confidential spiderwg roadmap agendas...– currently psse v34.5 does not have an automatic command...

CONFIDENTIAL

1

SPIDERWG roadmapLegend:

RG: Reliability GuidelinesS: SurveyR: RecommendationsRV: ReviewMN: Modeling NotificationWP: White PaperEM: Educational Materials

Jun 2019

Sep 2019

Dec 2019

Jun 2020

Ongoing

Modeling

M1. S. DER modelingM4. RV. MOD-32 for DER data collectionM5. MN. Dispatching DER off PMAX in case creation

M2. RG. DER data collection for modelingM3. RG. DER modeling

Coordination

C4.

C5. R. Coordination of terminology

C1. RV. IEEE standard 1547-2018 for impacts to BPSC6. RV. NERC Reliability Standards

C2. RG. Communication and coordination strategies for transmission and distribution entities regarding DERC3. EM. To support information sharing between industry stakeholders

C7. Tracking and reporting DER growth

Verification

V1. RG. DER performance and model verificationV2. RG. DER forecasting practices and relationships to DER modeling for reliability studies

Studies

S2. RV. TPL-001 for incorporating DERS3. R. Simulation improvements and techniquesS4. RG. Recommended approaches for developing UFLS and UVLF with increasing DER penetrationS5. WP: Beyond positive sequence RMS simulations for high DER penetration conditions

S1. RG. BPS planning under increasing penetration of DER

PC

PC

PCPCPCPCPCPCPCPCPC

PC

PC Reportable Items

NERC System Analysis and Modeling Subcommittee Meeting, January 30-31, 2019, Tampa, FL

IEEE P2800 Update

Jens C. Boemer, WG Chair*Kevin Collins, Bob Cummings, Babak Enayati, Ross Guttromson, Manish Patel, Chenhui Niu, Vice-ChairsWes Baker, Secretary

January 30, 2019*Also Chair of the sponsoring ED&PG Wind and Solar Plant Interconnection Working Group (Link to Website)

http://sites.ieee.org/pes-edpgcom-wsppidsc/working-groups-and-task-forces/wind-and-solar-plant-interconnection-working-group/

Filling the Gaps in North American Standards for Inverter-Based Generating Resources

1 NERC definition of Bulk Electric System: ≥100 kV with gross individual / aggregate nameplate rating greater than 20 MVA / 75 MVA

2 DER connected at typical (radial) primary and secondary voltage levels

• FERC Orders• NERC Reliability

Standards & GuidelinesBES1

• Not available

BPS

• IEEE Std 1547-2018DER2

•NERC compliance monitoring & enforcement

Performance Test & Verification & Model Validation

•Not available

•IEEE P1547.1•Ul 1741 (SA)•IEEE ICAP

IEEE P2800

IEEE P2800.1

Work in Progress

IEEE P2800

IEEE P2800.1

IEEE standards are voluntary industry standards and must be adopted by the appropriate authority to become mandatory.

IEEE P2800: Standard for Interconnection and Interoperability of Inverter-Based Resources Interconnecting with Associated Transmission Electric Power Systems

Scope:

This standard establishes the recommended interconnection capability and performance criteria for inverter-based resources interconnected with transmission and networked sub-transmission systems. Included in this standard are recommendations on performance for reliable integration of inverter-based resources into the bulk power system, including, but not limited to, voltage and frequency ride-through, active power control, reactive power control, dynamic active power support under abnormal frequency conditions, dynamic voltage support under abnormal voltage conditions, power quality, negative sequence current injection, and system protection.

Related activities:

IEC initiative to develop a single framework for connecting and controlling renewables. Contact: Charlie Smith, [email protected] , U.S. TA for SC 8A.

mailto:[email protected]

More than 170+ Interested PartiesAEP DNV GL ESC Eng. Inc. MEPPI PEACE® SouthernCo Opal-RT GridLabAMSC DOE FERC MISO PJM Tesla LADWP Entergy

AWEA Dominion First Solar National GridPower Grid Eng. LLC TVA FuelCell EnergyShell

Beckwith Electric Duke Energy GE NERC

S&C Electric Co.

University of Auburn

Xanthus Consulting

…

Bernhard Ernst Energy Consulting

Electrotek Concepts Hydro One NextEra EnergySANDIA

University of North Carolina

Seminole Electric Cooperative

Brush Electric Machines, Ltd. Enercon Hydro Quebec NREL Sargent Lundy

WES Consulting, LLCINL

China State Grid ESIG Invenergy LLC NV Energy

Seattle City Light

Western Energy Board NYISO

Cinch, Inc. EnerNex IREQ

Open Access Technology Intrntl. Siemens

Wichita University

SCS Transmission Planning

ComEd EPRIISO New England Inc. Outback Power SMA XcelEnergy Avista

ComRent ERCOTLeidosEngineering Pacific Corp Southern XM Columbia

The University of Alabama

4

Variety of Stakeholders

5

Most of the inverter-based resource vendors

Many Transmission Planners

Many Service Providers & Consultants

Several Regulatory Bodies

Supported by Academics & Researchers Responses: 65

IEEE Standards Classification & LanguageStandardsdocuments

specifying mandatory requirements (shall)

Recommended Practicesdocuments in which procedures and positions preferred by the IEEE are presented (should)

Guidesdocuments that furnish information – e.g., provide alternative approaches for good

practice, suggestions stated but no clear-cut recommendations are made (may)

IEEE P1547.2

IEEE Std

1547

IEEE P1547.8

IEEE P2800

IEEE P2800.1

IEEE SA Balloting Rules

Consensus =

≥75% Quorum

≥75% Approval–WG Chair’s goal is ≥90%!

