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Power Systems AnalysisCompleted Technical Study

Jaji 6.45 MWp / 10 MWh Interconnected Mini-Grid - GIS Reconstruction & ETAP Power-System Study

Independent reconstruction and power-system assessment of an interconnected mini-grid in Jaji, Kaduna. Transformer coordinates were used to reconstruct the 11 kV network topology and approximate feeder routing in GIS before developing the ETAP model for grid-connected load flow, voltage regulation, islanded operation, BESS resilience, IEC 60909 short-circuit assessment, grid-strength sensitivity and worst-case device-duty screening.

Jaji 6.45 MWp / 10 MWh Interconnected Mini-Grid - GIS Reconstruction & ETAP Power-System Study project visual

Project Visual

Location

Jaji, Kaduna State, Nigeria

Period

2026

01 / Engineering Scope

Technical work and responsibilities.

  1. 01

    Reconstruct the 11 kV distribution network from supplied transformer coordinates and GIS-based feeder routing.

  2. 02

    Develop an ETAP model representing the PV plant, battery energy storage system, diesel generation, utility grid, transformers and distribution feeders.

  3. 03

    Assess high-PV grid-connected export and average-PV operating conditions.

  4. 04

    Evaluate distribution-voltage performance and targeted transformer tap optimization.

  5. 05

    Assess steady-state islanded operation with PV and BESS support.

  6. 06

    Evaluate zero-PV BESS-only islanded supply capability.

  7. 07

    Estimate practical BESS autonomy under a defined operating SOC window.

  8. 08

    Perform IEC 60909 short-circuit assessment under grid-connected and islanded operating conditions.

  9. 09

    Evaluate fault-level sensitivity for 50 MVA, 100 MVA and 250 MVA utility short-circuit assumptions.

  10. 10

    Screen the 11 kV PCC breaker against worst-case interrupting, making and thermal short-circuit duty.

02 / Delivery Outcomes

Measured project results.

  1. 01

    Reconstructed approximately 30.41 km of 11 kV network across 45 modelled line sections using GIS-supported topology development.

  2. 02

    Demonstrated a high-PV grid-connected operating case with approximately 6.06 MW solar generation and significant surplus export to the utility.

  3. 03

    Established an average-PV case using six active PV inverters producing approximately 1.817 MW with near-zero active-power exchange at the grid interface.

  4. 04

    Reduced utility reactive-power dependence using inverter reactive support and investigated the resulting voltage response.

  5. 05

    Improved customer-side LV voltage performance through targeted distribution-transformer tap optimization rather than increasing the entire utility source voltage.

  6. 06

    Demonstrated steady-state islanded operation under both PV-plus-BESS and zero-PV BESS-only conditions.

  7. 07

    Estimated approximately 2.5 hours of BESS autonomy between 80% and 20% SOC under the modelled zero-PV island load using an equivalent battery-discharge model.

  8. 08

    Completed IEC 60909 short-circuit assessment using a 100 MVA utility fault-level base assumption with 50 MVA weak-grid and 250 MVA strong-grid sensitivity cases.

  9. 09

    Quantified grid-strength dependence at the 11 kV PCC, where three-phase fault current increased from approximately 2.97 kA under the 50 MVA case to 13.44 kA under the 250 MVA case.

  10. 10

    Assessed hybrid islanded short-circuit performance with PV, BESS and one 2.5 MVA diesel generator; the model indicated no effective 11 kV zero-sequence source path for single-line-to-ground faults under the configured grounding arrangement, requiring field verification before protection decisions.

  11. 11

    Verified the modelled 11 kV PCC breaker remained within its stated interrupting, making and one-second thermal capabilities under the assumed 250 MVA strong-grid screening case.

Technical Areas

Methods, tools and disciplines.

01

ETAP 24

02

GIS Network Reconstruction

03

Power Flow Analysis

04

Battery Energy Storage Analysis

05

Islanded Operation Assessment

06

Voltage-Drop Assessment

07

Transformer Tap Optimization

08

IEC 60909 Short-Circuit Analysis

09

Grid-Strength Sensitivity Analysis

10

Device Duty Screening

Related Disciplines

Interconnected Mini-GridETAPPower SystemsBESSSolar PVIslanded OperationLoad FlowGISVoltage RegulationShort CircuitIEC 60909Device DutyEnergy Resilience

Project Evidence

Selected engineering evidence.

Field photographs, drawings, GIS outputs, commissioning records and technical reports approved for public portfolio use.

01

Engineering Drawings

2 items

02

Reports / PDFs

12 items

PDF

Reports / PDFs

Case 1 - High-PV Grid-Connected Export

ETAP load-flow assessment of the interconnected mini-grid under high solar generation and utility export conditions.

Sep 2026

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PDF

Reports / PDFs

Case 2 - Average-PV / Near-Zero Grid Active Exchange

Average-PV operating case assessing network performance with approximately 1.817 MW of solar generation and minimal active-power exchange with the utility.

Sep 2026

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PDF

Reports / PDFs

Case 3 - Targeted Distribution Transformer Tap Optimization

Voltage-performance study evaluating localized transformer tap adjustments to improve customer-side LV voltage without raising the complete utility-source voltage.

Sep 2026

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PDF

Reports / PDFs

Case 4A - Steady-State Islanded Operation: PV + BESS

Islanded load-flow assessment with solar PV and battery energy storage supporting the mini-grid independently of the utility.

Sep 2026

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PDF

Reports / PDFs

Case 4B - Zero-PV Islanded Operation: BESS-Only Supply

Zero-solar islanded operating case assessing whether the BESS can sustain the network load without utility or diesel support.

Sep 2026

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PDF

Reports / PDFs

Case 4C - BESS Autonomy Under Zero-PV Islanding

Battery-discharge endurance assessment used to estimate practical supply duration between the selected upper and lower SOC operating limits.

Sep 2026

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PDF

Reports / PDFs

ETAP Single-Line Diagram - Full Resolution

Full-resolution PDF export of the ETAP single-line model used for the Jaji power-system assessment.

Sep 2026

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PDF

Reports / PDFs

Case 5A - Grid-Connected IEC 60909 Short-Circuit Assessment - 100 MVA Base Case

IEC 60909 grid-connected short-circuit assessment using a 100 MVA utility fault level at 11 kV as the documented base modelling assumption.

Sep 2026

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PDF

Reports / PDFs

Case 5B-1 - Grid-Strength Sensitivity - 50 MVA Weak Grid

Weak-grid short-circuit sensitivity case used to quantify the effect of reduced utility source strength on fault levels across the network.

Sep 2026

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PDF

Reports / PDFs

Case 5B-3 - Grid-Strength Sensitivity - 250 MVA Strong Grid

Strong-grid sensitivity case assessing the increase in available fault current as the assumed utility short-circuit strength increases to 250 MVA.

Sep 2026

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PDF

Reports / PDFs

Case 5C - Islanded Short-Circuit Assessment - PV + BESS + 1 x 2.5 MVA Diesel

IEC short-circuit assessment of the islanded hybrid network with PV, BESS and one 2.5 MVA diesel generator supplying the mini-grid.

Sep 2026

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PDF

Reports / PDFs

Case 5D - Worst-Case Device Duty Screening - 250 MVA Strong Grid

Worst-case screening of the 11 kV PCC breaker against calculated interrupting, making and one-second thermal short-circuit duty under the assumed 250 MVA strong-grid condition.

Sep 2026

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