Phase distance relay (21) directional – toward the Transmission system installed – Generator bus voltage corresponding The impedance element shall be set less than the calculated on generator-side of to 1.0 per unit of the high-side impedance derived from 130% of the maximum aggregate the GSU 10 nominal voltage times the turns ratio nameplate MVA output at rated power factor (including the transformer of the generator step-up transformer Mvar output of any static or dynamic reactive power devices) If the relay is installed on the high-side of the Generator step-up GSU transformer transformer(s) use Option 17 connected to asynchronous generators only Phase overcurrent (including relay (51) installed – based installations) on generator-side of Generator bus voltage corresponding the GSU to 1.0 per unit of the high-side The overcurrent element shall be set greater than 130% of the transformer nominal voltage times the turns ratio calculated current derived from the maximum aggregate 11 of the generator step-up transformer nameplate MVA output at rated power factor (including the If the relay is for overcurrent relays installed on the Mvar output of any static or dynamic reactive power devices) installed on the low-side high-side of the GSU transformer use Option 18 The same application continues on the next page with a different relay type
Generator step-up transformer(s) connected to asynchronous generators only (including installations) Phase distance relay (21) – directional toward the Transmission system – installed on generator-side of the GSU transformer If the relay is installed on the high-side of the GSU transformer use Option 17 10 Generator bus voltage corresponding to 1.0 per unit of the high-side nominal voltage times the turns ratio of the generator step-up transformer The impedance element shall be set less than the calculated impedance derived from 130% of the maximum aggregate nameplate MVA output at rated power factor (including the Mvar output of any static or dynamic reactive power devices) Phase overcurrent relay (51) – installed on generator-side of the GSU transformer If the relay is installed on the high-side of the GSU transformer use Option 18 11 Generator bus voltage corresponding to 1.0 per unit of the high-side nominal voltage times the turns ratio of the generator step-up transformer for overcurrent relays installed on the low-side The overcurrent element shall be set greater than 130% of the calculated current derived from the maximum aggregate nameplate MVA output at rated power factor (including the Mvar output of any static or dynamic reactive power devices) The same application continues on the next page with a different relay type based
PRC_025_2_Generator_Relay_Loadability_Draft_2017_05_23.docx