### March 30 , 201 1 Draft F. Local Reliability Rule The l ocal reliability

r ule for Northport Gas Burn (IR
- 5) for 2011 remains the same as last ye ar and are provided as a guide for unit commitment. Use of information from the 20 10 Summer Operating Study are still valid since there have been no significant system changes in the area
. For the 2010 period an anal ys is was conducted to determine the Long Island load level up to which Northport units can be permitted to burn gas depending on how many

units are online as well as the number of cables in service
. P ower flow simulations were prepared to represent the instantaneous loss of fuel , with those units continuing to produce MVAR output for 20 minutes. During this time, operators would be able to put quick start GTs online, increase remaining steam units to their DMNC capabilities, adjust phase shifters, and switch on capacitor banks as needed. **T ABLE**  **II -** **F -**  **1 Steam Generation Resources at Northport**  Unit Rating s (MW)

DMNC Continuous Northport Steam 1 395.0 

### 363 Northport Steam 2 381.7 

### 363 Northport Steam 3 395.2 

### 363 Northport Steam 4 399.2 

### 363 Total 157 1.1 1452 1. Assumptions Several base assumptions , depending on the case, were made to observe conservatism and to make a stressed case. These assumptions are as follows:

· 91% System Power Factor (note: it does vary by bus location)

· Northport Units online at DMNC

· One Barrett Steam Unit online

· Caithness CC online

· Dunwoodie and Sprainbook series reactors in service (Y49 series reactor by passed)

· Four (4) shunt reactors in service on Y49 and Two (2) shunt reactors in service on Y50

· Northport Norwalk Harbor (NNC)

i. In service 1. Importing 1 00 MW with only 2 Cable in Service 2. Importing 200 MW with 3 Cables in service 1



### · Neptune import of 660 MW with 0 MVAR flow

· Contractual MVAR flow split on Y49 , Y50 & NNC

· Capacitor banks and generation were adjusted based on load level

1 LIPA received permission to increase the flow from 100 MW to 200 MW effective April 1, 2010 on the condition that all 3 cables are in
- service. With only 2 cables the limit remains at 100 MW. Note, importing 200 MW with all 4 units at DMNC would result in overloads above LTE on the Northport exits

– See Northport exit section of the report.

### March 30 , 201 1 Draft
2. Analysis Attached Tables and Diagrams:

· Diagrams II
- F
- 2 (a
- c) show the results of this analysis for two, three, and four Northport units ,

· Tables II
- F
- 2 (a
- c) list the generation dispatch assumed to obtain operating limits

· Table II
- F
- 2d is the listing of the reactive resource dispatch assumed2



### · Table II
- F
- 2e is the guideline for how many units must be run on oil at various load levels depending on how many Northport units are online All charts included in the following section, assume 2 NNC cables in
- service with 100 MW of imports. Additional tests were performed with 3 NNC cables in
- service and 200 MW of imports but are omitted here as the results are very similar. Additional Comments:

· At each load level, the loss of gas suppl y was simulated by reducing the MW output of the Northport steam units to zero and fixing the ir MVAR output to pre fault levels.

· The point at which the voltage on the 138 kV system crossed 0.95 p.u. on contingency

(violates criteria) was used as the operating limit. Using a 5% safety margin from that point is the recommended Lo ng Island system load level for running Northport units on gas
.

· With the new NNC cables and LTE/STE rating s in place , the LTE overload s on the NNC for loss of three Northport units have been reduced from prior ye ars. With 2 cables in
- service there is a small LTE overload and c ompleted e liminated with 3 cables in
- service. 3 , 4 

### Adjusting inter
- ties and on - island generation can be used to rebalance loadings if needed
.

· For the loss of Northport units, turning on quick start GTs at Barrett and Holtsville and/or reducing the Con Edis on wheel help s compensate for the MW los s . A fter the quick start GTs are online, system voltages are within criteria
. Load flow simulations confirm that after the MVARs from the Northport units are lost, system voltages recover to acceptable levels.

