The Impact of Using Low-Power Voltage Transformers (LPVT) When Performing Cable Diagnostic Testing in Medium-Voltage Distribution Networks

As power networks move toward increased digitalization and the smart grid is becoming more of a reality, power networks are hosting elements of smart grids to meet the growing demands and requirements of advanced digital networks. One of the components of a smart grid is the use of measuring sensors. Low-power instrument transformers are one part of these advanced systems and are increasingly being used within distribution networks. As these sensors are being widely installed, network operators must ensure that the addition of such sensors will not affect the normal operation of the network. This paper discusses the potential impact of using voltage sensors in power networks to perform VLF (very low frequency) cable testing, which is a common practice in distribution networks and is used during commissioning tests and to support maintenance and condition monitoring of underground cables. This paper also investigates and compares the impact of different sensor technologies on the performance of cable VLF diagnostic testing.