Compress paper into strict 10 pg limit
This commit is contained in:
jaseg
parent
713564b829
commit
319d4a7f9c
3 changed files with 123 additions and 125 deletions
Binary file not shown.
|
|
@ -2,12 +2,12 @@
|
|||
<!-- Created with Inkscape (http://www.inkscape.org/) -->
|
||||
|
||||
<svg
|
||||
width="73.642357mm"
|
||||
height="64.569092mm"
|
||||
viewBox="0 0 73.642357 64.569092"
|
||||
width="131.0421mm"
|
||||
height="21.495766mm"
|
||||
viewBox="0 0 131.0421 21.495766"
|
||||
version="1.1"
|
||||
id="svg5"
|
||||
inkscape:version="1.1 (c4e8f9ed74, 2021-05-24)"
|
||||
inkscape:version="1.2.1 (9c6d41e410, 2022-07-14, custom)"
|
||||
sodipodi:docname="flowchart.svg"
|
||||
xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
|
||||
xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
|
||||
|
|
@ -29,15 +29,15 @@
|
|||
inkscape:object-paths="true"
|
||||
inkscape:snap-smooth-nodes="true"
|
||||
inkscape:snap-global="false"
|
||||
inkscape:zoom="3.0574005"
|
||||
inkscape:cx="150.12754"
|
||||
inkscape:cy="162.5564"
|
||||
inkscape:window-width="2173"
|
||||
inkscape:window-height="1573"
|
||||
inkscape:window-x="2485"
|
||||
inkscape:window-y="245"
|
||||
inkscape:window-maximized="0"
|
||||
inkscape:current-layer="layer2"
|
||||
inkscape:zoom="4.3238173"
|
||||
inkscape:cx="171.60762"
|
||||
inkscape:cy="22.896435"
|
||||
inkscape:window-width="3840"
|
||||
inkscape:window-height="2091"
|
||||
inkscape:window-x="0"
|
||||
inkscape:window-y="0"
|
||||
inkscape:window-maximized="1"
|
||||
inkscape:current-layer="layer1"
|
||||
showguides="false"
|
||||
fit-margin-top="3"
|
||||
fit-margin-left="3"
|
||||
|
|
@ -46,7 +46,9 @@
|
|||
showborder="true"
|
||||
units="mm"
|
||||
lock-margins="true"
|
||||
borderlayer="true" />
|
||||
borderlayer="true"
|
||||
inkscape:showpageshadow="2"
|
||||
inkscape:deskcolor="#d1d1d1" />
|
||||
<defs
|
||||
id="defs2">
|
||||
<rect
|
||||
|
|
@ -84,17 +86,17 @@
|
|||
inkscape:label="Layer 1"
|
||||
inkscape:groupmode="layer"
|
||||
id="layer1"
|
||||
transform="translate(-15.310265,-14.455001)">
|
||||
transform="translate(-16.855997,-22.893207)">
|
||||
<rect
|
||||
style="fill:#ffffff;fill-opacity:1;stroke:none;stroke-width:0.499999;stroke-linecap:round;stroke-linejoin:bevel;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1;stop-color:#000000"
|
||||
id="rect9475"
|
||||
width="91.448166"
|
||||
width="150.64792"
|
||||
height="82.638519"
|
||||
x="5.2928662"
|
||||
x="5.2928667"
|
||||
y="7.8876767" />
|
||||
<g
|
||||
id="g8024"
|
||||
transform="translate(49.567338,-3.9821704)">
|
||||
transform="translate(126.13798,-33.292455)">
|
||||
<path
|
||||
id="use7208"
|
||||
style="fill:#000000;fill-opacity:1;stroke:none;stroke-width:0.297093;stroke-linecap:round;stroke-linejoin:bevel;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1;stop-color:#000000"
|
||||
|
|
@ -122,7 +124,7 @@
|
|||
</g>
|
||||
<g
|
||||
id="g2866"
|
||||
transform="translate(5.6025171,2.5388793)">
|
||||
transform="translate(3.2776964,11.150229)">
|
||||
<rect
|
||||
style="fill:#000000;stroke:none;stroke-width:0.132292;stop-color:#000000"
|
||||
id="rect846"
|
||||
|
|
@ -397,7 +399,7 @@
|
|||
</g>
|
||||
<g
|
||||
id="g4557"
|
||||
transform="translate(1.7320415)">
|
||||
transform="translate(-3.158304,5.4382063)">
