Power Technology
Newsletter Issue 96
October 2004
TURBO-CHARGING PSS/E™
Stephen F. Mauser
Assistant Vice President
stephen.mauser@shawgrp.com
Leonardo G. Lima
Executive Consultant
leonardo.lima@shawgrp.com
Ya-chi Lin
Consultant
ya-chi.lin@shawgrp.com
Dan Tarullo
Systems Administrator
dan.tarullo@shawgrp.com
Shaw PTI and Axceleon, Inc. have recently entered agreement to jointly develop and provide PSS/E™ in a
grid or blade computer environment, thus expediting PSS/E solutions when running multiple contingencies in
IDV, IPLAN, PSAS, or Python, or for parametric-driven studies.
Axceleon has developed EnFuzion, a software application that interfaces with PSS/E through a simple
scripting language to generate and dispatch multiple PSS/E cases across a grid or blade computer
environment. EnFuzion also tracks and manages the output files on the user’s machine.
For purposes of this discussion, a grid computer environment consists of a group of PCs on a common
network. The PCs can either be dedicated to the grid configuration, or they can be a group of existing PCs
that multi-function as a grid group. On the other hand, a blade computer configuration is generally thought of
as a rack-mount configuration of high-speed CPUs, interconnected with a high-speed network, that also
includes local hard drives and is specifically designed for high-speed parallel operation.
Using the features of EnFuzion and PSS/E’s automation (IDV, IPLAN, PSAS, and now, Python), the user sets
up and executes PSS/E and EnFuzion using their present desktop or laptop. Then EnFuzion takes control of
the PSS/E executions, dispersing the cases across the CPUs in the grid/blade. The total elapsed time for the
full set of PSS/E cases is reduced in proportion to the number of CPUs in the grid/blade system, and is also
reduced in proportion to the speed of the user’s CPU and the speed of the CPUs on the grid/blade system. To
the user, it appears as though PSS/E has been executed on their machine, but at greatly improved speeds.
The speed increases can be so great that Shaw PTI sees the new PV/QV analysis available in PSS/E (V30)
coupled with running PSS/E dynamics on a blade system making it possible to run the full PSS/E modeling
capability in the control center as the preferred Dynamic Security Assessment (DSA) tool. Our real-time data
transfer that develops a PSS/E case from the EMS State Estimator/Load Flow application, coupled with our
ability to control bus numbers and names from the EMS to the PSS/E case, allows the user to automatically
run PSS/E as a complete on-line DSA package. A major benefit from using PSS/E is the ability to use
PSS/E’s full dynamics model, rather than an equivalent or simplified dynamic model. Furthermore, the use of
Power Technology
October 2004
PSS/E and its automation provides much greater flexibility, without approximations, to initialize dynamics
cases based on proven model data.
Shaw PTI uses EnFuzion in-house in a hybrid configuration of five dedicated dual-processor PCs and eight of
our engineers’ dual-processor desktop PCs (26 total CPUs). EnFuzion, controlling a grid of shared CPUs
honors user priorities such that only un-used CPU time is allocated to the externally-driven computation,
making the use of the PC for the grid virtually transparent to the primary PC user.
Due to EnFuzion’s extremely low latency overhead, this configuration provides a speed improvement of 26
times if the user PCs are otherwise idle. Further, since only case setup is performed on the originating user’s
PC, the speed of this PC is not a significant factor in the running times of PSS/E using EnFuzion. In Shaw PTI
this means that an engineer with a laptop running on a 2 GHz CPU can take advantage of the 3.2 GHz grid
machines to achieve even greater improvements in turnaround times, even when the user is operating from
off-site to the Shaw PTI grid behind our firewall.
EnFuzion’s scripting capabilities and GUI-driven execution setup have been found to generally reduce the
required IDV or IPLAN code to achieve the same results. EnFuzion allows the user to replace numeric values
in IDV and IPLAN files with variables that are then managed by EnFuzion. To perform a parametric study,
such as a critical clearing time study for instance, the user replaces a numeric series of absolute clearing
times in the IDV file with a variable such as $CLR_TIME. Then using EnFuzion’s GUI, the user simply
specifies that EnFuzion is to generate PSS/E cases where $CLR_TIME begins at 2 cycles and proceeds in 1
cycle steps to 10 cycles. EnFuzion then immediately generates nine PSS/E dynamics cases and instructs
nine of the grid/blade CPUs to execute one PSS/E case each. When concluded, EnFuzion brings the output
back to the initiating machine’s hard drive. Consequently, to the user it appears that all of the PSS/E cases
were run on their local machine.
Shaw PTI and Axceleon generally propose a progression of steps from a demo to full implementation of
PSS/E and EnFuzion in a grid/blade architecture:
1. A demo installation of PSS/E and EnFuzion on up to 10 CPUs for a period of 30 days. This element
includes one day of installation, configuration, and training in EnFuzion.
2. Following the demonstration period, the demonstration license for EnFuzion is modified to provide the
user a perpetual license for up to 5 CPUs, and the number of PSS/E licenses reverts to the original
number of licenses prior to the demonstration.
3. Full implementation of PSS/E and EnFuzion on a grid or blade configuration. Shaw PTI also has an
agreement with Hewlett Packard whereby we can deliver all licenses and hardware in a turn-key
installation of PSS/E, EnFuzion, and the HP blade system.
Depending on circumstances, Corporate IT groups may not wish to run EnFuzion over the corporate network
in the long term. In this case, the demonstration (that may be run over the corporate network) is replaced with
either a self-contained grid or blade environment. Shaw PTI and Axceleon are prepared to design and deliver
into whichever configuration our clients require.
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