ECE 562 - Spring 2020

Project 4 - Due Feb 25

You may use any power flow software you wish. However, if you don't use MATPOWER, then make a note on your project report describing the software that you used (e.g., PTI's PSS/E version xx, attached C code, attached Excel spreadsheet). Use the Project 3 secure (no overload) ESCA 64 Bus Model. Note that branches 1,20,1 and 1,20,2 are identical, so you only need to monitor one, not both.

You will study the Available Transfer Capability (ATC) of an interface by increasing all of the Pgen in Area 1 or Area 3 (your choice) and increasing both Pload, Qload for all loads in Area 2. The load increase should be uniform (i.e., all PQ loads increase by the same percentage). Therefore, the PQ loads in Area 2 will be uniformly scaled by the same "load scaling factor" to mimic peak loading conditions.

Available Transfer Capability (ATC) based on base case dispatch

  1. You need to investigate the impact of a transfer from all of the generators in your Area. To mimic the peak loading conditions of the transfer, you first need to determine the relative contribution of each generator in your Area. This should be done by determining proportionality factors based on the initial Pgen output of each generator in your Area.
  2. The transfer will feed additional load in Area 2. You need to determine the relative contribution of each load bus in the total increase of Pload and Qload in Area 2. This should be done by determining proportionality factors based on the initial Pload demands of each load bus in Area 2.
  3. Use the Power Transfer Distribution Factors (PTDF's) and the proportionality factors from the previous two steps to calculate the Participation Factors for the branches in your Area (the "From Area") and the tie-lines between your Area and Area 2 (the "To Area"). You can ignore the branches within Area 2 as well as those connected to and within the remaining Area (i.e., you don't have to monitor them).
  4. Calculate the Available Loading Capacities (ALC's) for the branches you are monitoring.
  5. Calculate the individual ATC's for the branches that you are monitoring.
  6. Determine the system ATC and the critical element for the normal case transfer (i.e., all facilities in-service) based on the PTDF's.
  7. Solve a single power flow with the new PQ load values (any increase to a PQ load must retain the original PQ load power factor) and the new Pgen values that correspond to the maximum transfer point (i.e., the point at which a branch MVA limit is reached, hence the maximum transfer capability is reached). Ignore the generators' Pmax values.
  8. Compare the "monitored" branch MW flows from your PTDF calculations with the actual MVA branch flows from power flow. When computing the actual MVA branch flow, use the MVA flow at the "FROM END" of the branch.

Deliverables

  1. Submit a brief description of your ATC study (e.g., transfer direction, critical element, etc.).
  2. Submit the following tables for the "monitored branches" which list the from bus, to bus, base case MW and MVAR flows, the ParFac's, the ALC's, the iATC's, the estimated MW flows at the limit point, the actual MW and MVAR flows, the actual MVA flows, the "MW relative percentage error" defined by (MW estimate - actual MW)/MVA rating, and the "MVA relative percentage error" defined by (|MW estimate| - actual MVA)/MVA rating.
    1. Top 10 loaded branches based on actual MVA percentage loading
    2. Top 10 MW percentage loading prediction errors (ranked by magnitude of prediction error, but shown in table with sign of error)
    3. Top 10 MVA percentage loading prediction errors
    4. Any other ranking that illustrates an important point
  3. Submit formulas for the branch MW flow estimates. Include the dependence on the PTDF's.
  4. Analyze the accuracy of your ATC values with respect to the actual MVA flows. Did the distribution factors underestimate the ATC? Did they overestimate the ATC?
  5. Discuss the advantages/disadvantages of using distribution factors for ATC calculations.
  6. Propose solutions that would overcome the disadvantages of using distribution factors for ATC calculations. Be sure to mention any negative side-effects of your proposed solutions.
  7. All students must submit the code (MATLAB, C, Excel spreadsheet, etc.) they used to calculate the ATC values as a section within the report. Then, the report file must be submitted via SafeAssignment on Blackboard. Main Campus students also must submit a hardcopy report at the beginning of class.

Updated 3 Mar 2020