International Journal of Applied Power Engineering (IJAPE)
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PMU-Based Transmission Line Parameter Identification at China Southern Power Grid
Get PDFChina Southern Power Grid Company (CSG) recently developed and implemented an online PMU-based transmission line (TL) parameter identification system (TPIS). Traditionally, TL parameters are calculated based on transmission tower geometries, conductor dimension, estimates of line length, conductor sags, etc. These parameters only approximate the effect of conductor sag and ignore the dependence of impedance parameters on temperature variation. Recent development in PMU technology has made it possible to calculate TL parameters accurately. The challenges are that such application requires highly accurate PMU data while the accuracy of PMU measurements under different working/system conditions can be uncertain. With a large number of PMUs widely installed in its system, CSG plans to improve and update the EMS database using the newly developed TPIS. TPIS provides an innovative yet practical problem formulation and solution for TL parameter identification. In addition, it proposes a new metric that can be used to determine the credibility of the calculated parameters, which is missing in the literature. This paper discusses the methodologies, challenges, as well as implementation issues noticed during the development of TPIS
Combined Operation of SVC, PSS and Increasing Inertia of Machine for Power System Transient Stability Enhancement
Get PDFIn this paper improvement of transient stability by coordination of PSS (Power System Stabilizer) and SVC (Static var Compensator) and increasing inertia of synchronous machine has been observed. Because single method is not sufficient for improving stability. For this purpose a 9 bus multi machine system has been considered. Transient stability improvement has been tested subjected to three phase fault at bus 3 after 0.5 second and fault has been cleared after 1 second. By the use of PSS, SVC and by increasing inertia method for the test system the electromechanical oscillation for generator electrical power has been reduced and the steady state power transfer has been enhanced. In this paper the Inertia of the machine is not so much increased. Because after increasing inertia of the machine rotor will be havier.so that it is kept always within limit as considering its reliability and economy. And field voltage is also kept limite
Improving Light-Load Efficiency by Eliminating Interaction Effect in the Grid Connected Doubly-Fed Induction Generator
Get PDFA wind turbine equipped with doubly-fed induction generator (DFIG) is used in wind power plant industry. This paper studies the maximum power extraction of DFIG via evaluation of state-space equations in closed loop control condition for improving light-load efficiency. The DFIG state-space equations have been considered in the form of a multi-input- multi output (MIMO) system. Also, the tracing table has been used to determine the speed which the generated power will be proportional to the maximum load. The tracing table input is the generator speed, and its output is the optimum active power that has been considered as the reference power of the active power control system of the convertor. A controller is presented for the tracing table and the extracted power is able to follow the reference power with minimum ripple. Then, the results are compared with the single-input and single-output (SISO) case, for the values up to 0.2 times of the rated load. Therefore, in MIMO modeling, in the case that the DFIG connected to the grid, by eliminating the interaction effect, the efficiency in light-load can be increased
Assessment of Electric Field Distribution Inside 500/220 kV Open Distribution Substations During Working Conditions
Get PDFThe high level electric field intensity produced by high voltage (HV) equipments inside 500/220 kV substations is harmful for the human (staff) health. Therefore the minimum health and safety requirements regarding the exposure of workers to the risk arising from electric fields produced inside these substations is still considered as a competitive topic for utility designers, world health organization (WHO) and biomedical field researchers. It is very important to have knowledge about levels distribution of electric field intensity within these high voltage substations as early stage in the process of substation design. This paper presents results of investigation 50Hz electric field intensity distribution inside 500/220 kV power transmission substations in Cairo, Egypt. This paper presents a method for assessment the distribution of 50HZ electric field intensity distribution inside this substation, this method of analysis is based on the charge simulation technique (CSM). This study will serve for planning service works or for inspection of equipment on HV power transmission substations
Fuzzy Logic Controller Based Single Buck Boost Converter for Solar PV Cell
Get PDFThis paper deals with solar power production controlled by Fuzzy Logic Controller (FLC) and Single Input Buck-Boost (SIBB) converter. Since the solar energy is continuously varying, according to the irradiation the FLC generates control pulses to switch on the MOSFET device. To analyze the real time feasibility of this method, the system is simulated by using MATLAB/Simulink 2010a. A simulation model of the system is developed with solar Photovoltaic (PV) cell, FLC and SIBB in contradiction of the real world conditions. The results are presented and discussed in this paper
Load Flow Analysis for Process – Tank Loading Power Generation Networks Interconnection
