Hogyan befolyásolja a villamosenergia-hálózatról rendelkezésre álló információ a fizikai támadások által okozott sérülékenységről alkotott képet?
Authors: Hartmann Bálint 
Published: October 2021

Összefoglaló. A villamosenergia-rendszerek fizikai támadásokkal
szembeni ellenálló képessége a közelmúltban világszerte történt események
ismeretében egyre nagyobb hangsúlyt kap a tématerület kutatásaiban. Az ilyen
eseményekre való megfelelő felkészüléshez elengedhetetlen az üzemeltetett
infrastruktúrának, elsősorban annak gyengeségeinek pontos ismerete. A cikkben
Magyarország villamosenergia-hálózatának adatai alapján készített súlyozatlan és
súlyozott gráfokon végzünk vizsgálatokat, hogy megértsük a különböző stratégia
mentén kiválasztott célpontok elleni támadások milyen mértékben csökkentik a
topológiai hatékonyságot. A cikk célja egyben a magyar hálózat sérülékenységének
általános bemutatása is, mely hasznos bemeneti információ lehet a kockázati
tervek elkészítésekor.

Summary. Tolerance of the power grid against physical intrusions has
gained importance in the light of various attacks that have taken place around
the world. To adequately prepare for such events, grid operators have to possess
a deep understanding of their infrastructure, more specifically, of its
weaknesses. A graph representation of the Hungarian power grid was created in a
way that the vertices are generators, transformers, and substations and the
edges are high-voltage transmission lines. All transmission and sub-transmission
elements were considered, including the 132 kV network as well. The network is
subjected to various types of single and double element attacks, objects of
which are selected according to different aspects. The vulnerability of the
network is measured as a relative drop in efficiency when a vertex or an edge is
removed from the network. Efficiency is a measure of the network’s performance,
assuming that the efficiency for transmitting electricity between vertices i and
j is proportional to the reciprocal of their distance. In this paper,
simultaneous removals were considered, arranged into two scenarios (single or
double element removal) and a total of 5 cases were carried out (single vertex
removal, single edge removal, double vertex removal, double edge removal, single
vertex and single edge removal). During the examinations, all possible removal
combinations were simulated, thus the 5 cases represent 385, 504, 73920, 128271
and 193797 runs, respectively. After all runs were performed, damage values were
determined for random and targeted attacks, and attacks causing maximal damage
were also identified. In all cases, damage was calculated for unweighted and
weighted networks as well, to enable the comparison of those two models. The
aims of this paper are threefold: to perform a general assessment on the
vulnerability of the Hungarian power grid against random and targeted attacks;
to compare the damage caused by different attack strategies; and to highlight
the differences between using unweighted and weighted graphs representations.
Random removal of a single vertex or a single edge caused 0.3–0.4% drop in
efficiency, respectively, which indicates a high tolerance against such attacks.
Damage for random double attacks was still only in the range of 0.6–0.8%, which
is acceptable. It was shown that if targets are selected by the attacker based
on the betweenness rank of the element, damage would be below the maximal
possible values. Comparison of the damage measured in the unweighted and the
weighted network representations has shown that damage to the weighted network
tends to be bigger for vertex attacks, but the contrary is observed for edge
attacks. Numerical differences between the two representations do not show any
trend that could be generalised, but in the case of the most vulnerable elements
significant differences were found in damage measures, which underlines the
importance of using weighted models.