Document C-29 Procedures for System Modeling: January 5 th, 2016 TFSS Revisions Clean Open Process Posting Prepared by the SS-37 Working Group on Base Case Development for the Task Force on System Studies. May 21, 2001 March, 2007 December, 2015
Table of Contents 1. Introduction... 1 2. Data Submission Requirements... 1 2.1. Load Serving Entity... 1 2.2. Generator Owner... 2 2.3. Transmission Owner... 2 3. System Modeling... 2 3.1. Power Flow Base Case Development... 3 3.1.1. Data Format... 3 3.1.2. Level of Detail... 3 3.1.3. Area Interchange... 4 3.1.4. Facility Ratings... 4 3.1.5. Modeling of Wind Farms... 5 3.1.6. Dispatch... 5 3.1.7. Load Modeling... 6 3.1.8. Tie Lines... 6 3.2. Dynamics Model Development... 6 4. Base Case Development Data Requirements 6 5. Data Requirements of Facility Owners.8 6. Data Requirements of Load-Serving Entities, Purchasers/Sellers/Marketers..9 7. Facility Ratings....... 9 APPENDIX.....12 i
1. Introduction NPCC, Inc. Document C-29 NPCC, through its SS-37 Working Group on Base Case Development, builds a series of power flow base cases and dynamics simulation models which are used by NPCC and its members for performing reliability and planning studies. Cases and models developed by SS-37 are shared and used in the creation of cases and models for the Eastern Interconnection. The ability of power flow base cases and dynamics simulation models to realistically simulate steady state and dynamic behavior of the transmission system relies on the use of complete, accurate, and timely data. This document provides an overview of the data reporting procedure associated with steady-state, dynamics, and short-circuit modeling data which includes, but is not limited to, system component characteristics, system configuration, customer demands, electric power transactions, short-circuit interrupting capabilities, and facility thermal ratings. Deleted: The following NERC Reliability Standards pertain directly to the steady-state and dynamic data requirements, reporting procedures, and model validation for use by the applicable Functional Entities: MOD-032-1, Data for Power System Modeling and Analysis Purpose: To establish consistent modeling data requirements and reporting procedures for development of planning horizon cases necessary to support analysis of the reliability of the interconnected transmission system. MOD-033-1, Steady-State and Dynamic System Model Validation Purpose: To establish consistent validation requirements to facilitate the collection of accurate data and building of planning models to analyze the reliability of the interconnected transmission system. 2. Data Submission Requirements 2.1. Load Serving Entity In coordination with its interconnected transmission owner (TO), the load-serving entity (LSE) shall provide coincident demand levels for each of the scenarios specified in Section 3. The LSE shall use the bus numbers assigned to it by the TO. Table 1 provides a summary of the data required to be submitted by the LSE. Table 1: Data to be submitted by the LSE Steady State Dynamics Aggregate real and reactive power demand at Load Composition and Characteristics the substation bus directly connected to the transmission system through one or more transformers Location of new expected loads Deleted: load serving entity Deleted: them Deleted: interconnecting transmission owner Deleted: or 1
2.2. Generator Owner In coordination with its interconnected TO, the generator owner (GO) shall provide the necessary data to model its generating facilities. The GO shall use bus numbers assigned to it by the TO. Table 2 provides a summary of the data required to be submitted by the GO. Deleted: generator owner Deleted: interconnecting transmission owner Table 2: Data to be submitted by the GO Steady State Dynamics Generator parameters Generator Generator step up (GSU) transformer data Excitation System (including limiters) Seasonal output capabilities Turbine Governor Station Service Load Power System Stabilizer Reactive Power Compensation Protection Relays Wind Collector System Station Service Load Composition and Characteristics (low voltage trip point) AC transmission line(s) interconnecting Generation facility to TO s high voltage network 2.3. Transmission Owner The TO is responsible for providing the necessary data to model the items listed in Table 3. Table 3: Data to be submitted by the TO Steady State Dynamics System Topology: Static VAR Systems Buses HVDC Facilities AC transmission lines FACTS Devices HVDC transmission facilities Protection Relays Transformers Reactive Power Compensation (including Static VAR Systems [SVS]) Initial Generator Output (to be submitted by the TO whose model area the unit is located within) 3. System Modeling The NPCC SS-37 Working Group on Base Case Development builds a library of power flow base cases and dynamics simulation models each year for internal use by NPCC, its members, and the NERC Designee for base case development. The NERC Designee establishes the individual power flow base cases (including load levels) and dynamics simulation models each year to be developed for the Eastern Interconnection. In addition to the cases and models developed of the Eastern Interconnection, the NPCC Task Force on System Studies (TFSS) identifies additional cases (including load levels) and models, if any, to be developed to meet the needs of the NPCC members and groups. Deleted: Deleted: ( Deleted: ) Deleted: in MOD Deleted: control 2
