Executive Summary Firm point to point transmission service has been requested by Transmission Service Request (TSR) #80439788, under the SaskPower Open Access Transmission Tariff (OATT). The purpose of TSR #80439788 and the corresponding MH TSR #80375458 is to transfer power from Island Falls Hydroelectric Station in the northern SaskPower (SPC) system to the southern SPC system. The northern SPC system is connected to the southern SPC system through the Manitoba Hydro (MH) system and therefore, the power needs to be wheeled through MH. TSR #80439788 consists of a request for 60 MW firm transmission service from SaskPower generation at Island Falls hydroelectric station (POR IFHS) to the MH-SPC 110 kv interface. The MH-SPC 110 kv interface consists of the two 110 kv tie-lines (I1F and I2F) between the Island Falls station (in SPC) and Border station (in MH). The corresponding MH TSR #80375458 requests a 60 MW transfer through the MH system, from the MH-SPC 110 kv interface to the MH-SPC 230 kv interface. The MH-SPC 230 kv interface consists of the three 230 kv tie-lines between MH and SPC. There is no corresponding TSR for the southern SPC system requesting a transfer of the power from the 230 kv MH-SPC interface to the southern SPC system. The TSR indicates that it will use the service under TSR #663837 to complete the path. TSR #663837 is owned by SPC and is Network Integrated Transmission Service associated with Island Falls under a grandfathered agreement with MH. This study only addresses the transmission service from Island Falls Hydro Station (POR) to Manitoba Hydro 110 kv interface (POD). It does not grant any service beyond that, or grant service to TSR #663837. Summary details for SPC TSR #80439788 and MH TSR #80375458 are shown in Tables ES.1 and ES.2: SPC TSR # Point of Point of Service Start Date Receipt Delivery Requested 80439788 IFHS MH.115 60 MW, firm 2015-01-01 00:00:00 CS Stop Date Queue Date 2022-01-01 00:00:00 CS 2014-11-07 08:56:59 CS Table ES.1: Summary Details for SPC TSR #80439788. MH TSR # Point of Receipt Point of Delivery Service Requested Start Date 80375458 MHEB.IF SPC 60 MW, firm 2014-12-31 23:00:00 CS Stop Date Queue Date 2021-12-31 23:00:00 CS 2014-10-23 08:04:21 CS Table ES.2: Summary Details for MH TSR #80375458
ES.1 System Impacts of TSR #80439788 on SPC System Based on a pre-existing study done for 105 MW TSR from IFHS to SPC-MH 110 kv interface, system impacts were not identified in SPC system due to the requested 60 MW transfer of TSR #80439788 from the designated POR to POD (from Island Falls Hydroelectric Station to MH- SPC 110 kv interface). ES.1.2 Conclusion The study identified that full service of firm point-to-point 60 MW of transmission capacity associated with Transmission Service Request #80439788 may be granted with roll-over. The service under TSR #80439788 cannot however be redirected to any other POD/sink on a firm basis. A separate TSR would be required for redirection.
Table of Contents 1.0 INTRODUCTION... 4 2.0 STUDY OBJECTIVES... 5 3.0 STUDY SCOPE... 5 4.0 STUDY CRITERIA... 6 5.0 STUDY METHODOLOGY... 7 6.0 BASE CASE DEVELOPMENT... 8 7.0 IDENTIFIED IMPACTS... 8 7.1 EQUIPMENT OVERLOAD ANALYSIS FOR TSR #80439788... 8 8.0 CONCLUSIONS... 9 9.0 OTHER TRANSMISSION SERVICE CONSIDERATIONS... 9
1.0 Introduction This study determines the system impacts associated with Transmission Service Request (TSR) #80439788, as per the SaskPower Open Access Transmission Tariff (OATT). Firm point to point transmission service has been requested by Transmission Service Request (TSR) #80439788, under the SaskPower Open Access Transmission Tariff (OATT). The purpose of TSR #80439788 and the corresponding MH TSR #80375458 is to transfer power from Island Falls Hydroelectric Station in the northern SaskPower (SPC) system to the southern SPC system. The northern SPC system is connected to the southern SPC system through the Manitoba Hydro (MH) system and therefore, the power needs to be wheeled through MH. TSR #80439788 consists of a request for 60 MW firm transmission service from SaskPower generation at Island Falls hydroelectric station to the MH-SPC 110 kv interface. The MH-SPC 110 kv interface consists of the two 110 kv tie-lines (I1F and I2F) between Island Falls station (in SPC) and Border station (in MH). The corresponding MH TSR #80375458 requests a 60 MW transfer through the MH system, from the