7

Clarifications of the Scope Voluntary standard, requires reference by responsible parties’, e.g., interconnection

requirements / agreements– Candidate parties are transmission owners, state regulators, NERC, and FERC

Technical minimum requirements, intention is that responsible parties can specify additional requirements– Some participants see a risk that it may be regarded as exhaustive requirements– Strive for balance between the common denominator and exhaustive requirements– May want to consider tiered requirements by use of “performance categories”

Only “inverter-based” resources, e.g., wind power, solar photovoltaic, energy storage– Some participants suggested renaming to “inverter-coupled”– “Type 3” wind turbines (doubly-fed induction generators) are in scope

Applicable to transmission and meshed sub-transmission grids (broad BPS definition)– May need different set of requirements for transmission and sub-transmission

Coordination Approach

Project Sub-Working Groups

Sponsors

Liaisons

Joint WorkingGroup

JointTaskForce

ED&PGCom

(Sponsor)

Wind and Solar PP Interc. & Design

SubCom

Wind and Solar Plant Interc.

WG

P2800 - Individual(performance)

P2800.1 - Entity(test & verif.)

EM Com(Joint Sponsor)

RE Machines and SystemsSubCom

Wind and Solar Plant Interc.

WG (Mirror)

PSRC Com(P2800 Joint Sponsor,

P2800.1 Liaison)

C - System ProtectionSubCom

C.24 (Modeling) & C.32 (Impact of IBR)

WGs

NERC IRPTF (Liaison)

PSDP(Liaison)

Power System Stability Controls SubCom

WG on Dyn. Perf. of RES

Wind and Solar Power Coordinating Com

(Liaison)

T&DCom

(Liaison)

Distribution SubCom

Distributed Resources Integration WG

SCC21(Liaison)

IEC

Others?

IEEE P2800 Leadership TeamRole Name Affiliation Stakeholder Group Liaison

Chair Jens C. Boemer EPRI Academic/Research EDP&G, SCC21

Secretary Wesley Baker Power Grid Eng. Service Provider/ Consulting EMC, IRPTF

Vice-Chair Bob Cummings NERC Regulatory and Governmental Bodies

NERC IRPTF

Vice-Chair Kevin Collins FirstSolar Users, Industrial NERC IRPTF

Vice-Chair Babak Enayati NationalGrid Stakeholders represented in IEEE Power & Energy Society

T&D, SCC21, PES GovBrd

Vice-Chair Ross Guttromson SANDIA National Lab

Academic/Research DOE

Vice-Chair Chenhui Niu State Grid Corporation of China

Stakeholders represented in IEEE P2800.1 Working Group

IEEE P2800.1,IEC SC8A

Vice-Chair Manish Patel Southern Company Utility, Transmission PSRC, IRPTF

10

Anticipated Resource Commitments Commitments Officers

(Chair, Vice-Chairs,

Secretary)

Sub-WG Leads &

Facilitators

Sub-WG Members

Liaisons

Regular attendance of 3-4 in-person meetings per year (2-3 days each) over the duration of the project of 2-3 years

In person In person In person or remotely

In person or remotely

Regular attendance of approx. monthly P2800 leadership calls (1hr each)

X

Review of draft requirements X X X X

Attendance/contributions to Sub-Working Group draft requirements and calls as needed (may vary, but typically bi-weekly calls of 1 hour)

X X as needed

11

Please send your (self-)nominations to Jens C Boemer, [email protected] and Wes Baker, [email protected]



Tentative Sub-Working Groups

12

I. Overall Document II. General Requirements III. Active Power – Frequency Control IV. Reactive Power – Voltage ControlV. Low Short-Circuit Power VI. Power Quality VI. Ride-Through Capability Requirements VII. Ride-Through Performance RequirementsVIII. Inverter-Based Resource Protection IX. Modeling & Validation X. Measurement Data and Performance

Monitoring*XI. Interoperability, information exchange,

information models, and protocols*XII. Tests and verification requirements

* May be merged with another Sub-WG

Sub-WG scoping is currently underway

If you are interested, please sign up at https://www.surveymonkey.com/r/MRW9SLQ

Plan to kick off Sub-WG in the February/March 2019 timeframe (likely bi-weekly calls)

https://www.surveymonkey.com/r/MRW9SLQ

Proposed Timeline ahead of approved PAR

P2800 Kick-Off WG DraftingInitial

Sponsor Ballot*

Recirculation Submit to RevCom* Publication

P2800.1 Kick-Off WG Drafting …Initial

Sponsor Ballot**

Recirculation Submit to RevCom** Publication

Related activities

IEEE P1547.1 NERC IRPTF NERC SARs

13

Jan 2019 2019-2020 Dec 2020

* The P2800 PAR states June 2021 for Initial Sponsor Ballot and October 2022 for submission to RevCom.** The P2800.1 PAR states Dec 2021 for Initial Sponsor Ballot and October 2022 for submission to RevCom.

2021 Dec 2021 May 2022 2021

Ability to meet this accelerated timeline or an even more ambitious timeline may be subject to strong commitments (a.k.a. support/funding) of Working Group leadership team.

Anticipated Timeline and Next Steps

14

Stakeholders suggested to accelerate the proposed timeline by 6 months Enter initial ballot in June 2020?

