Calculate the impedance from one bus to all others

answered 2013-04-09 04:08:09 -0500

JervisW
1298 ●20 ●34 ●55

updated 2013-04-09 04:12:03 -0500

Picking up on the thread in your question, here is how I'd add load to a bunch of buses and measure the response at the slack bus:

electrical_distance = {}

buses = subsystem_info('bus', ["NUMBER", "TYPE", "AREA"])
buses_in_qld = filter(qld_only, buses)

for busno, type, area in buses_in_qld:

  # rolls back to original saved case on each for-loop iteration.
  with transaction():

    # add one MW load to this bus
    add_load_to(busno, {"pl": 1}) 

    # solve probably with fixed taps, shunts, fixed everything
    psspy.fnsl(**options)

    # difference at slack bus
    slack_diff = get_p(slack_busno) - original_slack 

    electrical_distance[busno] = slack_diff

I've tied some code up into helpful functions. You'd have to write add_load_to, define some options for fnsl and write a function get_p.

The transaction function has already been written: http://www.whit.com.au/blog/2011/09/turn-back-time-using-python-and-psse/

and subsystem_info has been written too: http://www.whit.com.au/blog/2011/08/designing-easier-subsystem-data/

Here is what I'd expect electrical_distance to look like after running through the buses:

{101: 1.10, 102: 1.14, 104: 1.15, ... }

It's just a dictionary listing the increase in slack MW due to your 1MW of load added.