Surge arrester

• Main Authors: MUELLER,WALTER,DR, STEIN,WERNER,DR, DEML,HUBERT
• Format: Patent
• Language: English; German
• Published: 04.04.1985
• Edition: 3
• Subjects: BASIC ELECTRIC ELEMENTS; CORONA DEVICES; ELECTRICITY; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES; OVERVOLTAGE ARRESTERS USING SPARK GAPS; RESISTORS; SPARK GAPS; SPARKING PLUGS

In recent times, surge arresters have frequently been pressed or sintered from metal oxides, in particular from zinc oxide. They are often made up of at least approximately cylindrical arrester elements whose end faces have terminal contacts and whose lateral surfaces are formed by a single-layer or multilayer insulating sheath. According to the invention, to build such surge arresters into liquid-cooled transformers, each of the end faces having terminal contacts is covered by a cup-type sheet-metal cap (3) having a rim encompassing the joints between the lateral surface and the end faces. The sheet-metal caps (3) are held by means of an oil-tight adhesive layer (4) which fills at least the joint between the rim and the lateral surfaces. The rims of the sheet-metal caps (3) are encased on the outside, along with the lateral surfaces situated between them, with an oil-tight additional skin (5) made of insulating material. The joint between the sheet-metal caps (3) and the oil-tight additional skin (5) is also sealed in an oil-tight manner. The use of such surge arresters is advantageous, in particular, in liquid-cooled transformers because any deterioration in the resistance behaviour of the surge elements (1) is eliminated by the reliable encapsulation of the metal oxide body with respect to the transformer oil.