IEEE C57.127-2007

1 Overview
   1.1 Scope
   1.2 Purpose
   1.3 Safety warnings
2 Definitions
3 Detection and measurement of PD-Background information
4 Introduction to acoustic PD systems
   4.1 All-acoustic system
   4.2 Acoustic system with an electrical PD trigger
   4.3 On-line (continuous) acoustic monitoring system
5 Acoustic signal and 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 PD monitoring systems
   6.5 External sensor
   6.6 Internal sensor
   6.7 Three-sensor system
   6.8 Band-pass filter
7 AE testing
   7.1 Personnel qualification and certification
   7.2 Field versus factory test differences
   7.3 General considerations on the application of sensors
8 AE 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 followup
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 AE signals
   10.1 Introduction
   10.2 General-AC systems
   10.3 Acoustic systems that record single events
   10.4 DSP workstations that record acoustic data over
        extended periods
   10.5 On-line (continuous) acoustic partial discharge
        monitoring 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 and case studies for detection
        and location of AE from PD

Pertains to the detection and location of acoustic emissions from partial discharges and other sources in oil immersed power transformers and reactors. Both electrical sources (partial discharge) and mechanical sources (such as loose clamping, bolts, or insulation parts) generate these emissions.