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OutlineOverview of Control Area Operation
Basic Control Area OperationFrequency, voltage, reserves, regulation, component loading
NYISO Security and RegulationSCD and AGC
NYISO Transmission System Constraints
Summary
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Overview of Control Area Operation
We are all in this together….
…like it or not!
Every generator action effects system conditions. Laws of physics trump economics, legal contracts, and legislative mandates.
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Overview of Control Area Operation
If your unit burps, it will be detectable on the interconnected electric system
from
Saskatoon, Saskatchewan to Florida City, FL
from
Lawton Oklahoma to Prince Edward Island
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Overview of Control Area Operation
If we don’t coordinate the collective security of the interconnected power system, the whole business can collapse like a house of cards.
It has happened, and it’s not pretty:
The Great Northeast Blackout
November 9th 1965.
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What is a Control Area?
“An electric system or systems, bounded by Interconnection metering and telemetry capable of controlling generation to maintain its interchange schedule with other Control Areas and contributing to frequency regulation of the Interconnection.” NERC Operating Manual
Overview of Control Area Operation
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Key Security IndicatorsFrequency
Controlled by load an generation balance
VoltageGenerator voltage controls, static shunt devices
Interchange flows with neighboring control areasControlled managing system flows through dispatch (load following)
Contingency Reserve availabilityControlled managing system flows through dispatch
Equipment limitsControlled managing system flows through dispatch
System limits – (e.g.. system stability, voltage stability)Controlled managing system flows through dispatch
Overview of Control Area Operation
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Timeframe
Control Area operational security is evaluated and acted upon in two time frames:
Forecast - day ahead, hours ahead
Real time
Overview of Control Area Operation
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Overview of Control Area Operation
In order to maintain system security, each control area must:
Monitor all key system parameters to insure real-time compliance.
Evaluate the impact of all criteria contingencies to insure that no one event will cause security problem.
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Overview of Control Area Operation
MW
Mvar
KV
HZ
Bkrkr status
Basepoints
Reserve Pickup flag
NYISONYISO
Transmission OwnersTransmission Owners
OntarioOntario
ISONEISONE
QuebecQuebec
PJMPJM
Communications, Communications, Data & MonitoringData & Monitoring
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Contingency Evaluation
Standard Contingencies are evaluated to insure security
Loss of any single generatorLoss of any single lineLoss of multiple circuit towerLoss of a single element with a single breaker failure
Overview of Control Area Operation
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BALANCING BALANCING GENERATIONGENERATION
WITH LOADWITH LOAD
CONTROL AREA OPERATION MEANS:CONTROL AREA OPERATION MEANS:
WHILE RESPECTING TRANSMISSION LIMITATIONSWHILE RESPECTING TRANSMISSION LIMITATIONS
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Key Security IndicatorsFrequencyVoltageInterchange flows with neighboring control areasContingency Reserve availabilityEquipment limitsSystem limits
Basic Control Area Operation
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Contingency Frequency Control
Nominally the US electric system is operated at 60 Hz. Normally maintained
Imbalance in load an generation will cause frequency to rise or decline
Large unit trips – L/0 1000 MW causes a .03Hz decline in the Eastern Interconnection
In-service governors required to arrest frequency declines due to load and generation imbalance
Basic Control Area Operation
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Frequency Control – Governors
Governor Action – AutomaticMechanical interaction set to maintain 60 Hz at a specific RPM. There is a specific dead band where the governor will not respond to frequency. This is typically .036 Hz.
Basic Control Area Operation
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Generator InteractionGovernors
Assure governor in service
No specific NYISO related operational requirements
Basic Control Area Operation
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Key Security IndicatorsFrequency
VoltageInterchange flows with neighboring control areasContingency Reserve availabilityEquipment limitsSystem limits
Basic Control Area Operation
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Voltage ControlTwo categories of voltage control equipment
Automatic Matches the reactive demands of the loadProvides instantaneous response to contingency conditions
ManualEquipment under supervisory control by the transmission system operatorsOperation coordinated with automatic controls to optimize, to the extent possible, system security.
Basic Control Area Operation
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Voltage ControlAutomatic Voltage Regulators (AVRs)
Regulates generator excitation to export or import VARs (lag-lead) in order to maintain terminal voltage at a specific setpoint.
Static VAR Compensators (SVCs)Static Var Compensators(SVCs) and STATCOM devices perform a special function of high speed voltage response.
