Introduction
1 Overview
   1.1 Scope
   1.2 Purpose
   1.3 Safety warning
2 Definitions
3 Detection and measurement of partial discharge - background
   information
4 Introduction to acoustic partial discharge systems
   4.1 The all-acoustic system
   4.2 The acoustic system with an electrical PD trigger
   4.3 The on-line (continuous) acoustic system
5 Acoustic signal transmission characteristics
   5.1 Acoustic signal
   5.2 Acoustic signal propagation from source to tank wall
   5.3 Acoustic signal propagation within the tank wall
   5.4 Velocity of sound in oil
6 AE systems: equipment specifications
   6.1 Introduction
   6.2 Acoustic systems that record single events
   6.3 Digital signal processing (DSP) workstations that
       record acoustic data over extended periods
   6.4 On-line (continuous) acoustic partial discharge
       monitoring systems
   6.5 External sensor
   6.6 Internal sensor
   6.7 Three sensor system
   6.8 Band-pass filter
7 Acoustic emission testing
   7.1 Field vs. factory test differences
   7.2 General considerations on the application of sensors
8 Acoustic emission field test procedure
   8.1 Introduction
   8.2 Test setup
   8.3 Sensor placement and initial scan
   8.4 Monitoring techniques
   8.5 Locating the source of the signal
   8.6 Reporting and follow-up
9 Factory test procedure using an electrical trigger
   9.1 Introduction
   9.2 Initial sensor placement
   9.3 Measurements and changing of sensor placement
10 Characterization of acoustic emission signals
   10.1 Introduction
   10.2 General - alternating current systems
   10.3 Acoustic systems that record single events
   10.4 DSP workstations that record data over extended periods
   10.5 On-line (continuous) acoustic partial discharge systems
   10.6 HVDC transformers and reactors
   10.7 Characteristics of PD from static electrification
   10.8 Acoustic activity from thermal faults, the core,
        mechanical noises and other sources
   10.9 Comparison between electrical and acoustic signals
11 Integrating AE results with data from oil analysis
12 Acoustic activity interpretation
Annex A (informative) Bibliography
Annex B (informative) Signal processing
Annex C (informative) Wavelet signal processing theory
Annex D (informative) Tutorial: detection and location of
        acoustic emissions from partial discharge