Creation of a new LN for protection function
To detect faults occurring between the busbar and the HV side of a transformer/autotransformer, a specific function based on impedance measurement is installed of the LV side of the transformer/autotransformer. This function shares similarities with the distance protection (PDIS) : it computes the 6 impedance loops based on voltage and current measurements to detect if a fault has occurred. However, to detect phase-to-ground faults, the traditional approach of using the k0 factor to compute the phase-to-ground impedance loops cannot be used as it is the case for distance protection, especially if the transformer coupling is delta-delta (residual current cannot flow). The phase-to-ground impedance loops are thus computed by simply dividing the voltage by the current without taking into consideration neither the k0 factor nor the residual current.
Proposal : a new LN (PIMP = Impedance protection ?), with associated DO and DA should be created to deal with this use case.
RTE to provide list of DO/DA for PDIS along with use-case/description.
Also, it would be good to have justification why is needed to create new LN and not only to extend PDIS.
Updated by Maud Merley about 1 year ago
The process to manage request from WG10 will be discussed in next plenary meeting of TC95 on October 6, 2022.
The proposal is to assign WG2 convener as entry point for this type of request from WG10 and to organise joint MT4/WG2 web meetings to define a position of TC95 (to be confirmed after TC95 plenary).
In parallel, TC95's advice about creating a dedicated LN for the PIMP protection function will be addressed in a joint MT4/WG2 meeting.