The Otago Daily Times contacted Aurora last week to ask about an Aurora report on the Eureka St pole, and an independent URI Engineering review of Aurora’s pole inspection process.
The URI report said there were "still some issues with lack of information around the accuracy of the inspection methods" but, even though it had not been asked to assess the accuracy of the methods, there was enough evidence "anecdotally and from our own observations" to continue Aurora’s use of the Deuar pole inspection method.
However, the "traditional" method previously used by Aurora did not comply with electricity safety regulations and was "not an accurate method".
There were also issues with Aurora’s documentation process, including from parts of pole inspections and all pole failure assessments being captured on paper, then entered into a Xivic database, then exported into Microsoft Excel for further analysis and imported into a geographic information system (GIS). The multiple points of entry meant there were "multiple points at which failure can occur", the report said.
The report recommended improving the documentation, and conducting a "comprehensive and defendable" assessment of the accuracy of the Deuar method.
The report said Aurora was reinspecting 2910 red-tagged poles to better identify which poles "truly need replacement", and when. It recommended the Deuar method be used exclusively until the traditional method could be improved. But it said there was "still much to gain" by reassessing the poles, "as we suspect that many of the poles will have their grade changed".
The Aurora incident cause analysis method investigation (Icam) report on the August 2017 falling of the Eureka St pole, which Aurora described as a "failing", said the pole was assessed using the traditional pole inspection method and a Deuar inspection would have provided "a more accurate indication" of the pole. It also said four months of wet weather that preceded the pole failing might have contributed to the pole "losing its base integrity".
Aurora chief executive Steve Thompson said in December the investigation into the Eureka St pole showed "an issue with inspection methodology" that "didn’t take into account pole top loading" and the inspection methodology had then immediately been changed.
However, some of his comments contradict Aurora’s Icam report.
In December Mr Thompson said the Eureka St pole, and two others that failed in Chicago and Ventry Sts, were rated condition 2 or 3.
But the Icam report says a red tag was placed on the Eureka St pole following its assessment in March 2017, meaning it was rated condition 0.
Mr Thompson also said in December that the inspection methodology had been "immediately changed" following the investigation into the pole that fell in August.
But the Icam report says the traditional assessment method was suspended in June 2017, following an independent review of the method’s integrity and validity of results.
The Otago Daily Times asked Aurora about the inconsistencies, but it did not respond to those questions, although a spokesman said modifications to the process to take account of pole top loading were introduced in August 2017. A spokesman said the Otago Daily Times had asked "a wide range of detailed questions, including technical matters that are not well suited to explanation via email", and that another spokesman had "without going into exhaustive detail", provided "a general summary and update", as well as an update on Aurora’s fast-track pole programme.
The general response said Aurora continued to "maintain its network using industry standard methods based on expert engineering advice and independent review and that includes working transparently with the safety regulator to ensure our approach meets the required standards."
It said Aurora had its pole testing methods independently assessed and verified by engineering specialists in the utility sector last year, and independent verification confirmed "that our pole testing and identification methods are robust, consistent and meet the required regulatory standards".
The ODT asked if the independent verification it was referring to was the URI report, but Aurora did not respond.
Pole inspection methods
• Aurora Energy uses two main inspection techniques — the Deuar mechanical pole-testing device and ‘‘traditional’’.
• The Deuar device can be generally classified as non-destructive.
• The traditional inspection method involves a visual and semi-intrusive test and measurement of the residual pole diameter (among other things).
Information: URI Engineering Review of Aurora Energy Pole Inspection Process — Part 1. May 2017.
