The same application continues on the next page with a different relay type The overcurrent element shall be set greater than 115% of the calculated current derived from: Generator bus voltage corresponding (1) Real Power output 100% of the aggregate generation gross – to 0.95 per unit of the high-side 9a MW reported to the Transmission Planner, and nominal voltage times the turns ratio (2) Reactive Power output 150% of the aggregate generation – of the generator step-up transformer Phase directional MW value, derived from the generator nameplate MVA rating at time overcurrent rated power factor relay (67) – OR directional toward the Transmission The overcurrent element shall be set greater than 115% of the Calculated generator bus voltage system installed calculated current derived from: – Generator step-up corresponding to 0.85 per unit on generator-side of transformer(s) nominal voltage on the high-side (1) Real Power output 100% of the aggregate generation gross – the GSU connected to 9b terminals of the generator step-up MW reported to the Transmission Planner, and transformer synchronous transformer (including the (2) Reactive Power output 150% of the aggregate generation – generators If the relay is transformer turns ratio and MW value, derived from the generator nameplate MVA rating at installed on the impedance) rated power factor high-side of the OR GSU transformer use Option 16 The overcurrent element shall be set greater than 115% of the Simulated generator bus voltage calculated current derived from: coincident with the highest Reactive Power output achieved during (1) Real Power output 100% of the aggregate generation gross – 9c in response to a 0.85 per unit MW reported to the Transmission Planner, and nominal voltage on the high-side (2) Reactive Power output of the aggregate generation –100% terminals of the generator step-up maximum gross Mvar output during field-forcing as determined transformer prior to field-forcing by simulation A different application starts on the next page
The same application continues on the next page with a different relay type Generator step-up transformer(s) connected to synchronous generators Phase directional time overcurrent relay (67) – 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 16 9a 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 overcurrent element shall be set greater than 115% of the calculated current derived from: (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 9b 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 overcurrent element shall be set greater than 115% of the calculated current derived from: (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 9c Simulated generator bus voltage coincident with the highest Reactive Power output achieved during in response to a 0.85 per unit nominal voltage on the high-side terminals of the generator step-up transformer prior to field-forcing The overcurrent element shall be set greater than 115% of the calculated current derived from: (1) Real Power output – 100% of the aggregate generation gross MW reported to the Transmission Planner, and (2) Reactive Power output –100% of the aggregate generation maximum gross Mvar output during field-forcing as determined by simulation A different application starts on the next page
PRC_025_2_Generator_Relay_Loadability_Draft_2017_05_23.docx