A new non-communication protection technique for transmission lines

This paper proposes a new non-communication protection technique for transmission lines. The technique relies on firstly detection of fault generated high frequency current transient signals. A specially designed multi-channel filter unit is then applied to the captured signals to extract desired bands of high frequency signals. Comparison between the spectral energies of different bands of the filter outputs determines whether a fault is internal or external to the protected zone. In addition to the saving in costs through negating the need for a communication link, the technique also retains many advantages of the ʹtransient based protectionʹ technology, such as insensitivity to fault type, fault position, fault path resistance and fault inception angle. It is also not affected by CT saturation, the power frequency shortcircuit level at the terminating busbar or the precise configuration of the source side networks.