MH-SPC 110 kv interface to the MH-SPC 230 kv interface. The MH-SPC 230 kv interface consists of the three 230 kv tie-lines between MH and SPC. There is no corresponding TSR for the southern SPC system requesting a further transfer of power from the 230 kv MH- SPC interface to the southern SPC system. The TSR indicates that it will use the service under TSR #663837. TSR #663837 is owned by SPC and is Network Integrated Transmission Service associated with Island Falls under a grandfathered agreement with MH. The study agreement for TSR #80439788 identifies that the source for the power transfer is generation in the northern SPC system (POR of Island Falls Hydroelectric Station) and the sink for the transfer is load in the southern SPC system. This study only addresses the transmission service from Island Falls Hydro Station (POR) to Manitoba Hydro 110 kv interface (POR). It does not grant any service beyond that, or grant service to TSR #663837. Summary details for SPC TSR #80439788 and MH TSR #80375458 are shown in Tables 1.1 and 1.2: SPC TSR # Point of Point of Service Start Date Stop Date Queue Date Receipt Delivery Requested 80439788 IFHS MH.115 60 MW, firm 2015-01-01 00:00:00 CS 2022-01-01 00:00:00 CS 2014-11-07 08:04:21 CS Table 1.1: Summary Details for SPC TSR #80439788. MH TSR # Point of Point of Service Start Date Stop Date Queue Date Receipt Delivery Requested 80375458 MHEB.IF SPC 60 MW, firm 2014-12-31 23:00:00 CS 2021-12-31 23:00:00 CS 2014-10-23 08:56:59 CS Table 1.2: Summary Details for MH TSR #80375458.
2.0 Study Objectives The System Impact Study for TSR #80439788 has the following objectives: To assess the impact of TSR #80439788 on the SaskPower (SPC) Far North and Manitoba Hydro (MH) transmission systems, including tie-lines. To determine if any identified impacts results in violation of SPC and MH performance criteria. To determine if a level of partial service is available, given that identified impacts for the requested power transfer levels are unacceptable. To identify mitigation options, given that identified impacts for the requested power transfer levels are unacceptable. To determine if rollover of the TSR is possible. The System Impact Study Agreement for TSR #80439788 defines the following objectives: To determine the adequacy of the SPC north transmission systems to accommodate the TSR. To determine whether any additional costs may be incurred in order to provide transmission service. The System Impact Study will not address the cost of the system additions or upgrades outside of SPC. To identify partial service, if applicable. To identify the system constraints. To identify the potential re-dispatch options, potential direct assignment facilities, or potential network upgrades required to provide the requested transmission service. 3.0 Study Scope The System Impact Study considers: Applicable SPC system topology and load levels using the latest available modeling information for the time frame studied.
Most-likely stressed summer and winter load and generation scenarios for the SPC system. Applicable planned system modifications, or additions to primary facilities or operations for the time frame studied. Previously queued requests for interconnection studies and reserved transmission service that stress system conditions. Applicable planned SPC generation outages for the time frame studied. SPC system performance for steady-state system-intact normal operating conditions. SPC system performance for applicable events resulting in the loss of a single (N-1) SPC bulk electric system element, or the loss of two (N-2) or more SPC bulk electric system elements. Impacts on the SPC tie-lines to Manitoba. Impacts on MH facilities. This System Impact Study does not consider: Impacts on facilities outside of the SPC and MH systems, unless otherwise noted. System performance following extreme events resulting in the loss of two or more bulk electric system elements. Previously queued requests for interconnection studies and reserved transmission service that stress system conditions. Applicable planned SPC generation outages for the time frame studied. SPC system performance for steady-state system-intact normal operating conditions. 4.0 Study Criteria SPC and NERC transmission planning standards were used to assess the system impacts of TSR #80439788 on system performance (system-intact and post-contingency).
