FAQ
The Substation Preliminary Sizing Tool solves this problem by giving engineers, developers and EPC teams a structured Excel tool for early-stage HV/MV substation sizing.
It helps you move from a generic substation allowance to a more defensible preliminary technical configuration and CAPEX estimate.
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Size preliminary HV/MV step-down substations for renewable energy projects
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Analyse PV Utility, Wind Onshore, BESS Standalone, Hybrid PV+BESS and Hybrid Wind+BESS assets
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Select project stage: Pre-Feasibility, FEED or Detailed Design
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Configure AC capacity, power factor, apparent power, HV voltage, MV collector voltage and fault level at point of connection
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Select substation type: Outdoor AIS, Indoor GIS or Hybrid AIS+GIS
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Automatically select transformer unit rating based on plant MVA, number of transformers and target utilisation
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Run N-1 compliance check using plant MVA versus available transformer capacity with one unit out
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Use transformer configuration inputs: quantity, rating override, vector group and impedance
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Estimate annual no-load losses, load losses and annual loss cost
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Use transformer database with 20 standard ratings, losses, impedance and cost assumptions
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Generate equipment schedule for HV, MV, protection, civil works and ancillary systems
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Estimate total substation CAPEX with breakdown: equipment, civil works, installation, engineering, project management, commissioning and contingency
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Estimate site footprint for Outdoor AIS and Indoor GIS configurations
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Review key outputs: selected unit rating, total installed MVA, actual utilisation, N-1 load factor, total CAPEX, CAPEX/MW and annual loss cost
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Compare against reference benchmarks for 132 kV and 220 kV AIS substations and CAPEX/MW ranges
This tool is especially useful for:
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Electrical engineers preparing preliminary substation sizing
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EPC teams building early-stage electrical design assumptions
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Renewable energy developers estimating substation CAPEX before detailed engineering
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Grid connection teams checking transformer configuration and N-1 logic
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Technical advisors reviewing substation assumptions in due diligence
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Project managers comparing AIS, GIS and hybrid substation options
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Financial analysts who need a defensible substation CAPEX input before building the full model
Excel tool · editable assumptions · transformer database · equipment schedule · CAPEX breakdown · N-1 check · instant download.
100% money-back guarantee: if the tool does not meet your expectations, you get a full refund.
What is the Substation Preliminary Sizing Tool?
It is an Excel engineering tool for preliminary sizing of HV/MV step-down substations for renewable energy projects.
Which technologies does it cover?
The tool covers PV Utility, Wind Onshore, BESS Standalone, Hybrid PV+BESS and Hybrid Wind+BESS projects.
Does the tool size transformers automatically?
Yes. It automatically selects the transformer unit rating based on plant apparent power, number of transformers and target utilisation.
Does it check N-1 compliance?
Yes. The tool calculates the N-1 load factor and checks whether the plant can be supplied with one transformer out of service.
Which substation configurations are included?
The tool supports Outdoor AIS, Indoor GIS and Hybrid AIS+GIS configurations.
Does it include a transformer database?
Yes. It includes a transformer reference database with 20 standard ratings, losses, impedance and cost assumptions.
Does the tool calculate losses?
Yes. It estimates no-load losses, load losses and the annual cost of transformer losses using the selected energy price.
Does it generate an equipment schedule?
Yes. It generates a preliminary bill of materials covering HV equipment, MV equipment, protection, civil works and ancillary systems.
Does it calculate CAPEX?
Yes. It calculates total substation CAPEX with breakdown for equipment, civil works, installation, engineering, project management, commissioning and contingencies.
Does this replace detailed substation engineering?
No. It is a pre-feasibility sizing tool. It does not replace detailed electrical design, protection studies, load flow analysis, DSO/TSO approval or manufacturer quotations.
Need the full project business case?
Use this tool to validate substation sizing, transformer configuration and CAPEX before finalising the business case. When you need full IRR, NPV, DSCR, debt schedule, grid connection cost, revenue waterfall and 20-year cash flow modelling, move to the Solar PV Ultimate Model, Wind Ultimate Model, BESS Ultimate Model or Complete Utility-Scale Bundle.