|
||||
<path
|
||||
id="path2901"
|
||||
style="fill:none;stroke:#000000;stroke-width:0.264583px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
|
||||
|
|
@ -436,7 +438,7 @@
|
|||
</g>
|
||||
<g
|
||||
id="g4557-2"
|
||||
transform="translate(14.766767,8.8851365)">
|
||||
transform="translate(10.22469,7.8001723)">
|
||||
<path
|
||||
id="path2901-8"
|
||||
style="fill:none;stroke:#000000;stroke-width:0.264583px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
|
||||
|
|
@ -475,7 +477,7 @@
|
|||
</g>
|
||||
<g
|
||||
id="g2203"
|
||||
transform="translate(1.3449329,-0.86064309)">
|
||||
transform="translate(-3.1118099,-1.7943002)">
|
||||
<rect
|
||||
style="fill:#000000;stroke:none;stroke-width:0.7;stroke-linecap:round;stroke-linejoin:bevel;stroke-miterlimit:4;stroke-dasharray:none;stop-color:#000000"
|
||||
id="rect4581"
|
||||
|
|
@ -769,7 +771,7 @@
|
|||
</g>
|
||||
<g
|
||||
id="g5542"
|
||||
transform="matrix(0.44387819,0,0,0.44387819,28.028396,19.994804)">
|
||||
transform="matrix(0.44387819,0,0,0.44387819,74.113674,6.1034872)">
|
||||
<g
|
||||
id="g3526">
|
||||
<path
|
||||
|
|
@ -866,12 +868,12 @@
|
|||
y="0"
|
||||
xlink:href="#g5542"
|
||||
id="use5544"
|
||||
transform="translate(-17.260891,6.4288113)"
|
||||
transform="translate(16.011582,4.7541556)"
|
||||
width="100%"
|
||||
height="100%" />
|
||||
<g
|
||||
id="g6078"
|
||||
transform="translate(27.098966,-13.723158)">
|
||||
transform="translate(107.10903,-48.591882)">
|
||||
<rect
|
||||
style="fill:#000000;fill-opacity:1;stroke:none;stroke-width:0.37892;stroke-linecap:round;stroke-linejoin:bevel;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1;stop-color:#000000"
|
||||
id="rect5854"
|
||||
|
|
@ -917,7 +919,8 @@
|
|||
</g>
|
||||
<g
|
||||
id="g7086"
|
||||
transform="translate(-26.40076,-23.564466)">
|
||||
transform="translate(-26.40076,-23.564466)"
|
||||
style="display:inline">
|
||||
<rect
|
||||
style="fill:#000000;fill-opacity:1;stroke:none;stroke-width:0.461378;stroke-linecap:round;stroke-linejoin:bevel;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1;stop-color:#000000"
|
||||
id="rect6696"
|
||||
|
|
@ -951,15 +954,15 @@
|
|||
inkscape:groupmode="layer"
|
||||
id="layer2"
|
||||
inkscape:label="Layer 2"
|
||||
style="display:inline;mix-blend-mode:screen"
|
||||
transform="translate(-15.310265,-14.455001)">
|
||||
style="display:inline;mix-blend-mode:screen;stroke-width:0.748484"
|
||||
transform="matrix(1.7849846,0,0,1,-26.152629,-22.893207)">
|
||||
<rect
|
||||
style="fill:#586276;fill-opacity:1;stroke:none;stroke-width:0.499999;stroke-linecap:round;stroke-linejoin:bevel;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1;stop-color:#000000"
|
||||
style="fill:#586276;fill-opacity:1;stroke:none;stroke-width:0.374241;stroke-linecap:round;stroke-linejoin:bevel;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1;stop-color:#000000"
|
||||
id="rect9371"
|
||||
width="78.648399"
|
||||
height="71.852043"
|
||||
x="13.421401"
|
||||
y="9.7267618"
|
||||
x="11.66457"
|
||||
y="10.166819"
|
||||
rx="0"
|
||||
ry="0" />
|
||||
</g>
|
||||
|
|
@ -967,25 +970,26 @@
|
|||
inkscape:groupmode="layer"
|
||||
id="layer3"
|
||||
inkscape:label="Layer 3"
|
||||
transform="translate(-15.310265,-14.455001)">
|
||||
