Robert Schlueter
Professor
-
- Department of Electrical and Computer Engineering
- Michigan State University
- East Lansing , Mi 48824
- Telephone: 517-355-5244
- Fax: 517353-1980
- Email address: Schluete@egr.msu.edu
Key Words:
voltage collapse,
security assessment,
stability
Research description:
A Voltage Stability Security Assessment and
Diagnosis, that performs contingency selection and can answer the
diagnostic questions of where, when, why, and what can be done to prevent
voltage stability, has been a primary focus of the research.
The program has three stages:
1) a breakup of the system into non-overlapping set of coherent bus groups
called voltage control areas. For each voltage control area, there is a
reactive reserve basin composed of the reactive resources on generators,
synchronous condensers, and FACTS that protect that voltage control area
from voltage instability. The voltage control area and its reactive
reserve basin form an agent that has a unique voltage instability problem.
The structure of the agent does not change but becomes more clearly
defined as the network undergoes stress and contingencies. It is proven
each agent, composed of the voltage control area and its reactive reserve
basin, has a unique loadflow jacobian eigenvalue that approaches zero as
the reactive reserve on its reactive reserve basin approaches zero;
2) a contingency search and ranking for the most severe single or multiple
contingencies that affect that agent. The contingency can be a
combination of an equipment outage, transaction combination or operation
change.The contingencies are ranked on either the percentage of reactive
reserves remaining in the agents' reactive reserve basin or the percentage
of voltage control areas in the agents' reactive reserve basin that still
have reactive reserves and still provide voltage control for the agent;
3) a diagnosis of the where (agent), why ( loss of voltage control in the
agent or clogging of reactive power flow to the agent), when
(contingencies that do not have a solution or have zero reactive reserves
in the agents' reactive reserve basin): proximity (using the proximity
measures for voltage instability in each agent mentioned above); and cure
(suggestion on how to obtain a loadflow solution or how to alleviate the
voltage instability even though a solution is obtained). The diagnosis for
any contingency is theoretically justified;
The above capabilities are being extended to identifying agents in a
differential algebraic model for each kind (saddle node, Hopf) and class
(inertial or flux decay dynamics of generators or induction motors),
performing contingency selection for each agent for each kind and class of
instability, and answering the diagnostic questions of where, when, why,
proximity, and cure for each equipment outageand transaction combination.
A bifurcation subsystem theory has been developed to establish the
theoretical foundation for this work. A bifurcation subsystem trajectory
sensitivity analysis has been developed to explain the cascading
bifurcations in a power system model. Cascading has been explained in a
loadflow and in a differential algebraic model.
The Open Access System Dispatch problem of determining the active power
dispatch and the voltage control, reactive resource and stabilization
control device dispatch that would correct voltage instability on any
stability agent, low voltage on any voltage agent, and thermal overload on
any thermal agent for all equipment outage and transaction combinations is
formulated . The optimization assures that correction of instability on
one agent does not produce it on any other agent. The corrective form of
the Open Access System Dispatch determines the transmission capacity
reduction due to a contingency and exactly compensates for it only when it
occurs.The protective form of the Open Access System Dispatch reduces
transmission capacity as stress and contingencies develop that threaten to
produce thermal overload,voltage limit violations or instability.
Lab Facilities:
The Power System Laboratory contains two new
workstations and two new printers. It contains the Power Technology
loadflow on each that is used in the research. It was the first lab to
obtain the PTI loadflow and only one of relatively few in the United
States with this program. It also contains the EPRI PSAPAC programs and
the Power System Toolbox.
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