Frequency Events

There have been big improvements to the Mainland system frequency reporting, both under the hood, and in terms of functionality and utility. We have made our frequency measurement hardware and software significantly more accurate, robust, and fault-tolerant, including introducing more intelligent filtering and processing. Time Error (the accumulation of frequency deviation) is now computed on our hardware, rather than calculated from the frequency measurement. This means the numerical error of successive time error calculations is greatly reduced using the new method. Frequency is measured and stored in milli-Hz, and time-Error in tenths of a millisecond.

In the event of contingencies (where the system frequency exceeds the normal range of 49.85 - 50.15Hz), high resolution (200ms) frequency data is captured and stored for the duration of the event, as well as 5 minutes before and after. We are bringing you new reports in NEOmobile and NEO/NEOpoint that show high resolution Mainland frequency contingency events, as well as aggregated reports such as contingency Gantt charts and bar charts for number of contingencies per interval.

Live Market Events are now generated from the frequency data as follows:

  • Frequency out of range - if the frequency exceeds the normal frequency band, e. 50Hz  +/- 0.15Hz;
  • Frequency emergency - if the frequency enters the emergency band, i.e. 50Hz +/- 0.5Hz; and
  • Large frequency change - if the frequency rapidly drops or increases significantly - usually attributable to a unit trip or lost load respectively.

The point to note from the above is that the “Large Frequency Change” event picked up the unit trip of between 330MW – 590MW a full two minutes before the “Unit trip” event of LYA2. This is expected because we only now about unit trips on the next DI.

These frequency related Market Events have a 10-minute cool-down, and you can set up alerts to notify you by email or to your mobile device running the NEOmobile app. An example of a creating an alert is shown below:

MTPASA Capacity Change Event

The MTPASA Capacity Change event calculation has been modified to make the event more reliable and informative. The old event message simply calculated the date range over which the magnitude of the difference between the current MTPASA capacity forecast and the previous was the same. This would sometimes group multiple events of the same magnitude together. Also, 2 overlapping events may be reported as 3 separate events. The new version of the event instead attempts to match start and end times of individual capacity change events, even if these events overlap. Multiple, separate events of the same magnitude are also correctly identified. In the case where matching start/end times for a capacity change cannot be determined, the event still reports that a significant difference was detected at a specified date so that no changes are missed. We have also reduced the event magnitude filter from 100MW to 50MW.

NEOmobile Phone Application

Just a reminder that the NEOmobile phone application is available for iPhone or Android and is free of charge from the AppStore or PlayStore. If you login with a paid for account then you can access extra features like Alerts. The mobile alerts work even if the app is not running and it uses the push notification. Alerts are very fast – virtually always less than one second – so you will be the first to know about market events.