New England Tie Benefit Discussion – Operational View

Peter Brandien, Vice President System OperationsNEPOOL Reliability Committee MeetingJuly 20, 2010

Agenda Items 2.0

Reliability Committee Meeting

July 20, 2010

Overview

• At the June 18 Reliability Committee Meeting:– Discussed system restrictions that limited the New England

overall import capability

– Reviewed NERC Standard requirement to maintain “contingency reserves”

– Attempted to communicate how operating reserves could be allocated internally within New England and in other control areas to comply with Standards

• Review limitations to the New England Import Capability

• Operating Reserve Allocation

2

New England Interconnection Ties

• New York AC Ties• 2x 345 kV• 1x 230 kV• 4x 115 kV• 1x DC Converter• 1x 138 kV PST (NNC)

• Hydro Quebec Ties• 2x Asynchronous DC

• New Brunswick• 2x 345 kV

3

New England Transmission Transfer Capability (MW)

Interface

HQ Phase 2 1400

HQ Highgate 200

New Brunswick 1000

New York (AC) 1500

Total 4100

4

New England Transmission System Import Capability

5

New York – New England Interface –Review• Capability to import power to and across the NY-NE

Interface is variable and dependents on transmission margins external to New England

• Operations performed an analysis to determine what level of NY-NE interface flows could be relied upon based on available actual transmission margins when NE was importing power from NY

• The analysis evaluated June through September for the last three years (2007, 2008 & 2009)

6

Real Time NY Transfer Capability (MW)

Daily Average Available MW from NY on peak when peak is 08 - 23

Count Average

June July August September June July August September

42 22 39 74 639 1036 1076 1394

4 31 99 48 623 866 923 1247

20 19 66 24 767 853 990 1171

31 113 58 24 855 951 872 1159

9 33 20 11 677 809 1361 1095

14 30 41 58 767 867 797 917

12 18 14 60 746 1076 678 979

40 13 18 44 761 776 891 1248

6 31 27 57 626 676 880 1077

29 19 38 58 927 640 920 1083

6 36 11 95 537 848 1335 1209

2 63 22 83 386 821 1206 1253

6 23 4 55 619 726 487 1193

37 13 6 65 985 1090 994 1178

49 6 13 17 973 955 1300 1225

31 26 36 55 958 874 852 1016

45 76 47 65 838 1023 1173 903

61 14 89 67 868 676 1129 879

51 32 109 83 720 672 1184 901

48 17 22 104 810 547 786 1156

47 17 42 119 831 849 1002 1090

44 18 44 79 678 1371 885 1035

45 1 17 80 920 962 841 980

37 5 33 67 1085 653 720 926

29 7 106 81 746 948 1138 1032

13 28 115 124 815 772 1115 977

64 46 10 128 995 1118 806 1015

60 8 12 137 913 919 937 984

39 50 19 72 655 1362 1187 893

36 40 84 82 712 1060 1252 980

  43 76     1183 1263  

7

NY Transfer Capability Duration Curve

8

Real Time NY Transfer Capability (MW)

9

Hour

New Brunswick – New England Interface

• Maximum import capability of 1000 MW into Maine

• Full import capability is dependent on numerous Special Protection Schemes

• Internal New England transmission limitations prevent transfers up to full import capability when utilizing all northern generation

• Approximately 350 MW constrained in northern Maine at peak load

10

Reductions to Transmission Transfer Capability (MW)

Interface

HQ Phase 2 1400

HQ Highgate 200

New Brunswick 1000

- 350 (Orrington South)

New York (AC) 1300*

- 600 (Central East)

Total 2950

11

* Based on historical real time transfer capability

12

Operating Reserve Allocation

13

NERC Reliability Standard BAL-002-0, Disturbance Control Performance

• Requirement 1. Each Balancing Authority shall have access to and/or operate Contingency Reserve to respond to Disturbances. Contingency Reserve may be supplied from generation, controllable load resources, or coordinated adjustments to Interchange Schedules

• Requirement 3.1. As a minimum, the Balancing Authority or Reserve Sharing Group shall carry at least enough Contingency Reserve to cover the most severe single contingency

• In NPCC, “Contingency Reserves” is referred to as “Ten-minute Reserves”

• NPCC also requires “Thirty-minute Reserves” which shall be at least equal to one-half the second contingency source loss

– Shall restore thirty-minute reserve within four hours if it becomes deficient

System Response following a Source Loss

• Following a source loss in New England, most of the generation inertial response is from west of New England

• This generation response will show up as increased power flows into New England on the New York ties

• Neighboring areas must operate their system recognizing this response

• 30% of this power will flow across the NY Central/East Interface because of the inertial response

• New England must restore the external ties back to the scheduled power flows within 10 minutes

14

Operating Reserve Allocation

• The NERC Standard allows for reserves to be allocated to coordinated adjustments to Interchange Schedules

• Under expected capacity shortage conditions, if we assume that New England can arrange with New York to take advantage of the inertial response and some additional level of shared activation of reserves, then New England could meet the NERC operating requirement by maintaining approximately 700 MW of internal reserves

– Need to shed 700 MW of load within 10 minutes

• This level of internal reserves is also consistent with the NPCC requirement for spinning reserves (50% of the largest source contingency)

15

Questions?