NYISO: Dynamic Line Rating in Real Time Markets

Transcription

1 NYISO: Dynamic Line Rating in Real Time Marets Muhammad Marwali Manager - Energy Marets roducts, Maret Structures New Yor Independent System Operator ECC Worshop Bedford Springs, A June 4, 2013

2 resentation Overview Introduction Real-Time Marets Overview Networ Security Analysis Benefits of the proposed ost- Contingency Modeling methodology 2

3 The Roles of the NYISO Reliable operation of the bul electricity grid Managing the flow of power nearly 11,000 circuit-miles of transmission lines from more than 300 generating units Administration of open and competitive wholesale electricity marets Bringing together buyers and sellers of energy and related products and services lanning for New Yor s energy future Assessing needs over a 10-year horizon and evaluating the feasibility of projects proposed to meet those needs Advancing the technological infrastructure of the electric system Developing and deploying information technology and tools to mae the grid smarter 3

4 Reliability Regulation NYISO must comply with all Reliability Rules established by: North American Electric Reliability Corporation (NERC) Independent, self-regulatory, not-for-profit organization with mission to improve the reliability and security of the bul power system in the U.S., Canada and part of Mexico Compliance with NERC Reliability Standards became mandatory and enforceable in the U.S. in 2007 Northeast ower Coordinating Council (NCC) Includes New Yor, New England, Ontario, Québec, and the Maritimes Formed as voluntary, not-for-profit, regional reliability organization in 1966 Restructured in 2007 to act as Regional Entity to NERC for the Northeast New Yor State Reliability Council (NYSRC) Not-for-profit organization established in 1999 Responsible for Reliability Rules specific to the New Yor State ower System U.S. law authorizes New Yor State to impose more stringent reliability standards New Yor SC adopted NYSRC Reliability Rules 4

5 NY Facts And Figures 19.4 million people 2012 load 162,842 GWH 320+ Maret articipants Over 300 generating units Record pea -- 33,939 MW (Aug. 2, 2006) 11,005 miles of high voltage transmission 2013 Required Installed Capacity 38,936 MW $7.5 billion in maret transactions annually 5

6 NYISO Transmission Legend: 765 V 500 V 345 V 230 V DCCable 230 V and Above Erie South Bec 2013 acard S. Ripley Niagara Dunir Somerset Huntley 2013 New Yor Independent System Operator, Inc. All Rights Reserved. Sta. 80 annell Robinson Rd. Stolle Rd. Homer City Meyer Hillside Oswego Comple x Sithe Oswego Volney Elbridge Watercure Nine Mile E. Towanda Clay Lafayette Oadale Saunders Adirondac Marcy Moses Central East Interface Fitzpatric Scriba Edic Total East Interface H.T. orter Fraser Massena Chases Lae Gilboa Coopers Corners Roc Tavern Chateauguay Willis atnod e Ryan Rotterdam Roseton lattsburgh New Scotlan d Leeds leasan t Valley Alps Long Mountain E. Fishill Bear Swamp Bershire Frost Bridge New Haven Buchanan Norwal Millwood Ramapo Cross Sound Cable leasantvill Ladentown e Sprainbroo Branchburg Waldwic Dunwoodie W. Haverstraw Mott Haven Northport W49St/Rainey Hudson Shore Rd. Farragut Linden Shoreham Linden V.F.T Goethals New Bridge Sayreville, NJ E. Garden City Duley Athen s Neptune Cable Total East Interface LEEDS LEASANT VALLEY 6

7 NYCA Load rofile by Zones August 2, ,939 MWs 2,735 MW A 50% of electric load located in New Yor City and Long Island B 2,110 MW C 3,128 MW E 1,435 MW J 11,300 MW F 2,380 MW G 2,436 MW D 767 MW H 596 MW I 1,467 MW K 5,585 MW A. WEST B. GENESSE C. CENTRAL D. NORTH E. MHK VL F. CAITL G. HUD VL H. MILLWD I. DUNWOD J. N.Y.C. K. LONGIL 7

