| 摘要 |
A partial discharge detector 60 for gas-insulated electric apparatus such as a high voltage conductor 50 detects an electromagnetic wave ascribable to a partial discharge in the gas insulation by means of a slot antenna (61, figure 3) placed in contact with or near to an insulating spacer 30 which is located between flanges 12, 22 of conductive pipes 10, 20. The slot antenna may be covered with an elastic member (65, figure 3) of dielectric material which contacts the insulating spacer 30 and transmits the electromagnetic wave and minimizes losses into the antenna. Alternatively, the slot antenna may directly contact the spacer 30 without an elastic layer (figure 7). The casing of the antenna may form a resonant cavity. Coaxial cable 70 connects the antenna to a signal processing unit 80. The slot of the antenna is sized for optimal pick up of the partial discharge signal. The spacer 30 supports the conductor by means of a hole at its centre and also seals between the flanged conductive pipes to form a hermetically sealed container for the insulating gas. |
