8/12/2019 Objective of Distribution Plan

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Objectives of distribution plan

Distribution system planning is part of a more general problem, that of energy and economic development planning.

Its objective is therefore to determine a minimum cost strategy for long-range expansion of the distribution systems

adequate to supply the load forecast within a set of technical, economic and political constraints. Traditionally,

distribution system planning has been mainly related to Transmission expansion planning. This is due mainly to the

fact that investment in distribution lines is a relatively small fraction of the investment in the construction Grid stations

and that investment in the distribution of electric energy to customers, although sizeable.

The main steps in Distribution system planning may be summarized as follows:

(a) Study of the electric load forecast 5 to 10 years into the future, based on the most reliable information.

(b) Evaluation of the foreseeable trends in technical and economic developments.

(c) Evaluation of the economic and technical characteristics of the existing system of distribution system These

characteristics include capital investment cost, operation and maintenance costs, efficiencies, construction times, etc.

(d) Determination of technical and cost characteristics of the distribution system available for expansion.

(e) Determination of the economic and technical parameters affecting decisions such as discount rate, level or

reliability required from the distribution system, etc.

(f) Choice of a procedure to determine the optimal expansion strategy within the imposed constraints.

(g) Qualitative review of the results to estimate the viability of the proposed solution. The determination of most of

these data must take into account the present and future economic and technical environment within which the

electric sector is expected to operate. Thus, available resources and fuel prices are related to the energy policy of the

country; economic development policies, existing and foreseeable, should be considered in the

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Future development of electric power systems must pursue a no: of different goals. The power system

should be economically efficient, it should provide reliable energy supply. At the same time, operation &

development of system is influenced by variety of factors. The planner attempts to find the best strategy

from large no: of alternatives. Thus the complexity of the problems related to power system planning is

mainly caused by multiple objectives, uncertain information & large no: of variables.

In presence of uncertainty the planner aims at finding robust & flexible plans to reduce the risk of

considerable losses.

In planning of distribution power systems, a no: of goals must be achieved and correspondingly, a no: of

objectives, which are often conflicting must be optimized. The planning goals include minimization of

power losses and required investments, enhancement of reliability, personal safety, & power quality. It

is impossible to define relative importance or to express the corresponding attributes in monetary

terms, the planner has to deal with multi criteria optimization tasks.

Despite the possible simplifications, the problem of distribution network planning remains an extremely

complicated optimization & decision making problem due to:

Conflicting objectives

Large no: of variable

Dynamic nature

Uncertainties

Each problem may have several possible solutions may have several possible solutions. Possible

reinforcement actions may include for example building new lines, providing alternative network

configurations, installation of capacitors, change / Augmentation of Transformers, enlargement of

conductor cross section or transition to alternative voltage level.

The planning process consists several steps including identification of possible alternatives, theirevaluation, & selection of most suitable alternatives, which form the development strategy