PowerGEM’s PROBE LT Production Cost Modeling Software

WECC PMWG and PDWG – April 25, 2019

Brian Thomas (PowerGEM)

Jim David (PowerGEM)

Boris Gisin (PowerGEM)

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Agenda

• Introduction to PROBE

• Overview of Modeling Features in PROBE

• Software Neutral Input Format in PROBE

• Overview of Outputs

• Our experience using WECC ADS PCM with PROBE

• How can PowerGEM assist with WECC modeling activities?

• Q & A

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PROBE Introduction

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PROBE Introduction

• Versatile market simulation and production cost software offering a wide range of capabilities

• Short & long term production cost modeling

• Day-ahead market simulation

• Multi-day unit commitment

• Sub-hourly market simulation

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PROBE History

• PROBE is a mature product with an off-the-shelf version (PROBE LT) and custom versions for several ISOs

‐ Development started 2001 in conjunction with experts from PJM, CAISO, NYISO, MISO, and ISO-NE

‐ PJM has used PROBE daily since 1/1/2005 as part of DA market clearing

• Licensing to non-ISOs as a PCM software began in 2009

• The PowerGEM consulting team has performed countless long-term PCM studies with PROBE LT over the last 10 years

‐ All U.S. regions

‐ From one year to 15 years into the future

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Overview of Modeling Features in PROBE

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Overview of Modeling Features in PROBE

• Single Market vs. Multi Markets

• Solution Engine (SCUC, SCED and Solution Technology)

• Transmission model and network constraints

• Contingency Analysis

• Generator Model including wind, solar, hydro, energy storage

• Load Model

• Ancillary Services model

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Single Market vs. Multi Markets

• PROBE can simulate a single market OR multi markets‐ Example: CAISO Single Market PCM vs WECC ADS PCM

• Allows hurdle rates to model market friction and inefficiencies as well as wheeling for multi market model

• Same power flow models can be used for single market or multi market (if desired)

• Easy to switch from multi-market to single market

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MIP – Mixed Integer Programming

• MIP – mathematical method to solve optimization problem in which some or all of the variables are restricted to be integers

• MIP is typically solved via third party off-the shelf solvers ‐ Results depend on implementation details and chosen product

• MIP can be implemented in house – this is the PowerGEM approach‐ Better integration with N-1 and non-linear load flow

‐ Doesn’t require licensing external solvers

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PROBE Solution Engine• In-house proprietary solver highly optimized over last 15+ years

‐ Combined solver for security constrained unit commitment (SCUC) and security constrained economic dispatch (SCED)

‐ Solver specially built for power systems problem

‐ Known for fast performance

• Objective Function‐ Minimize Production Cost

‐ Enforcing traditional operational and transmission constraints

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PROBE Implementation OverviewPowerGEM doesn’t decouple SCUC, SCED and N-1

It is a single integrated application

• SCUC calls SCED and N-1 CA internally many times until converged

• Numerous heuristics and constraint relaxation during SCUC search

• Little value in refining UC solution until all N-1 constraints enforced and flows are computed via non linear load flow near final solution

• SCED is based on dual simplex LP• Allows enforcing traditional N-1 with thousands of contingencies - discussed later• Same SCUC Solver for ISO versions and PROBE LT

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PROBE Transmission Model – Power Flow• Similar to what is used in Transmission planning software

‐ Planning bus-branch power flow or EMS node-breaker power flow model (for ISOs)‐ Can read in PSLF EPC files (version 19-21) or PSS/E RAW files (version 24-34)

• Models all power flow equipment from PSLF or PSS/E such as: ‐ Transmission lines, multi-section lines, two winding and 3 winding transformers, phase shifters‐ Generators, load, DER (distributed energy resources), HVDC

• Solves iterative non-linear load flow several times per each time interval‐ Update for losses change and marginal loss factors

• Every hour may have different topology driven by transmission outages (if desired)‐ Outages and rating changes are easily entered in csv format

• Round Trip feature available to export hourly power flow cases from PROBE

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PROBE Transmission Model – Constraints

• Branch and Interface/Path thermal limits (continuous or emergency) under base case or contingency conditions

• Nomograms – Supports all WECC ADS PCM nomograms

• Hurdle Rates – Supports all WECC ADS PCM hurdle rates

• Flowgates – general concept for most types of constraints

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PROBE Transmission Model – Flowgates

• Flowgates – any “mon/con” pair ‐ “Mon” – single or several branches, possible with weighting factors for nomogram or

interfaces‐ “Con” – any continency or base case‐ General approach allowing to model variety of constraints, commonly for PCM‐ Popular in the East and used by NERC

• Most PCM products are limited to a few hundred flowgates/constraints‐ Performance reasons‐ Not easy to define many flowgates that may be limiting 10 years out

• PROBE fast performance allows to easily enforce 10,000-20,000 flowgates‐ Proxy for N-1 constraints‐ PowerGEM separate product (TARA) has unique function to identify all possible flowgates for

any future model and dispatch permutation

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PROBE Transmission Model – Contingency Analysis

• Conventional N-1 contingency analysis‐ Enforce flows on thousands of monitored branches for thousands of contingencies in preventive mode every hour

‐ PowerGEM position – Why delay N-1 for round trip analysis if it impacts PCM results? Enforce during PCM run

• Any type of contingency can be modeled (branch open/close event, generation or load event, islanding event) via CSV file

‐ Can read contingency files in common PSS/E or PSLF format

• RAS can be modeled as part of contingency

• Generator/Load/Islanding contingencies‐ Inertial/governor response or AGC based response for frequency events in contingency analysis. Advanced option

available to exclude wind, solar, baseload units from frequency response

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PROBE Generator Model

• Generator characteristics‐ Bids defined via price based bid curves or incremental heat rates & fuel price;

heat rate / fuel price can change seasonally, daily, or hourly

‐ All operational constraints enforced (generator min/max, run times, down times, ramp rates, no-load costs, and start-up cost/time)

