Dynamic Line Rating in Real Time Markets

NYISO:
Dynamic Line Rating in
Real Time Markets
Muhammad Marwali
Manager - Energy Markets Products, Market Structures
New York Independent System Operator
EPCC Workshop
Bedford Springs, PA
June 4, 2013

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

NYISO
Transmission
Legend:
765 kV
500 kV
345 kV
230 kV
DCCable
230 kV and Above
Erie South
Beck
2013
Packard
S. Ripley
Niagara
Dunkirk
Somerset
Huntley
© 2013 New York Independent System Operator, Inc. All Rights Reserved.
Sta. 80
Pannell
Robinson Rd.
Stolle Rd.
Homer
City
Meyer
Hillside
Oswego
Comple
x
Sithe
Oswego
Volney
Elbridge
Watercure
Nine
Mile
E. Towanda
Clay
Lafayette
Oakdale
Saunders
Adirondack
Marcy
Moses
Central East
Interface
Fitzpatrick
Scriba
Edic
Total East
Interface
H.T.P
Porter
Fraser
Massena
Chases
Lake
Gilboa
Coopers
Corners
Rock
Tavern
Chateauguay
Willis
Patnod
e
Ryan
Rotterdam
Roseton
Plattsburgh
New
Scotlan
d
Leeds
Pleasan
t Valley
Alps
Long
Mountain
E. Fishkill
Bear Swamp
Berkshire
Frost Bridge
New Haven
Buchanan
Norwalk
Millwood
Ramapo
Cross Sound Cable
Pleasantvill
Ladentown
e
Sprainbrook
Branchburg
Waldwick
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 –PLEASANT VALLEY
3

NYCA Load Profile by Zones
August 2, 2006
33,939 MWs
2,735
MW
A
50% of electric load
located in New York 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. CAPITL
G. HUD VL
H. MILLWD
I. DUNWOD
J. N.Y.C.
K. LONGIL
4

Real-Time
Markets

Energy Market Timeline
Who
What
Market Participants NYISO Market Participants NYISO
Load Forecast, Load
Energy Bids, Generator
Offers for Energy, Reserve
and Regulation and
DADRP bids submitted for
the day-ahead market
Posting of
day-ahead
schedules and
LBMPs
Real-time bid submission
deadline
Dispatch
signals and
calculation
of RT LBMPs
When
Day Ahead
5 A.M.
11 A.M.
75 Min.
prior to
Op. Hr.
Real Time
Operating
Hour
How SCUC RTC & RTD
6

Real-Time Market
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
Post Results
• Clearing Prices
• LBMP (GEN & Zonal)
• Reserve, Regulation
• Commitments, x15min, 3hrs
• Transactions
• Generator---15min
• Dispatch, x5min, 1 hr
• Energy---5 min
• Reserve---5 min
• Regulation---6 sec
7

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 network analysis programs.
Revised Unit
Commitment
and Generation
/Load Schedule
Network
Data
Preparation
Network
Security
Analysis
Network
Constrained
Unit
Commitment
Network Flow
Base Cases
Network
Constraints
Network Data Preparation (NDP)
Develops hourly, un-solved power flows based
on the commitment and generation schedule
from IUC and the network data
Network 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.
Network 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)
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Network Security
Analysis

NYISO Normal Operating State Criteria
• Pre-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
• Post-Contingency Flow Criteria:
• Preventitive 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 PAR 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
10

NSA Mathematical Model
All network 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 P
pre , ij represents the precontingency flow in branch, and this branch flow is the
violated security constraint then:
max
P
(1)
pre , ij
Ppre
, ij
max
• Where P pre,ij is the pre-contingency rating (Normal rating).
The constraint to be enforced is of the following form
max
P
ij
Ppre, ij
Ppre,
ij
(2)
11

NSA Mathematical Model Continued
• Equation (2) is translated into a linear function of the control variable C in terms of shift
factors S,
'
max
S
kC
k
Sk
( Ck
Ck
) Ppreij
,
Ppreij
,
• Equation (3) is further rearranged into
' max
S kCk
Ppre,
ij
Ppre,
ij
'
• C k denotes the latest dispatch passed to NSA by NCUC/NCED and C k is the new
dispatch to be solved by NCUC/NCED.
S
k
C
k
(3)
(4)
12

Potential Research Areas: Post-
Contingency Modeling Methodology
• For both preventive mode and preventive/corrective mode:
• Base network constraints are secured to the pre-contingency
ratings
• Post-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
13

Modeling of Post-Contingency
Ratings
All post-contingency ratings are modeled as monotonically decreasing
piecewise-linear functions of the pre-contingency flows
max
P
post,
ij pre,
ij
P
Pre-Contingency Rating
14

Post-Contingency Constraint Limit
Calculation Comparison
' max
S kCk
Ppre,
ij
Ppre,
ij
S
k
C
k
(4)
(
post, k prek , k preij ,
postij ,
postk ,
prek ,
' 0
0
S S
) C P
P
( S S ) C
k
(9)
C k
'
C k
• denotes the latest dispatch passed to NSA by NCUC/NCED, and is the
new dispatch to be solved by NCUC/NCED.
15

Benefits of the improved Post-
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
16

The New York Independent System
Operator (NYISO) is a not-for-profit
corporation responsible for
operating the state’s bulk electricity
grid, administering New York’s
competitive wholesale electricity
markets, 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.
www.nyiso.com
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