Get PDFEstablishment of interconnection links between Process -Tank Loading electrical networks bring some advantages as there are excess capacity at Process which can be utilized in principle to feed Tank Loading. Some result of power system study will be as an input for operational purposes. Concerning Motor Starting Studies and Load Flow Studies and taking into account that the transformer is off load tap changing, the best tapping position for Isolation Transformer is at -5% (primary side). The best technical power generation configuration is proposed with configuration 2 (two) Process -TEG and 1 (one) Tank Loading-TEG running with 2 (two) interconnection, provided with appropriate load shedding system. Bare in mind that during smooth power transfer from each Process-TEG which requires 3 (three) Process-TEG running in parallel, there is an issue on kA capacity of Process switchgear. Existing setting of protection relay shall be reviewed according to the result of protection coordination stud
Modeling and Simulation of SVPWM Based Application
Get PDFRecent developments in power electronics and semiconductor technology have lead to widespread use of power electronic converters in the power electronic systems. A number of Pulse width modulation (PWM) schemes are used to obtain variable voltage and frequency supply from a three-phase voltage source inverter. Among the different PWM techniques proposed for voltage fed inverters, the sinusoidal PWM technique has been popularly accepted. But there is an increasing trend of using space vector PWM (SVPWM) because of their easier digital realization, reduced harmonics, reduced switching losses and better dc bus utilization. This project focuses on step by step development of SVPWM technique. Simulation results are obtained using MATLAB/Simulink software for effectiveness of the study
Hybrid Generation Power System for Domestic Applications
Get PDFThis work presents the plan and model of the control strategy for the interconnection of the hybrid energy system able to regulating this load’s voltage and controlling the energy generation with the energy options. The control strategy contains controlling the energy generated through each energy source, in a hierarchical mode using sliding/dropping mode control, while consuming consideration elements that have an impact on each electrical power source and transform the energy generated in order to suitable circumstances for lower power and domestic programs. The cross alternative energy system consists of photovoltaic cellular material, fuel cellular material and battery packs. A numerical equation in order to estimate the perfect voltage involving photovoltaic systems for virtually every solar irradiance and temperature circumstances is suggested. Simulations of a single or a lot more systems interconnected towards the load with the entire proposed control scheme, under different ecological and weight conditions, usually are introduced to indicate this efficiency with the procedure
Enhancing Photoelectric Conversion Efficiency of Solar Panel by Water Cooling
Get PDFPhotovoltaic solar cell generates electricity by receiving solar irradiance. The electrical efficiency of photovoltaic (PV) cell is adversely affected by the significant increase of cell operating temperature during absorption of solar radiation. This undesirable effect can be partially avoided by cooling the back side of the photovoltaic panel using water absorption sponge which was fixed on of PV panel and maintain wet condition by circulation of drop by drop water. The objective of the present work is to reduce the temperature of the solar cell in order to increase its electrical efficiency. Experiments were performed with and without water cooling. A linear trend between the efficiency and temperature was found. Without cooling, the temperature of the panel was high and solar cells were achieved an efficiency of 8–9%. However, when the panel was operated under water cooling condition, the temperature dropped maximally by 40C leading to an increase in efficiency of solar cells by 12%
Economic Load Dispatch for Multi-Generator Systems with Units Having Nonlinear and Discontinuous Cost Curves Using Gravity Search Algorithm
Get PDFEconomic Load Dispatch aims at distributing the load demand between various generation stations in a system such that the total cost of generation is minimum. This is of vital importance since it not only reduces the operation cost of the generation utility but also helps in conserving fast dwindling energy resources. Modern day power systems are large interconnected systems with a large number of generator units each having its own cost curve. Ideally the cost function of a unit is a quadratic function of the power generated by the unit and the cost curve obtained is a smooth parabola. But in practice cost curves deviate from the idealised one due the several reasons such as valve point effect, multi fuel operation, existence of forbidden zones etc. and as such may not be continuous or analytic. Also for a large interconnected system it becomes essential to consider the effect of transmission losses. Conventional numerical method based approaches work well with systems without losses but for large systems with losses obtaining convergence becomes difficult as the number of iterations required as well as the computational time are very high. These methods fail entirely if non ideal cost curves are considered. Hence soft computing based methods become essential. Here Gravity Search Algorithm(GSA) has been used to for finding economic load scheduling in a multi generator system, given a certain load demand, and taking into consideration the effects of practical constraints on the idealised load curve. The algorithms for finding the economic scheduling has been written in Matlab and has provided satisfactory results based on the given tolerance values. Also the traditional and soft computing based approaches have been compared to demonstrate the advantages of one over the other