A Proposed Underground Medium Voltage Feeder-Design Considering Ampacity and Temperature of Cable for High Rise Buildings in Pakistan /

Abstract

A common aspect of modern power distribution systems (MPDS) is the substantial use of underground power cables (UPC) due to space scarcity, human safety, and aesthetic reasons. These insulated UPCs are either directly buried in the ground or laid in conduits or concrete ducts. Selecting a cable of a suitable ampacity for catering to anticipated load, under expected operating temperature and thermal resistivity of soil is a challenging problem. In this thesis, a new medium voltage UPC design is proposed for a high-rise building (HRB) in the G-13 Sector of Islamabad, Pakistan. The HRB contains several types of loads but due to the shortage of gas in Pakistan, the future planning for the residential buildings to add electric oven load for cooking purposes. However, in recent electric vehicles have quickly become a viable alternative to gasoline automobiles. So, governments all over the globe have made a concerted effort to encourage the use of electric vehicles (EV) to overcome carbon emissions. So, for this purpose different levels of electric oven and EV loads are calculated and modeled. However, after power flow analysis of the selected HRB’s load for estimation of cable size, the number of UPC feeders of adequate ampacity is decided for delivering power to the selected HRBs. Furthermore, steady-state temperature analysis is performed on the directly buried UPC feeders for the analysis of temperature effects around the cables. The underground distribution system, as well as the HRB’s loads, are modeled in Electrical Transient Analyzer Program (ETAP) according to IEC and IEEE standards. Simulation results indicate that the designed system can also handle the additional future load to accommodate the government policy of promoting electric vehicles (EV).