Abstract

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Project Requirements • Design Objectives • Must output the most economical dispatch solution by supplying which generators should increase or decrease their power output and the cost of the change • Must obtain the solution within five minutes of the detected overload • Functional Requirements • The solution must be the most economical solution available based on economic dispatch analysis using linear programming • The program must supply the solution within five minutes of the detected overload, consisting of data acquisition, algorithm computations, and display of the final dispatch solution • The program must allow for manual input of the generation shift factors in matrix form • Design Constraints • The program solves for a 20,000 bus/50 generator system • Need 100% accuracy for generator redispatchassignments • There is a 5% tolerance for the amount of power increased and decreased during redispatch • The software shall utilize Microsoft Excel as the interface • Measurable Milestones • Understand the problem as defined to the team by MidAmerican Energy • Design the algorithm upon which the program will be based • Implement the algorithm developed and test it based on a small scale system model • Test the algorithm on the full scale system as given to the team by MidAmerican Energy • Give the end-product to the client for use Output solution Manually load user inputs Run algorithm Input power transfer distribution factors Faculty Advisor Professor Jim McCalley jdm@iastate.edu Corrective Actions for Relieving Overloads in a Transmission System Dec05-03 Abstract Due to a change in demand, high voltage transmission circuits can become overloaded. Overloads are resolved by the dispatch of power based on hand calculations performed by a reliability coordinator. The project team will develop a software application that receives data from a power network and recommends a change for the network to control overloads in an economically minded manner. Optimal results will allow for power to be dispatched at the lowest cost to the client while protecting the network from overloaded transmission lines. Introduction • Problem Statement • General Problem Statement • The MidAmerican reliability coordinator currently adjusts generator levels to fix overloaded transmission circuits and does not look at the economic impact of these shifts in generation. • General Problem Solution • Create a program to identify the most economically attractive shift in generation that will relieve the overloaded circuits. • Operating Environment • Inside a climate controlled working environment at MidAmerican Energy • User • MidAmerican Energy reliability coordinator • Uses • Determine most economical redispatch of generation to correct the overloaded transmission circuits • Help economically dispatch generators during non-overload situations • Assumptions • MidAmerican will supply previous network data to help design and test the algorithm • Network data shall include the eastern interconnection of 20,000 buses • Incremental heat rate curves shall be piece-wise linear • Limitations • Software shall use Microsoft Excel as the interface • MidAmerican generators shall only be considered when shifting generation • Power transfer distribution factors (PTDF’s) can be manually inputted into the program in matrix form • Expected End-Product • The end-product shall function within Microsoft Excel • Documentation shall accompany the end-product to provide an explanation of how to use and maintain the software • PowerPoint presentation to demonstrate how to properly enter data and run the end- product • Frequently asked questions and a troubleshooting guide will also accompany the end-product Resources and Schedule Project Schedule Gantt Chart Proposed Approach • Proposed Approach • Research optimization and economic dispatch • Create algorithm to compute the chosen method of optimization • Test algorithm • Technologies Considered • Visual Basic Application programming language for software application • Microsoft Excel (required by the client) • MatLab for mathematical modeling • Testing Considerations • Unit testing – test each fundamental block of the algorithm • Integration testing – units will be tested as they are integrated together • System tests – show the overall functionality of system and conformity to the client’s specifications • Client test – on-site testing of the program by the customer Personnel Efforts Financial Requirements Block diagram of proposed program Other Resources None required Closing Summary The project team will develop a software application that provides the most economic dispatch of power to correct for overloaded high voltage transmission circuits. A program will be written that utilizes Microsoft Excel as its interface and will output which generating units to increase or decrease power output from. MidAmerican Energy will benefit from this project by receiving the least expensive combination of generator output power modifications in order to maintain system reliability. Team Members Client Tien Huynh EE tienbh@iastate.edu Zakaria Joundi EE zjoundi@iastate.edu Bryan Pauls EE bpauls@iastate.edu Mark Scheibe EE scheibe@iastate.edu Matt Mitchell mmitchell@midamerican.com Webpage http://seniord.ee.iastate.edu/dec0503/ References: Pictures from midamericanenergy.com and energyquest.ca.gov