‐ De-rates or outages schedule can be specified on hourly basis via CSV input

‐ Generators can be easily aggregated

• Emission rates and emission hub prices (CAISO AB 32 or RGGI in North-East)

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PROBE Generator Model – Renewable & Storage

• Renewables ‐ Hourly profiles/shapes for Wind, Solar and Hydro

‐ Allows curtailment if not deliverable

• Hydro Model

• Peak Shaving, Proportional load following (PLF)

• Can be scheduled against load or net load with wind or net load with wind and solar

• Energy Storage Model ‐ Detailed model for battery energy storage systems (BESS) & pumped storage

‐ PCM storage model derived from PowerGEM experience optimizing pumped storage for PJM’s day-ahead market for over 10 years

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PROBE Phase Shifters (PARS)

• Control Modes‐ Mode 1: Optimized to manage congestion/overloads subject to angle limits

‐ Mode 2: Local - control the flow within the desired flow range subject to angle limits

‐ Mode 3: Can be disabled (locked)

• Angle limits and flow control range can be set explicitly and does not need to be the same as in power flow case. This will eliminate one of the issues with high congestion observed with PARS as discussed at the April PDWG meeting.

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PROBE Load Model

• Hourly Load Bids (MW and price offers) ‐ User can enter more than 1 bid for the load (price sensitive bids)

• Hourly load forecast internally allocated to buses

• Option to ignore scaling non-conforming loads

• Identify DER (distributed energy resource) associated with composite load model from WECC power flow models and model separately from load forecast for the region

• Loads can be aggregated at different levels and grouped by WECC regions‐ Example, PGE sub zones -> PGE -> CAISO -> WECC

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PROBE Ancillary Service Model

• Ancillary services (AS) are co-optimized consistent with ISO approaches

• Lost opportunity costs are factored into pricing as a natural by-product of AS co-optimization

• An options menu specific to AS enables users to turn off ancillary modeling or customize modeling to the specific study needs – such as long-term PCM study versus next-day CAISO study

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Software Neutral PROBE Input format and PROBE Outputs

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PROBE Software Neutral Inputs

• Other than a power flow file typically in PSS/E raw, PSLF epc, or EMS format, and the flowgate file, all other data is defined in CSV files

‐ Including overrides to the power flow files, i.e. transmission outages and ratings changes can be entered in convenient CSV formats at seasonal, daily, or even hourly granularity

• Column configurable CSV files‐ Sequence of columns is not important

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Overview of Inputs in the GUI

• PROBE Inputs via user interface

• Allow users to run entire year, partial year, or even a single day from one interface

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PROBE Software Neutral Inputs

Sample Generator Data

• File headers define what data will be read in

• Different types of generators may require defining different level of details

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PROBE Software Neutral Inputs

Sample Demand Data (a more simplified format is available for users that don’t envision entering price sensitive demand)

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PROBE Interactive Analysis

• PROBE provides interactive analysis to study one selected day or short time period

‐ Users often want to study a particular time interval in more detail

• Drill down analysis allows users to find/review many details such as:‐ Detailed report for selected unit – why a unit was or was not committed

‐ Congestion analysis – which units had the most impact on binding constraints

‐ LMP decomposition by constraints

‐ Simple review of input data through the interface

• Excel based front end allowing direct use of Excel features

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PROBE Outputs• Excel based

Reporting

• Ability to compare different PROBE runs/reports

• Built-in plotting tools

• More than 80 output reports available

• Several advanced debugging reports and drill down analysis reports

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PROBE Outputs

• GIS based visualization to visualize output

• Latitude and longitude data would need to be defined in the case

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PowerGEM’s Experience using WECC ADS PCM with PROBE -

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Experience using WECC ADS PCM with PROBE

• Developed in-house conversion tool to convert WECC ADS PCM to PROBE format

‐ WECC ADS PCM case can be converted in less than an hour to PROBE format and used with PROBE

‐ DDVM maintained by WECC is very helpful

‐ WECC staff has been very helpful and responsive

• WECC ADS PCM is used for production cost simulations with PROBE by some WECC members

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Experience using WECC ADS PCM with PROBE• Minor updates which were required in WECC ADS PCM from our end

‐ Several Long lead units had very large min run time or min down time such as 168-hour min run time

‐ Contingencies

‐ Updated PAR settings based upon historical data• Some PARs can and are adjusted in the field

• Some PARs can be adjusted but are rarely adjusted in the field

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How can PowerGEM assist PMWG, PDWG, or other vendors with modeling & data efforts?

Ideas:

• Modeling Distributed energy resources (DER)‐ Linking to PSLF or PSS/E DG load component which is associated with

composite load model in WECC

• Assist WECC staff with error tracking of mapping of load forecast regions to load buses

• Developing a vendor neutral data format (if there is any interest)

• AC solution for round trip analysis using our AC solver to use the PCM case for further use in PSLF, PSS/E, PowerWorld, DSA Tools or PowerGEM TARA

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Summary

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Summary

• PROBE is a mature and high performance production cost simulation software which evolved from PowerGEM’s ISO experience

• Can be used for short term, mid term, and long term production cost simulations

• WECC members can easily load WECC ADS PCM into PROBE to run production cost simulations

• PowerGEM would like to be engaged in modeling activities similar to how vendors collaborate in MVWG

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Thanks

Questions or Comments

• Brian Thomas (bthomas@power-gem.com)

• Jim David (jdavid@power-gem.com)

• Boris Gisin (bgisin@power-gem.com)

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