APS Knowledge Library

Technical
Topics

APS publishes technical notes, study concepts, and practical engineering guides related to power system studies and commissioning. These resources support engineers working across grid-connected infrastructure, renewables, and industrial power systems.

TechnicalTopics

EMTP® Load Models

EMTP® Line & Cable Modelling

EMTP® Cable Modelling

Cable Designs & Parameters

Cable Sheath & Armour Grounding

Overhead Line Modelling

Overhead Line Equations

Corona in Line Modelling

Travelling Waves & Tower Surge Impedance

Lightning & Switching Waveforms

Tower Modelling for Lightning

Frequency-Dependent Soil & Footing

Impulse Resistance of Ground Electrodes

CIGRE Backflashover Method

Air-Gap & Insulator Flashover

Switching-Surge Insulation Strength

External-Insulation Strength

Mitigation of Resonant Temporary Overvoltages

Passive AC Harmonic Filters

Harmonic Study Domains & Modelling

Overhead Line Modelling for Harmonics

Cable Modelling for Harmonics

Transformer Modelling for Harmonics

Load & Harmonic Source Modelling

Synchronous Generator Modelling

Shunt, Series & Filter Modelling

FACTS Device Modelling for Harmonics

HVDC Converter Modelling for Harmonics

Converter-Based Generation & HVDC Models

Variable-Speed Drive Modelling

Harmonic Impedance Loci & Envelopes

Network Harmonic Impedance Envelopes

Fundamentals of Harmonics

Characteristics of Harmonics

Measures of Harmonic Distortion

Resonance in Harmonic Studies

Capacitor Banks & Harmonic Resonance

Harmonic Sources and Signatures

Effects of Harmonic Distortion

Harmonic Filter Design

Second-Order Damped Filters

Active Harmonic Filters

Harmonic Voltage Indices

Flicker Indices

Voltage Unbalance Indices

Voltage Dip Indices

Long Interruption Indices

Reviewing PQ Measurement Data

Recommended PQ Indices

PQ Objectives & Conclusions

Resonance and Ferroresonance: Part One

Resonance in Shunt-Compensated Networks: Part Two

Resonance and Ferroresonance: Part Three

Resonance and Ferroresonance: Part Four

Resonance and Ferroresonance: Conclusions

Subsynchronous Oscillation (SSO) Guide

Types of Overvoltages

Sources of Temporary Overvoltages

Transformer Energisation

Transformer Modelling in EMTP® — Overview & Model Selection

Transformer Modelling in EMTP® — Low-Frequency Models

Transformer Modelling in EMTP® — High-Frequency Models

Transformer Modelling in EMTP® — Device Catalogue

Transformer Modelling in EMTP® — Instrument Transformers

Transient Recovery Voltage (TRV) Guide

Fault-Current Breaking & Terminal-Fault TRV

Short-Line and Long-Line Faults

Transformer- and Reactor-Limited Faults

Out-of-Phase Switching Duty

Late Breakdown, Re-Ignition, Restrike & NSDD

Transient Recovery Voltage — Calculation Concepts

Re-ignition, Re-strike, Recovery Voltage & RC Snubbers

Switching of Shunt Capacitor Banks

Shunt Reactor Switching

Insulation Strength: BIL, BSL, CFO and Impulse Testing

Switching Impulse Strength of Transmission-Line Insulation

Lightning Impulse Strength of Line and Substation Insulation

Deterministic Line Design and Switching-Impulse Gap Factors

Switching-Overvoltage Distributions: Brute Force, Case Peak and E₂

Technical
Topics