AES Cables Ltd - Case Studies

Case Study 1 | Cable Oil Spill

During March 2003; Balfour Beatty Power Networks employed the expertise of AES as consultants to assist and advise them in dealing with an oil leak spillage, following a fire at Vauxhall Bridge Station which damaged an oil filled 33kv cable. The oil from the fire damaged 33kv cable spread onto the railway ballast and down through the ballast, onto the railway arches and into the premises below. AES successfully used two methods of clean up treatment. The first method used on the railway ballast was our company’s in-situ treatment system entailing the application of bacteria, enzymes and natural solvents which reduces the cable oil into CO2 and water. The second method was to pressure wash the oil off the railway arches and premises below with our OilOff biological cleaner. After soil sampling and monitoring of the contaminated areas over a 3 day period, the work was successfully completed with the recorded hydrocarbon p.p.m’s registering below 140. This figure is well below the “ICRCL Trigger Levels” and the “Dutch Target and Intervention Levels” for the land usage.

The principle personnel of AES have a wide and successfully long experience in dealing with the management, treatment and off-site disposal of petroleum oils/waste products extending over the last 25 years. The Managing Director is a biochemist with many years of experience in
bioremediation of waste products.

Case Study 2 | Redundant Cable Purging

In December 2005 AES Cables were requested to remove the cable oil from the underground 132kV single core oil filled cables at the National Grid Substation, Bramford, near Ipswich, Suffolk. Section A1. Sizewell (Number 4 circuit) and section A.2. Sizewell (Number 3 circuit) amounted to a combined total of 3,235 metres.

Three pairs of cables were connected to form a continuous loop to enable us to pump and recover from the same location. This method reduces cost of setting up two individual sites with associated manpower and equipment. One set were looped at the sealing joint ends, the other set were connected after excavation and uncovering the cut cable ends.

Our non-intrusive and in-situ method of removing the cable oil fluid from underground fluid filled electrical cables renders these redundant power cables environmentally safe and avoids the need for physical removal of the cable itself. The method involves using our environment approved and patented Hydrogel series PT1 and cross-linking gelling agent PD 2000 to purge the cables of free oil and in the final stage adding the cable fluid specific bacteria ABR Hydrocarbon.

A total of 1285 ltrs of cable oil was recovered from Section A1 Sizewell (No.4 circuit) and 822 ltrs of cable oil was recovered from Section A2 Sizewell (No.3 circuit)

A sample of cable cut from the purged system was sent for independent laboratory analysis by National Grid and showed approximately 97% recovery of oil had been achieved when the cores and papers had been dismantled for inspection. The bacteria left in the cable will continue to bio-degrade the remaining cable oil residues.