Was the grid having fun last night?

Our voltage normally fits within the 235 to 245 range 24/7 but last
night the UPS went into voltage trim modes several times, it does
this when the input gets above 250v. These were briefly just before
2100 and about 2215, from 0030 to 0230 and 0430 to 0530 (roughly).
The voltage plot from the UPS shows a couple of spikes above the
allowed upper limit of 253v.

Just wondering if it was a local problem (North Pennines, 33kV feed
comes from near Penrith) or more widespread.

--
Cheers
Dave.

On 03/03/2011 16:35, Dave Liquorice wrote:
Was the grid having fun last night?

Our voltage normally fits within the 235 to 245 range 24/7 but last
night the UPS went into voltage trim modes several times, it does
this when the input gets above 250v. These were briefly just before
2100 and about 2215, from 0030 to 0230 and 0430 to 0530 (roughly).
The voltage plot from the UPS shows a couple of spikes above the
allowed upper limit of 253v.

Just wondering if it was a local problem (North Pennines, 33kV feed
comes from near Penrith) or more widespread.


Looking at th log on my UPS' at the office, in Kingston upon Thames,
Surrey, it looked normal.

Over the last 24 hours it has been between 236v and 248v I cant see
anything unusual at the times you say!

--
Toby...
Remove pants to reply

Dave Liquorice wrote:
Was the grid having fun last night?

Our voltage normally fits within the 235 to 245 range 24/7 but last
night the UPS went into voltage trim modes several times, it does
this when the input gets above 250v. These were briefly just before
2100 and about 2215, from 0030 to 0230 and 0430 to 0530 (roughly).
The voltage plot from the UPS shows a couple of spikes above the
allowed upper limit of 253v.

Just wondering if it was a local problem (North Pennines, 33kV feed
comes from near Penrith) or more widespread.

Probably there was a gust of wind, and they couldnt turn the coal down
fast enough to compensate.:-)

OTOH the period between midnight and 4 a.m. is the lowest consumption
period.

By 6 a.m. it's pretty much up t daytime levels tho, where it stays until
the 7pm peak before falling back as people switch off and go to bed.