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P.O BOX 429, NUKU’ALOFA, Tel: (676) 21-400 Fax: (676) 23-047 Email: afernando@tongapower.to

25 August, 2014 Lord Dalgety Electricity Commission Tu’atakilangi Nuku’alofa

Dear Lord Dalgety

Re: Monthly Compliance Report – July 2014

In accordance with the reporting requirements of the Electricity Concession Contract and in response to

your request for additional information as specified in the suggested MOU dated May, 2012, TPL

submits the following reports for the month of July, 2014.

1. System Loss Report

2. Fuel Efficiency Report

3. Reliability Measures Report

4. Monthly Outage Events Report

The above report items are described in detail below.

1. System Loss Report, June 2014

The following graphs illustrate the 12 months Moving Average (smoothed) Systems Losses for all four

islands for the years 2012/13 and 2013/14. The 12 months moving average losses are used because of

the variability of monthly Real Time Systems Losses due to the impact of the number of days and fall of

the weekends in respect to meter reading cycle. In addition, system loss report is always one month late

as last month consumption data (i.e. meter readings) will only be read this month and available to

report next month. Hence July EC Report contains only June system loss data.

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For the month of June, 2014, all island moving average system losses have slightly decreased from

12.59% (May, 2014) to 12.29% (June, 2014) achieving the regulatory target 13%.

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The individual island group’s system losses are shown below.

The graph above shows that Tongatapu systems losses have decreased from 12.60% (May) to 12.26%

(June).

Vava’u losses have been steady since March, 2014 to June, 2014 at around 12.8%.

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Ha’apai system losses have always been below target until January, 2014. Since January, system losses

have increased due to Cyclone Ian effect.

Eua systems losses are trending downwards, and fell below 13% target in May but increased again in

June.

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2. Fuel Efficiency Report, June 2014

It is important to note that fuel efficiencies calculated here include both diesel and solar generation.

Hence the following fuel efficiencies are somewhat higher than than the diesel only generation. Targets

in the Concession Contract have been stipulated for diesel generation only.

Tongatapu fuel efficiency ratios have been erratic, but most of the time above the target.

Vava’u fuel efficiency ratios have been well above the taregt due to the two new 600KW generators

commissioned in May, 2010 and the introduction of Vava’u solar farm which was commissioned in

November 2013.

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Mostly, fuel efficiency ratios have been under achieved in Haapai but increased to a record high in

March and May, 2014.

Mostly, fuel efficiency ratios have been under achieved in Eua.

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Overall, all island fuel efficiency ratios have been above weighted average target of 4.17 KWh/L.

3. Reliability Measures, July 2014

SAIDI minutes (measuring average total duration of interruption per connected customer) for the

month of July, 2014 have significantly increased from 87.19 (June, 2014) to 171.37 (July, 2014) minutes

(see the table above). Some of the major HV faults contributed to the SAIDI minutes for the month of

June are described below.

Reliability Measures

Month 2011/12 2012/13 2013/14 2014/15 Month 2011/12 2012/13 2013/14 2014/15 Month 2011/12 2012/13 2013/14 2014/15

Jul 4.74 21.21 88.34 171.37 Jul 143.09 60.157 173.956 106.45 Jul 0.03 0.327 0.443 1.61

Aug 4.51 37.88 46.52 Aug 161.45 98.368 44.067 Aug 0.03 0.337 1.011

Sep 59.19 2.93 92.02 Sep 649.6 38.891 51.963 Sep 0.09 0.035 1.736

Oct 253.89 32.02 318.4 Oct 243.63 18.195 102.032 Oct 1.04 1.723 3.121

Nov 25.49 138.22 38.51 Nov 69.34 53.329 91.757 Nov 0.37 2.551 0.42

Dec 115.19 72.61 13.15 Dec 358.97 32.499 21.693 Dec 0.32 2.205 0.605

Jan 622.62 153.97 55.91 Jan 280.26 83.365 116.161 Jan 2.22 1.7 0.481

Feb 3010.76 189.06 47.3 Feb 412.1 206.295 124.67 Feb 7.31 0.884 0.379

Mar 23.32 146.48 138.91 Mar 55.81 58.538 58.889 Mar 0.42 2.44 2.272

Apr 336.9 236.17 94.02 Apr 219.97 119.239 63.835 Apr 1.53 1.949 1.473

May 294.55 100.64 37.85 May 98.59 23.137 97.391 May 2.99 0.521 0.389

Jun 14.72 7.26 87.19 Jun 66.45 126.29 145.14 Jun 0.22 0.027 0.601

Total 4765.88 1138.45 1058.12 171.37 Total 2759.26 918.303 1091.552 106.45 Total 16.57 14.699 12.931 1.61

SAIDI Monthly Performance (Minutes) CAIDI Monthly Performance (Minutes) SAIFI Monthly Performance

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Cumulative SAIDI YTD is showing below. The annual target is 5% less than the last year’s value.

CAIDI minutes (measuring average total duration of interruption per interrupted customer) for the

month of July 2014 have however decreased from 145.14 minutes (June, 2014) to 106.45 minutes (July,

2013).

