XXXX. Knob Hill Wind Farm Project. Interconnection System Impact Study

Transcription

1 XXXX Knob Hill Wind Farm Project Report No. August 2010 British Columbia Hydro and Power Authority British Columbia Hydro and Power Authority All rights reserved..

2 DISCLAIMER OF WARRANTY, LIMITATION OF LIABILITY This report was prepared by the British Columbia Hydro And Power Authority ( BCH ) or, as the case may be, on behalf of BCH by persons or entities including, without limitation, persons or entities who are or were employees, agents, consultants, contractors, subcontractors, professional advisers or representatives of, or to, BCH (individually and collectively, BCH Personnel ). This report is to be read in the context of the methodology, procedures and techniques used, BCH s or BCH s Personnel s assumptions, and the circumstances and constraints under which BCH s mandate to prepare this report was performed. This report is written solely for the purpose expressly stated in this report, and for the sole and exclusive benefit of the person or entity who directly engaged BCH to prepare this report. Accordingly, this report is suitable only for such purpose, and is subject to any changes arising after the date of this report. This report is meant to be read as a whole, and accordingly no section or part of it should be read or relied upon out of context. Unless otherwise expressly agreed by BCH: 1. any assumption, data or information (whether embodied in tangible or electronic form) supplied by, or gathered from, any source (including, without limitation, any consultant, contractor or subcontractor, testing laboratory and equipment suppliers, etc.) upon which BCH s opinion or conclusion as set out in this report is based (individually and collectively, Information ) has not been verified by BCH or BCH s Personnel; BCH makes no representation as to its accuracy or completeness and disclaims all liability with respect to the Information; 2. except as expressly set out in this report, all terms, conditions, warranties, representations and statements (whether express, implied, written, oral, collateral, statutory or otherwise) are excluded to the maximum extent permitted by law and, to the extent they cannot be excluded, BCH disclaims all liability in relation to them to the maximum extent permitted by law; 3. BCH does not represent or warrant the accuracy, completeness, merchantability, fitness for purpose or usefulness of this report, or any information contained in this report, for use or consideration by any person or entity. In addition BCH does not accept any liability arising out of reliance by a person or entity on this report, or any information contained in this report, or for any errors or omissions in this report. Any use, reliance or publication by any person or entity of this report or any part of it is at their own risk; and 4. In no event will BCH or BCH s Personnel be liable to any recipient of this report for any damage, loss, cost, expense, injury or other liability that arises out of or in connection with this report including, without limitation, any indirect, special, incidental, punitive or consequential loss, liability or damage of any kind. British Columbia Hydro and Power Authority, All rights reserved ii

3 COPYRIGHT NOTICE Copyright and all other intellectual property rights in, and to, this report are the property of, and are expressly reserved to, BCH. Without the prior written approval of BCH, no part of this report may be reproduced, used or distributed in any manner or form whatsoever. British Columbia Hydro and Power Authority, All rights reserved. iii

4 Executive Summary XXXX, the Interconnection Customer (IC), proposes to develop the Knob Hill Wind Farm Project to deliver electric energy to BC Hydro (BCH) through the 2008 Clean Power Call. The project is located on North Vancouver Island (NVI), British Columbia This report identifies the system modifications and additions required to interconnect the proposed Knob Hill Wind Farm Project. The maximum power injection into the BCH system is 94.7 MW. The Point of Interconnection (POI) is the Port Hardy Substation (PHY) 132 kv bus. The proposed Commercial Operation Date (COD) is October 1, Islanded operation is not allowed. Power quality protection is required to prevent/mitigate possible islanded operation. Direct transfer tripping schemes will be required to trip the Knob Hill generating units during various system conditions. The voltage dip due to transformer inrush when energizing the IC transformer after the plant is out of service appears to exceed the limits stated in the BC Hydro s interconnection guide. Consequently, a transformer inrush control scheme may be required. The IC will be responsible for undertaking the studies required to determine the necessity of an inrush mitigation scheme. The non-binding good faith cost estimate for the Interconnection Network Upgrades required to interconnect the proposed project to the BC Hydro Transmission System is $10.6M The time to construct the Interconnection Network Upgrades required is estimated to be 18 months. The Interconnection Facilities Study report will provide greater details of the Interconnection Network Upgrade requirements and associated cost estimates and estimated construction timeline for this project. British Columbia Hydro and Power Authority, All rights reserved. iv

