Leak location for liquid filled cables

The Electricity Utilities in the UK operate a widespread network of low pressure oil filled (LPOF) cables. This type of cable has a proven history of excellent service and continues to provide outstanding performance from the point of view of electrical characteristics. Operation of these cables is dependent on maintaining a positive fluid pressure along the total length at all times. It is normally necessary to add or remove any fluid throughout the life of the cable unless the system is breached. Once a leak starts the cable can be maintained in service, unless the leak rate is excessive, by pumping fluid into the cable and pumping continues until the leak is repaired. A major requisite is to minimise fluid loss to avoid contamination of ground and water courses and so it is necessary for leaks to be identified, located and repaired as soon as possible. This has led to a requirement for more careful management and operation leading to the introduction of improved fluid pressure monitoring systems that identify leaks as soon as they occur and further research into fluid leak location methods including on-line methods. The paper discusses monitoring systems and leak location methods