220kv地區(qū)變電所電氣一次初步設計劉沛然

220kv地區(qū)變電所電氣一次初步設計劉沛然,220kv地區(qū)變電所電氣一次初步設計,劉沛然,kv,地區(qū),變電所,電氣,一次,初步設計 1 Abstract This paper summarises the technical issues need to be considered when designing a hybrid renewable energy system This paper presents results of a study conducted on the technical aspects of a power supply system in which wind power and solar PV energy are combined with hydrogen fuel cell Although the power sources in this system are of intermittent nature but because an energy storage technology hydrogen is incorporated into the system the negative effects of intermittency would be minimal This paper also presents the results of a computer simulation developed for modelling the entire power generation and storage system This program allows us i to find a near ideal size of system s components and ii to predict the system s performance I INTRODUCTION he power system in this study consists of a solar photovoltaic PV array wind turbine and proton exchange membrane PEM fuel cell FC These components have very different characteristics But when they are engineered properly they can work together to generate power in a sustainable and reliable way The solar PV energy and wind power complement each other in the sense that in summer more sun light is expected while less wind is available and in winter less sun is expected while more wind is available Hence solar and wind together can supply to some extend relatively constant power However because of the intermittency nature of these two sources the power will not be delivered to load at a constant rate so there always would be excess or deficit in balance of electric power In the case of positive balance the excess electricity is converted to hydrogen in an electrolyzer and when the electricity balance is negative then the fuel cell will supply the deficits II ESCRIPTION OF THE SYSTEM UNDER INVESTIGATION The hybrid system proposed in this study follows the general concept considered for any hybrid power station Manuscript received September 19 2007 Ahmed Zahedi is with the Solar Energy Research Group SERG Monash University Victoria Australia ahmad zahedi eng monash edu au which is shown in Figure 1 The main components of this system are solar array wind turbine fuel cell electrolyzer and controller The electrical energy produced by the solar array height at which the wind data were collected is 10m Radius 30m RHO 1 225 kg m3 number of wind turbines 1 height of wind turbine is 60m roughness factor is 0 15 Simulation results are shown in Figure 10 to 18 Electricity is supplied to a community comprising 50 households consuming in average 20kWh per day so the total electricity demand in average would be 1 MWh per day or 365 MWh per year Size of PV array and wind turbines is determined based on the assumption that each of these two units is able to produce more than 50 of the electricity demand 3 IV INTERMITTENCY ISSUES Intermittent power sources are sources of energy that may be variable or intermittent such as wind and solar The variable nature of power generation from intermittent sources has raised concerns about the ability of electricity grids to absorb intermittent power and the economic implications However by integration of energy storage technology using of intermittent power sources has little effect on grid operations The negative effects of intermittency have to be considered in the economics of power generation There are known methods to manage variability of power supply increases the total cost of wind energy production especially at high levels of penetration The intermittency of wind power seldom creates problems when using wind power at low to moderate penetration level or if combined with another intermittent type of source of energy such as solar V ENERGY STORAGE One potential means of increasing the penetration level of wind energy To predict the performance of he energy flow To determine the amount of electricity produced by each power generator To determine the amount of electricity supplied to local load To determine the excess or deficit of electric power To determine the H2 production monthly The electrolyzer is run under the following circumstances 1 When the power available for the electrolyzer is equal to or within the operation range of the rated power and the tank is not full 2 When the power available to the electrolyzer is greater than the rated power and the tank is not full the electrolyzer is run at full capacity and the excess power is dumped If the tank is full the power available to the electrolyzer is dumped The dumped energy could be used in other facilities as water heating or water pumping but this is not discussed in this paper The simulation results have been shown in Figures 4 to 11 To simplify calculations for the time being we have assumed that the electricity is produced for 75 households each consuming 15 kWh per day and this consumption remains constant during the whole year 4 Water tank H2O Electrolyser Hydrogen H2 DC Bus DC power from Solar design and use the new World Publishing 1998 Australia 6 Zahedi A Energy Concerns and Possibilities Academia Press Australia 1997 7 US Department of Energy Website http www eere energy gov consumerinfo heatcool htm l 8 Electricity Australia 2003 published by Electricity Supply Association of Australia Limited ESAA website au 9 Gilbert M Masters Renewable and Efficient Electric Power Systems Wiley and Interscience 2004 10 Website of the International Energy Agency http www iea org 11 Global Wind Energy Council