3.1. Power Flow Base Case Development NPCC, Inc. Document C-29 In preparation for the annual development of power flow base cases, the Planning Coordinators within NPCC (herein referred to as NPCC PC s) shall collect and disseminate updates to: System topology and facility ratings Data dictionary (full names) of the buses NPCC Inter-Area Master Tie Line (MTL) data spreadsheet and interchange schedules ERAG Inter-Regional Master Tie Line (MTL) data spreadsheet and interchange schedules 3.1.1. Data Format Power Flow base cases are developed using the Siemens PTI PSS/E program. Data submitted should be compatible with the PSS/E version currently specified by the NERC Designee. Both the Inter-Regional Master Tie Line data spreadsheet and NPCC Inter-Area Master Tie Line data spreadsheet should be submitted in the spreadsheet format determined by the NERC Designee. 3.1.2. Level of Detail The following data shall be collected by the NPCC PC: On at least an annual basis, each NPCC PC shall update the TFSS Major Projects List (MPL). The MPL includes major projects planned within each NPCC area over the next 5 years. A list of generators with executed generator interconnection agreements (GIA) and associated network upgrades. At a minimum, all generators with a nameplate rating greater than 20 MVA or a facility with an aggregated nameplate rating greater than 75 MVA must be modeled (except for those meeting the exclusion criteria as specified in the NERC BES definition). Bus, load, generation, and device profiles, which include: o Load forecast for each scenario at the bus level representing a 50/50 forecast coincident with the company peak; to be submitted by LSE o Corresponding generation limits and level for each scenario in the model list (Pmin, Pmax, Qmin, Qmax, Pgen). Generation limits/capabilities to be submitted by GO to NPCC PC. GO shall submit generator capabilities, Pmin and Pmax, and corresponding reactive output limits (Qmax/Qmin) for both Pmin and Pmax. Generation output to be submitted by Transmission Owners 3 Deleted: bi- Deleted: G Deleted: / Deleted: / Deleted: eneration Owner Deleted: enerator owner Deleted: ( Deleted: /Qmax) Deleted: that Comment [ 1]: Qmin & Qmax are needed for both Pmin & Pmax since light load or minimumload studies can rely on reactive power absorption. Deleted: to a point Deleted: in the reactive capability curve
o Settings on regulating equipment such as transformers, switched shunts, SVS, and HVDC data to be submitted by data owner Any corrections that need to be made to existing system modeling in the NPCC Base Case library. Data owners shall provide facility retirement updates. GOs and LSEs will coordinate with their interconnected TOs in order to ensure that data is consistent with the TO submitted topology. The data submitted must be sufficient to perform reliability and economic studies on the bulk electric system (BES) as defined by NERC. To that extent, relevant data associated with sub-100 kv facilities may also need to be provided. Short-circuit analysis is generally not required for interregional reliability studies. Therefore NPCC will not collect, maintain, or distribute short-circuit cases to its members or to NERC. Short-circuit studies are normally carried out on an Area or individual company basis. This procedure stipulates that facility owners must maintain short-circuit data and Areas and Companies shall maintain shortcircuit models. The data and models should be provided to members on request. The interchange of short-circuit data is currently required by NPCC procedures to permit modeling of neighboring systems. Request for this data should be made with the NPCC PC. Deleted: Deleted:, Deleted: data Deleted: Deleted: analysis Deleted: 3.1.3. Area Interchange Area interchange shall be set to model firm inter- and intra- NPCC transactions. Data needed to model transactions will include source and sink areas, transaction MW amount (whole number), and start/end dates. The reported transactions need to be confirmed by both transacting parties. The method to collect and distribute transaction level data will be accomplished through an Area Interchange spreadsheet. 