SSR STUDY REPORT FINAL

Transcription

1 System Support Resource Study Escanaba 1 & 2: 25 MW Coal 36 Month Suspension 6/15/2012 6/15/2015 SSR STUDY REPORT FINAL June 21, 2012 Redacted version for January 3, 2013 filing

2 EXECUTIVE SUMMARY An Attachment Y notification submitted by the City of Escanaba (MI) was received on December 19, The request was for suspension of units 1 & 2 from 6/15/2012 to 6/15/2015. After being reviewed for power system reliability impacts as provided for under Section of the MISO s Open Access Transmission, Energy & Operating Reserve Markets Tariff ( Tariff ), Escanaba units 1 and 2 should enter into an SSR agreement until the completion of the American Transmission Company (ATC) Chandler-Old Mead Road project and the Chalk Hills-Old Mead Road 138 kv line of the Bay Lake project. 2

3 Contents I. Introduction... 4 II. Study objectives... 5 III. Models and Assumptions... 5 a. Model Assumptions... 5 b. Transmission Projects... 6 IV. Study Criteria and Methodology... 6 a. Steady State Thermal Criteria... 7 b. Steady State Criteria... 7 c. MISO Transmission Planning BPM - SSR Criteria... 7 d. Contingencies... 7 V. Study Results... 8 a Summer Peak Analysis b Shoulder Load with Maintenance Outages VI. Alternatives Analysis a. New Generation or Generation Redispatch b. System Reconfiguration and Operation Guidelines c. Demand Side Management and Load Shed d. Transmission Projects VII. Summary of Selected Solution

4 I. INTRODUCTION The City of Escanaba, MI submitted an Attachment Y form on December 19, 2011 for the notification of potential generation resource change of status per the requirement of MISO s Open Access Transmission, Energy & Operating Reserve Markets Tariff ( Tariff ). In the submitted Attachment Y, Escanaba generation units 1 and 2 (Total of 25 MW gross) located in Escanaba, Michigan, requested to be suspended for a period of 36 months. In a subsequent letter from the City of Escanaba received February 13, 2012, it was clarified that this would be a definitive study with a suspension start date of June 15, 2012 for a period of 36 months. Escanaba generating station is located in the Upper Peninsula of Michigan connected to the 69 kv system of the American Transmission Company as shown in Figure 1. The 69 kv system in the area is connected to the 138 kv system at Forsyth, Chandler, Nordic, and Chalk Hills. The Chalk Hills-Cornell tap 69 kv line is operated normally open between Harris and the Cornell tap. Figure 1.0: Location of Escanaba Generating Station in the Upper Peninsula of Michigan 4

5 II. STUDY OBJECTIVES Under Section of the MISO s Tariff, System Support Resource (SSR) procedures maintain system reliability by providing a mechanism for MISO to enter into agreements with Market Participants (MP) that own or operate Generation Resources or Synchronous Condenser Units (SCUs) which are required by MISO to maintain system reliability, if such Generation Resources or SCUs are uneconomic to remain in service and otherwise would be decommissioned, placed into extended reserve shutdown or disconnected from the MISO region. The principal objective of this SSR study was to determine whether the Escanaba steam generation units 1 and 2 are necessary for system reliability based on the criteria set forth in the Business Practices Manuals. The study work included monitoring and identifying the steady state thermal/voltage violations on transmission facilities due to the suspension of the Generation Resource. The relevant MISO Transmission Owner and/or regional reliability criteria were used for monitoring such violations. III. MODELS AND ASSUMPTIONS Corresponding to the anticipated suspension of the Escanaba generation units 1 and 2, the following power system analysis source models were used for the study: 2012 Summer Peak 2013 Shoulder Peak 2017 Summer Peak 2017 Shoulder Peak The Attachment Y study models were created following the MISO Transmission Planning Business Practice Manual (BPM-020-r6) Section This includes creating a set of models from each source model in which the units being studied are at full generation or taken out of service. a. Model Assumptions 1. Area load was modelled as provided by the local are Transmission Owner through the Model on Demand model building process. 2. The Upper Peninsula (UP) was modelled as open with both Indian Lake Hiawatha 69 kv paths open at Hiawatha (PSS/E bus# ) in the 2012 and 2013 models. The UP was modelled as closed in the 2017 model with the assumption that the DC project at Straits (expected in service date May 2014) will be completed by that time. 3. The load at Harris (PSS/E bus# ) 69 kv substation was fed radially (south) from Powers (PSS/E bus# ) in all models. This allows the Nordic (PSS/E bus# ) Felch Mountain (PSS/E bus# ) 69 kv circuit to operate at its highest rating. 4. The 2 nd 138/69kV transformer at Chandler was modelled and is presently in service 5

