Bangor Hydro s Local System Plan

Transcription

1 Bangor Hydro s Local System Plan Needs Assessment/Potential Solutions Local Planning Advisory Committee Meeting November 17, 2011 Bangor Hydro Representative: Jeffrey Fenn, P.E., SGC Engineering

2 Purpose of Local System Plan (LSP) Per Attachment K - The LSP is an annual report that: 1. Describes non PTF transmission system reliability needs 2. Reflects 1. System planning studies 2. Proposed solutions 3. Identifies 1. Local planning process 2. Criteria, Data and Assumptions 2

3 LSP Communication 1. LSP is communicated via Local Planning Advisory Committee (LPAC) meeting for stakeholders convenience, this is being done following an ISO-NE PAC meeting 2. The material is posted prior to the LPAC meeting (via the ISO- NE PAC posting system) 3. Transmission Customers and Stakeholders have 30 days after posting to provide written comments for consideration by BHE 3

4 LSP Communication (cont.) 1. BHE Contact: Lisa Martin PO Box Illinois Avenue Bangor, Maine (207) BHE LSP is located at: 4

5 Local System Planning Process The process is Needs Assessment followed by Solutions Proposals Local System needs can result from: Load Growth Sub-area reliability assessments Point of delivery request from customers Generation interconnection requests (in accordance with appropriate generator interconnection procedures) Local System Plan consists of: Summary of needs assessment results Listing of criteria, data and study assumptions Identification of proposed alternatives Solution study results and selection of preferred alternative 5

6 Criteria, Data and Assumptions Loads based on CELT Report forecasts for the New England area, BHE specific forecasts and local customer needs Studies based on the ISO-NE library base cases and short circuit database Studies use relevant assumptions regarding transmission, generation and demand resources found in the latest ISO-NE Regional System Plan 6

7 LSP Project List 1. The LSP project list is a cumulative listing of proposed regulated transmission solutions intended to meet local needs 2. Similar to the ISO-NE PTF RSP, the LSP contains the status of each project Concept Project is under consideration as a solution to a partial needs assessment Proposed Needs assessment completed and project proposed as a solution, but not formally budgeted Planned Formally budgeted and if necessary, approved by ISO- NE Under Construction Significant engineering and internal approvals in process and project is being implemented In-Service Project used and useful 7

8 Bangor Hydro Detailed System 8

9 LSP Concept Status Need Needs Assessment Service Area Project Name Status Solutions Project In- Service Month/Year Reliability Chester T1 and T2 Overloading Northern Chester T1/T2 OL Concept Possible solution as part of BHE Annual Transmission Needs and Solutions Assessment 12/2013 9

10 LSP Proposed Status Need Needs Assessment Service Area Project Name Status Solutions Project In- Service Reliability Support of area loads, eliminate overload of L22 and improve ability to maintain transmission circuits Eastern Bar Harbor support Proposed Additional 34.5kV circuit with diverse route. Part of area looping 12/2012 Reliability Line 87 from Chester to Lincoln Overload Northern Line 87 Overload Proposed Rebuild 12/

11 LSP Planned Status Need Needs Assessment Service Area Project Name Status Solutions Project In- Service Reliability Existing regulation is overloaded under first contingency Eastern Harrington LTC Planned Replace regulators and transformer with LTC including transformer swap from Ellsworth Falls Q2/2012 Reliability Line overload/rating Bangor Line 8 Reconductor Planned Reconductor 3.3 miles 46kV 12/2012 Reliability Need determined during MPRP study Eastern Trenton Cap Planned Cap addition to 34.5kV 12/2012 Reliability Transformer overload/rating Eastern Ellsworth Falls T2 replacement Planned Install new transformer, freeing old transformer to be redeployed at Harrington Q2/