transform="translate(-16.855997,-22.893207)"
|
||||
style="display:inline">
|
||||
<path
|
||||
style="fill:#ffcc00;stroke:none;stroke-width:0.151801px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
|
||||
d="m 41.385234,22.583392 0.36463,0.904354 -0.688353,0.961359 5.126828,-0.281048 -1.198089,6.25764 5.155654,-0.545247 -1.173413,1.277768 2.857932,-1.187651 -1.971426,-1.830066 0.26229,1.289957 -4.125094,0.128922 1.625597,-6.403604 z"
|
||||
d="m 36.169805,24.463614 0.36463,0.904354 -0.688353,0.961359 5.126828,-0.281048 -1.198089,6.25764 5.155654,-0.545247 -1.173413,1.277768 2.857932,-1.187651 -1.971426,-1.830066 0.26229,1.289957 -4.125094,0.128922 1.625597,-6.403604 z"
|
||||
id="path2410"
|
||||
sodipodi:nodetypes="ccccccccccccc" />
|
||||
<path
|
||||
style="fill:none;stroke:#cc0000;stroke-width:0.5;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1"
|
||||
d="m 58.914011,38.722204 c -2.370898,5.284044 -5.847495,7.731514 -11.383219,4.896464"
|
||||
d="m 84.144745,30.222721 c -2.370898,5.284044 -5.847495,7.731514 -11.383219,4.896464"
|
||||
id="path8441"
|
||||
sodipodi:nodetypes="cc" />
|
||||
<path
|
||||
style="fill:none;stroke:#cc0000;stroke-width:0.5;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1"
|
||||
d="m 38.075454,43.756421 c -4.177135,5.326658 -12.781728,6.762675 -17.200153,6.383813"
|
||||
d="m 100.5363,34.018516 c -2.216593,1.669715 -5.570142,-1.53889 -7.02099,-4.65777"
|
||||
id="path8443"
|
||||
sodipodi:nodetypes="cc" />
|
||||
<path
|
||||
style="fill:none;stroke:#cc0000;stroke-width:0.5;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1"
|
||||
d="m 30.551411,49.738753 c 1.086688,6.828773 4.127792,10.263383 7.281748,12.062812"
|
||||
d="m 109.72726,33.670576 c 2.965,0.830277 4.8719,-0.500685 6.17312,-3.388186"
|
||||
id="path8445"
|
||||
sodipodi:nodetypes="cc" />
|
||||
</g>
|
||||
|
|
@ -993,10 +997,11 @@
|
|||
inkscape:groupmode="layer"
|
||||
id="layer4"
|
||||
inkscape:label="Layer 4"
|
||||
transform="translate(-15.310265,-14.455001)">
|
||||
transform="translate(-16.855997,-22.893207)"
|
||||
style="display:inline">
|
||||
<g
|
||||
id="g15403"
|
||||
transform="translate(2.6052425,14.343918)">
|
||||
transform="translate(1.1509747,14.257149)">
|
||||
<circle
|
||||
style="fill:#ffffff;fill-opacity:1;stroke:#000000;stroke-width:0.653;stroke-linecap:round;stroke-linejoin:bevel;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1;stop-color:#000000"
|
||||
id="path10092"
|
||||
|
|
@ -1010,13 +1015,13 @@
|
|||
style="font-size:26.6667px;line-height:1.25;font-family:sans-serif;white-space:pre;shape-inside:url(#rect10866)"><tspan
|
||||
x="-28.917969"
|
||||
y="56.477896"
|
||||
id="tspan18143"><tspan
|
||||
id="tspan787"><tspan
|
||||
style="font-family:Bahnschrift;-inkscape-font-specification:Bahnschrift"
|
||||
id="tspan18141">1</tspan></tspan></text>
|
||||
id="tspan785">1</tspan></tspan></text>
|
||||
</g>
|
||||
<g
|
||||
id="g15411"
|
||||
transform="translate(23.735495,12.857313)">
|
||||
transform="translate(25.206735,20.345215)">
|
||||
<circle
|
||||
style="fill:#ffffff;fill-opacity:1;stroke:#000000;stroke-width:0.653;stroke-linecap:round;stroke-linejoin:bevel;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1;stop-color:#000000"
|
||||
id="circle15405"
|
||||
|
|
@ -1030,13 +1035,13 @@