5 Table of Contents DISCLAIMER OF WARRANTY, LIMITATION OF LIABILITY... ii COPYRIGHT NOTICE... iii Executive Summary...iv 1.0 Introduction Purpose of Study Terms of Reference Assumptions System Studies Steady State Pre-outage Power Flows Power Flow Based First Contingency Study Transient Stability Study Islanding Fault Analysis Analytical Studies Protection and Control & Telecommunications & Circuit Breakers BCH System Black Start Capability Transmission Line Upgrade Requirements Additional BCH Station Upgrades/Additions Other Issues Cost Estimate and Schedule Conclusion & Discussion...9 Appendix A Transmission System Single-Line-Diagram...11 Appendix B Knob Hill Wind Farm Model and Data...12 Appendix C Typical post disturbance stability swings of the BCH- Knob Hill Wind Farm interconnected systems...13 British Columbia Hydro and Power Authority, All rights reserved. v

6 1.0 Introduction The project reviewed in this SIS report is as described in Table 1 below. Table 1: Summary Project Information Project Name Knob Hill Wind Farm Project Interconnection Customer (IC) XXXX Point of Interconnection (POI) Port Hardy Substation (PHY) 132 kv bus IC Proposed COD October 1, 2012 Type of Interconnection Service NRIS ERIS Maximum Power Injection (MW) 94.7 (Summer) 94.7 (Winter) Number of Generator Units 62 Plant Fuel Wind XXXX, the Interconnection Customer (IC), proposes to develop the Knob Hill Wind Farm Project to deliver electric energy to BC Hydro (BCH) through the 2008 Clean Power Call (CPC). The proposed maximum power to be injected into the BCH system is 94.7 MW. The proposed Commercial Operation Date (COD) is October 1, The Knob Hill Wind Farm will be connected to the Point of Interconnection (POI), the PHY 132 kv bus, via a 40 km customer-owned 132 kv transmission line. The wind farm project will consist of 62 GE, 1.6XLE wind turbine units. Each of these units has a net rated output of 1.6 MW. Each unit will be stepped up via a 1.85 MVA, 0.69/34.5 kv transformer, and then connected to one of five 34.5 kv feeders. A collector station with a 34.5/132 kv transformer will connect the feeders to the customer-owned 132 kv transmission line. Figure 1 shows the connection of the Knob Hill Wind Farm to the Transmission System. The Transmission System single-line diagram for the NVI area is provided in Appendix A. British Columbia Hydro and Power Authority, All rights reserved Page 1 of 18

7 Figure 1 Connection of Knob Hill Wind Farm to the Transmission System. 2.0 Purpose of Study The purpose of this SIS is to assess the impact of the interconnection of the proposed project on the BCH Transmission System. This study will identify constraints and Network Upgrades required for the reliable operation of the Transmission System. 3.0 Terms of Reference The study investigates and addresses the voltage and overloading issues of the transmission networks in the vicinity of Knob Hill generating station as a result of the proposed interconnection. Topics studied include equipment thermal loading and rating requirements, system transient stability and voltage stability, transient over-voltages, protection coordination, operation flexibility, telecom requirements and high level remedial action scheme requirements. BCH planning methodology and criteria are used in the studies. Upgrades that are required in common with other IPP projects selected for development in the NVI area under the 2008 Clean Power Call exceed the scope of the studies required for this Knob Hill Wind Farm proposal and are not included in this report. The SIS does not investigate operating restrictions and other factors for possible second contingency outages. Subsequent internal network studies will determine the requirements for reinforcements or operating restrictions/instructions for those kinds of events. Impact to the bulk Transmission System is not included in the SIS and will be covered in a separate study. British Columbia Hydro and Power Authority, All rights reserved. Page 2 of 18

