Figure 1 shows an existing 132/11 kV Main In Take substation and a 11 kV Main Switching Station. Three - phase fault level at 132 kV bus 1 and 2 is 3000 MVA. Existing 11 kV underground cable between 132/11 kV Man In lake n No (2) of 3x500 mm sq single core Al and is length is 20 km. Short circuit rating of all elating 11 kV circuit breakers is 20 kA for 3 seconds.
A new mixed development with commercial and residential loads is in progress and in order to supply to the new development, the following job score is proposed.
1. Lay new 11 kV underground cable along the road shoulder from the 11 kV Main Switching Station to the proposed Commercial and Residential Substation. The cable route distance from the 11 kV Main Switching Station to the Commercial Substation is 2.5 km and from the Commercial Substation to Residential Substation is 1.8 km. The ultimate total peak demand of the commercial and Residential loads is 3.0 MW, with a power factor of 0.90 lagging.
2. Install switchgears with short circuit rating of 13 or 20 kA at the Commercial and Residential Substation
Tasks to Perform
a) Assess the operational safety of the power system by performing a power system study to determine its three phase short circuit current and site phase short circuit current.
b) Write a report based on your power system studies results.
Instruction to students
- the content of your report should follow the format provided.
- Studies must be done using any commercial software (such as Power World, PSS Adept, etc) that is available
- Parameters which are not provided but required to complete the simulation/analysis will have to be sourced and determined by the students.