6 5. For the 2017 models, the DC flow control project at Mackinac was modelled at 0 MW in the summer peak case and 40MW flowing from north to south in the shoulder case. 6. Local area generation: a. Escanaba CT (14 MW maximum capability modelled) is a market unit and is online in all cases for contingency and maintenance analysis b. Gladstone CT was modelled offline as the unit is only available during emergency conditions. It was not used in contingency analysis because the system is not planned such that Transmission System Emergency conditions will occur. It cannot be used to support planned maintenance. c. The generation at Manistique, MI (2 CTs, 5 MW total) was not turned on in any model. d. The wind farm connected to Garden Corners (PSS/E bus# ) is not a dispatchable resource and was studied at 0 MW in all cases. b. Transmission Projects The following transmission projects in the area are included in the MTEP models: 1. Indian Lake-Hiawatha 138 kv project P333, In Service Date (ISD) 6/1/2013, Appendix A 2. Mackinac HVDC Converter Station P2846, ISD 5/1/2014, Appendix A 3. Arnold 345/138 kv transformer P3125, ISD 6/1/2014, Appendix A 4. Chandler-18 th Road project P2779, ISD 6/1/2014, Appendix A a. New 18 th Road Substation b. 18 th Road 138/69 kv transformer c. Chandler-18 th Road 138 kv line d. Chandler-18 th Road 69 kv line e. 18th Road-Mead 69 kv line 5. Bay Lake Project P3679, ISD 12/31/2016, Appendix A a. Chalk Hills-18 th Road 138 kv line b. 18 th Road 138/69 kv transformer c. Green Bay-Morgan 345 kv line d. Green Bay 345/138 kv transformer e. Amberg 150 Mvar SVC IV. STUDY CRITERIA AND METHODOLOGY PSS/E and MUST were used to perform AC contingency analysis. Cases were solved with automatic control of LTCs, phase shifters, DC taps, switched shunts enabled (regulating), and area interchange disabled. Contingency analysis was performed on before and after cases. Results were compared to find if there were any criteria violations due to the suspension of Escanaba units 1 and 2. 6

7 a. Steady State Thermal Criteria ATC Transmission Planning Criteria version 12 applied for the thermal analysis is For Category A, all thermal loadings exceeding 100% of the normal rating for ATC System. For Category B and C contingencies, all thermal loadings exceeding 100% of the emergency rating for ATC System. b. Steady State Criteria ATC Transmission Planning Criteria version 12 applied for the voltage analysis is For Category A, all substation voltages less than 95% or above 105%. For Category B and C contingencies, all substation voltages less than 90% or above 110%. c. MISO Transmission Planning BPM - SSR Criteria As specified in the MISO BPM-020-r6, the System Support Resource criteria for determining if an identified facility is impacted by the suspension of the Escanaba units will be: Under system intact and category B contingencies, branch thermal violations are only valid if the flow increase on the element in the after retirement scenario is equal to or greater than: a) 5% of the to-be-retired unit(s) MW amount (i.e. 5% PTDF) for a base violation compared with the before retirement scenario, or b) 3% of the to-be-retired unit(s) amount (i.e. 3% OTDF) for a contingency violation compared with the before retirement scenario. Under system intact and category B contingencies, high and low voltage violations are only valid if the change in voltage is greater than 1% as compared to the before retirement voltage calculation. d. Contingencies A subset of the MISO Transmission Expansion Plan (MTEP) contingencies in Wisconsin and Michigan was used for AC contingency analysis. 69 kv contingencies were included for the study area. The following NERC Categories of contingencies were evaluated: 1. Category A when the system is under normal conditions. 2. Category B contingencies resulting in the loss of a single element. 3. Category C contingencies resulting in the loss of two or more (multiple) elements. 4. Maintenance outage condition with forced outage during shoulder load conditions. 7

8 V. STUDY RESULTS Significant thermal and voltage criteria violations associated with the Escanaba generating units 1 & 2 were identified when compared to the continued availability of the units. Tables 1a, 1b, and 1c below show contingent conditions causing criteria violations without the Escanaba SSR units and improvements resulting from operation of the Escanaba SSR units. These conditions are further described after the tables. Table 1a: Contingency Analysis Results Shoulder Load Model Facilities on Outage 2013 SH [REDACTED LINE 1] and [REDACTED LINE 2] 2013 SH [REDACTED LINE 3] and [REDACTED LINE 4] 2013 SH [REDACTED LINE 5] and [REDACTED LINE 6] NERC Outage Type PM + B PM + B Planned Maintenance + Category B Monitored Facility Monitored Facility (pu) Escanaba 1 & 2 Offline Escanaba 1 & 2 Online Relief Amount (pu) Chandler 69 kv Cornell Tap (UP) Delta 69 KV Escanaba Escanaba Masonville 69 kv Mead 69 kv Gladstone 69 kv West Side Tap West Side 69 kv Lakehead Tap North Bluff 69 kv Lakehead 69 kv Bayview Tap Bayview 69 kv Cornell Tap (WE) Cornell 69 kv Acceptable voltage range is between 0.90 per unit to 1.10 per unit voltage. Therefore, voltages less than 0.90 per unit are a criteria violation. 8