Next step is for the P2800 Leadership Team to develop a strawman based on IEEE Std 1547-2018 (structure,

terminology) NERC IRPTF Reliability Guideline

(specifications)

Kick off Sub-WGs once the strawman is available Responses: 67

Next Meetings

15

Coordinate with NERC IRPTF Meeting Schedule

Allow for remote participation via WebEx

Preferably no registration fee, as long as facilities and catering is provided in-kind

NERC IRPTF IEEE P2800 (tentative) Location Comment

Tue/Wed,May 21-22, 2019

Wed/Thu, May 22-23, 2019 Atlanta, GA (NERC) Confirmed

Wed/Thu,September 4-5, 2019

Tue/Wed,September 3-4, 2019

Salt Lake City, UT (WECC)

May be moved to PSRC Meeting Sep 10 – 14, 2018, in Minneapolis, MN

Tue/Wed,December 3-4, 2019

Wed/Thu,December 4-5, 2019 ____, __ (TBD) Not confirmed

Contacts

IEEE P2800Jens C Boemer,

[email protected]

Wes Baker, [email protected]

IEEE P2800.1Chenhui Niu,

[email protected]

Jens C Boemer, [email protected]

16





atcllc.com

PSSE v34.5.0 RC8 Node Breaker Testing

Kerry Marinan, P.E. 01/31/2019

atcllc.com

Steady State Node Breaker Model DevelopmentMembers who have created and provided Node Breaker Data

– American Transmission Company (ATC)• 44 Node Breaker Stations• 44 Node Breaker Station Slider files

– International Transmission Company (ITC)• 7 Node Breaker Stations • 5 Node Breaker Station Slider files

– Southern Companies (SOCO)• 38 Node Breaker Stations • 0 Node Breaker Station Slider files

– Tennessee Valley Authority (TVA)• 7 Node Breaker Stations • 0 Node Breaker Station Slider files

– Total of 96 Node Breaker substations and 49 Node Breaker Station Slider files

atcllc.com

Steady State Node Breaker Model Development

• Test Case information– MMWG 2016 Series 2018 Summer Peak Model

• 43 -500-kV stations plus lower voltage facilities• 38 - 345-kV stations plus lower voltage facilities• 5 -161-kV stations• 8 -138-kV stations• 2 -115-kV stations• 28 – Transformers with Under Load Tap changers• 10 - Stations with Capacitor Banks• 9 - Stations with Reactor banks• 11 – Fossil units• 6 – Simple Cycle Combustion Turbines• 3 - Wind Farms• 3 - Combined Cycle plants• 2 - Nuclear units• 1 – Phase Shifting Transformer• 1 – DVAR unit• 1 – Three Terminal Line• 1 – Line with a non-breakered tap

atcllc.com

Contingency Analysis Progress

• ACCC issues and observations:

– The default for the command to run all NB contingencies is to look for the next breaker up to 4 levels away.

– Currently PSSE V34.5 does not have an automatic command to use the node breaker information to create complete line contingencies (breaker to breaker). These must be explicitly defined.

– Currently PSSE V34.5 does not have an automatic command to use to monitor the node breaker nodes. The monitoring of each node must be specified in the Monitored Element file.

atcllc.com

Known Issues

• The current version of PSSE does not support the modeling of Node Breaker topology for multiple switched shunts on the same powerflow model bus.

atcllc.com

Phase II Considerations:

6

1.) Is the amount of data gathered and incorporated into the model sufficient for bench marking the AC contingency analysis?

2.) Should the sub-team proceed with development of the files necessary to per form the Node Breaker contingency analysis or wait for improvements in the software that will allow the use of automatic contingency commands?

3.) The Node Breaker sub-team does not have any members who can perform the stability analyses. We have one volunteer from the Node Breaker modeling group and are looking for more.

1

SUGAR: Simulation with Unified Grid

Analyses and Renewables

Larry Pileggi

30 January 2019

2

Ultimate Grid Planning Tool

• Goal: a robust platform for the most challenging grid planning applications

– Extreme contingency analyses

– Optimal siting and sizing of new infrastructure

– High renewable penetration analysis at T&D levels

– Cascading outage simulation

– Black start simulation

3

SUGAR

• Split circuit formulation models the power grid using true state variables: ‘I’ and ‘V’

• No need to separate transmission from distribution, or 3-phase from positive sequence– Combined T&D handled

naturally

• Circuit-based solver enables improved robustness and accommodates otherwise difficult models

1 2

G3

S

+

_

+

_

𝑉𝑉𝑅𝑅𝑘𝑘+1

𝑉𝑉𝐼𝐼𝑘𝑘+1

𝜕𝜕𝐼𝐼𝑅𝑅𝑘𝑘

𝜕𝜕𝑉𝑉𝑅𝑅

𝜕𝜕𝐼𝐼𝐼𝐼𝑘𝑘

𝜕𝜕𝑉𝑉𝐼𝐼





𝛼𝛼𝑅𝑅𝑘𝑘

𝛼𝛼𝐼𝐼𝑘𝑘

𝐼𝐼𝑅𝑅𝑘𝑘+1

𝐼𝐼𝐼𝐼𝑘𝑘+1

…

Real

Imag.…

…

…

Nonlinear Power Flow Problem

Split-EquivalentCircuit with I-V variables linearized for (k+1)th N-R iteration

4

SPICE and SUGARSimulation Program with

Integrated Circuit EmphasisSimulation with Unified Grid

Analyses and Renewables1 2

G3

S

Systemsettings

+

_

+

_















…

Real

Imag.…

…

…Split-EquivalentCircuit with I-V variables linearized for (k+1)th N-R iteration

Nodal eqns

=YR VR

N-Riterations

YI VI

JR

JI

Nonlinear System

+

_𝑉𝑉𝐷𝐷𝐷𝐷𝑘𝑘+1

𝜕𝜕𝐼𝐼𝐷𝐷𝐷𝐷𝑘𝑘

𝜕𝜕𝑉𝑉𝐷𝐷𝐷𝐷

𝜕𝜕𝐼𝐼𝐷𝐷𝐷𝐷𝑘𝑘

𝜕𝜕𝑉𝑉𝐺𝐺𝐷𝐷𝐼𝐼𝐷𝐷𝐷𝐷𝑘𝑘

𝐼𝐼𝐷𝐷𝐷𝐷𝑘𝑘+1

…

…+

_𝑉𝑉𝐺𝐺𝐷𝐷𝑘𝑘+1

…

… Linearized transistor model for (k+1)th N-R iteration

Nodal eqns

=Y V JN-Riterations

Inputsources

Nonlinear Circuit

BSIM4 model:24k lines of c

Up to billions of nodes

4

5

Guaranteed Convergence

• Circuit simulation methods can be applied that exploit the known circuit model characteristics

