Environmental Engineering Reference
In-Depth Information
allow understanding the risk proliferation and
develop the recommendations and measures for
NPP safety assurance.
All technical problems mentioned could
stipulate the risks associated with the NPP-PG
interaction. There are some extra causes beside all
mentioned, which could lead to the disturbances
of power grid. They are classified as internal and
external basic causes.
The basic internal causes, which lead to dis-
turbances of the power grid's operational mode
(NUREG-75/014, 1998), are:
NPP - POWER GRID SAFETY
ASSESSMENT BASED ON
MUTUAL INFLUENCE ANALYSIS
Approach for NPP-PG
Influence Formalization
•
The stable short circuit on the high-volt-
age transmission lines followed by their
removal from service (50-70% out of - all
power grid accidents) (it caused the black-
out 2003);
Key technical problems of power industry of
Ukraine, which could lead to NPPs' disturbances
(Tsarenko et al., 2008, differgroup.com) are:
•
The short circuits, which stipulate the acti-
vation of diferential bus protection (more
than 10%);
1. The production capacities in Ukrainian
electricity sector are outdated: nearly 95%
of power units have worked out their useful
life, the residual life of thermal power plants
is 5-7 years. Currently 95% of power units
already worked out their normal service
life (100 000 hours), more than a half have
been working for 200 000 hours. 80% of
power plants have been operating for 30
years. Such a deterioration was stipulated
by low quality fuel, fickle regime of TPPs
capacities due to poor maneuverability and
lack of funds for reconstruction. NPPs will
approach the end of their designed service
life in 2011-2030. This poses a problem for
the possible equipments' failures.
2. There is a lack of maneuverability capacities
in Ukraine, a share of electricity produced
by Hydro power station (HPS) accounts for
about 10,2%.
3. The level of technological losses constitutes
14.4% of the electricity produced, which is
2-2.5 higher than in developed countries. It
is necessary to modernize the transmission
and distribution networks. The growing
demand for electricity cannot be satisfied
using the old transmission and distribution
networks.
•
The emergency shutdown of the power
block (near 5%);
•
The staf's errors (near 5%).
The basic external causes, which lead to dis-
turbances of the power grid's operational mode:
•
The seismic vibration;
•
The wind inluences on power grid's
facilities;
•
The icing on transmission lines (quite fre-
quently in Ukraine);
•
The natural disasters (ires, looding, hur-
ricanes, pollutions).
Grid interconnectivity and redundancies in
transmission paths and generating sources are key
elements in maintaining reliability and stability
in high performance grids. However, operational
disturbances can still occur even in well main-
tained grids. Similarly, even an NPP running in
base load steady-state conditions can encounter
unexpected operating conditions that may cause
transients or a complete shutdown in the plant's
electrical generation. When relatively large NPPs
are connected to the electric grid, abnormalities
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