deuar - pole test

Spread Sheet Demonstration of MPT Cost Savings

Below is an example cost analysis of the present and new system of maintenance of 100,000 power pole population.

PRESENT SYSTEM

Note: It has been assumed that 5% of poles fail the present pole inspection criteria and 25% of failed poles need to be replaced rather than reinstated.

Cost of pole inspection and pole treatment: 100,000 x $25 = $2,500,000
Cost of reinstatement of 75% of failed poles: 100,000 x 0.05 x 0.75 x $500 = $1,875,000
Cost of replacement of 25% of failed poles: 100,000 x 0.05 x 0.25 x $2,500 = $3,125,000
Total cost of present system   = $7,500,000

NEW SYSTEM

Using mechanical proof load test instead of the present pole inspection and chemical treatment of poles.

Note: It has been assumed that 90% of all poles is tested mechanically instead of the present pole inspection. Also, it is assumed that at least 50% of poles currently failed by the present pole inspection will be saved by mechanical test, i.e. 2.5% of all poles tested mechanically will fail (instead of 5% failed by the present pole inspection).

Cost of present inspection and treatment (to 10% of all poles): 0.10 x 100,000 x $25 = $250,000
Cost of mechanical test: (to 90% of all poles): 0.90 x 100,000 x $20 = $1,800,000
Cost of pole reinstatement of 75% of poles failed by present system (to 10% of all poles): 100,000 x 0.10 x 0.05 x 0.75 x $500 = $187,500
Cost of reinstatement of 75% of poles failed by new system (to 90% of all poles): 100,000 x 0.90 x 0.025 x 0.75 x $500 = $843,750
Cost of pole replacement of 25% of poles failed by present system (to 10% of all poles): 100,000 x 0.10 x 0.05 x 0.25 x $2,500 = $312,500
Cost of replacement of 25% of poles failed by new system (to 90% of all poles): 100,000 x 0.90 x 0.025 x 0.25 x $2,500 = $1,406,250
Total cost of new system   = $4,800,000
Total savings due to replacement of present pole inspection and treatment with mechanical proof load test:   = $2,700,000

NEW SYSTEM

Using mechanical proof load test in addition to present pole inspection and chemical treatment.

Note: It has been assumed that 90% of all poles is tested mechanically in addition to the present pole inspection. Also, it is assumed that at least 50% of poles currently failed by the present pole inspection will be saved by the mechanical test, i.e. 2.5% of all poles tested mechanically will fail (instead of 5% failed by the present pole inspection).

Cost of present inspection and treatment (to all poles): 100,000 x $25 = $250,000
Additional cost of mechanical test: (to 90% of all poles): 0.90 x 100,000 x $20 = $1,800,000
Cost of reinstatement of 75% of poles failed by present system (to 10% of all poles): 100,000 x 0.10 x 0.05 x 0.75 x $500 = $843,750
Cost of replacement of 25% of poles failed by present system (to 10% of all poles): 100,000 x 0.10 x 0.05 x 0.25 x $2,500 = $312,500
Cost of replacement of 25% of poles failed by new system (to 90% of all poles): 100,000 x 0.90 x 0.025 x 0.25 x $2,500 = $1,406,250
Total cost of new system   = $7,050,000
Total savings due to addition of mechanical proof load test to present pole inspection and treatment:   = $450,000

CONCLUSIONS

Present methods of pole inspection are approximate and generally subjective. As a result they reject many serviceable poles and fail to identify some dangerous poles.

The new Deuar system, based on the most objective and accurate direct measurement of the needed pole strength, saves poles from premature replacement and pinpoints all dangerous poles.

It provides not only a more cost effective mainenance of power pole assets but at the same time increases the safety to the public and utility personnel.

Analysis by independent structural engineers has validated the new system and vast experience and statistics clearly indicate that the risk of pole failure prior to the next inspection is many times less than the present risk.

 

Advanced Present Value Analysis of Mechanically Tested Poles

1. Introduction

The ECTEST14 computer program can accurately check whether it is economic to mechanically test any particular condemned or suspect pole or a group of such poles with some average features.

The ECTEST12 computer program can additionally make any economic comparison between the reinstated pole and mechanically tested pole, which may still be reinstated after its failure.

The ECTEST11 computer program can check whether it is economic to mechanically test all poles or any group of sericeable poles.

2. Method Description

The advanced present value analysis incorporates probabilistic enhancements which allow for reasonable coverage of the number of uncertain economic data, such as future discount rate, etc.

The programs ask a number of questions about the pole costs, serviceable life, discount rate as well as corresponding standard deviations for all data if the probabilistic analysis is required.

After the requested information is input, the ECTST14 and ECTEST11 programs calculate the present value of the maintenance of a new pole and mechanically tested pole, net savings or losses to utility per one pole, and minimum savings (or maximum losses) per one pole guaranteed with the chosen confidence level if the probabilistic analysis is required. The ECTEST12 program calculates additionally the present value of the maintenance of a reinstated pole and mechanically tested pole, which may still be reinstated after it failure.

The economic analysis is run until the present value of the successive pole replacement is less than one dollar. This condition enables very accurate and explicit comparison between the analysed pole management options.

3. Assumptions

As in any analysis some assumptions had to be adopted of which the most imporant are:

a) The additional cost of mechanical testing of one pole, resulting from the necessity of temporary supporting of some failed poles, is calculated as $50.00 * (100 - PPS) / PPS

where: 50.00 = average cost of temporary supporting of one pole (assuming that approximately half of the failed poles does not require any temporary support) and PPS = percentage of poles saved by the mechanical test from replacement

b) All the time data are input in full years and within the economic analysis all the time values are rounded up to a full number of the pole inspection cycles.

 

 


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