Voltage collapse is a type of blackout-inducing
dynamic instability that occurs when the power demand exceeds
the maximum power that can be transferred through the
network. The traditional (preventive) approach to avoid voltage
collapse is based on ensuring that the network never reaches
its maximum capacity. However, such an approach leads to
inefficiencies as it prevents operators to fully utilize the network
resources and does not account for unprescribed events. To
overcome this limitation, this paper seeks to initiate the study
of voltage collapse stabilization.
More precisely, for a DC star network, we formulate the
problem of voltage stability as a dynamic problem where each
load seeks to achieve a constant power consumption by updating
its conductance as the voltage changes. We show that such a
system can be interpreted as a game, where each player (load)
seeks to myopically maximize their utility using a gradient-based
response.
Using this framework, we show that voltage collapse is the
unique Nash Equilibrium of the induced game and is caused
by the lack of cooperation between loads. Finally, we propose a
Voltage Collapse Stabilizer (VCS) controller that uses (flexible)
loads that are willing to cooperate and provides a fair allocation
of the curtailed demand. Our solution stabilizes voltage collapse
even in the presence of non-cooperative loads. Numerical
simulations validate several features of our controllers.
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Reactive Power Optimization for Flat Voltage Profiles in Distribution Networks
This paper considers achieving flat voltage profiles in
a distribution network based on reactive power optimization
(RPO) through voltage regulation devices (VRD). These devices
include capacitor banks, load-tap-changing and regulating
transformers, whose statuses can only assume pre-determined
integer value levels, making this a non-convex problem. Two
RPO-based algorithms are proposed, which can be applied to any
initial states, node priority, topology and load model types. The
first algorithm focuses on finding a practical solution by ensuring
the VRD constraints are observed at each step. The second one
focuses on finding the globally optimal solution by applying a
convex relaxation technique and solving the resulting problem
with the barrier interior point method. Here, the gradients are
computed numerically, thus requiring no analytical functions of
voltages in terms of VRDs. Numerical results and their analysis
are examined on two test networks: 1) single feeder; and 2)
network with laterals.
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- Award ID(s):
- 1710944
- NSF-PAR ID:
- 10163319
- Date Published:
- Journal Name:
- 2019 North American Power symposium
- Page Range / eLocation ID:
- 1 to 6
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/NAPS46351.2019.9000354