5.0 Study Methodology Simulations to assess the impacts to the SPC system due to TSR #80439788 were conducted using the PSS/E software package. 1 The following methodology process was used to assess the system impacts of TSR #80439788: Conduct contingency analysis to identify impacts on the SPC system due to TSR #80439788, for applicable N-1 and N-2 contingencies. Identify facilities required to mitigate the system impacts of TSR #80439788. TSR #80439788 identifies the point of receipt (POR) as the Island Falls station and the point of delivery (POD) as the MH-SPC 110 kv interface. The corresponding MH TSR #80375458 requests a 60 MW transfer from the MH-SPC 110 kv interface to the MH-SPC 230 kv interface. There is no corresponding TSR for the southern SPC system requesting a transfer of the power from MH-SPC 230 kv interface into the southern SPC system. To assess the intended purpose of TSR #80439788 to transfer power through the I1F/I2F lines from Island Falls to MH-SPC 110 kv interface, power flow cases capturing wide range of scenarios for the requested and further out years were analyzed. In order to represent stressed conditions for power transfer on the 110 kv interface between MH and the northern SPC system, Island Falls Return was modeled at 105 MW. A transmission reliability margin (TRM) of 75 MW for the MH-SPC 230 kv interface was used to account for SPC load variations and area control impacts on this interface. The TRM was held constant at 75 MW for this study. Transmission reliability margin of 10 MW was assumed in this study for the MH-SPC 110 kv interface. Applicable N-1 and N-2 contingencies for the 110 kv SPC systems were used for the postcontingency assessment of TSR #80439788. These include: Tripping of SPC generators (N-1). Loss of a single-circuit SPC grid transmission line or tie-line (N-1). N-2 contingency analysis was not required as loss of both I1F/I2F circuits would take the facilities out-of-service to provide the requested transmission service. 1 PSS/E is a software package by Siemens PTI (Power Technologies International). It is widely used by power utilities to perform steady-state, transient, and dynamic simulation of power system operation.
6.0 Base Case Development Base case development is intended to produce a range of operating cases to ensure that potential system impacts and associated mitigation requirements across a wide range of operating conditions are identified, and to provide for an acceptable level of firm transmission service by minimizing transmission loading relief (TLR). For this study, the following cases were assessed: 2015 Summer Off-Peak, Summer Peak, and Winter Peak cases for analysis of requested reservations in the near-term. 2019 Summer Off-Peak, Summer Peak, and Winter Peak cases for analysis of rollover potential. 7.0 Identified Impacts For this analysis, the SPC and MH bulk-electric systems and tie-lines were assessed. The contingency analysis included the following applicable N-1 contingencies: Generator tripping (N-1). Loss of a single-circuit grid transmission line (N-1). 7.1 Equipment Overload Analysis for TSR #80439788 Based on a pre-existing study for 105 MW TSR from the designated POR to POD (from Island Falls Hydroelectric Station to the MH-SPC 110 kv interface), overloads on SPC equipment were identified for the northern SPC system. These overloads are summarized in Table 7.1.1. Overload Equipment I1F 110 kv Line I2F 110 kv Line Contingencies Resulting in Overloads N-1 loss of I2F 110 kv line N-1 loss of I1F 110 kv line Table 7.1.1: Summary of Overload Issues that occurred Due to 105 MW TSR The overloads of the I1F and I2F 110 kv tie-lines (between Island Falls station and MH) occurred for N-1 contingencies of the adjacent line (i.e I1F overloads occurred for trips of I2F, and vice-versa) as shown in Table 7.1.1. The lines are not overloaded beyond the
thermal rating of the conductor for 60 MW transfer from Island Falls to SPC-MH 110 kv interface for such contingencies. The study for 105 MW TSR from Island Falls to SPC-MH 110 kv interface identified that 60 MW would be within the identified partial interim service. 8.0 Conclusions The study identified that full service of firm point-to-point 60 MW of transmission capacity associated with Transmission Service Request #80439788 may be granted with roll-over. 9.0 Other Transmission Service Considerations The results of the System Impact Study will be deemed invalid 3 months after the completion of the System Impact Study. Completion of the System Impact Study is deemed to occur upon signing and issuing of the System Impact Study. The Customer must execute a Service Agreement for TSR #80439788 within 15 days of receipt of the completed System Impact Study. If the Customer does not execute the Service Agreement within 15 days, the results of the System Impact Study will be deemed invalid, and TSR #80439788 shall be deemed terminated and withdrawn. SPC, at its discretion, may elect to augment the proposed options or develop other options that would meet the technical requirements. However, any additional associated costs would not be allocated to TSR #80439788. Any roll-over granted will need to be conditioned by third party impacts or constraints. That is, third party impacts or constraints not known at the time of this study may be reevaluated at the time of roll-over to determine if service can still be granted. Firm service for TSR #80439788 may not be available for extreme load and dispatch patterns in Manitoba and Saskatchewan that were not assessed as part of this study. Firm service for TSR #80439788 is dependent upon system-intact operation of the SPC system. If SPC facilities that have an impact on the transfer capability of TSR #80439788 are not available due to maintenance or repair, curtailment of the TSR may be required. For example: loss of I1F or I2F circuits may require curtailment of TSR #80439788 and loss of generation from Island Falls Hydro Station may impact the service under TSR #80439788. The Study Agreement for TSR #80439788 identified that the source for TSR #80439788 was Island Falls Hydro Station and the sink for TSR #80439788 was load in the southern SPC system. Firm service for TSR #80439788 should be conditioned on the source and sink remaining as previously identified, otherwise a request for re-direct or potential reassessment of the transmission service may be required.