Transmission Operations Real Time System Security Operations & Real Time System Security ... NERC Operating Manual Overview of Control Area Operation. 8 ... 600 MW min + 600 MW What

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Transmission Operations &

Real Time System Security

David MahlmannSpring 2003

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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

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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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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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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


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Typical Control Area

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OntarioOntario

QuebecQuebec

NENE

PJMPJM

New York Control Area


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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


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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


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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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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


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Basic 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


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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.


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Generator InteractionGovernors

Assure governor in service

No specific NYISO related operational requirements


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Key Security IndicatorsFrequency

VoltageInterchange flows with neighboring control areasContingency Reserve availabilityEquipment limitsSystem limits


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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.


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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


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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.


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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.


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Key Security IndicatorsFrequencyVoltage

Interchange flows with neighboring control areasContingency Reserve availabilityEquipment limitsSystem limits


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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


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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


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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.


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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


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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


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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


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Key Security IndicatorsFrequencyVoltageInterchange flows with neighboring control areasContingency Reserve Equipment limitsSystem limits


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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.


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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


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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


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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


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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.


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Key Security IndicatorsFrequencyVoltageInterchange flows with neighboring control areasContingency Reserve availability

Equipment limitsSystem limits


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Equipment limits

Thermal heating Limits

Ramp rates

Voltage limits - high and low


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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


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Key Security IndicatorsFrequencyVoltageInterchange flows with neighboring control areasContingency Reserve availabilityEquipment limitsSystem limits


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System Limits

Thermal

Stability Limits

Voltage Collapse limits

Locational Reserve limits

Local Reliability constraints


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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.


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NYISO Security and

Regulation

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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


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


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NYISO Transmission System

Constraints

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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


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


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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.

Transmission Operations Real Time System Security Operations & Real Time System Security ... NERC Operating Manual Overview of Control Area Operation. 8 ... 600 MW min + 600 MW What

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