| 摘要 |
<p>Method and on-line measurement system for on-line measurement in a power cable (1). The power cable (1) has a conductor (2), a dielectric (3) and a conductive earth sheet (4). A master measuring unit (10) is provided at a first location along the power cable (1). During normal operation of the power cable (1) the following steps are executed:
- detecting a direct pulse (Pd) originating from a partial discharge (PD) in the power cable (1);
- detecting a reflected pulse (Pr) originating from the same partial discharge (PD), the reflected pulse being reflected by an impedance change (11) at a second location of the power cable (1); and
- determining the distance (y) of the partial discharge (PD) from the second location using a time difference measurement between the direct pulse detection and the reflected pulse detection, and a pulse travelling speed (s) in the power cable (1).</p> |