8 Real-Time Marets

9 Energy Maret Timeline Who What Maret articipants NYISO Maret articipants NYISO Load Forecast, Load Energy Bids, Generator Offers for Energy, Reserve and Regulation and DADR bids submitted for the day-ahead maret osting of day-ahead schedules and LBMs Real-time bid submission deadline Dispatch signals and calculation of RT LBMs When Day Ahead 5 A.M. 11 A.M. 75 Min. prior to Op. Hr. Real Time Operating Hour How SCUC RTC & RTD 9

10 Real-Time Maret Input RT Offers Updates DAM Commitments RTC RTD Output Least Cost Solution Meet reliability requirements Offers RT Supply Imports/Exports Updates Transmission Model Zonal Load Forecast Changes in Operation Real Time Commitment Real Time Dispatch Software ost Results Clearing rices LBM (GEN & Zonal) Reserve, Regulation Commitments, x15min, 3hrs Transactions Generator---15min Dispatch, x5min, 1 hr Energy---5 min Reserve---5 min Regulation---6 sec 10

11 Security Constraint Unit Commitment and Economic Dispatch Overview Generator/load data Load/reserve requirements Initial generator status Initial Unit Commitment Commitment Schedule Initial Unit Commitment (IUC) Solves for generation, reserve and load schedules that meet the generation and reserve requirements and the generator constraints. This module produces a base generator/load schedule which is used to obtain the initial solved power flows for the networ analysis programs. Revised Unit Commitment and Generation /Load Schedule Networ Data reparation Networ Security Analysis Networ Constrained Unit Commitment Networ Flow Base Cases Networ Constraints Networ Data reparation (ND) Develops hourly, un-solved power flows based on the commitment and generation schedule from IUC and the networ data Networ Security Analysis (NSA) Solves hourly security analysis cases. If lines (or interfaces) limits are not satisfied for the input schedule then NSA generates additional constraints for use by the NCUC function so that NCUC, in the next iteration, produces a schedule that is closer to satisfying the constraints. Networ Constrained Unit Commitment (NCUC) Solves for generation, reserve and load schedules that meet the generation and reserve requirements, the generator constraints, the branch-flow constraints (produced by NSA) 11

12 Networ Security Analysis

13 Networ Security Analysis (NSA) urpose: Evaluates the feasibility of the generation schedule in terms of the base case networ and the potential impact of a set of contingencies where feasibility is defined as satisfaction of all the networ constraints Networ constraints : Base Case Networ thermal branch flow limits interface MW flow limits ey bus voltages Contingency Networ thermal branch flow limits interface MW flow limits 13

14 Networ Security Analysis (NSA) cont. Feasibility Evaluation : Base case networ Full AC power flow Contingency networ incremental DC (linear) approach NSA differs from the normal Optimal ower Flow All violated constraints are identified and passed to the NCUC module simultaneously; All identified constraint violations are submitted to the NCUC module regardless of their binding status -- no constraint is ever removed from the list, only new ones are added. 14

15 NYISO Normal Operating State Criteria re-contingency (Actual) Flow Criteria: Actual loading of equipment defined as part of the NYS Transmission System should not exceed the associated Normal ratings of the equipment ost-contingency Flow Criteria: reventive mode: the loss of any single generator, single circuit, or adjacent circuits on the same structure, together with other facilities, which will trip at the same time due to pre-set automatic devices, will not cause any portion of the NYS Transmission System to exceed its LTE rating. Corrective mode: Underground cable : may exceed its LTE rating, but not its STE rating, provided 10- minute reserve or AR control is available to return its post-contingency loading to its LTE rating within 15 minutes, without causing another facility exceed its LTE rating Overhead Transmission: with prior approval of the NYISO, the post-contingency loading of any portion of the NYS Transmission System may exceed its LTE rating, provided sufficient control is available to return the loading on the facility to its LTE rating within 15 minutes, without causing another facility to exceed its LTE rating 15