• Homotopy methods have been shown to guarantee global convergence to the physical solution in circuit simulation*

• SUGAR uses a Tx stepping approach to ensure convergence to the correct voltage solution for power flow

+

_

+

_















Real

Imag.…

…

…

*Jaijeet Roychowdhury, Robert Melville, “Delivering Global DC Convergence for Large Mixed-Signal Circuits via Homotopy/Continuation Methods”, IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, Vol. 25, No.1, January 2006.

6

• Can simulate any complex large-scale or “hard to solve” system• Example: US Eastern Interconnection

• Must be able to identify infeasible systems – “no solution” results are not helpful

Scalable and Robust

✔ converged X diverged

Case ContingencyType

No. ofBuses

StandardCommercial

ToolSUGAR

From initial solution orarbitrary initial conditions

1 N-2 75456 X ✔2 N-2 78021 X ✔3 N-3 80293 X ✔4 N-3 81238 X ✔

Extreme Contingency Operation

7

Formulate ascircuit eqns

SUGAR: Circuit Formulation

Optimization

Objective 𝓕𝓕𝒐𝒐𝒐𝒐𝒐𝒐+ Constraints

Minimize Infeasibilities Minimize Cost of Generation Minimize Losses Estimate System State Estimate Network Topology Optimize Load Shedding ….

Newton Raphson

Nonlinear Power Flow1 2

G3

G

+_

+_















Linearized split-circuit (I-V)

…

Real

Imag.……

…

Solve using SUGAR

𝝏𝝏𝓕𝓕𝒐𝒐𝒐𝒐𝒐𝒐

𝝏𝝏𝑽𝑽𝑹𝑹

𝝏𝝏𝓕𝓕𝒐𝒐𝒐𝒐𝒐𝒐

𝝏𝝏𝑽𝑽𝑰𝑰

Adjoint split-circuit

+_

+_

𝜆𝜆𝑅𝑅

𝜆𝜆𝐼𝐼

𝔗𝔗𝑅𝑅

𝔗𝔗𝐼𝐼

𝜕𝜕𝐼𝐼𝑅𝑅𝜕𝜕𝑉𝑉𝐼𝐼

𝜕𝜕𝐼𝐼𝐼𝐼𝜕𝜕𝑉𝑉𝐼𝐼

𝜕𝜕𝐼𝐼𝑅𝑅𝜕𝜕𝑉𝑉𝑅𝑅

𝜕𝜕𝐼𝐼𝐼𝐼𝜕𝜕𝑉𝑉𝑅𝑅

Adjoint split-circuit (I-V)

Real

Imag.………

…

8

Power Flow with Feasibility

• Non-zero feasibility sources indicate and locate infeasibility• Can provide for preventive and corrective actions in planning

Ill-conditioned 11 bus IEEE test case

Synthetic U.S. transmission system (courtesy of ARPA-E)

Example: Applied branch contingency – Infeasibility identified at bus 23510

9

Combined T&D Simulation

• SUGAR models and techniques are directly applicable to any combined T&D network

• Compatible with parallel simulation of combined network

Reduction of bus voltage at POI w/ and w/o distributed generation (DG)

50 distribution sub-station voltagesLoading factor on distribution system

Volta

ge a

t PO

I [p.

u.]

Eastern Interconnection +8000 node distribution system

Eastern Interconnection + 50 distribution grids (~1.2M nodes)

10

Renewable Penetration Study

• Decommissioning conventional plants and replacing them with distributed renewables creates challenging planning problems

• Example: Highly modified future planning grid– Power flow solution includes infeasible real and reactive power

throughout the entire grid model

Original caseInfeasibility throughout the system

– SUGAR optimization used to re-dispatch user-specified generators to obtain a feasible grid model with all devices within limits

11

Difficult Models: Generator Limits

• Existing tools use discontinuous piecewise models for incorporating PV/PQ switching that can result in:− Oscillatory behavior− Convergence to unstable solution

J. Zhao et al. “ON PV-PQ Bus Type Switching Logic in Power Flow Computation,” 16th PSCC, Glasgow, Scotland, July 14-18, 2008.

Nigerian grid testcase withouter loop piecewise models

12

Continuous Analytical Models

• Analytical models for Q limits are preferred

• Challenge: highly nonlinear models create convergence issues

• N-R limiting and homotopycan ensure convergence

• Avoids oscillatory behavior or unstable operation for Q limits

• Similar models can be used for switched shunts, transformer taps, etc.

