Collecting information on cable facilities takes less time with the cable testing and diagnostic units from BAUR Prüf- und Messtechnik GmbH. Now the BAUR frida TD and viola TD units can handle the Monitored Withstand Test (MWT) for lines up to 34 kVpeak and 60 kVpeak, respectively. The test combines VLF cable testing with dissipation factor measurement diagnostics and provides users significantly more information than the cable tests alone – and often in less time.
There are two parts to the sequence programmed in the units. In the first phase, only the dissipation factor is measured at voltages of 0.5 U0, U0 and 1.5 U0. This nondestructive test method enables the condition of cables to be determined so those with signs of excessive aging can be replaced before a critical situation occurs. The MWT phase follows. It combines cable testing with continuous tan δ diagnostics at approximately 2 U0. If the dissipation factor drifts below the test voltage, this provides further indications of the cable's condition. The tan δ MWT is an IEEE-approved method and is recommended in IEEE 400 as a useful measurement method for cable systems aged in operation.
One of the best features of MWT is that the test duration is influenced by condition. The test duration can be shortened (if permitted), saving costs. The cable can be exposed to the higher test voltage for just as long as required. There's no added effort for connections compared to normal cable testing because the integrated tan δ measurement makes MWT with a single unit possible.