4 Historic Cost and Service Performance
4.8 Service Target Performance Incentive Scheme Performance 2013-17
The Service Target Performance Incentive Scheme (STPIS) provides an economic incentive for TNSPs to maintain and further improve delivery of transmission services.
This section sets out Powerlink’s overall performance result under the AER’s STPIS for the current regulatory period (from 1 July 2012 to 30 June 2017). In this period, Powerlink is subject to Version 3 of the scheme.
Under Version 3, network performance is measured against seven parameters under the Service Component (SC) and also against the Market Impact Component (MIC) as identified below:
• Service Component:
Peak transmission circuit availability;
Transmission line availability;
Transformer availability;
Reactive plant availability;
Frequency of loss of supply events > 0.10 system minutes;
Frequency of loss of supply events > 0.75 system minutes; and Average outage duration.
• Market Impact Component:
Dispatch Interval (DI) count.
Powerlink’s historical STPIS performance since 1 July 2012, which is on a calendar year basis, is summarised in Table 4.7.
It should be noted that the performance shown in Figures 4.8 to 4.15 is for the full calendar year based on Version 3, regardless of the transition to a new regulatory period halfway through 2007 and 2012.
Table 4.7: Historic STPIS performance (2012 2Ha to 2015)
Parameter Measure Calendar Year
2012 2Ha 2013 2014 2015b
Service Component
Peak transmission circuit availability % 98.71 99.03 98.91 99.01
Transmission line availability % 98.46 98.68 98.36 98.29
Transformer availability % 98.77 98.22 98.88 99.03
Reactive plant availability % 98.01 98.79 97.72 97.33
Loss of supply events > 0.10 system minutes Events 1 0 3 1
Loss of supply events > 0.75 system minutes Events 0 0 0 1
Average outage duration Minutes 900 645 742 628
Market Impact Component Dispatch intervals 0 97 3941 65
(a) Powerlink’s 2012 STPIS performance was based on the second half-year period from 1 July 2012 to 31 December 2012, given that its new targets were applicable to the new regulatory period from 1 July 2012 to 30 June 2017.
(b) Powerlink’s 2015 STPIS performance will be submitted to the AER for review on 1 February 2016 as part of the AER’s annual reporting requirements.
4.8.1 Historic transmission circuit availability performance
Powerlink’s transmission circuit availability since 2007 for peak, transmission line, transformer and reactive plant is presented in Figures 4.8 to 4.11, respectively. These figures show availability performance for all four measures in relation to performance target, collar and cap values set by the AER for the current regulatory period.
Powerlink’s performance during the current regulatory period for the peak circuit and reactive plant availability has consistently exceeded target, while transformer availability performance was above target for three of the four years. Transmission line performance remained below the AER target for the period.
The peak availability measure encourages Powerlink to plan outages at times of the year with least potential impact on the network, which is typically outside the peak summer load times between November and March each year.
Reactive plant, and in particular capacitor banks, are most useful during times of high load demand which is also in the summer months. As can be seen from Figure 4.8, Powerlink has achieved positive results from implementing outage planning to avoid peak times where possible, resulting in above target outcomes.
Figure 4.8: Powerlink historic performance - peak transmission circuit availability
97.0 97.5 98.0 98.5 99.0 99.5 100.0
2007 2008 2009 2010 2011 2012 2013 2014 2015
Percent
Peak transmission circuit availability RR13-17 Target
Source: Powerlink data.
Transmission line availability (see Figure 4.9) has trended below target during the current regulatory period, primarily as a result of planned project outages for operational refurbishment and capital transmission line works and secondary systems upgrades that required line outages.
Figure 4.9: Powerlink historic performance - transmission line availability
97.0 97.5 98.0 98.5 99.0 99.5 100.0
2007 2008 2009 2010 2011 2012 2013 2014 2015
Percent
Transmission line availability RR13-17 Target
Source: Powerlink data.
