Dated: 17 February 2016 Instructor :Kashif Mehmood

  The electrical utility industry was born 1882 at pearl street electric station in New york city.  Electrical power system includes a generating, a transmission and distribution.  In the past, the distribution system contains 80% of total investment.  Figure 1.1 shows Electrical utility plants in service for the years 1960 to  Total operation and maintenance (O&M) costs for the privately owned utilities have increased from $ 8.3 billion in 1969 to $ 40.2 billion in  Production expense contains 64% of total O&M expenses in 1978.This is because of rapidly increasing in fuel costs.  In short the economic importance of distribution system is very high and the amount of investment involved dictates careful planning,design, construction and operation. Introduction RiseMark2

 3 Microelectronics Economy

 Distribution system and planning RiseMark4  System planning is necessary to overcome the demand of electricity which can be done by the addition of distribution system.  It should be appropriate and economical.  The deficiency of available land in urban areas and environmental consideration is main problem of optimal distribution system beyond the resolving power of unaided human mind.  Distribution system planners must determine the load magnitude and its geographical planning.

 RiseMark5

  The distribution system is important to an electrical utility for two reasons:- Its close proximity to the ultimate customer. Its high investment cost. As the distribution system of power supply system is the closest one to the customer, its failure affects customer service more directly than for example failure on the transmission and generating system which usually do not cause customer service. RiseMark6

 Logic Families RiseMark7

  The hurdles which prohibit designer have also become more difficult.  These include shortage of land in urban areas, limitations on fuel choices etc.  In short, the planning problem is an attempt to minimize the cost of sub transmission, substations, feeders and so on as well as the cost of losses. RiseMark8 Factor Effecting System Planning

  The load growth of geographical area served by a utility company is the most important factor influencing the expansion of distribution system.  There are two common time scales of importance to load forecasting:- Long Range : with the time horizons in the order of 15 or 20 years away. Short range with time horizons of up to 5 yrs. Away. These forecast would predict future load in details. RiseMark9 Load Forecasting

 Disadvantages of ICs over discrete components RiseMark10

  The planner makes a decision based on tangible and in tangible information.  For example the forecast load, load density and load growth may require a substation expansion or a new substation construction.  In the system expansion plan the present system configuration, capacity and the forecasted loads can play major role. Substation Expansion RiseMark11

 RiseMark12

  The distance from the load center and from the existing sub transmission line as well as other limitations, such as availability of land, its cost and land use regulation are important.  It may be defined as territory of the utility.  Three basic alternative uses of the consideration are Quantitative versus qualitative evaluation. Adverse versus beneficial effects evaluation. Absolute versus relative scaling of effects. Substation site selection RiseMark13

 RiseMark14

 Substation site selection procedure RiseMark15

 Factor effecting total cost of the dist. System Fig. 3.1 (a) Fig. 3.1 (b) RiseMark16

  Today, many electrical distribution planners in the industry utilize computer programs, usually based on ad hoc, such as load flow program, short circuit and fault current calculation programs, voltage drop calculation program, as well as other tools such as load forecasting, voltage regulation, regulator setting, capacitor planning etc. RiseMark17 Present distribution system Planning technique

  The acceptability criteria representing the companies policies, obligation to consumer :-  Service continuity.  The max. allowable peak load Voltage drop to most remote customer on the secondary.  The max. allowable voltage dip occasioned by the starting of motor of specified starting current characteristics at the most remote point on the secondary.  The max. allowable peak load.  Service reliability.  Power losses. RiseMark18

 RiseMark19

 20RiseMark