3.1.4. Facility Ratings Facility owners are responsible for maintaining rating data for equipment and facilities. The ratings of all static equipment must be consistent with documentation available from equipment owners as required by the NERC Standard FAC-008-3 and in accordance with the procedures herein. The ratings included in each specific power flow case shall be appropriate to the case (summer, winter, etc.). The ratings of generation equipment must be consistent in all submissions from case to case. Only real and reactive power set points, voltage set points, and station service loads should change unless physical re-rating of the equipment is anticipated. Comment [ 2]: How does this work since generators often have different capabilities depending on the season (summer vs. winter)? 4
3.1.5. Modeling of Wind Farms NPCC,Inc.Document C-29 Data should be submitted to allow wind farms to be modeled as a single equivalent machine with at least the following: Point of Interconnection Transformer (Medium to High voltage) Equivalent generator step-up transformer (Low to Medium voltage) Collector System Equivalent (transmission lines representing the equivalent impedance of the collector system) Wind Turbine Generator modeled at the appropriate low voltage bus Any reactive power compensation required for the wind farm Appropriate Wind Machine Control Mode (WMOD) and wind Power Factor (WPF) Interconnection Transmission Line POI Transformer Collector System Equivalent GSU Equivalent High Voltage (i.e. 345 kv) Plant Reactive Support Mid Voltage (i.e. 34.5 kv) Figure 1: Single equivalent machine representation for wind farm Low Voltage (i.e. 690 V) Generator Reactive Support Modeling multiple equivalent machines for a single wind farm is acceptable when trying to model: Different turbine types/manufactures Geographic diversity Explicit ownership Different development phases Bus numbers for buses shown in Figure 1 should be coordinated with the interconnecting TO. 3.1.6. Dispatch Power flow cases provided by the Areas shall have seasonally expected dispatches appropriate for the specific case (e.g., summer, winter, etc.). The dispatch conditions will be the Areas best available forecast of expected 5
conditions. Units not dispatched must be modeled with a status of 0, or off-line, in the power flow case. 3.1.7. Load Modeling Power flow cases provided by the Areas shall have seasonally expected loads appropriate for the specific case (e.g., summer, winter, etc.). The load conditions will be the Areas best available forecast of expected conditions. Additionally, scalable load should be easily identifiable by being designated as YES if scalable and NO if not scalable. All generator station service load should be identified as not scalable and with a load ID corresponding to the generating unit(s) for which it applies. Also, manufacturing facility load which is consistent month-to-month throughout the year should be identified as not scalable. 3.1.8. Tie Lines The SS-37 Working Group will maintain a Master Tie Line workbook for its members ties with external (non-npcc) entities. The workbook format will be determined by the NERC Designee. A tie line will not be represented in a particular power flow base case unless both parties have agreed to include it. Tie lines between NPCC entities need to be coordinated between both parties. The bus name and bus number for each tie line connection point should be standard and unique within each area for all models. These connection points are where one party s facilities end and another party s facilities begin. 3.2. Dynamics Model Development The NERC Designee maintains a system dynamics database. NPCC will ensure that the database is updated annually such that the power flow cases and the dynamics data submitted to MMWG are compatible. The system modeling in the power flow cases is intended to be such that realistic events and conditions can be simulated using analytical software which NPCC has adopted as its current standard. While the data from these cases may be used by other software programs, no attempt is made by NPCC to ensure that the system modeling provided in these cases is such that commercially available software, other than its current standard, will realistically simulate system events. Deleted: BCD 4. Base Case Development Data Requirements 1) Ratings of static equipment must be consistent with documentation available from facility owners as required by NERC Reliability Standard FAC-008-3 and in accordance with the procedures herein. Ratings included in each case shall be appropriate to the case (summer, winter, etc.). Deleted: Planning 2) Power flow cases provided by Areas must have system loads and dispatches appropriate to the case (summer, winter, etc.) as defined in the MMWG Procedure 6