· Installation of Caithness in 2009 provide d additional voltage support on contingency

s ince the unit has more MVAR capability than other on - island generators and with its higher efficiency, it is expected to be in operation
. This allowed for Northport units to burn gas at slightly higher load levels.

2 This dispatch did not apply for the higher load levels at which point the pre
- contingency voltage was outs ide criteria so the capacitors were allowed to adjust for voltage . 3 MW Flows on the Y49 and Y50 interties were split for this study . If Y49 c arries more than about 630 MW, it will reach LTE for the loss of 3 Northport unit s. 4 With 3 cables in service there would be no LTE overload on NNC occurs for loss of three Northport units due to the use of the new LTE ratings of 540 MVA (the old LTE limit for the 1385 cable system was 335 MVA). However, with 2 cables in service there would be an approximate 10 % overload based on the 2 cable LTE rating of 384 MVA. Separately, the administrative limit on the normal rating for NNC of 286 MW with 3 cables in
- service will no longer be binding for 2011 due to approval of an SIS in December of 2010. Actual normal ratings will be based on actual equipment limitations.

### March 30 , 201 1 Draft **D IAGRAM**  **II -**  **F -**  **2 A**  **Transmission Voltages for the Loss of Gas Supply at Northport**

**L/O 2 Northport Unit**  **s with 2 Units Online 2 Cables In**  **- Service 100 MW on NNC** 

**T ABLE**  **II -** **F -**  **2 A**  **Generation Dispatch for Diagram II -**  **F -**  **2A**

**Tra ns** **mis**

**si on Volt** 

**ag e**  **L/O 2 Northport Units (** **2 Online**  **) wi**  **th Pre**  **-conti nge**  **ncy MVA**  **R Limit** 

0.90 0.91 0.92 0.93 0.94 0.95 0.96 0.97 0.98 0.99 1.00 1.01 1.02 1.03 1.04

2925 2975 3025 3075 3125 3175 **Sys te**  **m Load (M**  **W) V** **o l** **t a** **g e** **( p** **. u** **. )** 

5pc t RV RHD 138 CA NA L 138 RONKONK 138 C. IS LI P 138 PT JE FF1 138 Ser ies 4 Ser ies 8 Ser ies 9

**5% Saf**  **et y**  **Ma rgin**  **3100** *** 9 5%**  **=2 945**  **MW**

**Inter-ties 3000**  **3050 3100**  **3150 3200**  **3250** Purchases via Y49 469 494 519 544 571 594 Purchases via Y50 470 494 521 545 571 594 Con Ed W heel -286.4 -286.9 -286.9 -287.4 -286.9 -287 Purchases via NNC 101 100 100 101 100 101.8 Purchases via CSC 330 330 330 330 330 330 Purchases via Neptune 661 661 661 661 661 661 MVAR Flow on Neptune -5.8 -4.6 -8.2 -7.2 -5.6 -8.4 **Generation** Barrett 1 191.2 192.8 192.9 184.1 184.4 193.4 Northport 2 381.7 381.7 381.7 381.7 381.7 381.7 Northport 3 395.2 395.2 395.2 395.2 395.2 395.2 Caithness CC 286.0 286.0 286.0 286.0 286.0 286.0 **2 N orthports Online Load Level (M**  **W)**

### March 30 , 201 1 Draft **D IAGRAM**  **II -**  **F -**  **2 B**  **Transmission Voltages for the Loss of Gas Supply at Northport**

**L/O 3 Northport Units with 3 Units Online 2 Cables In**  **- Service 100 MW on NNC** 

**T ABLE**  **II -** **F -**  **2 B**  **Generation Dispatch for Diagram II**  **- F**  **- 2B** 

**Tra ns** **mis**

**si on Volt** **ag e**  **L/O 3 N orthport**  **Uni ts**  **( 3**  **Onl ine**  **) wi**  **th Pr** **e- continge**  **ncy MVA R**  **Limit**

