dispersed power Generator bus voltage corresponding The overcurrent element shall be set greater than 130% of the producing resources to 1.0 per unit of the high-side calculated current derived from the maximum aggregate 5 Phase overcurrent nominal voltage times the turns ratio nameplate MVA output at rated power factor (including the relay (51 or 51V-R of the generator step-up transformer Mvar output of any static or dynamic reactive power devices) voltage-restrained – Phase time overcurrent relay Generator bus voltage corresponding (51V-C) voltage to 1.0 per unit of the high-side Voltage control setting shall be set less than 75% of the – 6 controlled (Enabled nominal voltage times the turns ratio calculated generator bus voltage to operate as a of the generator step-up transformer function of voltage) A different application starts on the next page The impedance element shall be set less than the calculated impedance derived from 115% of: Phase distance relay Generator bus voltage corresponding (1) Real Power output 100% of the aggregate generation gross – (21) directional to 0.95 per unit of the high-side – 7a MW reported to the Transmission Planner, and toward the nominal voltage times the turns ratio (2) Reactive Power output 150% of the aggregate generation – Transmission of the generator step-up transformer MW value, derived from the generator nameplate MVA rating at system installed – Generator step-up rated power factor on generator-side of transformer(s) the GSU OR connected to transformer The impedance element shall be set less than the calculated synchronous Calculated generator bus voltage If the relay is impedance derived from 115% of: generators corresponding to 0.85 per unit installed on the nominal voltage on the high-side (1) Real Power output 100% of the aggregate generation gross – high-side of the 7b terminals of the generator step-up MW reported to the Transmission Planner, and GSU transformer transformer (including the (2) Reactive Power output 150% of the aggregate generation – use Option 14 transformer turns ratio and MW value, derived from the generator nameplate MVA rating at impedance) rated power factor OR
dispersed power producing resources Phase overcurrent relay (51 or 51V-R – voltage-restrained 5 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 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) Phase time overcurrent relay (51V-C) – voltage controlled (Enabled to operate as a function of voltage) 6 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 Voltage control setting shall be set less than 75% of the calculated generator bus voltage A different application starts on the next page Generator step-up transformer(s) connected to synchronous generators 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 14 7a Generator bus voltage corresponding to 0.95 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 115% of: (1) Real Power output – 100% of the aggregate generation gross MW reported to the Transmission Planner, and (2) Reactive Power output – 150% of the aggregate generation MW value, derived from the generator nameplate MVA rating at rated power factor OR 7b Calculated generator bus voltage corresponding to 0.85 per unit nominal voltage on the high-side terminals of the generator step-up transformer (including the transformer turns ratio and impedance) The impedance element shall be set less than the calculated impedance derived from 115% of: (1) Real Power output – 100% of the aggregate generation gross MW reported to the Transmission Planner, and (2) Reactive Power output – 150% of the aggregate generation MW value, derived from the generator nameplate MVA rating at rated power factor OR
PRC_025_2_Generator_Relay_Loadability_Draft_2017_05_23.docx