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ETAP Reference

Free reference guide: ETAP Reference

25 results

About ETAP Reference

The ETAP Reference is a searchable quick-reference covering 24 core topics of ETAP power system analysis software. It spans modeling elements such as buses, transformers, cables, generators, and motors, as well as load flow, voltage profile analysis, short circuit calculations per IEC 60909 and ANSI/IEEE standards, and protective device coordination including relay TCC curves and arc flash hazard assessments.

Beyond steady-state studies, this reference includes dynamic analysis topics like motor starting, transient stability simulations, harmonic analysis per IEEE 519, battery sizing, optimal power flow, reliability assessment (SAIFI/SAIDI), and cable ampacity derating calculations. Each entry provides the relevant ETAP menu path, key parameters, formulas, and practical threshold values used in real engineering projects.

All content is organized into five categories: Modeling, Load Flow, Short Circuit, Protection Coordination, and Dynamic Analysis. The tool runs entirely in your browser with no server processing, making it suitable for on-site use at substations, design offices, or anywhere you need fast access to ETAP procedures and engineering values.

Key Features

  • Complete bus modeling reference with Swing, Voltage, and Load bus types and voltage level settings for 154kV, 22.9kV, and 380V systems
  • Short circuit calculation guidance for both IEC 60909 (voltage factor c, Zk impedance) and ANSI/IEEE (half-cycle, 1.5-4 cycle, 30-cycle duties)
  • Arc flash analysis per IEEE 1584-2018 with PPE category thresholds from Cat 1 (4 cal/cm2) to Cat 4 (40 cal/cm2)
  • Relay coordination workflow covering OCR pickup, time dial, IEC curve types, and 0.3-0.4 second coordination margins
  • Motor starting analysis checklist: voltage drop limits below 20%, acceleration torque, DOL/Y-Delta/VFD starting methods
  • Harmonic analysis with IEEE 519 THD limits and filter design for VFD, UPS, and arc furnace harmonic sources
  • Cable ampacity derating calculations with temperature, burial depth, soil thermal resistivity, and grouping correction factors
  • Power factor correction capacitor bank sizing with Qc formula, automatic switching stages, and 6% series reactor for harmonic filtering

Frequently Asked Questions

What ETAP analysis modules does this reference cover?

This reference covers load flow (Newton-Raphson), voltage profile, short circuit (IEC 60909 and ANSI/IEEE), protective device coordination, arc flash (IEEE 1584-2018), motor starting, transient stability, harmonic analysis (IEEE 519), cable ampacity, battery sizing, optimal power flow, reliability assessment, and unbalanced load flow.

How do I use the short circuit calculation entries?

The IEC entry shows the formula Ik" = c*Vn/(sqrt(3)*|Zk|) with voltage factor c values, while the ANSI entry explains half-cycle (instantaneous device selection), 1.5-4 cycle (MCCB/LVCB interrupting duty), and 30-cycle (steady-state) current calculations. Each includes the corresponding ETAP menu path.

What voltage limits should I check after running a load flow?

Standard voltage tolerance ranges are: 154kV at +/-5% (146.3-161.7kV), 22.9kV at +/-5% (21.755-24.045kV), and 380V at +/-6% (357.2-402.8V). Bus voltages should stay within 0.95-1.05 pu, with line loading below 80% and power factor above 0.9.

How is arc flash PPE category determined?

ETAP calculates incident energy in cal/cm2 per IEEE 1584-2018. The PPE categories are: Cat 1 up to 4 cal/cm2, Cat 2 up to 8 cal/cm2, Cat 3 up to 25 cal/cm2, and Cat 4 up to 40 cal/cm2. The tool also computes the arc flash boundary distance.

What cable ampacity correction factors are included?

The reference covers four derating factors: ambient temperature correction (Kt), burial depth correction (Kd), soil thermal resistivity correction (Kr), and multi-circuit grouping correction (Kg). A worked example shows XLPE 325mm2 22.9kV cable derated from 430A to 298A with 40C ambient and 3-circuit grouping.

How do I size power factor correction capacitors?

Use the formula Qc = P*(tan(phi1)-tan(phi2)). For example, correcting 1000kW from PF 0.8 to 0.95 requires 420 kvar. The reference also covers automatic switching in 6-12 stages, harmonic filter design with 6% series reactors, and inrush current limiting reactors.

What reliability indices does ETAP calculate?

ETAP computes SAIFI (interruption frequency per customer per year), SAIDI (interruption duration in minutes per customer per year), CAIDI (average interruption time per event), and ENS (energy not supplied in kWh/year). Typical equipment failure rates are also provided for transformers, cables, and circuit breakers.

Is this reference suitable for real engineering projects?

Yes. Every entry includes practical engineering values such as transformer impedance percentages, cable R/X/B parameters per km, generator transient reactances, motor starting current ratios, and protective device ratings commonly used in Korean 154kV/22.9kV/380V power distribution systems.