PI/PSLF Based Model Validation Application

Eric Bakie and Milorad Papic WECC JSIS Meeting Tempe, AZ January 21-23, 2014

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OUTLINE

1. Background Information 2. What is PI/PSLF Based PPMV Application? 3. IPCO PI/PSLF Based Tools 4. Play-In validation examples using PI data 5. Lessons Learned and Future Work

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1. Background Information

Grid Planning and Operating Decisions relay on good/realistic models of power system and its elements such as (generators, lines, transformers, loads, etc.) Having realistic models is very important for safe, reliable and economic system operation Validation and benchmarking of planning and operation models have always received a great deal of attention in the past and will receive increasing attention in the future by the utility industry Need for Validation exist for both Component and System-wide Models Observation, measurement and analysis of multiple system events provide the best opportunity for model validation

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1. Background Information After major disturbances on July 2 and August 10, 1996, the WSCC Control Work Group (CWG) and the Modeling and Validation Work Group (M&VWG) were tasked with developing guidelines for testing generators, excitation systems, power system stabilizers (PSS) and turbine governors for all units greater than 10 MW for verification of reactive limits, proper performance of the dynamic control systems, and validation of the computer models used for stability analysis. NERC Recommendation 14 from August 14, 2003 “The regional reliability councils shall within one year establish and begin implementing criteria and procedures for validating data used in power flow models and dynamics simulations by benchmarking model data with actual system performance. Validated modeling data shall be exchanged on an inter-regional basis as needed for reliable system planning and operation”. NERC/FERC Recommendation 17 from September 8, 20111 “WECC, as the RE, should lead other entities, including TOPs and BAs, to ensure that all facilities that can adversely impact BES reliability are either designated as part of the BES or otherwise incorporated into planning and operations studies and actively monitored and alarmed in RTCA systems”.

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1. Background Information Study of WECC frequency Events by BPA over years and by IPC just recently indicates in many cases a wide discrepancy between simulations and recording of disturbance events. Finding from BPA show that differences in frequency have been noted in both the initial transient dips and in the “settling” frequencies. Assessment of the first transient dip is important for load shedding while the settling frequency is a measure of the responsiveness of turbine-governors in the system. Model validation by IPCO System Planning was performed to screen the quality of the dynamics models used to represent the turbine-governor system for all Units in Idaho system for ten major events in 2013. PI Data was used as the model validation input data.

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1. Component & system-wide Model validation

Component Model Validation – Generator model – Load model – HVDC, SVC model, etc.

System-wide model validation is not done routinely at present. Power flow simulation results are compared with time-synchronized recordings of bus voltages, angles, and key paths flows. The following aspects of a power system model that need to be matched to a specific event include:

• Network topology • Generation dispatch • Load profile • Load dynamics and composition • Power plant dynamics

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1. Background Information Several NERC MOD Standards deal with power system models and their

verification/validation to ensure they are accurate and up to date. MOD‐012 requires power plant owners to provide power plant data for dynamic simulations MOD‐026 requires power plant owners to verify that the provided dynamic models of excitation controls are accurate and up to date MOD‐027 requires power plant owners to verify that the provided dynamic models of governors and turbine controls are accurate and up to date MOD‐032‐1 exists in conjunction with MOD‐033‐1, both of which are related to

system‐level modeling and validation. Reliability Standard MOD‐032‐1 is a consolidation and replacement of existing MOD‐010‐0, MOD‐011‐0, MOD‐012‐0, MOD‐013‐1, MOD‐014‐0, and MOD‐015‐0.1, and it requires data submission by applicable data owners. Standard MOD‐033‐1 is a new standard, and it requires each Planning Coordinator to implement a documented process to perform model validation within its planning area. Validation using disturbance recordings has been recognized to be an acceptable method for periodic model validation.