9 Table 1b: Contingency Analysis Results Summer Peak Load Model Facilities on Outage 2013 SP [REDACTED LINE 1] and [REDACTED LINE 2] 2013 SP [REDACTED LINE 3] and [REDACTED LINE 4] 2013 SP [REDACTED LINE 5] and [REDACTED LINE 6] NERC Outage Type C3 C5 C5 Monitored Facility Monitored Facility (pu) Escanaba 1 & 2 Offline Escanaba 1 & 2 Online Relief Amount (pu) Chandler 69 kv Cornell Tap (UP) Delta 69 KV Escanaba 1 69 kv Escanaba 2 69 kv Masonville 69 kv Mead 69 kv Gladstone 69 kv West Side Tap West Side 69 kv Lakehead Tap North Bluff 69 kv Lakehead 69 kv Bayview Tap Bayview 69 kv Cornell Tap (WE) Cornell 69 kv Watson 69 kv Acceptable voltage range is between 0.90 per unit to 1.10 per unit voltage. Therefore, voltages less than 0.90 per unit are a criteria violation. 9

10 Table 1c: Contingency Analysis Thermal Results Summer Peak Load Escanaba 1 & 2 Offline Escanaba 1 & 2 Online Relief Model 2012 Summer Peak 2012 Summer Peak Facilities on Outage [REDACTED LINE 2] and [REDACTED LINE 7] [REDACTED LINE 5] and [REDACTED LINE 6] Outage Type (NERC) C5 C5 Monitored Facility Nordic - Felch Mountain 69 kv Cornell Tap (WE) - Cornell 69 kv Chandler - Cornell Tap (UPPC) 69 kv Cornell Tap (UPPC) - Watson 69 kv Forsyth - Watson 69 kv Nordic - Felch Mountain 69 kv Cornell Tap (WE) - Cornell 69 kv Facility Rating (MVA) Flow (MVA) % rating Flow (MVA) % rating MVA % a Summer Peak Analysis There are C3 and C5 contingencies that have voltage violations before and after the suspension of Escanaba generating units 1 & 2. The [REDACTED LINE 1] and [REDACTED LINE 2] C3 and [REDACTED LINES 3 and 4] C5 contingencies result in voltage collapse with and without the availability of the units. The [REDACTED LINES 5 and 6] C5 contingency would result in very low voltage or voltage collapse if the units were not available. There are thermal violations for the C5 outage of [REDACTED LINES 5 and 6] and [REDACTED LINE 2] + [REDACTED LINE 7] caused by the suspension of units 1 & 2 with an OTDF greater than 3%. b Shoulder Load with Maintenance Outages Known severe maintenance outages were studied in the 2013 Shoulder cases as these cases reflect the load level at which maintenance outages take place. The outages were studied with the specified contingency taking place. Since the first outage is considered planned, no loss of load is expected for a single event forced outage. Loss of the [REDACTED LINE 1] during the prior planned maintenance outage of the [REDACTED LINE 2]. Loss of the [REDACTED LINE 2] during the prior planned maintenance outage of the [REDACTED LINE 1]. Loss of the [REDACTED LINE 3] during the prior planned maintenance outage of the [REDACTED LINE 4]. 10

