I propose here a method we are using in Italy to allow ION meters with EN50160 framework to correctly detect and classify the voltage events when installed in MV systems.
EN50160 states that, for MV systems, all the voltage events have to be evaluated using line-to-line voltages. This method shows how to allow it even when the voltage measures are transduced by 3 PTs wired line-to-earth.
Has anyone already faced the same issue and has already found a different solution (maybe via framework programming)?
Of course, any comment or advice about our proposed solution in the attached file is welcome.
Thanks for the proposed solution Francesco.
Currently we have a ION 7650 on a HV installation. The L-L is 11kV (Delta), but the secondary on the PT's is 110V L-L (we had to use L-L to power the meter on the auxiliary, as L-N would damage it and not allow power up). There are three PT's (primary and secondary are Wye), and we currently have the active side of each PT going to V1, V2, & V3 on the 7650. The Installation Guide does not give any reference to a system that has three VT's (or PT's) that I can see, so is this installation suggestion best practice? It makes sense in theory, but do we have the backing of Schneider to actuate this in the field?
We also come across this configuration of PT's for MV systems quite often. It is a standard PT installation configuration for a lot of protection relays. As it is much easier to use existing PT's for a retrofit MV installation, it would really help if Schneider provide a wiring diagram for the ION7650's that supports this PT configuration. Would likely help us sell a few more ION7650's for existing sites as well.