13

Distributed Slack Model

• Can also apply analytical models for distribution of slack real power (with limits) instead of outer loops

• Can capture frequency response with continuous models too

N-R compatible piecewise model (Gen. 101)Generator Real Power with and w/o Distributed Slack

Gen. ID

𝑷𝑷𝑮𝑮𝑴𝑴𝑴𝑴𝑴𝑴

𝒑𝒑𝒑𝒑

Real Power Generation [MW]

MW

Pre-contingency

Post-contingency

Distributed-slack Enabled

Distributed-slack disabled

101 810 0.25 750 810 750

102 810 0.25 750 810 750

206^ 900 0 800 800 800

211* 616 - 600 Offline* Offline*

3011 900 0.5 258 840 864

3018^ 117 0 100 100 100*Generator taken off-line during a contingency^Generator not participating in distributed slack/AGC

14

Frequency Response Models

Primary Control ∆𝑷𝑷𝒅𝒅𝒅𝒅𝒐𝒐𝒐𝒐𝒑𝒑 = 𝑫𝑫∆𝒑𝒑

𝑷𝑷𝑳𝑳 = 𝑷𝑷𝟎𝟎(𝟏𝟏 + 𝑲𝑲𝒑𝒑𝒑𝒑∆𝐟𝐟)

𝑸𝑸𝑳𝑳 = 𝑸𝑸𝟎𝟎(𝟏𝟏 + 𝑲𝑲𝒒𝒒𝒑𝒑∆𝐟𝐟)

∆𝑷𝑷𝒅𝒅𝒅𝒅𝒑𝒑𝒑𝒑 = −𝑴𝑴 ∆𝒑𝒑

Frequencydependent loads

Inertia Response

Secondary Control AGC w/ distributed slack

Generator ID

Real Power Generation [MW]

Pre-contingency

Post-contingencyPrimary

Control ResponsePG

SET

Secondary Control Response

PGSET

101 750 782 810102 750 782 810206 800 834 800#

211* 600 - -3011 256 267 8403018 100 117 100#

∆𝑓𝑓 [Hz] 0 -0.13 0*Generator taken off-line during a contingency#Generator does not take part in AGC

-0.13 Hz * *

15

Cascading Simulation

*Present Industry Practices with Cascading Outages, Cascading Failures: Advanced Methodologies, Restoration and Industry Perspectives PES GM 2015, Milorad Papic

Industry Practice for Cascading Simulation*

• SUGAR can enable cascading simulation– Can guarantee convergence for

intermediate stages– “Infeasibility” feature helps

to identify path of collapse

• Frequency simulation:– Can incorporate relay trips due

to over or under frequency– Can incorporate under-frequency

load shedding (UFLS)

16

• Started with stable system with no violations

• Cascading event led to localized infeasibility• Analysis must be able to differentiate infeasibility from

simulation divergence

8k+ Bus Cascading Example

Initiating Event

CascadeStage 1

CascadeStage 2

CascadeStage 3

SystemBlackout

N-2 contingency5408->5702, Ckt. 1 5408->5687, Ckt. 1

Tripped5408->5702, Ckt. 2 Gen 5727 Gen 5828Gen 5865Gen 5866

TrippedLine 5408->10000 Gen 5652 Gen 5667Gen 5859Island created

Tripped5408->5687, Ckt. 2 Gen 5853

AGC, frequency response not modeled

Collapsed areas

17


• Can support system restoration in a similar way


Initiating Event

CascadeStage 1

CascadeStage 2

CascadeStage 3

SystemBlackout




Tripped5408->5687, Ckt. 2 Gen 5853

Collapsed areas


18


• Developing quasi-transient approach to capture the dynamics associated with this progression


Initiating Event

CascadeStage 1

CascadeStage 2

CascadeStage 3

SystemBlackout




Tripped5408->5687, Ckt. 2 Gen 5853

Collapsed areas

time


19

Dynamics

• Various control responses can be analyzed in terms of their quasi transient behavior using continuous models

• Unification of transient and steady state models is needed for a comprehensive analysis

Steady stateresponse A

Steady stateresponse B

Transientresponse

Transient analysismust start from

a steady state

And asymptoticallyapproach a finalsteady state

20

Bottom-Up Models

• Physics-based circuit models can support compatibilitybetween steady state and transient analyses

Power flow (SS) and transient analyses of induction motor using SUGAR

model template

3-phase induction motor(i) Electrical circuit(ii) Mechanical Circuit

21

Top-Down (Load) Models

• Circuit-based approach provides foundation that can be used to unify steady state and transient models

• Can parameterize models using circuit synthesis techniques and machine learning

CompositeLoad Model

22

Load (Top-Down) Models

• Example: parallel conductance (G), susceptance (B) and current source (I)– I-source models nominal behavior– Impedances capture sensitivity w.r.t. voltage– Compatible with steady state and transient analyses

23

Training B-I-G Models• BIG model fitted with a machine learning algorithm PowerFit,

developed with our CMU colleague Christos Faloutsos

Fitting LBNL μPMUs using BIG model for a period of 12 days

B and G capture voltage

sensitivity

24

Empirical Load Models

• BIG models are linear within I-V formulation

• BIG models are compatible with dynamics andtransient analyses

• Can use ML to synthesize nonlinear circuit parameters too – e.g. Composite Load Model

25

• Licensed SUGAR from Carnegie Mellon• Compatible with industry-standard inputs and outputs • Secure cloud-deployed version also available through web

application

www.pearlstreettechnologies.com

26

Pearl Street Team

• Bromberg authored first SUGAR paper and led an industry team for computation product that included scalable cloud software

• Zheng has spent 15 years developing commercial circuit simulation software, including the world’s first parallelized SPICE

• Pandey worked in the power industry for 5 years before joining CMU for his PhD work on SUGAR

Hui Zheng, Ph.D. Amritanshu Pandey, Ph.D.David Bromberg, Ph.D.