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1. Background Information

Disturbance based model validation provides: A very effective way of filling in aspects of the models that cannot be validated effectively or safely through baseline testing A very effective way of detecting when baseline testing has produced misleading or inaccurate modeling The opportunity to observe and analyze generating unit behavior in operational situations that cannot possibly (or safely) be realized in the staged conditions of baseline testing. The opportunity to detect failures, changed adjustments, drifting, and improper operation of equipment that have occurred since baseline tests were done. [Ref. Power Plant Model Validation in BPA, July 12, 2012] 8

2. PPMV Application [Ref. BPA PPMV , Nov. 2011]

General Electric implemented a disturbance play-in function in their PSLF simulator in 2001. The function plays in recorded voltage bus, voltage and frequency at a power plant Point of Interconnection. The power plant active and reactive power are compared between the actual disturbance data and play-in simulations. BPA found that were quite few instances when a power plant model failed to match a disturbance response event. The most common modeling deficiencies include – Power System Stabilizers (PSS) – Turbine-governor models – Generator Inertia

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2. PPMV Application Power Plant Model Validation (PPMV) Application

Build a sub system by extracting data from the latest base case. Create a *.dyd file by extracting data from the latest dynamic file and solve load flow and confirm. Before running model validation studies, a mini-base case representing power plant conditions just prior to a disturbance is created. PPMV includes an automated mini-state estimation routine which sets up power plant initial condition using SCADA unit status information and PMU bus voltage, and active and reactive power. The model validation process is to “play-in” the recorded voltage and frequency of the disturbance and calculate real and reactive power using GE PSLF simulation tool.

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2. PPMV Application

Model Validation Setup An infinite-bus” model was developed and implemented in General Electric PSLF program. The model injects recorded bus voltage and frequency in dynamic simulations. The “infinite bus” is modeled with a large synchronous machine with fast-responding exciters and governors. Recorded bus voltage and frequency are input as references for the governor voltage regulator and governor respectively. If the turbine-governor model is correct, the simulated power should be very similar to the recorded power for events of system frequency excursions

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Inject Recorded Voltage and Frequency

Compare Recorded and Simulated Power: MW and MVAR

Validation Overview - GE PSLF Simulations

Disturbance “playback” is a standard feature in PSLF

2. PPMV Application

2. PPMV Application

• PPMVa_SetBaseCase_v1b.p

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PSLF - Mini State Estimator

Power Flow Template (plant.sav)

SCADA Data File: SCADA_Plant_Event.

dat

Event Data File: PMU_Plant_Event.csv

Powerflow File: PLANT_EVENT

.sav

2. PPMV Application

PPMVa_SetBaseCase_v1b.p Purpose: – Create a validation base case with initial conditions matching those prior to a

disturbance

Pre-requisites: – A “template” file with power flow model (*.sav) – A disturbance data file compatible with play-in format (*.csv) – A SCADA file with generating unit status and loading (*.dat)

Result – A powerflow file with initial conditions matching those during the event

(*.sav)

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2. PPMVa_SetBaseCase_v1b.p

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• Powerflow case with kV, MW, MVAR at POI matching initial conditions of disturbance record

• EPCL is setup for one facility - one disturbance

2. FRresponse_v1r.xls

Event on 03-14-2013 at 18:14 mdt Plot Function

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59.8859.9

59.9259.9459.9659.98

6060.02

18:10 18:11 18:12 18:14 18:15 18:17

FREQUENCY

168170172174176178

18:10 18:11 18:12 18:14 18:15 18:17

BROWNLEE UNIT 5 MW

2. PPMV Application

PPMVa_RunValidation_v1b.p

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PSLF

Power Flow File: PLANT_EVENT.sav

Plant Dynamic Data: PLANT.dyd

Event Data File: PMU_PLANT_EVENT.

csv

Channel File: PLANT_EVENT.

chf

2. PPMV Application

PPMVa_RunValidation_v1b.p Purpose: – Perform play-in simulation of a disturbance event

Pre-requisites: – A powerflow file with initial conditions matching those during the event

(*.sav) – A disturbance data file compatible with play-in format (*.csv) – Dynamic data file with a power plant model (*.dyd)

Result – Channel file with disturbance data (*.chf)

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2. PPMVa_RunValidation_v1b.p

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• Validation Comparison of Model to Disturbance Recording

• EPCL is setup for one validation run of one facility

2. Minimum File Requirements for Play-In in PSLF

Powerflow case representing disturbance I.C. (*.sav) Dynamics data (*.dyd) Disturbance data in PSLF Play-In format (*.txt, *.csv) EPCL that calls the PSLF Play-In Functions (*.p)

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Input Files

Output File

3. IPCO Tools: Modified FRresponse_v1r.xls

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3. IPCO Tools: Plot Macro

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3. IPCO Tools: *.csv Macro

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• Separate Tab for each unit with disturbance data in PSLF Play-In format

• Macro writes a (*.csv) file to the specified working directory for each unit

3. IPCO Tools: *.dat Macro

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• Separate Tab with SCADA Initial Conditions Data for each unit

