Comparison of Analytical and Heuristic Techniques for Multiobjective Optimization in Power System

1. Introduction

Industries are the back bone of the economic system of any country and these industries need uninterruptable supply to work properly. If this will not happen then production of the industries will be adversely affected. Traditionally energy to all the consumers is provided by centralized generating plants but as demand is increasing rapidly, these conventional methods of supplying electricity needs a revolutionary change. This motivated industries to install their own power plant to full fill their power requirements and if any excess amount of power is available at their ends then they can sell it to the grid also. These small size power plants, such as Solar Photovoltaic System, Solar thermal Power Plant, Wind Power Plant, Biomass etc. are generally considered as DG. There are several distributed generation technologies available in the market. Some of them are discussed as follows:

• 1.

  Solar Power Plants: In case of solar power plants solar energy is directly converted into the electrical energy. For this purpose different types of solar collectors are used for collecting the solar radiations. Generally flat plat collectors are used and the solar energy is collected on these collectors. The collectors are placed on the roof top or in the open area where solar light intensity is appropriate. Energy created by these solar cells, arranged in the array in collectors, is stored in batteries in form of DC. Then an inverter is used to convert this DC power in AC power. Output of the inverter can be connected to the load directly or this can be directly fed to the grid. These power plants are lower maintenance and long life because of absence of moving parts. Generally these types of power plants can be used for peak shaving mode of operation. Limitations associated with this technology are high installation cost, lower efficiency, higher area requirement and discontinuous availability of solar energy.

• 2.

  Wind Power Plants: In these types of distributed generations wind energy is converted in the electrical energy. Wind turbine is used for the conversion process. For harnessing the wind energy, a turbine with the blades is mounted on the top of a tower. Blades of the turbine rotated by the wind. This rotation of blades rotates the turbine also. Turbine is connected to the generator. The generator produces electrical energy. Wind power is available as free of cost. This is a process harnessing the renewable energy resources. These plants create zero environment pollution. Installation of these plants requires suitable site selection where availability of the wind is maximum. Power generation by these plants is intermittent in nature. These also produce noise pollution in the nearby areas.

• 3.

  Fuel Cell Technology: In Fuel Cell the electrical energy is generated from the electrochemical reaction and heat energy is generated at a byproduct of electrochemical reaction. Fuel cell consists of two electrodes submerged in the electrolytes. Out of these two electrodes one is positively charged (anode) and other is negatively charged (cathode). Electrically charges particles flow from one electrode to other electrode. A catalyst is used to enhance the reaction speed. Fuel which basically used in fuel cell is hydrogen. Oxygen is also required for oxidation purpose which is natural air generally. These can supply electrical energy indefinitely till the availability of the hydrogen and oxygen. In oxidation process hydrogen and oxygen atoms reacts together to form water and releases some electrons. These electrons flow through the outer circuit connected to the electrodes. A single fuel cell generates very small amount of DC power. Due to this reason several small stacks of fuel cells are connected in series and parallel manner to extract the required amount of power from the fuel cell. Several types of fuel cells are available as Proton exchange membrane Fuel Cell (PEMFC), Alkaline Fuel Cells (AFC), Molten Carbonate Fuel Cell (MCFC), Solid Oxide Fuel Cells (SOFC), Phosphoric Acid Fuel Cell (PAFC), and Direct Methanol Fuel Cells (DMFC).

Basic advantage of the fuel cell is pollution free production of electrical energy. Byproducts of the electrochemical reaction are also harm free. Operation of fuel cell is noise free and these do not require charging. Since there is no moving part hence zero frictional losses. These can be used as base load power plant.