3.4 EPOXY RESIN RICH MICA PAPER, HEATED PRESS CURED
With reference to Table 14, the case of load related slot
discharge detected by directional couplers in 1981 for a 17
kV 160 MVA synchronous condenser operating in
hydrogen at 200 kPa (gauge) at Dorsey remains an
important example [31]. It was found that this horizontal
stator had 308 mm long diagonal split wedges in the slots.
These had fallen out around 12 o’clock allowing the
associated stator bars to move approximately 10 mm in the
direction of the air gap. At full load the radial bar force is
estimated to be 1.6 kN/m of slot length.
The rewinds of three of the 11 kV units up-rated from
32.5 MVA to 43 MVA at Seven Sisters were associated
with the installation of new turbines with draft tube water
depression to facilitate operation as synchronous
condensers.