8 The work necessary to implement the network improvements identified in this SIS report will be described in greater detail in the Interconnection Facilities Study report for this project. 4.0 Assumptions The power flow conditions studied are base cases that include generation, transmission facilities, and load forecast representing the queue position applicable to this project. Applicable seasonal conditions and the appropriate study years for the study horizon are also incorporated. Although the Knob Hill Wind Farm is proposed to enter service in 2012, the 2014 heavy winter, heavy summer and light summer load flow base cases were selected for this study due to the need to assess the system impacts of these projects on a joint basis. The study is based on the model and data information provided by the proponent in the Generator Interconnection Data Form for this project. Reasonable assumptions are made to complete the study and the report, whenever such information is unavailable. Further system assumptions: The NVI 230/138 kv system presently has system constraints under N-1 conditions between JHT and DMR that are resolved via generation shedding/runback Remedial Action Schemes (RAS). For study purposes, its been assumed that these RAS will be retained and possibly expanded to resolve system constraints that could be exacerbated by the Kokish River and Knob Hill Projects. Generation interconnection projects with higher queue positions considered in the study include Green Island Energy (GIE) and Clint Creek Hydro (CLH). System upgrades required for these projects have also been considered in the study. The EFM industrial load is in operation and has been considered in this SIS although the load status may become uncertain in future. 5.0 System Studies Power flow, short circuit and transient stability studies were carried out to evaluate the impact of the proposed interconnection. Studies were also performed to determine the protection, control and communication requirements, and to evaluate possible over-voltage issues. 5.1 Steady State Pre-outage Power Flows Pre-outage power flows are prepared to assess the impact of the proposed interconnection using three load conditions (2014 winter peak load, 2014 summer light load and 2014 summer peak load). Table 2 provides the power flow study results for the Knob Hill Wind Farm interconnection, and the results are: No voltage violation is observed. No circuits overloaded before or after the Knob Hill Wind Farm connection. British Columbia Hydro and Power Authority, All rights reserved. Page 3 of 18

9 Table 2: Pre-outage Power Flow Results Base Case Contingency KNB injection at POI (MW) PHY 132 Volt. (pu) KKS POI Volt. (pu) GLD 132 Volt. (pu) 1L125 loading (%) 2L154 loading (%) 1L120 loading (%) 1L121 loading (%) 1L117 loading (%) 1L119 loading (%) 1L101 loading (%) 1L102 loading (%) 1L106 loading (%) 2014 LS None HS, None HW None Note: LS: light summer load; HW: heavy winter load; HS: heavy summer load 5.2 Power Flow Based First Contingency Study. Power flow based single contingency (N-1) studies have been conducted to check if the post-disturbance performance including bus voltage deviation and facility loading meets the planning criteria under different system load conditions including 2014 heavy winter, heavy summer and light summer conditions. Detailed results are provided in Table 3. The studies have indicated the following: During single contingency outages on 2L154 (DMR-GLD), generation shedding is required at the Knob Hill Wind Farm to avoid overloading transmission lines 1L120 (GLD-SCA) and 1L121 (SCA-LDR). Direct transfer tripping schemes will be required from DMR and GLD to the Knob Hill Wind Farm to trip its generating units for a protection trip on 2L154, on the GLD 230/138 kv transformers (2L154 and the GLD transformers share a common protection tripping zone), or when the 2L154 circuit breakers at DMR - or the transformer circuit breakers at GLD are opened. (Note: If the NVI generating stations, including Knob Hill Wind Farm, are operating at their seasonal Expected Load Carrying Capacity (ELCC), no generation shedding or curtailment will required as indicated in the tables below.) With the generation shedding mentioned above implemented, no voltage violation or new transmission equipment overload will be caused by interconnection of the Knob Hill Wind Farm. However, overloads on the 138kV lines between JHT and DMR (i.e., 1L119/101/102) presently exist during outages on 2L154 or any of the JHT-DMR transmission lines and they will be exacerbated by the interconnection of the Knob Hill Wind Farm. Generation shedding or curtailment may be required resolve these overloads. The JHT-DMR constraints are existing system deficiencies that will be resolved in a different project. The identification of a preferred option to resolve these constraints is outside the scope of this interconnection study and will be dealt with in a separate study. However, depending on the option selected and its completion date, the Knob Hill Wind Farm may be required to participate in area generation shedding schemes on either a British Columbia Hydro and Power Authority, All rights reserved. Page 4 of 18

