Styrene applied to H.T. cable systems

The method of restricting longitudinal flow in oil impregnated cables by employment of styrene joints was primarily developed in connexion with life tests on short lengths of cable. The success of the method has led to development of technique for producing styrene barriers in cables and styrene cable terminations. Attempts were made to produce "welded" joints by use of styrene containing chlorinated aromatic hydrocarbons which are solvents for both oil and polymerised styrene. "Styrenated" joints, which are made by taping with paper impregnated with monomeric styrene and then bringing about polymerisation by heat are described. Such joints have proved perfectly satisfactory both in laboratory tests and in operation on power networks at 66 kV working voltage. Barriers are produced by passing styrene into an oil impregnated paper cable by means of a nipple made in the lead sheath, the oil displaced passing out through another nipple. The terminations of cables have been styrenated in a similar manner. A discussion of the factors involved in the flow of oil in cables with reference to the best position of barriers to prevent the movement is also given.