NPP: Power Grid Mutual Safety Assessment - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 411

Figure 9. The fragment of the operational hierarchy of power grid criticality matrices after Zaporozhe
NPP unit 2 shut down

principle of influence balance was suggested as
one of principles of infrastructure safety assurance.

safety analysis, taking into consideration tech-
nical, organizational, and individual aspects, is
proposed in (Linstone, 1984). The PG safety
analysis is supplemented by a set of geographic
and economic aspects in (Kaijser, 1984). An ap-
proach for PG safety assessment based on pro-
cessing statistical data related to PG operation is
proposed in (Holmgren, 2006). The main task of
the safety statistical analysis is to determine the
failure probability distribution function and to
assess power grid risk. Lack of statistics prevents
the use of traditional statistical methods for PG
safety assessment.
Beside well known techniques of probabilistic
and deterministic PG safety analysis there are a
lot of approaches used for NPP safety assessment.
Logic methods (Fault Tree Analysis and Event
Tree Analysis), used for NPP safety analysis,
are applied in (Bedford et al., 2001). Typical PG
safety analysis techniques are connected with the
equipment failure analysis, environment and hu-
man factor. Nowadays, a new type of grid hazards
- intentional attacks occur. This type of hazards
is analyzed by the use of probabilistic approach
together with conditional probabilities calculation.
However, mutual influence of systems, taking into
account dynamical aspects of functioning and

POWER GRID SAFETY:
DYNAMICAL CRITICALITY
CWW-BASED ANALYSIS

The PG is a huge and interconnected network
composed of power-generation stations, high-
voltage transmission lines, lower voltage distri-
bution systems, and other support components.
Disturbances in power grid operation can originate
from natural disasters, failures, human factors,
terrorism, and so on.
In its turn, the PG safety is stipulated by the
NPP safety. Outages and faults will cause seri-
ous problems and failures in the interconnected
power systems. Therefore, PGs require continuous
control and balancing actions based on engineer-
ing systems.
It is of high priority to consider PG safety, mu-
tual influence of NPP and PG systems and forecast
possible accidents and failures considering their
severity and high costs of recovery.
There are a lot of approaches and techniques
of PG safety assessment. An approach to PG