|
|||
style="font-size:26.6667px;line-height:1.25;font-family:sans-serif;white-space:pre;shape-inside:url(#rect15413)"><tspan
|
||||
x="-28.917969"
|
||||
y="56.477896"
|
||||
id="tspan18147"><tspan
|
||||
id="tspan791"><tspan
|
||||
style="font-family:Bahnschrift;-inkscape-font-specification:Bahnschrift"
|
||||
id="tspan18145">2</tspan></tspan></text>
|
||||
id="tspan789">2</tspan></tspan></text>
|
||||
</g>
|
||||
<g
|
||||
id="g15411-5"
|
||||
transform="translate(46.239689,16.01096)">
|
||||
transform="translate(45.006286,14.134323)">
|
||||
<circle
|
||||
style="fill:#ffffff;fill-opacity:1;stroke:#000000;stroke-width:0.653;stroke-linecap:round;stroke-linejoin:bevel;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1;stop-color:#000000"
|
||||
id="circle15405-5"
|
||||
|
|
@ -1050,13 +1055,13 @@
|
|||
style="font-size:26.6667px;line-height:1.25;font-family:sans-serif;white-space:pre;shape-inside:url(#rect15413-1)"><tspan
|
||||
x="-28.917969"
|
||||
y="56.477896"
|
||||
id="tspan18151"><tspan
|
||||
id="tspan795"><tspan
|
||||
style="font-family:Bahnschrift;-inkscape-font-specification:Bahnschrift"
|
||||
id="tspan18149">3</tspan></tspan></text>
|
||||
id="tspan793">3</tspan></tspan></text>
|
||||
</g>
|
||||
<g
|
||||
id="g15411-6"
|
||||
transform="translate(12.280177,27.882868)">
|
||||
transform="translate(78.977383,22.001498)">
|
||||
<circle
|
||||
style="fill:#ffffff;fill-opacity:1;stroke:#000000;stroke-width:0.653;stroke-linecap:round;stroke-linejoin:bevel;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1;stop-color:#000000"
|
||||
id="circle15405-56"
|
||||
|
|
@ -1070,13 +1075,13 @@
|
|||
style="font-size:26.6667px;line-height:1.25;font-family:sans-serif;white-space:pre;shape-inside:url(#rect15413-7)"><tspan
|
||||
x="-28.917969"
|
||||
y="56.477896"
|
||||
id="tspan18155"><tspan
|
||||
id="tspan799"><tspan
|
||||
style="font-family:Bahnschrift;-inkscape-font-specification:Bahnschrift"
|
||||
id="tspan18153">4</tspan></tspan></text>
|
||||
id="tspan797">4</tspan></tspan></text>
|
||||
</g>
|
||||
<g
|
||||
id="g15411-7"
|
||||
transform="translate(30.411115,42.721095)">
|
||||
transform="translate(113.31251,7.4801985)">
|
||||
<circle
|
||||
style="fill:#ffffff;fill-opacity:1;stroke:#000000;stroke-width:0.653;stroke-linecap:round;stroke-linejoin:bevel;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1;stop-color:#000000"
|
||||
id="circle15405-4"
|
||||
|
|
@ -1090,9 +1095,9 @@
|
|||
style="font-size:26.6667px;line-height:1.25;font-family:sans-serif;white-space:pre;shape-inside:url(#rect15413-3)"><tspan
|
||||
x="-28.917969"
|
||||
y="56.477896"
|
||||
id="tspan18159"><tspan
|
||||
id="tspan803"><tspan
|
||||
style="font-family:Bahnschrift;-inkscape-font-specification:Bahnschrift"
|
||||
id="tspan18157">5</tspan></tspan></text>
|
||||
id="tspan801">5</tspan></tspan></text>
|
||||
</g>
|
||||
</g>
|
||||
</svg>
|
||||
|
|
|
|||
|
Before Width: | Height: | Size: 43 KiB After Width: | Height: | Size: 43 KiB |
|
|
@ -50,7 +50,7 @@ Conference}{December 5--9}{Austin, TX, USA}
|
|||
\city{Tel Aviv}
|
||||
\country{Israel}
|
||||
}
|
||||
\email{lirankat@tau.ac.il}
|
||||
\email{lirankatzir@tau.ac.il}
|
||||
|
||||
\author{Björn Scheuermann}
|
||||
\affiliation{
|
||||
|
|
@ -196,7 +196,7 @@ modifications.