Manual. Load and dispatch conditions will be the Areas best available forecast of expected conditions. Areas on each side of a tie line will agree to transfers between those Areas on a case-by-case basis. 3) Each Area, for the purpose of preparing power flow cases for stability analysis, will provide appropriate files to facilitate conversion of loads and generators and the netting of generators with load, as required for transient stability studies. The files are to be based on the Areas best available data concerning load characteristics. 4) Ratings of generation equipment must be consistent in all submissions from case to case. Only real and reactive power set points, voltage set points, and station service loads should change unless physical re-rating of equipment is anticipated. 5) Modeling of generators, plants, and generator step-up transformers (GSU) must be consistent from case to case. This applies to unit ratings, GSU representation, Pmax, Pmin, and dynamics modeling. 6) Representation of Units and Plants Units at a particular bus may be lumped together and represented as one unit when they have the same electrical and control characteristics. Units that are lumped together should be rated less than 50 MVA each and units lumped together at any location should have a combined rating of not more than 300 MVA. Units or plants rated less than 20 MVA may be netted with loads. The netting or lumping of units and plants in excess of the guidelines above is acceptable only when such representations are deemed acceptable for system studies in the judgment of the Areas affected. 7) Generator step-up transformers should be represented explicitly as transformers. Correct impedance data derived from test data should be used for GSU impedance. Data for generator step-up transformers should include manufacturer nominal rating (MVA), per-unit impedance on the manufacturer s nominal rating base, all no-load taps and under-load tap changer (if equipped) taps, and the correct no-load tap appropriate to the case (summer, winter, etc.). Three-winding transformers shall be modeled using a three- winding model and not a collection of two-winding models. Deleted: a Comment [ 3]: How does this work since generators often have different capabilities depending on the season (summer vs. winter)? Comment [ 4]: How does this work since generators often have different capabilities depending on the season (summer vs. winter)? Comment [ 5]: Isn t Pmax, Pmin, redundant since previously wrote unit ratings? Deleted: and Deleted: effective Deleted: ratio 8) The representation of AC transmission lines and circuits (overhead and underground) should include nominal voltage, impedance, line charging, line shunt equipment, and ratings consistent with procedures and appropriate to the case. 9) Transformers shall be modeled in accordance with the application guide of the software program, adopted as NPCC s current standard, and be the best equipment data available. Three-winding transformers shall be modeled using a three-winding model and not a collection of two-winding models. Regulated bus and voltage set points shall be included for transformers with an under-load tap changer. Tap changer impedance tables should be included only where they are judged necessary for studies for which the base cases may be used. Deleted: where devices are operated in automatic mode 7
10) Units not dispatched must be modeled with a status of 0, or off-line, in the power flow model. 11) The modeling of tie lines should use a unique bus for modeling in order to separate the ratings and impedances submitted by one tie line owner to represent their portion of the tie line from the ratings and impedances submitted by the other tie line owner to represent their portion of the tie line. 12) Each year, for the purpose of base case development, each Area will submit power flow cases to NPCC in a standard format as agreed upon by the working group. One file shall be provided for each case under development. The provider of data will ensure that the representation of generators and generator bus names are consistent with the previous year s cases. Any changes from the previous year should be noted in a readme" file. 13) Each year, for the purpose of base case development, each Area will submit dynamics data to NPCC in a form as agreed upon by the working group. This data will include all appropriate files for dynamic simulation. Instructions should be also provided in the form of a readme file to guide the user in creating dynamics cases from these files and merging the data with that from other areas. Each Area will also provide dynamics data updates in a form that is compatible with the remaining cases in the set. 14) After SS-37 has merged the power flow and dynamics data into preliminary library cases, each Area will review the power flow cases for correctness and test the dynamics data by simulating limiting events within their systems. Comment [ 6]: This