Distribution System Planning and Design

Sub-transmission and Distribution systems span the voltage level of 0.4/0.415/0.43 kV to 66 kV in India. In general 66/11 kV substations are established at major load centers and are supplied from 400/66 or 220/66 or 132/66 or 110/66 kV substations. From the 11 kV substations, the distribution powers are either supplied directly at 11 kV [or in some cases at 66 kV level if needed to larger single HT customer load]. In most other cases, where the consumers use LT power supply, the power is supplied at 0.4/0.415 kV using  11/0.4 kV or 11/0.415(or 0.43) kV step down transformers. Many of the LT consumers may use single phase power supply with connected load less than 10 KW.

The following studies/aspects/factors  must be considered for distribution system planning and Design

• Spatial Load Forecast based on geographical location, type of consumers in the specified geography
• Assessment of the demand requirements area wise for the future years
• Identification of suitable locations for 66/11 kV substations and the number of transformers in each geographical area and their MVA rating.
• Identification of HT consumers at 11 kV or if needed at 66 kV
• Identification of possible number of 11/0.4 kV or 11/0.415 kV transformers and their location for LT consumers
• Techno commercial evaluation of the various options distribution feeders to meet existing and new customers[conductors, transformers, reactive power compensations], involving power system studies.
• Geographical mapping of the distribution system with or without application of Geographical Information System
• Distribution Substation and feeder design, with power flow studies, short circuit studies, earthing requirements, reactive power compensation, transformer size, tap , kV, MVA requirements, related detailed engineering services.
• Metering, Protection, Operation and Control Requirements
• Demand side management