27

Pearl Street SUGAR Interface

Searchable and sortable repository of your organization’s case files

Full record of simulations for each case, including settings and results

28

Pearl Street SUGAR Interface

View and edit cases and results

Visualize results over an interactive map

Modification to PRC-019-2Standards Authorization Request (SAR)

RELIABILITY | ACCOUNTABILITY2

It is clear to the industry that PRC-019 is a standard developed and written for traditional synchronous generation.

Inverter Based Resources (IBR) are designed and operated in a completely different manner than synchronous generators.

This misalignment forces entities to make interpretations and assumptions of the

requirements.


Revise PRC-019 standard to address the ambiguity and conflicts within the existing standard.

Identify and delineate the differences

between synchronous and asynchronous

generation

Clearly specific requirements that

align with these differences and support system

reliability.

Purpose


Reliability Need

Clarification of Facilities

Verify that reactive compensating devices are within the purview of the standard for all generating

resource types.

Revise Inclusion I4 to accurately depict

asynchronous and non-rotating resource configurations

Revise 4.2.3.1 to include inverter and plant control regardless of where voltage control is being

“solely” performed at


Standard Requirements• Ensure language is clear and accurate for

all generation types.

R2 Coordination Time Frame• Current language can be interpreted as

allowing coordination 90 days AFTER a change. This would allow an entity to put a unit back into service without performing coordination.

Reliability Need


• Add language to eliminate momentary cessation functionality

• Entities should place limiters to prevent an inverter from going into momentary cessation.

Momentary Cessation

• VAR control, Power Factor Control, Reactive Power Control, Active Power Control

• Power Factor or Voltage Control Mode

Inverter & Facility Control

Systems

• Verify Firmware upgrades are classified as “changes” under R2

Firmware Upgrades

Reliability Need


SSSL:Determine if SSSL

should be removed or revise language to

align with industry standards

Stability Analysis:Verify stability analysis

is required for other types of generation

and provide a methodology

Voltage Drop:Verify that a voltage drop across collector

bus system and GSU is required for coordination

Synchronous Condensers:

Verify that SSSL must be

considered for coordination

Reliability Need

PRC-026Possible Reliability Gap


.

Transients

RelaysModel


Requirement R1.4

“An Element identified in the most recent annual Planning Assessment where relay tripping occurs due to a stable or

unstable power swing during a simulated disturbance.”

Is this requirement implying or assuming that the stability model has accurate relay characteristics?

Are regions explicitly inserting actual in-service relay settings into their transient model?


Attachment A

Phase Distance

Loss-of-Field

Phase Overcurrent

Out-of-Step


Model DISTR1

Source: PSS®E


Stable Power Swing Performance

Source: PSS®E


Model TIOCR1

Source: PSS®E


Model CIROS1

Source: PSS®E


Model SLNOS1

Source: PSS®E


Model LOEXR1

Source: PSS®E


• If a relay element has a time delay greater than 15 cycles then it can be excluded from transient simulations.

• Communication Assisted Protection Schemes (POTT, DCB, etc.) are excluded

• Relay element supervised by power swing blocking are excluded What if the system experiences an unstable power swing and the element

does not trip??

Attachment A


Case Study From Prabha Kundur

Source: Kundur

RELIABILITY | ACCOUNTABILITY13 Source: Kundur


Protection engineers need to know which of their in-

service protection schemes are susceptible

to insecurities

We must decide which relays should be modeled

(Attachment A)

Do the major stability software vendors have all

of the required relay modesl?

Reliability Guidance Joint SAMS/SPCS Task Force

Where Do We Go From Here?

PES-TR68 Impact of Inverter Based Generation on Bulk Power System Dynamics and Short Circuit PerformanceIEEE PES/PSRC/NERC


NERC Standards Effected by IBR

NERC PC or SAMSMOD-032• This standard is outside the scope of the NERC SPCS

NERC SPCS/SMSPRC-002• There are potentially multiple groups identifying gaps within the standard. Hence, the efforts must be synchronized• A key factor is NERC’s belief that they are receiving poor data quality during system events

NERC SPCS/SAMSPRC-006• Regions may have to create more UFLS trip categories, lower UF relay time delays, or increase amount of load shed per

category• High levels of Rate of Change of Frequency (RoCoF) in relation to UFLS must be evaluated

NERC SAMSPRC-026• Will increased penetrations levels of Inverter-Based Resources (IBR) change angular stability assumptions and power

swings?

NERC SPCSPRC-027• Increased penetration levels of IBR will reduce fault current contributions which may effect coordination

NERC PCTPL-001• This standard is outside the scope of the NERC SPCS


PRC-006

SOURCE: IEEE PES-TR68


PRC-026

SOURCE: IEEE PES-TR68

RELIABILITY | ACCOUNTABILITY5 SOURCE: IEEE PES-TR68


PRC-027

Trigger PRC-027

Requirements

Large fault current

deviations

Coordination of existing schemes

Negative Sequence

current impacts


Analyze PRC-006 & PRC-026 with respect to the findings

in the IEEE Report

Develop a white paper

Develop a SAR if warranted

Where Do We Go From Here?


White Paper Topics

• In each of the interconnections (and Regions), is system frequency response changing enough due to inverter based resources to warrant modification of (i) Reliability Standards, (ii) UFLS trip settings, (iii) methods to avoid UFLS?

• Are there existing studies analyzing this already (i.e., ERCOT is looking at this since they’re the only interconnection that has this problem)?

• What is SAMS thoughts on frequency stability (via study) in the EI and WI? Do we have a ballpark idea when frequency stability (hitting UFLS) will be a problem? Will it ever be a problem (in the foreseeable future) in the EI and WI?

• Can we simply analyze the 2019 and 2029 cases to show a comparison using the MOD-032 Designee cases with some minor changes? To get a ballpark? Can we report back on that?

