Design of Effective 33/11 kV Injection Substations Using International Standards

This research focuses on the design of an effective 33/11 kV modelled injection substation that conforms to an appropriate standard for equipment protection, the safety of personnel and power quality compliance. This is to provide a solution to one of the major problems industries in Nigeria faces due to sudden voltage fluctuations in the power system which results in damages to equipment and thus outage of power supply and damages to substation equipment. The methodology involved designing an effective 33/11 kV injection substation and associated distributive substation elements using international codes and applicable algorithms. 60% loading of transformer and additional 1.25 factor of future expansion (F.E) were considered too. The results showed that a 7.5 MVA injection transformer was designed to operate at 60%. Also, the results revealed that the injection substation would feed 15 numbers of 500 kVA distributive transformers. Each distribution substation was sized in accordance with the 7.5MVA injection transformer philosophy in this work. This research concludes that the injection substation must be loaded at 60% with an additional 1.25 F.E. in order to increase the transformer life span, and the 7.5MVA injection substation can crater for 15nos of 500 kVA distribution transformers in this research. Each substation will reliably and effectively carry the expected load demand. This research recommends that injection substations should be designed for areas with high energy requirements for reliable power quality. It recommends that substations should conform to 60% loading at the initial years of usage and that the substation design should conform to appropriate standards used in this work.