases. Weibull CDF can represent most of the AC breakdown voltage data of RBDPO at different moisture content

Optimal power demand curve: a case study in Universiti Putra Malaysia

The necessitation in the optimal power demand model, make it an impetus to present this work as a glaring path in determining the optimum power demand curve, using the available data of a substation. The data are used to find the equation and its coefficients of determination that can give the best-fit curve of the power demand of a substation, based on the available data. This will produce a model that can be validated by comparing the data and figured out the equation