CONFIDENTIAL – Limited Distribution

NATF Planning and Modeling Practices Group

UpdateJanuary 31, 2019

NERC SAMS MeetingEd Ernst- NATF Program Manager

CONFIDENTIAL – Limited Distribution (NERC)Copyright © 2019 North American Transmission Forum. Not for sale or commercial use. Limited Distribution documents are confidential and proprietary. Limited Distribution documents may be used by employees of North American Transmission Forum (“NATF”) member companies who have a need to know the information in the document, by NATF staff, and by entities who have permission to receive Limited Distribution documents pursuant to a written agreement with the NATF, for purposes consistent with the NATF’s mission. All rights reserved.


NATF Planning and Modeling Practices Items in Flight

• Completed– Updated NATF TPL 001-4 Modeling Reference Document

posted as Open Distribution document at www.natf.net• Underway

– Distributed Energy Resources Reverse Power Flow– FAC-008– Planning for System Resiliency– June NERC/NATF/EPRI Planning and Modeling workshop

• Pending– TPL-001-5


Public Posting of NATF documents• Located at www.natf.net/documents

3

http://www.natf.net/documents


2019 Joint NATF-NERC-EPRI Planning and Modeling workshop

• Dates: June 18-19, 2019• Host: ITC• Location: Novi, MI (Detroit area)• Details and Registration: Late 1st quarter 2019


Coordination between NATF and NERC • Document development• Jointly Sponsored Modeling Workshops

– June 2017 - Exelon(Com Ed) in Chicago – June 2018 - AEP in New Albany, Ohio (Columbus, Ohio area)– June 2019 - ITC in Novi, Michigan (Detroit area)

• Joint EPRI/NATF/NERC/UVIG Inverter-Based Resources webinar series

• Regular NATF-NERC meetings at CEO level to coordinate efforts

• Ryan Quint of NERC staff has standing slot on Monthly NATF Practice Group calls to cover topics as needed

• Ed Ernst has standing slots on SAMS calls to cover topics as needed

5


NATF Planning and Modeling Practices Group Update

Questions?

6

Resources Subcommittee (RS) –Synopsis of Activities Tom Pruitt, RS Chair, Duke EnergySandip Sharma, RS Vice Chair, ERCOTElsa Prince, Secretary, NERC

January 31, 2019


Purpose: The Resources Subcommittee (RS) Balancing resources and demand, interconnection frequency, and control

performance.

The RS working groups: Frequency Working Group Inadvertent Interchange Working Group Reserves Working Group

RS - Scope


The RS accomplishes this by: Reviewing and assisting in the development of generation and load

“balancing” standards, which includes developing any necessary reference documents.

Reviewing and assisting in the development of interconnection balancing standards to assure problems resulting from balancing do not adversely affect reliability.

Providing industry leadership and guidance on matters relating to balancing resources and demand issues as well as resulting issues related to interconnection frequency.

Addressing the reliability aspects of inadvertent interchange creation, accounting, and payback.

RS - Scope


The RS accomplishes this by: Review balancing authorities’ control performance (e.g., CPS and DCS) on a

periodic basis.

Address technical issues on automatic generation control (AGC), time error correction, operating reserve, and frequency response.

Provide oversight and guidance on aspects of interchange scheduling as it applies to impacts on balancing and inadvertent interchange.

Providing oversight and guidance to its working groups and task forces.

RS - Scope


• Assistance in the determination and issuance of yearly Frequency Bias Settings and Frequency Response Obligations

• Subcommittee report for the regularly scheduled OC meetings

• Review and endorsement of the Frequency Response Annual Analysis Report (Determination of the annual IFRO)

• Support for the development of the frequency response and balancing related sections of the NERC State of Reliability

• Respond to other directives and requests of the NERC OC

RS – Deliverables


Current RS Activities

Balancing and Frequency Control Technical Document Target: ready for OC approval by June 2019 Final RS Approval during the April 2019 meeting

Reliability Guideline: Integrating Reporting ACE with the NERC Reliability Standards

Target: ready for OC approval by Dec 2019

Time Monitoring Reference Document Target – ready for OC approval by Dec 2019


Current RS Activities

Primary Frequency Response Guideline Target – ready for OC approval by Q1 2019

Changes in BA Area Footprints Reference Document Target – ready for OC approval by Q1 2019

Dynamic Transfer Reference Document Target - ready for OC approval by Dec 2019

“New Power System Modeling Standard”

Contact: Garth [email protected]

SAMS Meeting“System Analysis and Modeling Subcommittee “

January 30-31, 2019

1

Andrew [email protected]

Background Power system models are currently developed as follows:1. Generic Models (developed by WECC, PSLF, PSS/E and others)

• Generic model performance is tested against the standards (note testing is only done under selected conditions – ie N-0 small signal stability tests etc..)

2. Custom Models• developed by manufacturers or by experts working with

suppliers• Custom written for each program

3. Real Code Models (commonly used in EMT/PSCAD)• Interfaces manually written (or in some cases automated)• Call to actual code at the precise time step• Most accurate methods possible (and relatively easy to do)

2

1. Generic Models- Least accurate (inherently generic)

- Testing only performed under select conditions- Time consuming - every program developer (PSS/E, PSLF, PSCAD

etc.) has to write/test models- Suppliers are not happy:

- Control concepts can be very different from the real controls- Often no protection models (or very simplified)

- Should be easy to use and reliable

3

2. Custom Models- More accurate (but still not real-code so somewhat generic)

- Testing only performed under select conditions- Algorithms often simplified (how is frequency or rms

measurements done?)- Time consuming/complex to develop - every program developer

(PSS/E, PSLF, PSCAD etc.) or manufacturer has to write/test models for each device.