is good since then each facility owner will provide the ratings and impedances for their part of a circuit. No one will need to aggregate impedances or determine net ratings. Also, one facility owner will be able to update or correct their data without affecting any the data from any other owners of the circuit. Deleted: - Deleted: BCD 5. Data Requirements of Facility Owners Generation and Transmission Facility Owners must develop and maintain data for their facilities suitable for power flow and dynamics modeling and analysis as required by the NPCC Working Groups. Facilities owners must also develop and maintain short-circuit data. Facility owners must provide this data in a suitable format on request by the NPCC PC. Data provided by facility owners must comply with the MMWG Procedural Manual and the procedures herein. Some typical data required for power flow and dynamics modeling to conduct studies and analysis are described in the following sections. 5.1. Generation Facility Owners: a) Bus (substation and switching station): names, nominal voltage, and location. b) Generating Units (including synchronous condensers, pumped storage, etc.): location, minimum and maximum ratings (gross real and reactive power), regulated bus and voltage set point, maintenance requirements as appropriate to the analysis, station service and auxiliary loads, and dynamics data. 8
c) AC Transmission Line or Circuit (overhead and underground): nominal voltage, impedance, line charging, nominal and emergency ratings based on the most limiting element in the circuit, maintenance requirements as appropriate to the analysis, and metering locations. d) Transformer (voltage and phase-shifting): manufacturer rated capability (MVA), nominal voltages of windings, impedance on manufacturer rated capability base, all high-side and low-side taps (including voltage and/or phase angle tap step size), winding location of no-load taps, no-load tap setting appropriate to the case (summer, winter, etc.), winding location of under-load tap changer (if equipped) and regulated bus and voltage set point, normal and emergency ratings, and maintenance requirements as appropriate to the analysis. e) Detailed unit-specific dynamics data for generators, excitation systems, voltage regulators, turbine-governor systems, power system stabilizers, relays and protection equipment (out of step, over-speed, etc.), and other associated generation equipment. This includes complete and accurate IEEE-standard models (or non- IEEE-standard models available in the PSS/E version currently specified by the NERC Designee) of controls suitable for integration with the analytical software. In no case shall other than unit-specific data be used for generating units installed after 1990. f) Typical manufacturer s dynamics data, based on units of similar design and characteristics, may be used when unit-specific dynamics data cannot be obtained for generating units installed before 1990. g) Positive, negative, and zero sequence and mutual impedances. Deleted: ratio Deleted: ), 5.2 Transmission Facility Owners: a) Bus (substation and switching station): names, nominal voltage, and location. b) AC Transmission Line or Circuit (overhead and underground): nominal voltage, impedance, line charging, nominal and emergency ratings based on the most limiting element in the circuit, maintenance requirements as appropriate to the analysis, and metering locations. c) Transformer (voltage and phase-shifting): manufacturer rated capability (MVA), nominal voltages of windings, impedance on manufacturer rated capability base, all high-side and low-side taps (including voltage and/or phase angle tap step size), winding location of no-load taps, no-load tap setting appropriate to the case (summer, winter, etc.), winding location of under-load tap changer (if equipped) and regulated bus and voltage set point, normal and emergency ratings, and maintenance requirements as appropriate to the analysis. Deleted: ratio Deleted: ), d) Reactive Compensation (shunt and series capacitors and reactors, static var systems): nominal ratings, impedance, percent compensation, connection point, and controller device. 9
e) HVDC facility: nominal voltage, rated capability, and technology. These facilities shall not be modeled as a generator or a set of generators and must 10
