FFC Workshop case study. Alan Archer CMIOSH, Asset Lifecycle Engineer

Transcription

1 FFC Workshop case study Alan Archer CMIOSH, Asset Lifecycle Engineer

2 Breakout session 1 Referring to the Operating Code for the Management of Fluid Filled Cables, in the event of a possible pollution incident caused by a Fluid filled cable. Environment Agency What information have you currently available about fluid-filled cables, using the operating code what information would you be asking for, from whom and by when? UK Power Networks What information have you available to provide the information requested, is anything missing? Feedback, Do you feel that adequate information is available to provide an adequate understanding of the level of environmental risk, anything missing?

3 FFC Workshop case study Circuit: Brimsdown Buckhurst Hill situated in North East London. Voltage: 132,000V (132kV). Consists of: 2 circuits of 3 core cable fluid filled cable, each 4.0km long, installed in Network risk: Both cables are needed to remain in-service to maintain security of supply without re-configuring the network.

4 History During a 2km section of these cables was being replaced by solid cable as part of the FFC decommissioning programme, due to the poor condition of the sheath and location, as these cables are routed by the King George reservoir and Epping Forest in East London. The replacement cables were being commissioned into service during October 2008, this is undertaken, making one circuit dead at a time (Deenergised) which can take several weeks and involves network outage planning so as to prevent interference or interruption to the electricity supply. Work had stopped for the weekend around the 26th,27th October, with one circuit out of commission with no protection working.

5 Incident The following Monday, cable fluid was found to be missing from the pressure tanks, so a route patrol was carried out immediately to locate possible cable damage, as this was the most possible cause for a sudden loss of fluid. Over the weekend it was found that Billy Smarts circus had set up in the car park in Epping Forest to give a daily show to around 1000 people, as part of their annual tour. The Circus Tent was found to be located directly over the cable route. Using a Cable locator in the area by the tent the most likely point of damage, was confirmed to be by a set of tent anchor spikes. These steel spikes are up to 1.2m long and used to anchor the tent down.

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7 Circus tent and cable route

8 Incident It was one of these spikes which penetrated the dead cable (Fortunately nobody was injured) so without any warning the Circus did not know of the damage they had caused. Because the cable was out of commission with no protection, UK Power Networks did not know of the damage either? It was estimated that up to 800 Litres of cable fluid had been lost to ground.

9 The stake through the cable

10 Breakout session 2 Environment Agency Up to this point what would you expect UK Power Networks to be doing, information asked for and actions to be taken? UK Power Networks What assistance would you be asking from the Environment Agency officers up to this point? Feedback: Up to this point no environmental incident has been reported by UK Power Networks, what would be the next steps to be taken, is enforcement action required, what level of incident will it be initially logged as?

11 Incident Following further investigations by UK Power Networks, it was subsequently found; Prior to the company knowing about the incident, the Epping Forest rangers over the weekend were aware of a dog being contaminated with oil from a stream 150m away from the Circus site and thought the Circus was the cause of the pollution? The rangers set up soak away pads and booms to prevent the contamination from entering a larger watercourse further down stream. It was found that the cable fluid may have travelled along the cable route coming out near to the stream. UK Power Networks engaged their contractor Lloyds environmental to; Clean up and remediation work and Initiate monitoring of adjacent land

12 Incident

13 Breakout session 3 Environment Agency How would you report the level of incident 1,2,3 or 4 and why? What enforcement action would you consider now and on whom, taking into account third party damage? UK Power Networks What further mitigating actions can we take to minimise the level of environmental risk, how can the EA assist us? Feedback: Has the level of incident recorded through the EA changed, if so why.

14 Thank You Closing remarks