0.90 0.91 0.92 0.93 0.94 0.95 0.96 0.97 0.98 0.99 1.00 1.01 1.02 1.03 1.04

2925 2975 3025 3075 3125 3175 **Sys te**  **m Load (M**  **W) V** **o l** **t a** **g e** **( p** **. u** **. )** 

5pc t C. IS LI P 138 RONKONK 138 RV RHD 138 CA NA L 138 PT J EF F1 138 **5% Saf**  **et y**  **Ma rgi**  **n 3100**  *** 9 5%**  **=2945 MW** 

**Inter-ties 2950**  **3000 3050**  **3100 3150**  **3200 3250**  Purchases via Y49 248 272 298 322 349 372 399 Purchases via Y50 247.4 273.5 298 323 346 373.5 396 Con Ed W heel -286.9 -287.2 -286.8 -287.2 -287.5 -2 87 -286.9 Purchases via NNC 100.2 100.4 99.5 101 101 100.5 100.1 Purchases via CSC 330 330 330 330 330 330 330 Purchases via Neptune 661 661 661 661 661 661 661 MVAR Flow on Neptune -4.2 -3 .2 -7 -5 .6 -5 .8 -9 -7 .2 **Ge neration**  Barrett 1 187.7 188.6 189.7 190.7 186.7 187.8 189.6 Northport 1 395.0 395.0 395.0 395.0 395.0 395.0 395.0 Northport 2 381.7 381.7 381.7 381.7 381.7 381.7 381.7 Northport 3 395.2 395.2 395.2 395.2 395.2 395.2 395.2 Caithness CC 286.0 286.0 286.0 286.0 286.0 286.0 286.0 **3 N orthports Online Load Level (MW)** 

### March 30 , 201 1 Draft **D IAGRAM**  **II -**  **F -**  **2 C**  **Transmission Voltages for the Loss of Gas Supply at Northport** 

**L/O 3 Northport Units with 4 Units Online 2 Cables In**  **- Service 100 MW on NNC** 

**T ABLE**  **II -** **F -**  **2 C**  **Generation Dispatch for Diagram II -**  **F -**  **2C**

**Tra ns** **mis**

**si on Volt** **ag e**  **L/O 3 N orthport**  **Uni ts**  **( 4**  **Onl ine**  **) wi**  **th Pre**  **-conti nge**  **ncy MVA**  **R Limit** 

0.90 0.91 0.92 0.93 0.94 0.95 0.96 0.97 0.98 0.99 1.00 1.01 1.02 1.03 1.04

3250 3300 3350 3400 3450 3500 **Sys te**  **m Loa**  **d (M W)** **V o** **l t** **a g** **e (** **p .** **u .** **)**

Knee Of Curve 5pc t C. IS LI P 138 RONKONK 1 38 RV RHD 138 CA NA L 138 PT J EF F2 138 z

**3440** *** 9 5%**  **=3 268**  **MW**

**5% Saf**  **et y**  **Ma rgin** 

**In te**  **r-ti es**  **3250 3300**  **3350 3400**  **3450 3500**  Purchases vi a Y49 198 222 246. 5 273 298 322 Purchases vi a Y50 198.5 224. 3 248 272. 4 297. 6 322 Con Ed W h eel -2 87.1 -2 87. 3 -2 86.9 -2 86. 9 -2 86. 7 -2 87.2 Purchases vi a NNC 101.3 101. 3 101. 3 100. 2 100. 2 101 Purchases vi a CSC 330 330 330 330 330 330 Purchases vi a Nept une 661 661 661 661 661 661 MV AR Fl ow on Nept une -6.2 -1 0. 2 -9 .2 -8 .4 -8 -6 .8 **Generat io**  **n** Bar re tt 1 187.6 188. 6 190. 8 192. 0 192. 9 190.6 North port 1 395.0 395. 0 395. 0 395. 0 395. 0 395.0 North port 2 381.7 381. 7 381. 7 381. 7 381. 7 381.7 North port 3 395.2 395. 2 395. 2 395. 2 395. 2 395.2 North port 4 399.2 399. 2 399. 2 399. 2 399. 2 399.2 Cai th ness CC 286.0 286. 0 286. 0 286. 0 286. 0 286.0 **4 Nort**  **hport s O**  **nl in**  **e Load**  **Level (MW**  **)**