be modeled using the HVDC models available in the PSS/E version currently specified by the NERC Designee. f) Detailed dynamics data for all other facilities of significance and pertinent to dynamic simulations such as static var systems, FACTS devices, phase angle regulators, synchronous motors, HVDC facilities, relays, loads, etc. Data must include complete and accurate control models suitable for integration. g) Models of protective relay characteristics on all major interfaces and available on request for all transmission facilities. Deleted: VAR compensators Deleted: P Deleted: A Deleted: R h) Positive, negative, and zero sequence and mutual impedances. 6. Data Requirements of Load-Serving Entities, Purchasers/Sellers/Marketers Load-serving entities shall provide actual and forecast real and reactive power loads and characteristics for their respective customers for steady state and dynamics system modeling in a timely manner. Deleted: demands Purchasers, sellers, marketers, and load-serving entities shall provide their existing and future contracted firm (non-recallable reserved) capacity transactions (including sources, sinks, amounts, duration, associated transmission, etc.) for steady-state and dynamics system modeling in a timely manner. 7. Facility Ratings NERC Reliability Standard, FAC-008-3, Facility Ratings Methodology, states the following: To ensure that Facility Ratings used in the reliable planning and operation of the Bulk Electric System (BES) are based on technically sound principles. A Facility Rating is essential for the determination of System Operating Limits. Compliance with the above standard is provided for by the following procedure: 1) Facility owners shall document the methodology for determining facility ratings, including delineation and justification of assumptions, standards, and practices used in establishing the ratings. The documentation must state the ratings and their basis applicable to each of the six base case model types (summer peak, winter peak, etc.) as defined in the MMWG Procedural Manual. This document must be maintained and provided to NPCC on request. 11
2) Facility owners shall provide facility ratings (applicable normal and emergency) for all facilities required for system modeling (as defined in this Procedure) to NPCC appropriate for base case development as requested in a timely fashion. The requirement to submit data to NERC is being fulfilled through the NPCC base case development effort. 3) The rating of a system facility (e.g., transmission line, transformer, etc.) shall not exceed the rating of the most limiting series element in the circuit or path of the facility, including terminal connections and associated equipment. 4) In cases where protection systems and control settings constitute a loading limit on a facility, this limit shall become the rating for that facility. 5) Ratings of jointly-owned facilities shall be coordinated and provided on a consistent basis. The ratings submitted shall be agreed to through the consensus of the facility owners. For transmission lines where one end is owned by one party and the other end is owned by a different party, a border bus should be used to separate the ratings (and impedances) given by one party from those given by the other party. 6) Facility ratings should be based on or adhere to applicable national electrical codes and electric industry rating practices consistent with good engineering practice. Comment [ 7]: This is good since then each facility owner is responsible for their ratings and noone will need to make any determinations of the ratings of the overall circuit. 12
Prepared by: The SS-37 Working Group on Base Case Development for the Task Force on System Studies References: 1. NPCC Reference Manual, Document A-5, Bulk Power System Protection Criteria 2. ERAG/MMWG Procedural Manual, Version 14, October 22, 2015 3. Applicable NERC Reliability Standards a. FAC-008-3, Facility Ratings b. MOD-032-1, Data for Power System Modeling and Analysis c. MOD-033-1, Steady-State and Dynamic System Model Validation 13
NPCC,Inc.Document C-29 APPENDIX TABLE 1 SCHEDULE & RESPONSIBILITIES Each year the SS-37 Working Group, as directed by the TFSS, will develop a library of base cases for use the following year. MMWG Base Cases will be derived from this set as judged appropriate. A written description of the cases and procedures used to derive the MMWG Bases Cases from the library of cases will be provided with the case library by SS-37. The schedule and responsibilities necessary to achieve this are as follows: Activity Responsibility Date/Deadline Annual Kick off Meeting SS 37 February Approve SS 37 Base Case Development Schedule and Responsibility TFSS March Establish interchange schedules and tie line data SS 37 May Provide power flow data, specify revisions to interchange schedules and tie line Area data to NPCC Coordinators May Submit tie lines and interchange data to MMWG by MMWG interchange sub. deadline NPCC Staff June Meeting to build power flow cases SS 37 June Submit power flow cases to MMWG by MMWG power flow submittal deadline NPCC Staff July Provide dynamic data to NPCC Area Coordinators July Meeting to finalize dynamic cases SS 37 July Submit dynamic cases to MMWG by MMWG dynamics submittal deadline NPCC Staff August Deleted: BCD Deleted: Base C Deleted: Powertech Deleted: Powertech 14