PLANNING AN URBAN DISTRIBUTION SYSTEM - AN INDIAN EXPERIENCE

摘要

Planning for an optimum sub-transmission and distribution system requires detailed upto date data on the existing system, energy balance and demand pattern (MW and KWh) in the supply area, demand diversity at different voltage levels/feeders etc. For this purpose, the Utilities have to maintain records in a scientific manner and ensure its availability for taking up studies. It is needless to add that this data is also required for management of distribution on an accountable basis. It is seen that the metering system in the Sub-transmission and Distribution Systems is grossly inadequate and deficient (non-functioning) to undertake analysis demand pattern, system losses, diversity etc. Metering at distribution transformer level is enable an analysis of the pattern and trends in consumption of different category of consumers is non-existent. The metering can be improved substantially by installing electronic meters with data logging facilities. The data from that meter can be downloaded directly to a computer for analysis and building the data base for carrying out distribution planning studies. This data should also be analyzed to evolve the norms for connected load, diversities etc. It is seen that information on the system data particularly at 11 kV/0.4 kV system is widely scattered in different field offices ot the Utility. The changes made at field level to meet new sanctioned loads and contingencies remain unreported for quite some time and the coordination at the appropriate higher level is lacking. This is partly on account of the effort involved in updating even small changes. With the availability of modem computer based tools like Geographical Information System (GIS), it is now possible to create net work data in a spatial as well as tabular format and update it with great ease to reflect changes made in the system from time to time in the field. This would also offer very powerful tool to visualise the system and carry out modifications and evolve optimum distribution system development plans. All the utilities should plan to introduce the GIS at each distribution division level and gradually evolve an upward integration mechanism to district'state level data base. It is necessary that utilities pay attention to these two aspects immediately so that the distribution system planning is done on a scientific basis rather than making assumptions which can be questionable. Apart from the modernisation of the facilities in the distribution system, it would be necessary that the field level engineers are also properly trained to appreciate the data required and on the use of GIS and distribution analysis tools to carry out the studies to check the system adequacy on regular basis and evolve system improvement schemes which are then coordinated for integration in the state wise studies of the Utility.