Report Date No of Customers Off Fault Description Repair Comment

28/07/2014 15,432 Shut Down Replaced with a fault at Ha'utu where the power was fine

30/07/2014 15,432 Shut down fault changed, previous one was a false alarm

27/07/2014 5,021 Generation Nukualofa feeder 1 off Generator Nuku'alofa feeder 1 fault

NO Load:

Volt NA - 244V, NB - 245V, NC - 246V

Phase phase AB - 424V, AC - 424V, BC - 426V

Load:

Volt NA - 239V, NB - 240V, NC 243V

Phase phase AB - 423V, AC - 421V, BC - 421V

Current A - 81.4V, B - 87.5, C - 67.2V

materials: fuse 15A x 3 HV

16/07/2014 4,500 Shut down Shut down

15/07/2014 4,106 Power off Power off from generator at the power station

20/07/2014 4,106 Vaini Feeder FAULT HV pole broken L8309 VS HV & Inline pole at Tatakamotonga and it causes a FAULT to

Feeder Vaini at 16:00 pm at 16:55 the Feeder was feed back on from Folaha to Ha'ateiho

and end to Nakolo, at 21:13 from Malapo to Tatakamotonga, 21:21 Tatakamotonga to

Hoi, 21:27 from Tatakamotonga to Ha'asini, 21:32 Hoi to Niutoua. After that they were

resag and balance LV lines for clearance. ( Tauelangi Ma'asi ) is a Driver

27/07/2014 1,599 Shut down inline fuse 17:00 shut down inline fuse from Saint Andrew end to Ha'atafu .Partly off from Kolofo'ou

area to Hihifo the boys found out the problem and reported the Inline

Fuse loose tailer from HV Line at Longolongo Police Staition

27/07/2014 1,599 Power supply feed back On from Maui to Ha'atafu at 17:52

09/07/2014 700 Partly off Power partly off due to tree branch fell on HV line

09/07/2014 700 Power shut down from Hoi to Niutoua. Coconut tree felt on one phase of H.V. line and broken [ blue phase ] between Hoi and

Talafo'ou.

20/07/2014 650 Vaini Feeder FAULT After switching on part of the Vaini Feeder, from Folaha to Ha'ateiho and to Nakolo, the

linesman replaced the HV pole, resag and balance LV lines for clearance.

Malapo to Niutoua and Tatakamotonga to Ha'asini was still off

27/07/2014 485 power supply feed back On from Saint Andrew to Maui at 17:45

27/07/2014 485 power back to nomal Power back to normal at 20:11 part of Longolongo of causes by inline fuse loose tailer

from HV Line

20/07/2014 320 Vaini Feeder FAULT Power was switched on partly for the rest of Vaini Feeder.

Malapo to Tatakamotonga - 21:13

Tatakamotonga to Hoi - 21:21

Tatakamotonga to Ha'asini - 21:27

Hoi to Niutoua - 21:32

03/07/2014 300 Shut Down shut down

08/07/2014 200 Shut down Shut down from Tokomololo to Liahona.

17/07/2014 60 Partly off Partly off due to fuse blown A100 x 1 test result: 230V

31/07/2014 50 Power off Blown fuse low on line so they replace it with

1 x 80 A

phase red

ta- 243 v

31/07/2014 40 Power off Power off due to blown fuse on HV line so they replace fuse with 1 X 3 A

14/07/2014 30 Partly off Partly off due to IPC loose connection so they reconnect and tight up properly Material

uses: IPC 16-95x 1 Test result: before- 0V after- 234V

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Cumulative CAIDI YTD is showing below. The annual target is 5% less than the last year’s value.

SAIFI (measuring average number of interruptions per customer) has also increased signficantly from

0.60 to (June, 2014) to 1.61 (July, 2014).

Cumulative SAIFI YTD is showing below. The annual target is 5% less than the last year’s value.

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4. Monthly Outage Events, July 2014

There were total of 572 planned & unplanned fault events for the month of July, 2014 affecting 56,324

customers (it is possible that several outages would have struck the same customer more than once). As

per the table above, the number of fault events has slightly increased from 490 in June, 2014 to 572

events in July, 2014. HV/LV lines/transformer faults have increased from the last month. Both customer

premises faults and the service line faults have increased. Most of the customer services faults

included fuses at the service line tap off point for a premise. Street lights faults however have increased.

In total, the number of faults has decreased significantly from same month last year from 762 (July

2013) to 572 (July, 2014). There is no correlation between the 2013 and 2014 figures.

Should you have any queries with the information provided, please do not hesitate to contact me.

Yours Faithfully, Ajith Fernando Risk & Compliance Manager Tonga Power Limited

Fault Events 2014 vs. 2015

Planned/Unplanned Outage Events Jul-13 Jul-14 Aug-13 Aug-14 Sep-13 Sep-14 Oct-13 Oct-14 Nov-13 Nov-14 Dec-13 Dec-14 Jan-14 Jan-15 Feb-14 Feb-15 Mar-14 Mar-15 Apr-14 Apr-14 May-14 May-15 Jun-14 Jun-15 2013/14 2014/15

Generator problem 0 3 1 2 1 0 0 3 0 2 1 0 0 10 3

HV Lines 10 17 14 9 30 13 23 26 19 6 16 32 14 212 17

HV/LV Transformer 16 14 14 3 12 10 16 31 27 31 13 17 8 198 14

HV Pole 1 5 3 3 2 1 1 2 2 1 2 0 2 20 5

LV Lines 17 58 33 35 36 35 31 64 56 49 38 41 39 474 58

Service lines 341 200 167 202 155 189 197 261 169 336 169 228 209 2623 200

Customer premises 350 246 298 274 279 232 405 280 295 327 295 181 191 3407 246

Street Lights 21 27 23 30 51 34 38 20 21 44 36 12 21 351 27

Meter 6 2 8 3 1 6 4 5 7 14 4 3 6 67 2

Total 762 572 561 561 567 520 715 692 596 810 574 514 490 7362 572

YTD Total