### March 30 , 201 1 Draft **T ABLE**  **II -** **F -**  **2 D**  **MVAR Reactive Resource Dispatch for Loss of Northport Units** 

**2Cables In**  **- Service 100 MW on NNC**  **5 Bus Name**  **Ma x**  **Dispatch** BARRETT1 138.00
- 75 0 NRTHPT2 138.00
- 75 0 PILGRIM 138.00 104 0 HOLBROOK 138.00 104 0 HOLTS GT 138.00 104 0 RVRHD 138.00
- 27 0 FARRCK1 69.000 54 54 VLYSTRM2 69.000 54 54 E.G.C.2 69.000 54 0 GLNWD SO 69.000 54 54 MASPEQUA 69.000 54 54 NEWBRGE1 69.000 54 54 NEWBRGE2 69.000 54 0 FLWRFLD 69.000 27 27 INDIANHD 69.000 27 0 PILGRM 69.000 108 108 RULND RD 69.000 108 54 WOLFHILL 69.000 27 0 BRGHTWTR 69.000 54 0 BRNTWOOD 69.000 54 0 STERLING 69.000 54 0 WATSON 69.000 54 54 HOLBRK1 69.000 54 54 HOLBRK2 69.000 54 0 JAMESPRT 69.000 14 0 MORICHES 69.000 28.8 28.8 PECONIC 69.000 14 14 PT CHOGUE 69.000 27 0 RIDGE 69.000 28.8 0 SOUTHOLD 69.000
- 23.31 0 WILDWOOD 69.000 28.8 0 BRGHMPTN 69.000 14 0 BUELL 69.000 14 0 EHAMP 69.000 14 0 RIV 1 69.000 27 27 RIV2 69.000 27 0 SOHMPTN 69.000 22.55 14 TEMPLE 69.000 24.5 24.5 TIANA 69.000 27 27 GRN ACRE 34.500 12 12 MONTAUK 23.000 7.2 0 **TOTAL 1641.65**  **714.3 %On**  **43 %**  **%Off 57**  **%**
5 The above table reflects capacitor banks on line for all loads except for high load level case s, e.g., above 5,000 MW, in which all banks were dispatched.

### March 30 , 201 1 Draft

**T ABLE**  **II -** **F -**  **2 E**  **6** 

### Guideline for Running Northport Units on **Oil**

**NNC In -**  **Service 2 Cables In**  **- Service 100 MW Import**  **or 3**  **Cables In -**  **Service 200 MW Import** Load Level Northport Units Online One Two Three Four 0
- 2950 0 0 0 1 2951
- 3250 0 1 1 1 325 1
- 5 4 50 0 1 1 2 5 4 5 1
- 6000 0 1 2 3 Note 1 : Differences between 2 and 3 cable operation are not significant Note2: Northport Gas Burn Rule Guideline for NNC In Service in 2011 was provided as a guide and are based on the 2010 Summer Operating study since there have been no significant system changes.

6



### - Values in table II
- F
- 2 E above indicate the number of units that can be run on oil . For example, with NNC In
- Service, if three Northport units are online, none have to be run on oil ( all three can be on gas ) up to a load level of 2950 MW. Starting at 2951 MW , only one of the three units must be on oil (2 on gas) up to a load level of 545 0 MW after which 2 units must be on oil
.