You Can Download the DSA Software with the Username and Password Below

You Can Download the DSA Software with the Username and Password Below

Lecture31 – ECE504PS – Spring 2007

Goals of this lecture are to:

  1. Review HW
  2. Introduce expanded system
  3. More Nomograms
  4. Define “performance table” for our class
  5. HW assignment

Review HW

Our HW was to add damping criteria to Transaction Analysis and see how it would impact the interface “rating.” With “Transient Stability” selected as the only “Security Criterion”, the interface limit was 317 MW. With the default “Damping” also selected the as a security criterion the interface limit is reduced by 186 MW to 131 MW. (If the minimum damping criterion is set to 1%, then the interface limit is reduce 97MW to 220MW.

While looking at results summary, click “View” and select, “Transaction Analysis Details”

While looking at graphical results note arrows to left that expand graphs. Note that the graphs can be saved to a clipboard.

Note the ordinate changes from Bus voltage to Stability index in lower graph when going from basecase to transaction analysis. Upper graph is generator rotor angle in both examples.

Expanded system

Go to PSAT and look at 3 area system. Look at SLD and discuss interfaces and hoped need for a Nomogram (will tweak system if needed to get desired results).

Look at Bus table. Note different areas, and note 1 system swing bus

Look at Area table. Double click one line of table. Note net interchange and area swing buses.

Show example that demonstrates loop flow.

More Nomograms

Use overheads.

EE504pss performance table

For this class we’ll have a simplified performance table. At least for now, for the examples associated with this three area system for this class only:

  1. Assume no thermal limits
  2. Assume system is secure for any outages related to generation, step-up or step-down transformers (this limits us to only looking at contingencies associated with 230 lines and buses).

Level A contingencies:

  1. 3 phase faults with 5 cycle clearing
  2. 3 phase fault at 80% of line with primary and delayed clearing (5 and 20 cycles respectively)

Level A performance

  1. 0% Transient stability margin as defined by TSAT
  2. 1% damping (for modes between 0.2 and 2 hz & damping window of 5 s)
  3. No more than 20cycle dip below 80% of pre-fault voltage.
  4. No more than ? cycle dip below ? hz (want to check)

HW assignment

For review during Lecture 33: download ThreeArea TSAT case should be zipped with L31 package. You are looking to create a nomogram for the two paths from Area1 (to Area2 and Area3). Your goal is to make a first estimate of the corner points for your Nomogram.

First open powerflow in PSAT and note flow on path from Area1 to Area3 (this will be our abscissa – x-coordinate). Close PSAT Second, in TSAT, run basecase analysis to make sure everything is working. The click “Options” and select “computations.” Select tab, “Transaction.” Select Search For Transaction Limit For: Each Contingency (see figure on next page). Run transaction analysis. (Transaction Analysis will be increasing flow on path from Area1 to Area2 – our ordinate – y-axis). Look at result summary and record interface limit for each contingency

Next, open PSAT again and increase Area1 to Area 3 interchange (increase Area1 export by 200MW and increase Area2 import by 75MW). Note flow on path from Area 1 to Area3. Solve and save powerflow with a different name. Close PSAT. Repeat transient analysis and record new limit for each contingency. Sketch first draft of nomogram.

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