|
|||
|
||||
\begin{figure}
|
||||
\centering
|
||||
\includegraphics[width=0.4\textwidth]{flowchart}
|
||||
\includegraphics[width=0.45\textwidth]{flowchart}
|
||||
\caption{Structural overview of our concept. 1 - Government authority or utility operations center. 2 - Emergency
|
||||
radio link. 3 - Aluminium smelter. 4 - Electrical grid. 5 - Target smart meter.}
|
||||
\Description{A schematic overview of the safety reset system with its parts represented by icons. A signal is sent
|
||||
|
|
@ -394,8 +394,6 @@ communication for smart meter reading~\cite{ec03,rs48,gungor01,agf16}.
|
|||
\section{Related work}
|
||||
\label{sec_related_work}
|
||||
|
||||
\subsection{IoT and Smart Grid security}
|
||||
|
||||
The security of IoT devices as well as the smart grid has received extensive attention in the
|
||||
literature~\cite{nbck+19,acsc20,smp18,ykll17,anderson01,anderson02,zlmz+21,kgma21,hcb19,mpdm+10,lzlw+20,chl20,lam21,olkd20,yomu+20}.
|
||||
The challenges of IoT device security and the security of smart meters and other smart grid devices are similar because
|
||||
|
|
@ -612,30 +610,29 @@ distance between anode and cathode. In this setup, power can be electronically
|
|||
Since the system does not have any mechanical inertia, high modulation rates are possible.
|
||||
|
||||
In~\cite{depree01}, the authors describe a setup where a large Aluminium smelter in continental Europe is used as
|
||||
primary control reserve for frequency regulation. In this setup, a rise time of $\SI{15}{\second}$ was achieved to meet
|
||||
the $\SI{30}{\second}$ requirement posed by local standards for primary control. In their conclusion, the authors note
|
||||
that for their system, an effective thermal energy storage capacity of $\SI{7.7}{\giga\watt\hour}$ is possible if all
|
||||
plants of a single operator are used. Given the maximum modulation depth of $\SI{100}{\percent}$ for up to one hour that
|
||||
is mentioned by the authors, this results in an effective modulation power of $\SI{7.7}{\giga\watt}$. Over a longer
|
||||
time span of $\SI{48}{\hour}$, they have demonstrated a $\SI{33}{\percent}$ modulation depth which would correspond to a
|
||||
modulation power of $\SI{2.5}{\giga\watt}$. We conclude that a modulation of part of an aluminium smelter's power
|
||||
consumption is possible at no significant production impact and at low infrastructure cost. Aluminium smelters are
|
||||
already connected to the grid in a way that they do not pose a danger to other nearby consumers when they turn off or on
|
||||
parts of the plant, as this is commonplace during routine maintenance activities.
|
||||
primary control reserve for frequency regulation. Their system achieved a rise time of $\SI{15}{\second}$, meeting the
|
||||
local $\SI{30}{\second}$ requirement for primary control. The authors calculated that their system can provide an
|
||||
equivalent thermal energy storage capacity of $\SI{7.7}{\giga\watt\hour}$ using all plants of a single operator. At the
|
||||
maximum modulation depth of $\SI{100}{\percent}$ for up to one hour that the paper cites, the resulting effective
|
||||
modulation power is $\SI{7.7}{\giga\watt}$. Over a longer time span of $\SI{48}{\hour}$, they have demonstrated a
|
||||
$\SI{33}{\percent}$ modulation depth which would correspond to a modulation power of $\SI{2.5}{\giga\watt}$. The
|
||||
experiment from~\cite{depree01} shows that a modulation of part of an aluminium smelter's power consumption is possible
|
||||
at no significant production impact and at low infrastructure cost. Aluminium smelters are already connected to the grid
|
||||
in a way that they do not pose a danger to other nearby consumers when they turn off or on parts of the plant, as this
|
||||
is commonplace during routine maintenance activities.
|
||||
|
||||
\subsection{The operational model of a GFM-based safety reset}
|
||||
\subsection{Operating a GFM safety reset}
|
||||
|
||||
While a single large Aluminium smelter could conceivably provide sufficient modulation power to cover the entire
|
||||
continental European synchronous area, we have to consider operation during a black start, when the grid temporarily
|
||||
divides into a number of disconnected power islands. A single transmitter would only be able to reach receivers on the
|
||||
same power island.