16 NSA Mathematical Model All networ constraints passed to NCUC are expressed in terms of generator shift factors and constraint limits. The constraint limits are distinct from the original transmission constraint ratings. They represent the aggregate effect of the shift factors and violations on the constraints. If pre, represents the precontingency flow in branch, and this branch flow is the violated security constraint then: max pre, pre, (1) max Where pre, is the pre-contingency rating (Normal rating). The constraint to be enforced is of the following form max pre, pre, (2) 16

17 NSA Mathematical Model Continued All networ constraints passed to NCUC are expressed in terms of generator shift factors and constraint limits. The constraint limits are distinct from the original transmission constraint ratings. They represent the aggregate effect of the shift factors and violations on the constraints. Equation (2) is translated into a linear function of the control variable C in terms of shift factors S, ' max S C S ( C C ) pre, pre, (3) Equation (3) is further rearranged into ' max S C pre, pre, C ' denotes the latest dispatch passed to NSA by NCUC/NCED and C is the new dispatch to be solved by NCUC/NCED. S C (4) 17

18 otential Research Areas: ost- Contingency Modeling Methodology For both preventive mode and preventive/corrective mode: Base networ constraints are secured to the pre-contingency ratings ost-contingency constraints are secured to either STE or LTE ratings (either 6-hour or post-contingency continuous as specified by the user) via the preventive actions or a mixture of the preventive/corrective actions NSA mathematical model is appropriate when considering the pre-contingency constraints Mathematical model will need to be modified for the postcontingency constraints in which the post-contingency ratings are functions of the pre-contingency flows 18

19 Modeling of ost-contingency Ratings All post-contingency ratings are modeled as monotonically decreasing piecewise-linear functions of the pre-contingency flows max post, pre, re-contingency Rating 19

20 ost-contingency Constraint Limit Calculation If post, is the post-contingency flow in branch i j, and this branch flow is the violated security constraint, then: max post, post, max ost-contingency rating post, is a function of pre-contingency flows pre as illustrated in Figure 1. The post-contingency rating is modeled as monotonically decreasing piecewise-linear functions of the pre-contingency flow. (5), max post, pre, Where is the slope and is the interception. (6) 20

21 ost-contingency Constraint Limit Calculation Continued The constraint to be enforced is of the following form post, 0 post, pre, post, 0 ( pre,, pre ) (7) Equation (7) is translated into a linear function of the control variable C in terms of shift factors S, 0 post, ( S post, S post, S pre, C ) C ( 0 pre, ( S post, Equation (8) is further rearranged into S pre, S 0 post, denotes the latest dispatch passed to NSA by NCUC/NCED, and is the new dispatch to be solved by NCUC/NCED. C pre, ) )( C ' C ) 0 pre, ' 0 0 ( S post, S pre, ) C pre, post, ( S post, S, C pre ' C ) C (8) (9) 21

22 ost-contingency Constraint Limit Calculation Comparison ' max S C pre, pre, S C (4) ' 0 0 ( S post, S pre, ) C pre, post, ( S post, S, pre ) C (9) C denotes the latest dispatch passed to NSA by NCUC/NCED, and is the new dispatch to be solved by NCUC/NCED. ' C 22

23 Benefits of the improved ost- Contingency Modeling methodology The new methodology of post-contingency modeling offers several benefits Cost effectiveness Less constraint means cheaper production cost Congestion relief Higher rating means less congestion Does not compromise grid reliability Rating is set based on the pre-contingency flow or amount of MW flow (NOTE: precontingency flow impacts the temperature of the line, and temperature impacts the post contingency rating) Optimized asset utilization Lower prices to consumers True Line capacity in Real-Time Improved transmission efficiency 23

24 The New Yor Independent System Operator (NYISO) is a not-for-profit corporation responsible for operating the state s bul electricity grid, administering New Yor s competitive wholesale electricity marets, conducting comprehensive long-term planning for the state s electric power system, and advancing the technological infrastructure of the electric system serving the Empire State. 24