Senior Design Team Axum under sponsorship of Avista Corporation



Summary of the state of this project

Senior Design Team Axum under sponsorship of Avista Corporation is determining the Megawatt output capacity of the solar facility to be connected to Avista’s transmission network.  This connection will be at Lolo 230 kV substation, which is east of Lewiston, ID.

At the moment, our project is following the schedule according to the outline drawn at the beginning of the semester. However, there have been issues here and there. For example, there have been challenges in aligning our project with the expectations of the class. This is with regard to the last assignment of the month, which touched on technical specifications that created confusion due to the terms that we were using. This was sorted out by speaking to the professor in class. Another issue that has derailed our progress is a mistake in the PowerWorld software that we got assistance from our mentor. The problem is now corrected and we are back on track with our project.  Other useful resources that we have planned to use in a program that we enable us to determine transmission line costs. The costs will be based on materials, strength, and the length of the line. This information will be useful in the second part of the project as well as upgrading the grid.

Currently, we do not know the exact amount of power that can be injected into the grid at the 230kV level of the Lolo Substation. However, this is what our design mainly focuses on. Since this is, will be a large scale-solar facility the power output will be in megawatts. Part of reactive power capability will be in megavolt-ampere.  When the amount of power that can be safely injected into the grid system without upgrading the grid is known, then the next step will be to determine the amount of power that can be injected with a $100 million upgrade of the system. When one considers new 230kV transmission lines, the total cost will be around $1 million per mile of line. On the other hand, for 115kV transmission lines the cost is about $0.5 million for every mile of line. Moreover, the distance of transmission together with geographic area from bus to bus will be put into consideration. There is high probability that the report will recommend upgrading of more than one substations.  The cost for the upgrade is estimated to range from $10 to $20 million.

PowerWorld Simulator will be our primary means of analysis since this software can simulate high voltage power systems through the use of highly effective power ow analysis. To represent the seasonal load changes, a model of complete Avista transmission system will be under two scenarios. The load ow analysis has be done using alpha prototype that has been chosen from multiple interconnection designs. The aspects of interconnection plan that have been examined include cost and protection schemes.  In the future, contingency and transient analysis will be performed.

Currently, our goals are to become well adept with PowerWorld . This will be achieved using tutorials after which we will begin to work on the case file of Avista’s grid.  We have achieved a great deal of this goal. Another objective is that we aim to research on costs of equipment and parts of the grid upgrades that we want to achieve.  This goal like the first is in progress since some members are already in the process of researching costs.