|
||||
|
||||
To alleviate this constraint, the system can use a number of transmitters that are distributed throughout the network.
|
||||
Piggy-backing transmitters on existing industrial loads keeps the implementation cost of additional transmitters low. By
|
||||
running transmitters from stable, synchronized frequency standards such as gps-disciplined rubidium standards,
|
||||
transmissions can be precisely synchronized across power islands even after a holdover period of several days. This
|
||||
allows a transmission to continue uninterrupted while the utility rejoins power island into the larger grid, since the
|
||||
transmissions on both islands are precisely synchronized.
|
||||
To alleviate this constraint, a number of smaller transmitters throughout the network can be synchronized to act in
|
||||
unison. Using existing industrial loads keeps the implementation cost of additional transmitters low. GPS-disciplined
|
||||
frequency standards can keep transmissions synchronized across power islands even after a holdover period of several
|
||||
days. When the utility rejoins power islands into the larger grid, the synchronized transmissions will constructively
|
||||
interfere.
|
||||
|
||||
As illustrated in Figure~\ref{fig_intro_flowchart}, the transmitters are connected to a command center. For this
|
||||
connection, a redundant set of long-range radio or satellite links can be used, as well as wired connections through the
|
||||
|
|
@ -709,7 +706,7 @@ durations move our signals' bandwidth into the lower-noise region from $\SI{0.2}
|
|||
|
||||
\begin{figure}
|
||||
\centering
|
||||
\includegraphics[width=0.45\textwidth]{../notebooks/fig_out/dsss_gold_nbits_overview}
|
||||
\includegraphics[width=0.3\textwidth]{../notebooks/fig_out/dsss_gold_nbits_overview}
|
||||
\caption{Symbol Error Rate as a function of modulation amplitude for Gold sequences of several lengths.}
|
||||
\Description{A plot of symbol error rate versus amplitude in millihertz. The plot shows four lines, one each for 5
|
||||
bit, 6 bit, 7 bit and 8 bit. All four lines form smooth step functions, plateauing at a symbol error rate of 1.0 for
|
||||
|
|
@ -765,7 +762,7 @@ durations move our signals' bandwidth into the lower-noise region from $\SI{0.2}
|
|||
\label{fig_ser_chip}
|
||||
\end{figure}
|
||||
|
||||
\subsection{Parameterizing a proof-of-concept ``Safety Reset'' System Based on GFM}
|
||||
\subsection{Parameterizing a PoC GFM ``Safety Reset''}
|
||||
|
||||
%FIXME introduce scenario
|
||||
Taking these modulation parameters as a starting point, we proceeded to create a proof-of-concept smart meter emergency
|
||||
|
|
@ -832,7 +829,7 @@ without triggering them to reset.
|
|||
|
||||
\begin{figure}
|
||||
\centering
|
||||
\includegraphics[width=0.45\textwidth]{prototype.jpg}
|
||||
\includegraphics[width=0.35\textwidth]{prototype.jpg}
|
||||
\caption{The completed prototype setup. The board on the left is the safety reset microcontroller. It is connected
|
||||
to the smart meter in the middle through an adapter board. The top left contains a USB hub with debug interfaces to
|
||||
the reset microcontroller. The cables on the bottom left are the debug USB cable and the \SI{3.5}{\milli\meter}
|
||||
|
|
@ -854,6 +851,19 @@ connected to the main application microcontroller of a smart meter. The reset co
|
|||
authenticated reset commands on the voltage waveform, and on reception of such a command resetting the smart meter
|
||||
application controller by flashing a known-good firmware image to its memory.
|
||||
|
||||
For our proof of concept, before settling on the commercial smart meter we first tried to use an \texttt{EVM430-F6779}
|
||||
smart meter evaluation kit made by Texas Instruments. This evaluation kit did not turn out well for two main reasons.
|
||||
One, it shipped with half the case missing and no cover for the high-voltage terminal blocks. Because of this some work
|
||||
was required to get it electrically safe. The second issue we ran into was that the development board is based around a
|
||||
specific microcontroller from TI's \texttt{MSP430} series that is incompatible with common JTAG programmers.
|
||||
|
||||
Our initial assumption that a development kit would be easier to program than a commercial meter did not prove to be
|
||||
true. Contrary to our expectations the commercial meter had JTAG enabled allowing us to easily read out its stock
|
||||
firmware requiring neither reverse-engineering vendor firmware update files nor circumventing code protection measures.
