IEC Publication 60599 provides a coded list of faults detected by dissolved gas analysis (DGA) as follows:
PD = partial discharges
D1 = discharges of low energy
D2 = discharges of high energy
T1 = thermal faults of temperature < 300℃
T2 = thermal faults of temperature 300℃ < T < 700℃
T3 = thermal faults of temperature > 700℃
