New Zealand Gazette – 1999 – No. 190

Page 4540

✨ Reliability Performance Measures



4540

NEW ZEALAND GAZETTE

No. 190

Part 6
Reliability Performance Measures To Be
Disclosed By Transpower
(Disclosure Under Regulation 22)

  1. Total number of unplanned interruptions* 110 103 164 229
    Resulting from 69 loss of supply incidents in 1998-99

  2. Electricity customer interruptions in system minutes.................**
    planned 2.7 2.1 2.1 5.8
    unplanned 7.1 2.9 11.5 6.4

  3. Underlying electricity customer interruptions in system minutes...........**
    Underlying interruptions are those interruptions of 1 system minute or less duration
    planned 1.7 2.1 2.1 3.1
    unplanned 5.6 2.9 4.8 4.0

  4. Average supply reliability ..................% 99.9972 99.9985 99.9959 99.9963
    Measured by the energy supplied divided by the sum of the energy supplied and not supplied

  5. Uneconomic generation due to planned and unplanned transmission system unavailability .......................% 0.01 0.02 0.55 0.81
    Uneconomic generation relates to the amount of electricity generated from any source other than the most economic source.

  6. Uneconomic generation due to HVDC system unavailability ..................% Effectively 0 0.01 0.47 0.73

  7. Uneconomic generation due to unplanned transmission system unavailability .......................% 0.01 0.01 0.12 0.22

  8. Planned interruption restoration performance ..................% 94.4 90.5 72 80.5

  9. Unplanned interruption response............% 100 98.1 100 99.1

The information compiled using estimated information includes Part 6 sections 2,3,4,5,6 and 7. The methodology used to calculate the estimated information is documented and available from Transpower upon request.

The 1997/98 and 1998/99 figures for uneconomic generation are considerably different than in previous years. The data for these figures has been collected in line with the specified guidelines. However, uneconomic generation is not relevant in the market environment as scheduling is carried out differently and ‘offers to generate’ are made after taking constraints into account and it is not possible to predict what the generator would have offered if the constraint was not present.

  • Where two supply voltages, or two customers, at the same station are both interrupted this is counted as two interruptions.

** Any minor differences between the total and the sum of planned and unplanned are due to rounding.

DEPARTMENT OF INTERNAL AFFAIRS
TE TARI TAIWHENUA

PUBLISHED BY AUTHORITY OF DEPARTMENT OF INTERNAL AFFAIRS:
LEGISLATION DIRECT, WELLINGTON, NEW ZEALAND—1999

ISSN 0111-5650
Price $5.35 (inc. G.S.T.)
32571—99A


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✨ LLM interpretation of page content

🏭 Reliability Performance Measures To Be Disclosed By Transpower

🏭 Trade, Customs & Industry
Reliability Performance, Electricity Supply, Interruptions, Supply Reliability, Uneconomic Generation, Transpower