|
||||
The fact that its firmware was only available in its compiled binary form was not much of a hindrance as it proved not
|
||||
to be too complex and all we wanted to know we found with just a few hours of digging in
|
||||
Ghidra\footnote{\url{https://ghidra-sre.org/}}.
|
||||
|
||||
The signal processing chain of our PoC is shown in Figure~\ref{fig_demo_sig_schema}. To interoperate with existing
|
||||
implementations of SHA-512 and reed-solomon decoding, this implementation was written in the C programming language. To
|
||||
demonstrate an application close to a field implementation, we chose an Easymeter \texttt{Q3DA1002} smart meter as our
|
||||
|
|
@ -888,11 +898,17 @@ the meter's display after boot-up.
|
|||
To measure grid frequency in our demonstrator, we ported the same code we used in
|
||||
Section~\label{grid-freq-characterization} to our demonstrator, again using the voltage measured using the
|
||||
microcontroller's internal ADC but using a regular crystal instead of a crystal oven for the microcontroller's system
|
||||
clock. Since we did not have an aluminium smelter ready, we decided to feed our proof-of-concept reset controller with
|
||||
an emulated grid voltage sine wave from a computer's headphone jack. Where in a real application this microcontroller
|
||||
would take ADC readings of input mains voltage divided down by a long resistive divider chain, we instead feed the ADC
|
||||
from a $\SI{3.5}{\milli\meter}$ audio input. For operational safety, we disconnected the meter microcontroller from its
|
||||
grid-referenced capacitive dropper power supply and connected it to our reset controller's debug USB power supply.
|
||||
clock. We decided to feed our proof-of-concept reset controller with an emulated grid voltage sine wave from a
|
||||
computer's headphone output. Where in a real application this microcontroller would take ADC readings of input mains
|
||||
voltage divided down by a long resistive divider chain, we instead feed the ADC from a $\SI{3.5}{\milli\meter}$ audio
|
||||
input. For operational safety, we disconnected the meter microcontroller from its grid-referenced capacitive dropper
|
||||
power supply and connected it to our reset controller's debug USB power supply.
|
||||
|
||||
In the firmware development phase of our proof of concept, we tested every module such as DSSS demodulator, Reed-Solomon
|
||||
decoder, or grid frequency estimation individually. This approach proved very useful for debugging. The modular
|
||||
architecture allowed us to directly compare our demodulator implementation to our Jupyter/Python prototype, where we
|
||||
found that our C implementation outperformed the Python prototype. Despite the algorithms's complexity, the
|
||||
microcontroller C implementation has no issues processing data in real-time due to the low sampling rate necessary.
|
||||
|
||||
We performed several successful experiments using a signature truncated at 120 bit and a 5 bit DSSS sequence. Taking the
|
||||
sign bit into account, the length of the encoded signature is 20 DSSS symbols. On top of this we used Reed-Solomon error
|
||||
|
|
@ -901,49 +917,6 @@ other simulations as well this equates to an overall transmission duration of ap
|
|||
the demodulator some time to settle and to produce more realistic conditions of signal reception we padded the modulated
|
||||
signal with unmodulated noise on both ends.
|
||||
|
||||
\section{Lessons learned}
|
||||
|
||||
For our proof of concept, before settling on the commercial smart meter we first tried to use an \texttt{EVM430-F6779}
|
||||
smart meter evaluation kit made by Texas Instruments. This evaluation kit did not turn out well for two main reasons.
|
||||
One, it shipped with half the case missing and no cover for the high-voltage terminal blocks. Because of this some work
|
||||
was required to get it electrically safe. Even after mounting it in an electrically safe manner the safety reset
|
||||
controller prototype would also have to be galvanically isolated to not pose an electrical safety risk since the main
|
||||
MCU is not isolated from the grid and the JTAG port is also galvanically coupled. The second issue we ran into was that
|
||||
the development board is based around a specific microcontroller from TI's \texttt{MSP430} series that is incompatible
|
||||
with common JTAG programmers.
|
||||
|
||||
Our initial assumption that a development kit would be easier to program than a commercial meter did not prove to be
|
||||
true. Contrary to our expectations the commercial meter had JTAG enabled allowing us to easily read out its stock
|
||||
firmware requiring neither reverse-engineering vendor firmware update files nor circumventing code protection measures.