Transformer availability has been reasonably consistent over the past nine years with annual variations reflecting planned outages of transformers (Figure 4.10). During the current regulatory period transformer availability exceeded target for all years except 2013, where a higher than normal volume of planned outages for both maintenance and project works resulted in a lower availability for that year.
Figure 4.10: Powerlink historic performance - transformer availability
97.0 97.5 98.0 98.5 99.0 99.5 100.0
2007 2008 2009 2010 2011 2012 2013 2014 2015
Percent
Transformer availability RR13-17 Target
Source: Powerlink data.
Reactive plant availability has trended above target reflecting improved levels of availability for this class of equipment, being Static VAr Compensators (SVC), capacitor banks and reactors (Figure 4.11).
Figure 4.11: Powerlink historic performance - reactive plant availability
94.0 94.5 95.0 95.5 96.0 96.5 97.0 97.5 98.0 98.5 99.0 99.5 100.0
2007 2008 2009 2010 2011 2012 2013 2014 2015
Percent
Reactive plant availability RR13-17 Target
Source: Powerlink data.
4.8.2 Historic loss of supply event frequency performance
Powerlink’s performance under loss of supply event frequency exceeding 0.10 system minutes (x) and 0.75 system minutes (y) since 2007 is shown in Figures 4.12 and 4.13. The figures indicate that Powerlink has continued its better than the target loss of supply performance in relation to both thresholds.
In January 2015, Queensland experienced a significant storm which impacted Powerlink’s network supply to Far North Queensland. This resulted in a loss of supply event greater than 0.75 system minutes.
Figure 4.12: Powerlink historic performance - loss of supply event frequency greater than 0.10 system minutes
0 1 2 3 4 5 6 7
2007 2008 2009 2010 2011 2012 2013 2014 2015
Counts
Loss of supply event > 0.10 system minutes RR13-17 Target
Source: Powerlink data.
Figure 4.13: Powerlink historic performance - loss of supply event frequency greater than 0.75 system minutes
0 1 2 3
2007 2008 2009 2010 2011 2012 2013 2014 2015
Counts
Loss of Supply Event > 0.75 system minutes RR13-17 Target
Source: Powerlink data.
4.8.3 Historic average outage duration performance
Figure 4.14 illustrates Powerlink’s average outage duration performance from 2007 to 2015. This measure relates only to unplanned outage events and shows that Powerlink has consistently maintained an average outage duration performance at levels better than the AER target.
Figure 4.14: Powerlink historic performance - average outage duration
0 200 400 600 800 1000 1200
2007 2008 2009 2010 2011 2012 2013 2014 2015
Minutes
Average Outage Duration (minutes) RR13-17 Target
Source: Powerlink data.
4.8.4 Historic Market Impact Component performance
Powerlink’s MIC performance since 2007 is shown in Figure 4.15, which reflects the consistent application of established processes to minimise the impact of outage events on market participants.
For clarification, Powerlink was subject to report only arrangements under the MIC between 2007 and 2009.
Powerlink commenced the scheme in full on 13 July 2010.
In 2014, Powerlink undertook extended planned outages on its network connection between Queensland and New South Wales, which resulted in significant Dispatch Interval (DI) counts (as seen in Figure 4.15). As outages were required to deliver project works, Powerlink’s outage planning process scheduled these outages at the time of the year that would create least impact on the market. Powerlink also used efficient project staging and resourcing to minimise the duration of these outages.
Powerlink continues to work closely with customers to plan and coordinate network outages at times least likely to result in a market constraint. Powerlink also takes real-time action to reschedule works to reduce the impact of binding constraints on the market.
Figure 4.15: Powerlink historic performance - Market Impact Component
0 500 1000 1500 2000 2500 3000 3500 4000 4500
2007 2008 2009 2010 2011 2012 2013 2014 2015
Dispatch Intervals (DIs) Counts
Market Impact Component (DIs) RR13-17 Target
Source: Powerlink data.