Master planning is critical in the
electrical power systems for optimal operation and system expansion
planning. Planning is the process of identifying alternatives and
selected the best from among them satisfying economical and technical
constraints for both utility and end users. The objective of power
system planning is to provide an orderly and economic expansion of
equipment and facilities to meet the electric utility's future
electrical demand with an acceptable level of reliability. This involves
determining the future needs for the power system, including the correct
sizes, locations, interconnections, and time schedules for future
delivery system additions and changes satisfying minimized cost.
The planning process can be segmented
into five steps. Each step is an important part of the process of
accomplishing the goals of planning. Any of the five steps, poorly
performed, will lead to poor decisions, a poor plan, and ultimately
failure to attain those goals. These five steps are outlined as:
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Identify the Problem
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Identify the Goals
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Identify the Alternatives
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Evaluating the Alternatives
-
Selecting the Best Alternative
Power networks grew in capacity and
extent in most countries, through end users and services, often founded
by treasury loans or sanctioned loans from the financial markets. This
means that the government has to make a good case for the finance to be
forthcoming to add to the present system or build anew to meet expected
increase in electrical energy demand for all purposes. Consequently,
centrally planned systems needed expert forecasting of demand at least 5
years ahead to design, manufacture and commission the necessary
equipment and connections by cable or overhead line.
Achieving good Load forecasting helps
an electric utility to make important decisions purchasing and
generating electric power, load switching, and infrastructure
development. When Electricity Supply Industry (ESI) has been
underdeveloped and never matches supply to demand, or overdeveloped
where plant has been underutilized, inefficiencies and a higher price
for energy than necessary are the outcomes.
From 1940s to 1980s, to make central
planning, funding through the principles of the investment market was
seen to provide a more acceptable way of achieving the desired
objectives. During the latest decades, a movement by many governments to
deregulate and restructure the ESI such that central planning is no
longer the norm, but private finance is encouraged to take the risk of
getting a return on investment.
With a deregulated ESI, no longer is
there a planning authority but all investors need to plan for their own
investments and expected returns. This implies that companies who are
thinking of financing a venture into the ESI, must consider all options
open to them and estimate the risk and return on investment by
considering the following aspects:
-
the minimum cost investment to
meet the desired objectives over a given period;
-
the robustness of the proposal
against likely changes in market rates, social climate,
environmental constraints, etc.;
-
likely level of co-operation
between the company and the customers being served; and
-
the financial viability of the
whole proposal, including the attitude of the shareholders, the
regulator and the government.
In theory, any investment in new plant
(generation, transmission facility, supply services) should not occur
until the cost of alternative measures to achieve the same objectives is
equivalent to new plant costs. In practice, new plant investment may be
required because of new developments, economic boom, improved supply
security, availability of new technology etc.
Successful system planning has to
consider sustainability, reliability and cost of outage for both utility
and end users, substation allocation, demand side management
technologies, distributed generation, and the system power quality
indices accompanied to their effects on power system operation and
expansion planning.