Both types of automatic voltage control provide smooth control over a continuous range
Basic Control Area Operation
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Voltage ControlLoad Tap Changing Transformers (LTCs)
Supervisory controlled LTCs allow system operators to change tap ratios.
Shunt Capacitor and Reactors Placed in or out of service by system operations via supervisory controls when circumstances require additional resources.Unlike AVRs and SVCs, these device provide step changes in the VAR support.
Basic Control Area Operation
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Generator InteractionVoltage Control
Respond to NYISO requests for reactive support relayed by TO
Report AVR outages to the NYISO
Respond to TO requests for reactive support.
Basic Control Area Operation
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Key Security IndicatorsFrequencyVoltage
Interchange flows with neighboring control areasContingency Reserve availabilityEquipment limitsSystem limits
Basic Control Area Operation
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Load FollowingHourly Basis – scheduled in advance of real time by SCUC and BME
Off dispatch units are scheduled by the hour Transactions are scheduled by the hour
Five Min. Basis – Security Constrained Dispatch (SCD)
On-dispatch units
Six second - Automatic Generation Control (AGC)
On Control
Basic Control Area Operation
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Load Following - SCDSCD dispatches generators with basepoints to meet the 5 minute projected load
Primary control of generation based on availability, cost, operating limits, and response rates
Calculates calculates reserves an solves constraints.
Calculates real time prices
Basic Control Area Operation
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AREA CONTROL ERROR (ACE)
The measurement tool used to identify the
imbalance between generation & load (interchange)
while contributing to interconnection frequency
correction. It also discriminates between internal
& external control area faults and accounts for
governor response during frequency excursions
when operating in “Tie-Line Bias” mode.
Basic Control Area Operation
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Load Following - AGCCompensates for overgeneration or undergeneration; supplementary control for adjustments in interchange and frequency.
Calculates six second basepoints for all units
Passes through SCD basepoints for units not on control at six second intervals.
Tracks generation output with response to AGC for monitoring compliance with the NERC reliability standards CPS1, CPS2, and DCS
Basic Control Area Operation
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AGCAuxiliary application
Time Correction – Manual Intervention within centralized AGC
When the time exceed in the Eastern Interconnection exceeds the bounds of +- 8 seconds
Correct for time error with frequency offsets 59.98 or 60.02 in all the Control Areas
Basic Control Area Operation
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Generator Interaction with Load Following
Day ahead commitment and schedule from SCUC.Hour ahead commitment and schedule from BMEAGC control signals – six secondSCD dispatch signals – five minutesInstruction through the TO system operator
Basic Control Area Operation
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Key Security IndicatorsFrequencyVoltageInterchange flows with neighboring control areasContingency Reserve Equipment limitsSystem limits
Basic Control Area Operation
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Reserve RequirementsOperating Reserve
A real time quantity
1.5 times the largest contingency
Separate and distinct from “installed reserve” or Installed Capacity (ICAP). Installed capacity is acquired to assure that when the time comes there will be resources available to provide operating reserve.
Basic Control Area Operation
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Reserve RequirementsLargest Contingency
The New York requirement for reserve can vary in real time operation. Typically the reserve requirement is 1800 MW based on the based on a 1200 MW import from HQ or 9 Mile Point 2
Based on the loss of energy from the largest single contingency
HQ imports all come in on one line, loss of that line, creates an energy shortage in NY similar to a unit trip
Basic Control Area Operation
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600 MW min+
600 MW
What is needed in addition to 10 min SYNC (600) to total
1200 MW
SINGLE LARGEST CONTINGENCY 1,200 MW
RESERVE REQUIREMENT: 1,800MW
10 MIN SYNC
10 MINUTETOTAL
1,200 MW
30 MIN
10 MIN NON-SYNC
Basic Control Area Operation
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Generator Interactionwith Reserve Requirements
NYISO instituted – TO communicatedReserve Pick-up
Payment based on following NYISO basepointsEconomic selection, not necessarily units carrying reservePerformance penalties suspended
Max Gen Pick-upGeneration expected to produce at maximum capability – reimbursed for energy producedPerformance penalties suspended.
Selective Max Gen Pick-up Instituted on a company basis
Basic Control Area Operation
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Generator InteractionReserve
TO institutedReserve Activation
The TO can activate any reserve in his area.The TO notifies the NYISO of the reserve activation
Max Gen Pick-upGeneration expected to produce at maximum capability – reimbursed for energy producedPerformance penalties suspended.
