3.5 non-self-restoring insulation: Insulation which loses its insulating properties, or
does not recover them completely, after a disruptive discharge. [IEV 604-03-051
NOTE - The definitions of 3.4 and 3.5 apply only when the discharge is caused by the application of a
test voltage during a dielectric test. However, discharges occurring in service may cause a self-restoring
insulation to lose partially or completely its original insulating properties.
3.6 insulation configuration terminal: Any of the electrodes between any two of which
a voltage that stresses the insulation can be applied. The typeso f terminal are:
a) phase terminal, between which and the neutral is applied in service the phase-toneutral
voltage of the system;
b) neutral terminal, representing, or connected to, the neutral point of the system
(neutral terminal of transformers, etc.);
c) earth terminal, always solidly connected to earth in service (tank of transformers,
base of disconnectors, structures of towers, ground plane, etc.).
3.7 insulation configuration: The complete geometric configuration of the insulation in
service, consisting of the insulation and of all terminals. It includes all elements (insulating
and conducting) which influence its dielectric behaviour. The following insulation
configurations are identified:
- three-phase: having three phase terminals, one neutral terminal and one earth
terminal.
- phase-to-earth: a three-phase insulation configuration where two phase terminals
are disregarded and, except in particular cases, the neutral terminal is earthed.