Cutbank 810S and Thornton 2091S substations. To mitigate these violations, it would require a remedial action scheme (RAS) to trip the new Thornton 2091S substation. Following the 7L228 contingency, the load served by the Thornton 2091S substation would be left unserved. Following the loss of 7L40 (Little Smoky 813S to Simonette 733S) a minor post-transient deviation of 10.5% the Simonette 733S POD bus was noted; this is marginally higher than the 10% guideline. The TFO and DFO have confirmed that such marginal voltage deviation does not impose any operational restriction.] Mitigation Strategy and Sensitivity Analysis [as required] Please describe how to mitigate the identified Reliability Criterial violations in these and post-Project studies. Alternative Selected This section will provide which Alternative is preferred based on performed studies. Please provide how the study results impacted on the Alternative selections. Below is an example of the write up: Alternative [State selected Alternative #, e.g., 2] was selected as the preferred alternative since….. [Provide solid reasons why this Alternative was selected] Recommendation This section will provide the recommendation of this project including selected Alternative, new equipment and mitigation measure (if required). is an example of the write up: [The recommended alternative to connect the Facilities is Alternative 2, building the new 144/6.9 kV POD substation Vincent 2019S. The Project will include: Tapping the 144 kV line 7L65 and building 0.15 km of 144 kV line to connect the new Vincent 2019S POD substation. Installing one 20/26.6/33.3 MVA, 144 kV to 6.9 kV LTC transformer, one 144 kV transformer breaker, and associated equipment. The 25 MVAr 144 kV capacitor at Creek 706S, as identified in the 2015 Long-term Transmission Plan (LTP), is required prior to the Project ISD, since the inclusion of this capacitor bank mitigates all criteria violations noted in the pre- and post-connection results.]
3.1 Connection Studies Carried Out 15 3.2 Load Flow Analysis 15 3.2.1 Contingencies Studied 16 3.3 Voltage Stability (PV) Analysis 16 3.3.1 Contingencies Studied 17 3.4 Transient Stability Analysis 17 3.4.1 Contingencies Studied 17 3.5 Short-Circuit Analysis 17 3.6 Motor Starting Analysis 17 3.7 Sub-Synchronous Studies [as required] 18 3.7.1 Sub-Synchronous Torsional Interaction Study (SSTI) 18 3.7.2 Sub-Synchronous Resonance (SSR) and Sub-Synchronous Control Interaction (SSCI) Studies 18 3.8 Effectiveness Factor Analysis Studies [as required] 18 3.9 Sensitivity Studies [as required] 18 3.10 Mitigation Measures 18 4 19 4.1 Pre-Project Load Flow Analysis 19 4.1.1 20XX Season [Summer/Winter] Load Condition [Peak/Light] (e.g., 2016 Summer Peak – 2016 SP) 19 4.2 Pre-Project Voltage Stability Analysis [as required] 20 4.3 Pre-Project Transient Stability Analysis [as required] 20 5 21 5.1 Overview 21 5.2 Connection Alternatives Identified 21 5.2.1 Connection Alternatives Selected for Further Studies 21 5.2.2 Connection Alternatives Not Selected for Further Studies 21 6 22 6.1 Load Flow 23 6.1.1 Alternative 3 23 6.1.1.1 20XX Season [Summer/Winter] Load Condition [Peak/Light] (e.g., 2016 Summer Peak – 2016SP, Scenario 4) 23 6.1.1.2 20XX Season [Summer/Winter] Load Condition [Peak/Light] (e.g., 2016 Winter Peak – 2016WP, Scenario 5) 24 6.1.2 Alternative 4 24
Scenario Year/Season Load Condition Project Load (MW) Project Generation (MW) System Generation Dispatch Conditions 1 2016 SP Pre-Project 0 0 High Wind, High Import 2 2016 WP Pre-Project 0 0 High Wind, High Import 3 2016 SP Post-Project 20 0 4 2016 WP Post-Project 20 0 Load and Generation Assumptions Load Assumptions The Area and Region load forecasts used for this connection study is shown in Table 2.31 and is from [The AESO Forecast specified in the Study Scope, e.g., the AESO 2014 Long-term Outlook (2014 LTO)]. In this study the active power to reactive power ratio in the base case scenarios was maintained when modifying the planning area loads. Table 2.31: Forecast Area Load (201X LTO at AIL Peak) Area or Region Name and Season Forecast Peak Load (MW) 2016 2018 Area 37 (Provost) SP WP SL Central Region SP WP SL Region SP WP SL AIL w/o Losses SP WP SL Generation Assumptions Describe the generation assumptions (including N-G) and the AESO forecast applied (e.g., 2014LTO). Present existing and future units for consideration in the project studies (local generators) and the dispatch level of each. Describe the notable features of the local generators, as required. Below is an example of the write up:
conditions extracted from the power flow analysis. Table 6.43 shows the summary for Alternative 1. Table 6.43: Motor Starting Performance for Alternative 1 Contingencies Substation Category A (N-0) Category B (N-1) 681L (From Hardisty 377S to Tucuman 478S) Category C5 (N-2) 679L and 680L (From Nilrem 574S to Tucuman 478S) … … Substation A Nominal Bus Voltage (kV) 138 138 138 Before Start (kV) 142.83 129.38 129.38 After Motor Start (kV) 139.66 123.86 123.86 Voltage Dip (kV) 3.17 5.52 5.52 % Voltage Dip 2.22 4.27 4.27 Substation B Nominal Bus Voltage (kV) … .. .. Before Motor Start (kV) After Motor Start (kV) Voltage Dip (kV) % Voltage Dip The motor starting results show that the voltage dip caused by “across-the-line” motor starting at Substation A and B 138 kV busses are below 5% under both system normal and contingency conditions. The simulation results suggest that the impact on the voltage due to “across-the-line” starting of one motor is acceptable. The induction motor curves and the voltages at Substation A and B busses are provided in Attachment K.] Sub-Synchronous Studies Analysis The AESO will provide detailed guidance if sub-synchronous studies are required.
Fault Short-Circuit Analysis For load and generator connection, all the generators in the Study Area should be on-line. Include the short-circuit analysis for the preferred alternative amoung the listed alternatives in Section 5.2. If connection alternatives will impact short-circuit current, provide the results, include the short-circuit analysis for the studied alternative. Explain if the short-circuit current levels would not be materially changed or not. Highlight the short circuit current levels which are above 90% of equipment rating. Market participants can approach the AESO for advice with respect to long-term anticipated short circuit levels and can collaborate with the AESO on a system-based solution if a more locally-based solution cannot solve it. Pre-Project Provide pre-Project short-circuit current levels for the studied alternative. Use a table. 8.11: Summary of Short-Circuit Current Levels – Pre-Project (Year 20XX) Substation Name and Number Base Voltage (kV) Voltage (kV) 3-Φ (kA) Positive Sequence Thevenin Source Impedance (R1+jX1) (pu) 1-Φ (kA) Zero Sequence Thevenin Source Impedance (R0+jX0) (pu) Table 8.12: Summary of Short-Circuit Current Levels – Pre-Project (Year 20XX [Year of Proposed Connection + 10 Years]) Substation Name and Number Base Voltage (kV) Voltage (kV) 3-Φ Fault (kA) Positive Sequence Thevenin Source Impedance (R1+jX1) (pu) 1-Φ Fault (kA) Zero Sequence Thevenin Source Impedance (R0+jX0) (pu) Post-Project Provide post-Project current levels for the preferred alternative. Use a table. Table 8.21: Summary of Short-Circuit Current Levels – Post-Project (Year 20XX) Substation Name and Number Base Voltage (kV) Voltage (kV) 3-Φ (kA) Positive Sequence Thevenin Source Impedance (R1+jX1) (pu) 1-Φ Fault (kA) Zero Sequence Thevenin Source Impedance (R0+jX0) (pu)
Table C-1: Summary of Voltage Stability Outages; Initial Load Level for Area XX is YY MW System Condition Worst Case Outage Incremental Area Load Increase before Collapse (MW) Available Voltage Stability Margin (%) All figures must be easy to read and have proper labels for both the x axis and the y axis. See Figure C-1 for an example. The table headings must identify the initial amount of static load in the study region or the initial transfer level, whichever is applicable. Figure C-1: Overview of Voltage Stability Outages (Example) Figure C-1: Overview of Voltage Stability Outages (Example)
(Nature of constraint) (ex. thermal violation, instability, voltage range violation) (ex. Summer peak, year, and critical project assumptions) Planning Solution Thermal Voltage Stability (RAS) OR Real Time Practice Post RAS Action rating (MVA) rating Load Flow %I of MVA ratings Location Voltage Action 1 % of MVA Rating Action 2 % of MVA Rating xxxL (xxx xxxS to xxx xxxS Thermal Violation xxxL (xxx xxxS to xxx xxxS) 85 94 89.0 104.7 20xx Summer Peak Scenario 1 (List other critical project assumption) 201xLTP (Please specify on what portion of LTP will remove the temporary mitigation measure)