Basic Control Area Operation
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Key Security IndicatorsFrequencyVoltageInterchange flows with neighboring control areasContingency Reserve availability
Equipment limitsSystem limits
Basic Control Area Operation
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Equipment limits
Thermal heating Limits
Ramp rates
Voltage limits - high and low
Basic Control Area Operation
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Generator InteractionEquipment Limits
Primarily rolled into operating limits as part of the bid process.
Real time changes to equipment limits must be passed on to the NYISO via the TO.
Tube leaksLoss of feed pumpsEmission limitsFuel problems
Basic Control Area Operation
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Key Security IndicatorsFrequencyVoltageInterchange flows with neighboring control areasContingency Reserve availabilityEquipment limitsSystem limits
Basic Control Area Operation
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System Limits
Thermal
Stability Limits
Voltage Collapse limits
Locational Reserve limits
Local Reliability constraints
Basic Control Area Operation
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Generator InteractionSystem Limits
There is rarely an area where the generator would have interaction.
This is an area of coordination between Control Areas and Transmission Owners.
Basic Control Area Operation
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SCD88Normal OperationNormal Operation
88 SCD 5 minute dispatchSCD 5 minute dispatch--Or Operator initiatedOr Operator initiated88 SCD reSCD re--dispatch system from last dispatchdispatch system from last dispatch88 Calculates loadCalculates load88 EMS Monitors All:EMS Monitors All:88Device outagesDevice outages88Line flows & lossesLine flows & losses88Generation outputGeneration output88System interfacesSystem interfaces88ConstraintsConstraints88Reserves & regulation marginReserves & regulation margin88Energy schedulesEnergy schedules88Calculates inadvertent w/ external control areasCalculates inadvertent w/ external control areas
ISO Security & Regulation
SCD
AGC
PTS
SRE
SCUC
BME
CURRENTMARKET INFOSYSTEMDATA BASEUnaccepted & Unexpired
SORTERBY: SCHEDULE
DATE/TIMECATEGORY
OUTAGE SCHEDULER
BILATERAL
BIDS
GENERATION
BIDS
LOAD
BIDS
LOAD
FORECAST
ZONE
GENERATOR
LIMITS
OUTAGE SCHEDULER
REAL TIMEPHASE SHIFTERFLOWS
MIS
POST S D.A.00-23 TOMORROWGEN SKEDSBILATERALS
POSTS H.A.NEXT HOURGEN SKEDSBILATERALS
REAL TIMESYSTEM DATATO’s DATA LINK
SCD INPUTSSCD INPUTS
SECURITYCONSTRAINTS
ISO Security & Regulation
IS+IS+
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SCD
88 Reserve PickReserve Pick--up Operationup Operation88 SCD 10 minute dispatchSCD 10 minute dispatch88 SCD reSCD re--dispatch system from last real time outputdispatch system from last real time output88 Calculates loadCalculates load88 EMS Monitors All:EMS Monitors All:
88Device outagesDevice outages88Line flows & lossesLine flows & losses88Generation outputGeneration output88System interfacesSystem interfaces88ConstraintsConstraints88Reserves & regulation marginReserves & regulation margin88Energy schedulesEnergy schedules88Calculates inadvertent w/ external control areasCalculates inadvertent w/ external control areas
ISO Security & Regulation
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System Limits
Stability LimitsInvoked on a interface basis
Central East
Voltage Collapse limitsApplicable only to Central East
Locational Reserve limits
Local Reliability constraints
NYISO Transmission System Constraints
Niagara
Oswego
OakdaleFraser
Marcy
Massena
Moses-St. Lawrence
Chateauguay
Plattsburgh
Gilboa AlpsClay
Lafayette
Watercure
Stolle Rd.
Edic Porter
Rotterdam
PleasantValley
CoopersCorners
RockTavern
Roseton
Buchanan
RamapoSprainbrook
Complex
Homer City
Shore Rd.E.Garden City
Huntley
PannellSta.80
New York StateTransmission System
Somerset
Adirondack
Dunkirk
Meyer
Willis
NewScotland
Leeds
Hillside
Millwood
Dunwoodie
GoethalsFarragut
W49St/Rainey
Robinson Rd.
