Abstract:
Contactless current monitoring can play a vital role in electric power distribution side for applications such as power theft and unbalancing control. Operating current can be monitored by contactless magnetic field sensors around the lines. Magnetic flux concentrators (MFCs) are placed to concentrate the magnetic field generated by the current carrying conductor and amplify the magnetic field signals to the magnetic sensors in close vicinity. In this study, three sensors and three MFCs are placed to measure the magnetic field produced by three-phase HV side of the distribution system. Sensors are placed at 1.2 m from the conductors outside the induction zone. But magnetic fields are weak at this distance. If there is a small change in current through conductors, the resultant magnetic field will also be changed small and at a distance where magnetic fields are already weak, a small change in a magnetic field is difficult for the sensors to be detected. To amplify the weak magnetic field Rectangular shaped Mu metal material base MFCs are designed while the concentration effect can vary by changing the length of MFCs. By increasing magnetic field concentration consequently, effect of magnetic fields of other conductors also increase. So, we need to minimize the interference effect for more accurate results to detect power theft and unbalancing. In this Research we also worked on a shape of Magnetic Field Attenuator (MFA) to attenuate the effect of magnetic fields of other conductors to detect unbalancing in four wire system by placing a single magnetic field sensor around the neutral. As unbalanced Loading cause three phase unbalancing in distribution system, which causes unbalance current flow through the neutral, which can be monitor by magnetic fields through magnetic field sensor placing closer the neutral.
