NPP: Power Grid Mutual Safety Assessment - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 406

Figure 3. Organizational influence

ated their total influences. Their ranking might
determine the most and least influential system.
In Table 2 the different influences' factors are
combined.
It helps to estimate the value of total influence,
for instance, NPP on all of subsystems as:

NPP NPP NPP NPP NPP NPP

I ( I ( ), t I ( ), t I ( ), t I ( ), ..., t I ( )) t −

tot phys geo org inf soc

total NPP s ' inf luence ;

I

∑

NPP i

I ( ) t = I ( NPP → SPG );

phys phys i

i = 1

I

∑

NPP i

I ( ) t = I NPP ( → SPG ), ...;

geo geo i

i = 1

(

NPP

I H M L

w M L H w M H L
SPG S of power grid

= w + + + )

tot phys

( + + ) + ( + + + ) ...,

Similarly, the organizational influence might
be represented as shown in Figure 3.
The value of organizational influence could
be calculated as:

geo org

.

−

i i

(5)

We shall consider the relative influence value

rel ( ) . The relative influence value determines
the influence of one system on another system,
for example NPP on TPP. It might be calculated
as:

I t

I

∑ (

NPP i

)

I = I NPP → SPG ;

org org i

i = 1

I

∑ (

NPP i

I = I NPP → SPG ) =M + L + M.

(4)

org org i

I NPP ( → TPP ) = I NPP ( → TPP ) +

i = 1

rel geo

I NPP TPP
I NPP

( → ) + (6)

org

... + ( → TPP ).

The total influence value might be calculated
as a sum of the particular influence values on all
influence space existed for NPP-PG system.
The total influence value calculated as a sum
of the particular influence values characterizes the
absolute influence of NPP on other PG systems.
For each systems of power grid could be evalu-

soc

The different types of NPP's relative influence
are shown in Figure 4.
Similarly, the relative influences of different
power grid systems might be evaluated for NPP.

Table 2. The combined matrix of influences

Physical Geographical Informational

NPP TPP HPP DG NPP TPP HPP DG NPP TPP HPP DG

NPP 0 M L H 0 H M L 0 M H M

TPP M 0 M L H 0 M L H 0 H H

HPP L H 0 H H L 0 H H L 0 H

DG L L H 0 L M M 0 L M H 0