Patent ID: 6897784
Filing Date: 2005-05-24
Classification: G01M

Abstract:
1. A water monitoring system for a high voltage cable including at least one conductor and a screen surrounding said conductor, comprising: a1) a first water sensing wire extending in the screen between the cable beginning and the cable end; a2) at least a second wire connected to the first water sensing wire at the cable end for forming a loop and extending from the cable end to the cable beginning; b) a measuring circuit provided at the cable beginning and adapted to determine at least the occurrence of a water intrusion into the cable on the basis of voltage drop measurements at the first water sensing wire or the second wire; c) a first switching unit between the cable beginning and the measurement circuit, said first switching unit being adapted to assume, in response to a first switching signal, a first switching state in which said first water sensing wire and said second wire are connected to a screen potential when the first switching signal has a first state; and a second switching state in which said first water sensing wire and said second wire are disconnected from the screen potential when the first switching signal has a second state; and d) a control unit adapted to output the first switching signal in the first state over a first predetermined time interval and thereafter to switch the first switching signal into the second state over a second predetermined time interval; wherein e) said measurement circuit is adapted to perform said water intrusion measurement in said second predetermined time interval.