10 temporary basis (i.e., assuming a system capacity upgrade is implemented) or on a permanent basis (i.e., assuming generation reduction is used to resolve the constraints). Table 3: Power Flow Results after Single Element Contingency 5.3 Transient Stability Study A series of transient stability studies under various system operating conditions including the heavy winter case and the most severe light summer case have been performed. The model of the generating project was based on the IC s data submission plus additional assumptions where the IC s data was incomplete or inappropriate. The models and data values of the key components are provided in Appendix B. The Knob Hill Wind Farm stability performance was acceptable and no voltage violations were observed for the fault study cases reviewed. The transient stability study results for 2014 summer light load are summarized in Table 4 below. British Columbia Hydro and Power Authority, All rights reserved. Page 5 of 18

11 Table 4: Transient Stability Study Results (Pre-outage condition: 2014 LS with 94 MW Injections from Knob Hill Wind Farm and 45 MW Injection from Kokish River) Case Transmission Circuits Knob Hill Port Hardy line 1L130 (JUL KGH) 1L134 (GLD GRP) 1L120 (GLD SCA) 2L154 (GLD DMR) T5 DMR230 /DMR132 T1 GLD230 /GLD132 1L131 (GLD TSV) 1L121 (SCA LDR) 1L106 (DMR PUN) 1L125 (GLD-KKS) 1L125 (KKS-KGH) 3 Fault Location Fault Clearing Time (Cycles) Close End Far End PHY T1 high side 24 9 JUL 8 32 GRP Not critical 25 GLD 8 9 GLD 8 7 DMR T5 HV side 8 N/A GLD TSV 8 23 SCA 8 9 DMR 8 9 GLD KGH Stability Performance Acceptable Both Knob Hill and Kokish Acceptable Knob Hill only Acceptable Knob Hill only Acceptable Knob Hill only Acceptable Knob Hill only Acceptable Knob Hill only Acceptable Knob Hill only Acceptable Knob Hill only Acceptable Knob Hill only Acceptable Knob Hill only Both Knob Hill and Kokish are islanded Knob Hill islanded, Kokish Unstable Note 1: Unacceptable stability performance means unstable rotor angle results for conventional generators or violation of transient voltage dip according to BCH planning criteria. 5.4 Islanding Islanded operation is normally not an acceptable practice in BCH. Power quality protection will be required at the generating units to detect abnormal system conditions such as under/over voltage and under/over frequency and subsequently trip the units. The settings of these protective relays must conform to existing BCH practice for generating plants so that the generator will not trip for normal ranges of voltages and frequencies. British Columbia Hydro and Power Authority, All rights reserved. Page 6 of 18

12 5.5 Fault Analysis The short circuit analysis for the CPC System Impact Studies are based upon the latest BCH system short circuit model, which includes project equipment and impedances provided by the successful CPC Interconnection Customers. The model included higher queued projects and planned system reinforcements but excluded the Northwest Transmission Line (NTL) and other lower queued projects. At this stage, the report does not provide Thevenin impedances at the POI due to uncertainties associated with the system reinforcement options identified for the CPC projects and the statuses of higher queued projects. However, these Thevenin impedances, including the ultimate fault levels at POI, will be made available to Interconnection Customers upon request. BCH will work with the IC to provide accurate data as required during the project design phase. 5.6 Analytical Studies Due to the unavailability of a model for the wind turbine generators proposed for the wind farm, approximate models based on similar units installed at an existing wind farm were used for analytical EMTP study purposes. When the models are available for the proposed units, the Knob Hill Wind Farm should be subjected to a detailed PSCAD- EMTDC simulation for typical system disturbances including fault studies to assess the performance of the wind farm including its ride-through capabilities and its impact on the NVI Transmission System. Studies based on a simplified model for the Knob Hill Wind Farm indicated there is a low probability that excessive temporary over-voltages could occur in the isolated KKS- KGH-PHY-Knob Hill system due to non-protective opening (i.e., local or supervisory opening) of 1L137 (KGH-PHY) at KGH or 1L125 (GLD-KGH) at GLD or KGH. Consequently, for non-protective opening of these line terminals, direct transfer trips will be required from KGH to PHY to disconnect the Knob Hill Wind Farm from the system when opening 1L137 or 1L125 at KGH and from GLD to PHY to disconnect the Knob Hill from the system when opening 1L125 at GLD. Further, the opening of these line terminals must be delayed sufficiently to allow the Knob Hill Wind Farm to be disconnected prior to opening the line terminals. The need for these transfer trips should be reviewed when more accurate models are provided for the wind farm. The voltage dip due to the transformer inrush when energizing the Knob Hill Wind Farm transformer will exceed the limits allowed in the BC Hydro Interconnection Guide. Consequently, a transformer inrush control scheme may be required, for example via the installation of a 138 kv entrance breaker with independent pole operation and a point-onwave (POW) controller to control the timing and closing of the individual poles in order to minimize the transformer inrush. It is the responsibility of the IC to undertake the studies necessary to determine the requirements for an inrush investigation scheme and to identify a preferred scheme. British Columbia Hydro and Power Authority, All rights reserved. Page 7 of 18

