NPP: Power Grid Mutual Safety Assessment - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 409

Figure 7. Example of obtaining new criticality
matrixes, using influence matrixes

influences on the neighboring PG systems. This
database might be very useful when assessing
the consequences of NPP accidents for the power
grid systems and vice versa. This database is
constantly updated according to the Ukrainian
power grid structure changing. The Ukrainian PG
is divided in four zones according to the number
of Ukrainian NPPs.
Table 4 represents a fragment of total influ-
ence values database completed for Zaporozhe
NPP (ZNPP).
The similar influence matrices are built for
each level of hierarchy of power grid criticality
matrices.
The first stage is constructing an operational
hierarchy of power grid criticality matrices without
considering subsystem failures. The fragment of
the operational hierarchy of power grid criticality
matrices for Zaporozhe NPP is shown on Figure 8.
Criticality matrix M crt

S 0 is completed for the
power grid systems connected to Zaporozhe NPP
(S1), where S2 stands for Dnipro Substation, S3
stands for Krivyi Rih TPP, S4 stands for Zaporo-
zhe Substation, S5 stands for Kherson CHP.
Criticality matrix M crt

some actions should be taken to decrease critical-
ity and improve the smart grid safety.
Example of obtaining new criticality matrices,
using influence matrices, is shown on Figure 7.

S 1 is completed for Zaporo-
zhe NPP subsystems (power units, etc). Critical-
ity matrix M crt

Case - Study: Influence Analysis for
Zaporozhe NPP

S 1 is completed for Dnipro Substation
subsystems, etc.
These power grid criticality matrices are
regularly updated. Criticality values are calcu-

The influence values database might be completed
for all Ukrainian NPPs considering their possible

Table 4. Matrix of influence for Zaporozhe NPP

Z
NPP

Subst. Dnipro Krivyi Rih TPP Zapor.

Subst.

Khersonska CHP

ZNPP - M H H L

Subst. Dnipro L - M L L

Krivyi Rih TPP M H - M

Zaporozhe Substation M M M M M

Kherson CHP L L L M L

where CHP is combined heat power station.