In this post I show the local electricity generation and net import for each region of the Australian NEM around the time (7:30 am EST) of a power outage at the Adelaide electric railway system on the 28th April 2016. Queensland, New South Wales and Victoria all had fluctuations in local generation around this time, but all had compensating changes in net import, resulting in plausible variations of total consumption. South Australia had the combination of falling local generation, and a dip in net import, suggesting that the NEM failed to supply sufficient electricity to meet demand, with most of the shortfall occurring in South Australia. This shortfall in supply may have tripped the electric railway system.
The following figures show, for each region of the NEM (excluding Tasmania, disconnected at the time), for the period 6:00 to 9:00 am, the total local generation (black dots), the net import (mauve dots) and the sum of the two just mentioned (blue curve), i.e. the total local consumption.
Each quantity shown is displayed relative to its average value over the period shown (6:00 to 9:00 am EST).
QUEENSLAND:
NEW SOUTH WALES:
VICTORIA:
SOUTH AUSTRALIA:
Discussion
All regions except South Australia had plausible variations of total consumption, i.e.relatively smooth and rising. South Australia had an unusual dip in total consumption at 7:30 am, resulting from the combination of falling local generation and a dip in net import, giving an implausible variation of total consumption for an early morning period on a working day, suggesting the distinct possibility that the NEM failed to provide sufficient supply to meet demand at this time.
Sources
See the NEM ELECTRICITY DATA page for links to the archive data used, local generation was obtained by summing SCADA Values (from Dispatch SCADA files) over all generators in each region, net import was obtained by summing METEREDMWFLOW values (from Dispatch IS files) over all interconnectors serving each region.
Are all the times local? If so, the SA plot needs to be offset by half an hour to the right to show each plot at the same instant and basically shows no effect on the other plots.
For both Queensland and NSW, it would appear at first glance that Victoria’s (mainly brown coal) generators provided the support for the sags just before and after 7:30am AEST.
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All the plots use the same reference time, the one used by the NEM, which is Australian Eastern Standard Time, so I think the plots are all time-aligned, but local time varies a bit from East to West.
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