13 5.7 Protection and Control & Telecommunications & Circuit Breakers Protection, control and telecom requirements for the new Knob Hill Wind Farm addition have also been reviewed. The main items are summarized below: Provide primary and standby protection for the IC s transmission line and 1L137 (PHY-KGH) at PHY and upgrade the primary and standby protection for 1L137 at KGH. Direct transfer tripping using Class 2 telecommunication facilities (i.e., power line carrier, or PLC) may be required from GLD to PHY to disconnect the Knob Hill Wind Farm when opening the GLD terminal of 1L125 (GLD-KGH) via nonprotective means (i.e., opening via local or supervisory control) and the opening of the GLD terminal must be delayed sufficiently to ensure the Knob Hill Wind Farm is disconnected from the system prior to opening the GLD line terminal. Two sets of new direct transfer tripping facilities using Class 2 telecommunication facilities may be required from KGH to PHY to disconnect the Knob Hill Wind Farm when opening the KGH terminal of 1L137 (KGH-PHY) or 1L125 (KGH-GLD) via non-protective means (i.e., opening via local or supervisory control) and the opening of the KGH terminals must be delayed sufficiently to ensure the Knob Hill Wind Farm is disconnected from the system prior to opening the KGH line terminal. Direct transfer tripping using Class 2 telecommunication facilities will be required from GLD and DMR to the Knob Hill Wind Farm to shed its generators when 2L154 or GLD 230/138 kv transformer protection trips (2L154 and the GLD transformers are in a common protection tripping zone) or when the DMR 230 kv line terminal or GLD 230/138kV transformer bus position is open. Provide a RTU and SCADA at PHY for remote data acquisition and control purposes. 5.8 BCH System Black Start Capability BCH does not require the proposed project to have black start (self-start) capability. However, if the IC desires their facilities to be energized from the BCH system, the IC is required to apply for an Electricity Supply Agreement. Upon receipt of this application, a plant pick-up study would be required to assess the impact of energizing the IC s facilities. A high level plant pick-up screening was performed as part of the SIS and any issues are identified in Section Transmission Line Upgrade Requirements Relocation of 1L137 (KGH-PHY) at PHY to facilitate the re-termination of 1L137 in the PHY 132 kv bus and the provision of a dead-end structure outside the PHY substation fence to facilitate the termination of the IC s transmission line. British Columbia Hydro and Power Authority, All rights reserved. Page 8 of 18

14 5.10 Additional BCH Station Upgrades/Additions Re-termination of 1L137 (KGH-PHY) in the PHY 132 kv bus to provide space for the termination of the IC s transmission line and the installation of a 132 kv circuit breaker in the 132 kv bus to create line positions for 1L137 and the IC s transmission line Other Issues There is no other issue identified at this stage Cost Estimate and Schedule The non-binding good faith cost estimate for the Interconnection Network Upgrades is $10.6M. The Interconnection Facilities Study report will provide more detailed information of the cost estimates. The estimated time to construct the Interconnection Network Upgrades is estimated at 18 months after the Standard Generation Interconnection Agreement is signed and BCH capital project is approved. A more detailed construction timeline will be provided in the Interconnection Facilities Study report. BCH system upgrades triggered by CPC projects are being determined and the IC may be required to post security to cover one or more upgrade. Further information will be provided over the next few months. 6.0 Conclusion & Discussion In order to interconnect the Knob Hill Wind Farm to the BCH Transmission System, this SIS has identified the following issues and requirements: Relocate the 1L137 (PHY-KGH) line terminal into a new position at PHY, construct a new line position for the IC s transmission line, and install a new 138 kv circuit breaker in the PHY 132 kv bus to create separate line positions for 1L137 and the IC s transmission line. Direct transfer trip facilities may be required from GLD to PHY to disconnect the Knob Hill Wind Farm from the system when opening the 1L125 (GLD-KGH) line terminal at GLD via local or supervisory control (i.e., no fault opening) to avoid temporary over-voltages on the isolated GLD-KGH-PHY-Knob Hill system. The opening of the GLD line terminal will need to be delayed sufficiently to ensure the Knob Hill is disconnected prior to opening the line terminal at GLD. Two sets of direct transfer trip facilities may also be required from KGH to PHY to disconnect the Knob Hill Wind Farm from the system when opening the 1L137 (KGH-PHY) line terminal or the 1L125 (KGH-GLD) line terminal at KGH via local or supervisory control (i.e., no fault opening) to avoid temporary over-voltages on the isolated KGH-PHY-Knob British Columbia Hydro and Power Authority, All rights reserved. Page 9 of 18