12 LSP Under Construction Status Need Project In- Service Service Area Project Name Status Reliability Q1/2012 Eastern MDI Causeway Circuit Addition Under Construction Reliability Q1/2012 Bangor Line 7 Reconductor Under Construction Reliability 12/2012 Eastern Tunk Substation Under Construction Reliability 12/2011 Eastern Line 13 Franklin to Unionville Under Construction 12

13 LSP In- Service Need Project In- Service Month/Year Service Area Project Name Status Solutions None n/a 13

14 Maine and BHE Major Transmission System 14

15 Bangor Hydro Detailed System 15

16 Project Descriptions - Proposed 1 Bar Harbor capacity support 2 L87 Overload 16

17 Project Descriptions Proposed 17

18 1 Bar Harbor Capacity 18

19 2 Line 87 Overload 19

20 Project Descriptions - Planned 1- Harrington LTC 2 Line 8 Reconductor 3 Trenton Cap Bank Addition 4 Ellsworth Falls T2 Replacement 20

21 Project Descriptions - Planned 21

22 1 Harrington LTC 22

23 2 Line 8 Reconductor 23

24 3 Trenton Cap Addition 24

25 4 Ellsworth Falls T2 25

26 LSP Under Construction Status 1 MDI Causeway Circuit Addition 2 - Line 7 Reconductor 3 Tunk Substation 4 Line 13 Franklin to Unionville 26

27 Project Descriptions Under Const. 27

28 1 - MDI Causeway Circuit 28

29 2 Line 7 Support 29

30 3 Tunk Sub 30

31 4 Line 13 Rebuild 31

32 Local System Planning Criteria The transmission system for purposes of this study is defined as those system facilities that are operated at 34.5 kv and above and are not considered to be under ISO-NE planning (in general non PTF). The standard of service to be provided dictates the need for changes to the existing system. It is necessary to consider the capability of transmission system elements, possible equipment failures, and the impact of failures on the ability to serve area loads. Transmission equipment is designed to operate within certain capabilities. The power that may be transferred over transmission lines depends upon the current carrying capacity of the wire and/or the required clearances of lines above ground. Transformers are limited by their heat dissipation capability. Circuit breakers or switches are designed to sustain a certain continuous amount of current. Also, the operation of customer electrical equipment requires that voltage be maintained within a certain acceptable range. Transmission system facilities are capable of regulating voltage within a limited range by varying reactive power and changing transformer tap settings. 32

33 Local System Planning Criteria Since all equipment is subject to breakdown, it is necessary to consider the consequence of such failures. One possible outcome could be the overload of other equipment that remains in service. For example, if one of two parallel lines trips, the remaining line may become overloaded. Overload beyond emergency ratings must be avoided due to possible permanent damage to the equipment or for public safety. Another consequence of equipment failure is the loss of power supply to customer load. This could occur with the loss of a radial transmission line or as the result of the cascaded outage of a looped transmission system. The loss of supply is critical to loads such as industrial processing, home heating, and hospitals, and must be considered in the design of the transmission system. 33

34 Local System Planning Criteria CAPACITY CRITERION No facility is to be loaded in excess of its normal rating for any expected dispatch of system generation at any load level. For any single contingency, no facility is to be loaded in excess of its normal rating for the following load cycle or in excess of its emergency rating immediately following the contingency. Uneconomic generation dispatch may be utilized to maintain power flows within ratings following a contingency. VOLTAGE CRITERION Transmission system voltages are to be maintained between 95% and 105% of operating base voltage under normal system conditions and for any single contingency. Further, voltages on the regulated side of load serving buses are to be maintained between 100% and 105% of operating base voltage under normal system conditions. 34

35 Local System Planning Criteria LOSS OF LOAD CRITERION No loss of load in excess of 25 MW is to occur for any single contingency. Loss of load less than 25 MW should be resupplied within 24 hours, except under very adverse conditions. MAINTENANCE CRITERION Transmission system planned maintenance is to be possible without exceeding normal voltage and capacity limits and without loss of load. 35