8 1 2015 Monitoring technology Visileak VSL Subject to technical changes Measurement principle Measurement principle for location In order to locate the moisture or contact faults insulation faults a location voltage U is applied to the sensor loop At the start of the sensor loop between the sensor wire and the pipe a measurement is taken of voltage component U1 this is measured over the insulation fault on the sensor wire However the voltage component is not measured in volts but as a percentage of the total voltage so it represents the result of the location Since the sensor wire has a very high series resistance of 5 7 Ω m and the feedback wire is close to zero ohms the following relation is obtained U total voltage U1 voltage component R total loop resistance R1 loop resistance component x location result L total pipe length L1 fault distance The intensity of the insulation fault insulation resistance has no influence on the accuracy of the location this is because the device concept takes account of the intensity Location of an interruption in the sensor loop Where as the interruption of the sensor loop as such is signalled im mediately on automatic systems the location of the fault point must be carried out manually using different methods The most widespread measuring method is the runtime method which has proven its merits in these cases If a wire is broken off recourse can be had to a simple capacitance measurement method In order to prevent subsequent fault sources the integrity of the sensor loop should be ensured during the installation stage through continuous control measurements and manual checks on the strength and stability of wire connections U1 R1 x L1 U R 100 L Measurement principle for location 100 x U1 U Moisture sensor Sensor wire red Feedback wire green Location unit 8 120 A measurement expert will do the positioning The accuracy of positioning is 1 It is therefore necessary that the measuring loop have an access point at regular intervals usually house connections If the sections bewteen two house connections are longer than 200 m we recommend installing a wire model

Hinweis: Dies ist eine maschinenlesbare No-Flash Ansicht.
Klicken Sie hier um zur Online-Version zu gelangen.