15 Hill system. The opening of the KGH line terminals will need to be delayed sufficiently to ensure the Knob Hill Wind Farm is disconnected prior to opening the line terminals at KGH. Preliminary studies indicate that the voltage dip when energizing the Knob Hill Wind Farm transformer will exceed the limits stated in the BC Hydro interconnection guide. Consequently, a transformer inrush control scheme will likely be required. The IC will be responsible for undertaking the studies required to determine the necessity of an inrush mitigation scheme. No unacceptable voltage condition in the Transmission System was observed in the power flow and transient stability analysis under normal and N-1 contingencies; No unacceptable equipment overload condition in the Transmission System was observed in the power flow analysis under normal conditions. No voltage instability has been observed in the Transmission System. Islanded operation is not allowed. Power quality protection is required to prevent/mitigate possible islanded operation; Direct transfer trip schemes will be required from DMR and GLD to Knob Hill to trip its generating units out if service for a protection trip on 2L154 or on the GLD 230/138 kv transformers (2L154 and the GLD transformers share a common protection tripping zone) or when the 2L154 circuit breakers at DMR or the transformer circuit breakers at GLD are opened in order to avoid overloads on 1L120 (GLD-SCA) and 1L121 (SCA-LDR). Generation shedding/curtailment may also be required during outages on the JHT-DMR 132 kv circuits (i.e., 1L119, 101, 102 or 106) to avoid overloads on the remaining JHT-DMR transmission lines. This is due to an existing system deficiency that will be resolved by a system upgrade. However, depending on the system upgrade and its completion date, the generation shedding/curtailment required may be temporary (i.e., assuming a system capacity upgrade is implemented) or permanent (i.e., assuming generation reduction is used to resolve the constraints). Assuming the NVI generating stations are operating at their seasonal Expected Load Carrying Capacity (ELCC) including the Knob Hill Wind Farm, generation shedding/curtailment may only be required at JHT, LDR and SCA. British Columbia Hydro and Power Authority, All rights reserved. Page 10 of 18

16 Appendix A Transmission System Single-Line-Diagram British Columbia Hydro and Power Authority, All rights reserved Page 11 of 18

17 Appendix B Knob Hill Wind Farm Model and Data KNOB HILL WIND FARM Generator Model The contents of this section have been removed due to the proprietary nature of the information. British Columbia Hydro and Power Authority, All rights reserved Page 12 of 18

18 Appendix C Typical post disturbance stability swings of the BCH- Knob Hill interconnected systems Voltages: (Fault on GLD-DMR 230 kv line) British Columbia Hydro and Power Authority, All rights reserved Page 13 of 18

19 Flow on KNOB HILL WIND FARM Line (Fault on GLD-DMR 230 kv line) British Columbia Hydro and Power Authority, All rights reserved. Page 14 of 18

20 Voltages: (Fault on 1L134 GLD-GRP) British Columbia Hydro and Power Authority, All rights reserved. Page 15 of 18

21 Flow on KNOB HILL WIND FARM Line: (Fault on 1L134 GLD-GRP) British Columbia Hydro and Power Authority, All rights reserved. Page 16 of 18

22 Voltages: (Fault on 1L130 KGH-NRH) British Columbia Hydro and Power Authority, All rights reserved. Page 17 of 18

23 Flow on KNOB HILL WIND FARM Line: (Fault on 1L130 KGH-MRH) British Columbia Hydro and Power Authority, All rights reserved. Page 18 of 18