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 endproduct
• Frequently asked questions and a troubleshooting guide will also accompany the endproduct
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 redispatch assignments
• 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
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
Manually load user inputs
Run algorithm
Output solution
Personnel Efforts
Financial Requirements
Personal Effort (hours)
Mark
Scheibe
192
Tien
Huynh
165
Item
W/O Labor
With Labor
Bound project plan
$
20.00
$
20.00
Poster
$
65.00
$
65.00
Labor at $10 per hour:
Bryan
Pauls
177
Input power transfer
distribution factors
Zakaria
Joundi
184
Block diagram of proposed program
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
Team Members
Bryan Pauls
EE
bpauls@iastate.edu
Zakaria Joundi
EE
zjoundi@iastate.edu
Mark Scheibe
EE
scheibe@iastate.edu
http://seniord.ee.iastate.edu/dec0503/
$1,650.00
Joundi, Zakaria
$1,840.00
Pauls, Bryan
$1,770.00
Scheibe, Mark
$1,920.00
Other Resources
None required
Total
$
85.00
$ 7,265.00
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.
Client
Tien Huynh
EE
tienbh@iastate.edu
Webpage
Huynh, Tien
Matt Mitchell
mmitchell@midamerican.com
Faculty Advisor
Professor Jim McCalley
jdm@iastate.edu
References:
Pictures from midamericanenergy.com and energyquest.ca.gov