|
||||
The fact that its firmware was only available in its compiled binary form was not much of a hindrance as it proved not
|
||||
to be too complex and all we wanted to know we found with just a few hours of digging in
|
||||
Ghidra\footnote{\url{https://ghidra-sre.org/}}.
|
||||
|
||||
In the firmware development phase we tested every module such as DSSS demodulator, Reed-Solomon decoder, or grid
|
||||
frequency estimation individually. This approach proved particularly useful for debugging. The modular architecture
|
||||
allowed us to directly compare our demodulator implementation to our Jupyter/Python prototype, where we found that our C
|
||||
implementation outperformed the Python prototype. Despite the algorithms's complexity, the microcontroller C
|
||||
implementation has no issues processing data in real-time due to the low sampling rate necessary.
|
||||
|
||||
\section{Conclusion}
|
||||
\label{sec_conclusion}
|
||||
|
||||
In this paper we have developed an end-to-end design for a safety reset system that provides these capabilities.
|
||||
Our novel broadcast data transmission system is based on intentional modulation of global grid frequency. Our system is
|
||||
independent of normal communication networks and can operate during a cyber attack. We have shown the practical
|
||||
viability of our end-to-end design through simulations. Using our purpose-designed grid frequency recorder, we can
|
||||
capture and process real-time grid frequency data in an electrically safe way. We used data captured this way as the
|
||||
basis for simulations of our proposed grid frequency modulation communication channel. In these simulations, our system
|
||||
has proven feasible. From our simulations we conclude that a large consumer such as an aluminium smelter at a small cost
|
||||
can be modified to act as an on-demand grid frequency modulation transmitter.
|
||||
|
||||
We have demonstrated our modulation system in a small-scale practical demonstration. For this demonstration, we have
|
||||
developed a simple cryptographic protocol ready for embedded implementation in resource-constrained systems that allows
|
||||
triggering a safety reset with a response time of less than 30 minutes. In this demonstration we use simulated grid
|
||||
frequency data to trigger a commercial microcontroller to perform a firmware reset of an off-the-shelf smart meter. The
|
||||
next step in our evaluation will be to conduct an experimental evaluation of our modulation scheme in collaboration with
|
||||
an utility and an operator of a multi-megawatt load.
|
||||
|
||||
\subsection{Discussion}
|
||||
|
||||
During an emergency in the electrical grid, the ability to communicate to large numbers of end-point devices is a
|
||||
|
|
@ -967,7 +940,27 @@ a practical demonstration of broadcast data transmission through grid frequency
|
|||
controllable load as well as further optimization of the modulation and data encoding and the demodulator
|
||||
implementation.
|
||||
|
||||
\subsection{Artifacts}
|
||||
\section{Conclusion}
|
||||
\label{sec_conclusion}
|
||||
|
||||
In this paper we have developed an end-to-end design for a safety reset system that provides these capabilities.
|
||||
Our novel broadcast data transmission system is based on intentional modulation of global grid frequency. Our system is
|
||||
independent of normal communication networks and can operate during a cyber attack. We have shown the practical
|
||||
viability of our end-to-end design through simulations. Using our purpose-designed grid frequency recorder, we can
|
||||
capture and process real-time grid frequency data in an electrically safe way. We used data captured this way as the
|
||||
basis for simulations of our proposed grid frequency modulation communication channel. In these simulations, our system
|
||||
has proven feasible. From our simulations we conclude that a large consumer such as an aluminium smelter at a small cost
|
||||
can be modified to act as an on-demand grid frequency modulation transmitter.
|
||||
|
||||
We have demonstrated our modulation system in a small-scale practical demonstration. For this demonstration, we have
|
||||
developed a simple cryptographic protocol ready for embedded implementation in resource-constrained systems that allows
|
||||
triggering a safety reset with a response time of less than 30 minutes. In this demonstration we use simulated grid
|
||||
frequency data to trigger a commercial microcontroller to perform a firmware reset of an off-the-shelf smart meter. The
|
||||
next step in our evaluation will be to conduct an experimental evaluation of our modulation scheme in collaboration with
|
||||
an utility and an operator of a multi-megawatt load.
|
||||
|
||||
\appendix
|
||||
\section{Artifacts}
|
||||
|
||||
Source code for the demonstrator and simulations, as well as hardware EDA designs are available at the public git
|
||||
repository at the following URL:
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue