jaseg/master-thesis
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

MA: small fixes, add simulation/modeling blurb

Browse source
This commit is contained in:
jaseg 2020-05-19 14:56:43 +02:00
parent 2d78c07d37
commit a92caf0e99
1 changed files with 26 additions and 16 deletions
Download patch file Download diff file Expand all files Collapse all files

42
ma/safety_reset.tex
View file

@ -310,20 +310,30 @@ that can consume a good fraction of a gigawatt all on their own.
\subsection{Operational concerns}
\subsubsection{Modelling the electrical grid}
% FIXME
\subsubsection{Generator controls}
% FIXME
Modelling performs an important role in the engineering of a reliable power infrastructure. The grid is a complex,
highly dynamic system. To maintain operational parameters such as voltage in various parts of the grid, grid frequency
and currents inside their specified ranges complex control systems are necessary. To design and parametrize such control
systems simulations are a valuable tool. Using model calculations the effects of control systems on operational
variables such as transmission efficiency or generation losses can be estimated. Model simulations can be used to
identify structural issues such as potential points of congestion. The same models can then be used to engineer
solutions to such issues, e.g.\ by simulating the effect of a new transmission line.
\subsubsection{Load shedding}
% FIXME
\subsubsection{System stability}
% FIXME
\subsubsection{Power System Stabilizers}
% FIXME
There are several aspects under which the grid or parts of the grid can be simulated. There are static analysis methods
such as modal analysis that yield information on electromechanical oscillations by computing the eigenvalues of a
large system of differential equations describing the collective behavior of all components of the grid. Modal analysis
is one example of simulations used in grid planning. Using modal analysis likely oscillatory modes can be identified and
ultimately these results can inform a decision to install additional stabilization systems in a particular location.
In contrast to static analysis, transient simulations calculate an approximation of the time-domain behavior of some
variable of interest under a given model. Transient simulations are used e.g.\ in the design of control systems.
Power flow equations describe the flow of electrical energy throughout the network from generator to load. Numerical
solutions these equations are used to optimize control parameters to increase overall efficiency.
% TODO decide what of this to keep.
% \subsubsection{Generator controls}
% \subsubsection{Load shedding}
% \subsubsection{System stability}
% \subsubsection{Power System Stabilizers}
\section{Smart meter technology}
@ -339,9 +349,9 @@ is automatically disconnected until they pay their bill are significantly aided
controlled and monitored remotely. A remotely controllable load switch can also be used to coerce customers in
situations where that was not previously economically possible\footnote{
The swiss association of electrical utility companies in sec.\ 7.2 par.\ (2)a of their 2010 whitepaper on the
introduction of smart metering\cite{vseaes01} cynically writes that remotely controllable load switches lead a new
tenant to swiftly register with the utility company. Mysteriously, this whitepaper completely vanished from their
website some time after publication. Luckily for us, the internet archive had a copy.
introduction of smart metering\cite{vseaes01} cynically writes that remotely controllable load switches ``lead a new
tenant to swiftly register'' with the utility company. This whitepaper completely vanished from their website some
time after publication, but the internet archive has a copy.
}.
To the customer the utility of a smart meter is largely limited to the convenience of being able to read it without
@ -1087,8 +1097,8 @@ hundreds of local systems each with autonomous goverance.
Despite the awesome complexity of large power grids the physics underlying their response to changes in load and
generation is surprisingly simple. Individual machines (loads and generators) can be approximated by a small number of
differential equations and the entire grid can be modelled by aggregating these approximations into a large system of
linear differential equations. Evaluating these systems it has been found that in large power grids small-signal
steady-state changes in generation/consumption power balance cause a linear change in
nonlinear differential equations. Evaluating these systems it has been found that in large power grids small-signal
steady-state changes in generation/consumption power balance cause an approximately linear change in
frequency\cite{kundur01,crastan03,entsoe02,entsoe04}. \emph{Small signal} here describes changes in power balance that
are small compared to overall grid power. \emph{Steady state} describes changes over a timeframe of multiple cycles as
opposed to transient events that only last a few milliseconds.