• Macro writes a (*.dat) text file to the specific working directory with bus number, bus name, base kV, ID, status, generator kV, MW, MVAR, and baseload flag status data for each unit that was on-line during the disturbance

3. IPCO Tools: Set Base Case Batch (*.p) Macro

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• Macro writes a (*.p) text file containing the mailbox variables called by the Set Base Case batch EPCL

• Only writes records for units that were on-line during the disturbance

3. IPCO Tools: Run Validation Batch (*.p) Macro

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• Macro writes a (*.p) text file containing the mailbox variables called by the Run Validation batch EPCL

• Only writes records for units that were on-line during the disturbance

3. IPCO Tools: Get Plot Data Batch (*.p) Macro

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• Macro writes a (*.p) text file containing the mailbox variables called by the Get Plot Data batch EPCL

• Only writes records for units that were on-line during the disturbance

3. IPCO Tools: SetBaseCase_PI_FR_batch.p

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Template File (*.sav)

SCADA I.C. File (*.dat)

Disturbance Data File (*.csv) Disturbance Case

(*.sav)

PSLF EPCL to Match Boundary Conditions

(*.p)

3. IPCO Tools: RunValidation_PI_FR_batch.p

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Disturbance Case (*.sav)

Dynamics Data File (*.dyd)

Disturbance Data File (*.csv)

Channel File (*.chf)

PSLF Play-In (*.p)

3. IPCO Tools: Create Validation Files Macro

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3. IPCO Tools: GetPlotData_PI_FR_batch.p

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Channel File (*.chf)

SCADA I.C. (*.dat)

Tab Delimited Text File (*.txt)

PSLF Plot (*.p)

3. Play-In process using developed Tools

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3. Desired Play-In Validation Tool Features

Batch processing capability for validation multiple units Ability to easily process multiple events Retain program structure similar to ALLDYNS batch processor Query PI Data and plot disturbance records for all units Generate disturbance record files in PSLF Play-In format Generate SCADA Initial Conditions files for each generator Generate Powerflow files that reflect I.C. for each generator Create tab delimited text files from channel files for each validation run for external plotting in MATLAB Ability to re-run the process with modified dynamics data

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4. Play-In validation examples using PI data A List of WECC Frequency Events used to perform Model

Validation at IPCO Event 03-14-2013 @ 1814 mdt (59.89 Hz) Event 03-31-2013 @ 1905 mdt (59.90 Hz) Event 04-01-2013 @ 0908 mdt (59.84 Hz) Event 04-29-2013 @ 1148 mdt (59.86 Hz) Event 05-07-2013 @ 1137 mdt (59.88 Hz) Event 05-22-2013 @ 1621 mdt (59.88 Hz) Event 05-30-2013 @ 1621 mdt (59.70 Hz) Event 08-03-2103 @ 0351 mdt (59.88 Hz) Event 08-13-2013 @ 1630 mdt (59.89 Hz) Event 08-18-2013 @ 1704 mdt (59.82 Hz)

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4. Examples

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4. Examples

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4. Examples

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4. Examples

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• Modified hyg3 Ki from 0.35 to 3.25 • Added lcfb1 model

Red = Recording Blue = Simulation

4. Play-In Validation Process

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Post Process Results

Create Validation Report

10 Frequency Events

(2013)

Step 4

4. Cautions SCADA Problems – Noise, Poor Resolution PI update rate and dead band - Sampling intervals can be as high as 10 s Aliasing can result in incorrect conclusions if the sampling frequency is not sufficiently high. The minimum of 4-s resolution must be maintained. Another problem in SCADA could be the megawatt threshold before a new number is recorded. In some cases, the threshold is set as high as 10 MW, creating a dead band effect, exceeding the governor response during recordings of frequency disturbances. SCADA thresholds for unit and plant power recordings must therefore be set to appropriate lower threshold levels

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5. Lessons Learned

Approach works for Governor validation Bigger events to get outside of input data dead bands provided better matches Good for identifying undesired control behavior Good for identifying units represented with sustained frequency response but actually operate under load control

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5. Future Work

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Develop automation tools for creating validation reports Expand validation tool set for compatibility with PMU database Expand validation tool set for compatibility with DFR records Work with Generator Owners to identify areas for improving model performance Identify how the developed PSLF Play-In tools can be incorporated into the data validation process used to meet the proposed requirements of NERC MOD-033-1 Steady-State and Dynamic System Model Validation

Questions ?

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