Beck
Gardenville
Saunders
Sandbar
Hoosick
Whitehall
RichfieldSprings
Inghams
Blissville
Bennington
Legend:765 kV
345 kV230 kV
500 kV
115 kV
Dysinger East
Andover Palmiter
West - Central
Central - East
Dennison
ColtonMoses South
Upny - Con Ed
Total - East
Sprain Brook -Dunwoodie
4,400 MW
2,500 MW
4,700 MW 5,500 MW
8,000 MW
5,000MW
Con Ed-LIPA
NYISO Transmission System Constraints
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Dysinger East
NS1 & SR2Stolle - Meyer 67Andover - Palmiter 932Lockport - Telegraph Rd.114
- N. Akron1107- N. Akron2 108- Oakfield 112- Sweden 111- Sweden 113
West - Central
Pannel - Clay 1 & 2Stolle - Meyer 67Mortimer - Elbridge 1 & 2Quaker - Sleight Rd. 13Pannel - FarmingtonSo. Perry - RGE 906Clyde - NYSEGFarmington - NMPCQuaker - Macedon 930Andover - Palmiter 932
Central - East
Plattsburgh - Vermont PV20Edic - New Scotland 14Marcy - New Scottland 18Porter - Rotterdam 30 & 31Richfield Springs - Inghams 942Inghams PARInghams R81 (OCB)
Total East
Plattsburgh - Vermont PV20Edic - New Scottland 14Marcy - New Scottland 18Porter - Rotterdam 30 & 31Richfield Springs - Inghams 942Inghams PARInghams R81 (OCB)Fraser - Gilboa GF5-35West Woodbourne (T1-52)Ramapo - So. Mahwah 69 & 70 Ramapo - Branchburg 5018Coopers Corners - Rock Tavern 34 & 42Linden - Gothals “A” 2253Hudson - Farragut “B” 3402 & “C” 3403
UPNY - Con Ed
Ramapo - Buchanan 94Ladentown - Buchanan 88Roseton - East Fishkill 305Pleasant Valley - East Fishkill F36 & F37Pleasant Valley - Wood St. F30Pleasant Valley - Millwood F31Fishkill - Sylvan Lake 990East Fishkill Bank
Moses South
Massena - Marcy MSU1Dennison - Sand Stone 5Dennison - Colton 4Alcoa - BrowningMoses - Adirondak 1 & 2
Sprain Brook - Dunwoodie South
Dunwoodie - Rainy 71 & 72Dunwoodie - Sherman Creek 31Dunwoodie So. - E 179th StSprian Brook - Tremont X28Sprain Brook - W 49th M51 & M 52Jamaica - Valley Stream 901Jamaica - Lake Success 903
NEW YORK INTERNAL INTERFACES
Con Ed – LIPASprianBrook - E. Garden City Y49Dunwoodie - Shore Rd Y50Jamaca - Lake Success 901Jamaca - Valley Stream 903Northport - Norwalk Harbor 1385
Niagara
Oswego
OakdaleFraser
Marcy
Massena
Moses-St. Lawrence
Chateauguay
Plattsburgh
Gilboa AlpsClay
Lafayette
Watercure
Stolle Rd.
Edic Porter
Rotterdam
PleasantValley
CoopersCorners
RockTavern
Roseton
Buchanan
RamapoSprainbrook
Complex
Homer City
Shore Rd.E.Garden City
Huntley
PannellSta.80
New York StateTransmission System
Somerset
Adirondack
Dunkirk
Meyer
Willis
NewScotland
Leeds
Hillside
Millwood
Dunwoodie
GoethalsFarragut
W49St/Rainey
Robinson Rd.
Beck
Gardenville
Saunders
Sandbar
Hoosick
Whitehall
RichfieldSprings
Inghams
Blissville
Bennington
Legend:765 kV
345 kV230 kV
500 kV
115 kV
Andover Palmiter
Central - East
Dennison
Colton
PENALTIES ON CENTRAL - EAST
STABILITY LIMIT: = 3100 - PenaltiesSTABILITY LIMIT: = 3100 - Penalties
Total - East
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SummaryThe foundation for maintaining system security reliability comes from the the adequacy and and security of:
Frequency, Voltage, Reserve, Regulation, while respecting equipment and interface limits.
The NYISO uses SCD and AGC to dispatch generation, balance load and respect operating limits.
Interface constraints vary depending on system conditions. The Central East interface is usually most restrictive.
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