- Have a reputation for being slow, complex and not reliable- often developed by suppliers, not program experts

- NDA/Intellectual Property concerns- Have to be re-compiled for new/major program releases

(source code needed?)

- Higher confidence level from suppliers (ie better models)4

3. Real Code Models- Most accurate (actual code in the field running on your PC)

- Minimal testing/validation required- Developed with direct supplier support- Fast to develop- NDA/Intellectual Property concerns resolved (no source code of

models needs to be supplied – DLLs only)

- Have a reputation for being complex- Or is this real device/code problems/complexities

(ie a trip can occur if all protections are modeled)?- Interfaces to DLLs may need to be re-compiled for new/major

program releases (interface source code needed?)- Often done for EMT programs (but rarely for RMS tools)

5

Real-Code – EMT vs TS- Real-code models are common in EMT/PSCAD

- Small electrical time steps- ABC measured V and I (similar to real controls – not RMS)- Inner current and fast controls (PWM firing, PLL, IGBTs etc.)- Identical code from the field, running on your PC

- Transient Stability Modeling?- Normally custom models are written specifically for an RMS

program:- State/DState syntax, ABCD constant methods, - Integrations/solver done centrally by the main algorithm- Not how real controller works!

- Real-Code in RMS Tools – Yes!- Internal solvers for all integrations (ie solved in the code,

just like in real life)- More accurate! 6

"Use of Real-Code in EMT Models for Power System Analysis”

• New IEEE Task Force• First meeting IEEE PES Meeting, Portland, Monday, August 6, 2018

• Under AMPS Committee (Analytical Methods for Power Systems) and TASS Working Group (Transient Analysis and Simulation)

• >50 people attended (in a room that seats 25) – popular!• Feedback says this should become an IEEE standard!• Coordination with IEC-61400-27-1 and Cigre

• Objectives:• Prepare guidelines/white-paper on the techniques and methods for

developing models. • This paper will provide guidance to manufacturers, utilities,

consultants and system operators on the development and use of these models.

7

New Concept• Manufacturers compile their device source code into a DLL (conforming to

the standard). The DLL standard includes:• Exported functions which can be called (Initial time step and each

sample time)• Definition of all Inputs, Outputs and Parameters (including variable

types, units, array dimensions, min and max allowable settings etc.)• Sample time step (at which to call the controls each step)• DLL needs to be updated every time the code is changed/released

(version control!)• Program Developers (PSS/E, PSLF, PSCAD etc.) include a DLLImport tool:

• Run once by the end user• Tool opens/queries the DLL (to get Inputs, Outputs, Parameters,

sample time etc…)• Creates any interfacing code for that particular program• Tool may need to be re-run for each version update (but model source

code not needed!). DLL can be used for all future program versions.• End User:

• Get the DLL from the manufacturer• Run the DLLImport tool once

8

Model Settings• Getting the code is not enough – Settings are important!• Settings (control and protection gains, settings, constants etc…) are often

updated in the field.• Identical settings in the field should be used in studies (and vice-versa)

• Each utility requires a database of all devices in operation:• Contains code name and revision number used in the field

• End user can verify correct model and code revision is used• Contains parameter settings revision #:

• CRC checks?

• End User gets the DLL/model name and settings version from the database• The field code settings are directly used in simulation models

• Same settings used in RMS and in EMT models• Studies engineers get notified if site settings are changed

• Can decide if the setting change is important and can trigger re-studies

• Real device gets study-qualified settings

9

Real-Code - Challenges • State variable storage (real-code does not need this)

• Required for multiple instances (although DLL copying can avoid this)• Initialization

• Often not needed for real-code or in EMT analysis, but flat-start is required for TS

• Requires a routine that can accept powerflow terminal conditions, and can compute all required state variables

• Different time frames for models• EMT programs often use all code (fast and slow) and have ABC

quantities.• RMS programs cannot call fast code (constant current inner loops) and

have RMS quantitates only.• Multiple subroutine entry points (with different inputs and outputs)

required• Speed

• Each model is called once per step, taking inputs of V,I from last step• Internal solvers allow “threads” (parallel processing)• Use of real-code should make TS and EMT programs faster (not slower)

10

Applications• Almost all devices now use digital code and processors:

• Power Electronics:• Wind turbines, solar inverter, HVDC, SVC, Statcom, machine

drives, battery energy storage inverters• Protection relays• Generator Controls?

• Exciters, governors, stabilizers• RAS/SPS, wide-area controllers, PMU etc.

11

Example Experience• Interfacing to real-code done >40 times in EMT programs:

• Wind farms• Solar/PV• SVC, Statcom• HVDC VSC/LCC• BES (battery energy storage)• Protection Relays• Real-Code is the most common type of model used!

• IEC-61400-27-1 (used by at least one wind turbine suppliers)• Similar concept to what is proposed (IEC/IEEE/Cigre collaboration is

encouraged)• DLLImport tool written to automate the controller interface

• Fastest method to develop complete models • Most accurate modeling possible (including protection etc).• Source code never leaves the manufacturer site (NDA/IP concerns)• Reliable process• Real-code studies often showing device tripping for normal faults• Many examples of instabilities found that do not occur in RMS or simple

models. 12

"Use of Real-Code in EMT Models for Power System Analysis” Contact Information

Please contact me below to volunteer specific contributions towards the guidelines paper.

Project www site: www.electranix.com/IEEE-PES-TASS-realcodewg

Contact: Garth IrwinElectranix [email protected]

13

http://www.electranix.com/IEEE-PES-TASS-realcodewg


confidential spiderwg roadmap agendas...– currently psse v34.5 does not have an automatic command...

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