11 Loss of the [REDACTED LINE 5] during the prior planned maintenance outage of the [REDACTED LINE 6]. Loss of the [REDACTED transformer 1] during the prior planned maintenance outage of the [REDACTED transformer 2]. The planned and forced outage of both [REDACTED LINE 5] and [REDACTED LINE 6] would cause voltage criteria violations. The planned and forced outage of [REDACTED LINE 1] and [REDACTED LINE 2] or both [REDACTED LINE 3] and [REDACTED LINE 4] would cause voltage collapse. The suspension of the Escanaba units would either cause the violations to occur or aggravate the scenario under which the maintenance outage is taken. VI. ALTERNATIVES ANALYSIS a. New Generation or Generation Redispatch No new generation is currently planned for the impacted region. There are currently plans to convert the Escanaba steam plant to biomass type fuel. The Escanaba combustion turbine was fully dispatched in the reliability analysis. The only other dispatchable resource in the area is the Gladstone combustion Turbine. Gladstone is an Emergency Run Only unit due to its environmental emission permit and requires a Local Transmission Emergency declaration to run. It cannot be used in support of planned maintenance or construction outages for this reason. b. System Reconfiguration and Operation Guidelines The severe events affecting the Escanaba area would leave the Escanaba area to be served by Nordic (53 mi) and Forsyth (40 mi) 69 kv transmission lines. These long lines are not able to carry the Escanaba area load. The losses on these lines increase exponentially as they become more heavily loaded. System adjustments that effectively reduce the amount of load served during contingencies were included in the modeling assumptions. These modeling assumptions included: moving the transmission system split (normally open) in the Upper Peninsula west to the Hiawatha substation so that the loads east of Hiawatha are served by the Lower Peninsula and the Nordic Cornell 69 kv circuit is allowed its highest rating by leaving the line section from Cornell Tap to Harris open, serving Harris from Chalk Hills. No other system reconfiguration is available in this area to relieve contingent overloads and local area voltage collapse. c. Demand Response or Load Curtailment MISO estimated the amount of demand response or load curtailment required to mitigate reliability issues for three most severe contingencies using 2012 summer peak system condition with Escanaba CT on at 14 MW. The demand response values were 25 MW, 46 MW and 102 MW. The Escanaba area summer peak demand including loads on 69 kv lines from Nordic and Forsyth is 102 MW. The 102 MW demand response value is for an event which includes an area greater than the Escanaba area with demand in that area of 155 MW. For the most severe event the estimated demand response values is 66% of area demand (102/155). Implementing demand 11

12 response for such a large portion of area demand does not seem practical. Demand response estimates for the contingencies are show in Table 2 below. Table 2: Demand Response Estimates for Selected Contingencies Case 2012 Summer Peak Contingency [REDACTED LINE 5] and [REDACTED LINE 6] Reliability Issue collapse Demand Response 25 MW 2012 Summer Peak [REDACTED LINE 3] and [REDACTED LINE 4] collapse 46 MW 2012 Summer Peak [REDACTED LINE 1] and [REDACTED LINE 2] collapse 102 MW d. Transmission Projects The area is dependent on [REDACTED] transmission lines, some of which [REDACTED]. An additional source would be required to allow the Transmission Owner to perform planned and construction maintenance without the availability of Escanaba 1 & 2. Alternatives analysis was performed for transmission projects already proposed that are included in or adjacent to the area of study in an effort to determine what planned upgrades would allow for the suspension of the Escanaba generating units 1 and 2 without planning criteria violations. This analysis was performed using the 2017 summer peak and shoulder load models which contain the approved projects in Escanaba area. The known severe maintenance outages were also studied using the 2017 shoulder load case Summer Peak Analysis For system intact, Category B, C1, C2, C4, and C5 contingencies, the suspension of Escanaba generation units 1 & 2 resulted in no planning criteria violations due to ATC transmission upgrades, especially Chandler-18th Road and Chalk Hills-18th Road 138 kv lines Shoulder Maintenance Analysis For system intact, Category B, C1, C2, C4, and C5 contingencies, the suspension of Escanaba generation units 1 & 2 resulted in no planning criteria violation due to ATC transmission upgrades, especially Chandler-18th Road and Chalk Hills-18th Road 138 kv lines. Additionally, none of the maintenance scenarios listed previously resulted in planning criteria violations. The 2017 analysis demonstrates the effectiveness of the approved projects in addressing the identified reliability issues due to suspension of Escanaba steam units 1 and 2. 12

13 VII. SUMMARY OF SELECTED SOLUTION The following previously approved projects would allow for the suspension of the Escanaba units 1 and 2 without planning criteria violations: Indian Lake-Hiawatha 138 kv P333, ISD 6/1/2013, MTEP Appendix A Mackinac HVDC Converter Station P2846, ISD 5/1/2014, MTEP Appendix A Chandler-Old Mead Road P2779, ISD 6/1/2014, MTEP Appendix A The Chalk Hills-18 th Road 138 kv line, a part of P3679, ISD 12/31/2016, MTEP Appendix A The projects listed above have already been approved for other purposes. The completion of the Chandler-18 th Road project and Chalk Hills-18 th Road line would significantly strengthen the transmission system in the Escanaba area. Additionally, the Chalk Hills-18 th Road line would provide an additional 138 kv path from the south for power to flow, especially during maintenance outages or Category C5 events affecting the current transmission system. 13