The VV-Tester is a unique portable instrument that allows the performance of accurate vector-type power frequency and PD measurements within frequency band of 0.5MHz - 20MHz. The magnitude accuracy is better than 0.1% and the phase angle accuracy is 0.01 Degree in power frequency measurements.
For PD measurements VV-Tester has sophisticated noise filters including time of arrival, pulse polarity and pulse magnitude technologies used in a combination or separately. Dynamic range of 70dB without gain adjustment along with noise filters make the instrument an expert type tool in a research or a maintenance field related to medium or high voltage insulation systems.
Applications for the VV-Tester include the periodic on-line diagnostics of insulation integrity for high voltage bushings and current transformers. Electromagnetic type HV PTs turn ratio monitoring is also an option for the technology. The instrument is capable in measuring the bushing power factor and C1 capacitance in a set of three bushings. In addition VV-Tester allows for fast Partial Discharge analysis using the same primary bushing sensors as for power factor and capacitance.
Periodical measurements are a solution for less expensive and critical power and metering transformers. For mission critical and/or expensive equipment, continuous monitoring is recommended. EDI also offers a continuous monitoring solution.
Regardless to an approach: continuous or periodical, Bushing Sensors must be pre-installed during an outage in order to do on line measurements under real operating conditions. |
