Power Systems & Energy Course: Wind and Solar Grid Codes Jason MacDowell Wind Grid Codes - North American Experience © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 2/ US Grid Code Development In the US, relationships between transmission system operators (TSO), generators and users of energy are governed by multiple entities: • • • • • • • FERC (Federal Energy Regulatory Commission) NERC (North American Reliability Council) Regional Reliability Councils (e.g.:) - WECC (Western Energy Coordinating Council) - ERCOT (Electric Reliability Council of Texas) State Reliability Councils State Regulators Standards Organizations (ANSI/IEEE/NESC/NEC) A similar Federal/Provincial structure applies in Canada © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 3/ North American Grid Code Development In NA, rules are generally identified in terms of: • Reliability Standards • Interconnection Requirements • These interconnection requirements correspond approximately to European Grid Codes The objectives are: • To make sure generation and transmission is efficient and reliable, and • To regulate rights and responsibilities of generators, TSO’s and energy users Note: Interconnection Requirements for Wind Energy in the US are continuing to develop Regulating groups (FERC) and Reliability groups (NERC) are debating terms of current grid codes © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 4/ Grid Code Development Debate… • Should wind generation be treated differently? • What is the obligation of generation to provide voltage control? • How should generation respond to system disturbances? • How should generation prove it meets performance requirements? These questions are still being debated in the US today © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 5/ What consensus is emerging NA Grid Codes? • Reactive Power: +/- 0.95 pf @ POI • Voltage Control: required, with ISO voltage setpoints • Frequency Tolerance: +/- hz continuous • Voltage Tolerance (Low Voltage Ride-Through): ZVRT (FERC 661a), NERC PRC-024 • Models and Data: required cooperation • Telemetry and Metering: specific minima • Power Quality: IEEE 519 for Harmonics and Flicker • Frequency Control: debate just starting • Validation requirements: NERC MOD Standards • Plant Protection Coordination: NERC PRC-019 © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 6/ Wind Grid Codes - Development and Harmonization Discussion © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 7/ Grid Code Development – Utility and Operator Perspectives • Codes have significant impact on power system reliability, operations and control • Codes affect the level of wind power penetration in the power system • Codes affect the cost of operation and the final cost of energy (COE) to consumers • Individual Systems have particular requirements © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 8/ Grid Code Development – Manufacturer and Developer Perspectives • Codes affect the level of wind power penetration in the power system • Codes affect the cost of wind power equipment • Transmission operators need feedback to develop realistic codes based on current and physically realizable technology • Perceived system specific requirements may, in some circumstances, be primarily a function of past practice rather than true system needs © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 9/ Grid Code Development Tight More Expensive Equipment Reduced Efficiency Loose Compromised System Reliability Grid Code Functional Specifications Grid Codes should be no more specific than they need to be to avoid overdesigned equipment and reduced efficiency of wind generation, but should be specific enough for adequate system reliability © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 10 / Chapter 3: Performance During and After Disturbances Specific Recommendations Power Recovery  Standard recovery profiles can be counterproductive; the best profile is system-dependent  Detailed power recovery criteria is not necessary If studies show grid performance criteria are not met, TO can work with plant owner on a mitigation plan Standards for Manufactured Equipment  PV inverters designed to comply with IEEE 1547 not provide disturbance ride-through performance necessary to meet NERC’s grid reliability objectives  Utility-scale plants may have hundreds of small 1547-compliant inverters  NERC should develop new standards for utility-scale PV plants to drive the industry towards adoption of new inverter specifications, testing requirements, and certifications © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 42 / Table of Contents Executive Summary Introduction Reactive Power and Voltage Control Performance During and After Disturbances Active Power Control Capabilities Harmonics and Subsynchronous Interaction Models for Facility Interconnection Studies Communications Between Variable Generation Plants and Grid Operators Appendices Chapter 4: Active Power Control Capabilities Specific Recommendations  Require curtailment capability, but avoid requirement for excessively fast response  Require capability to limit rate of increase of power output  Encourage or mandate reduction of active power in response to high grid frequency (over-frequency governor function)  Consider requiring capability to provide increased active power in response to grid low frequency (under-frequency governor function)  Consider requiring inertial response in the near future © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 44 / Table of Contents Executive Summary Introduction Reactive Power and Voltage Control Performance During and After Disturbances Active Power Control Capabilities Harmonics and Subsynchronous Interaction Models for Facility Interconnection Studies Communications Between Variable Generation Plants and Grid Operators Appendices Chapter 5: Harmonics and Subsynchronous Interaction Although harmonics and SSR/SSI pose reliability risks in some locations, such situations are rare Problems can be avoided by prudent engineering practices Specific Recommendations Request design study reports that assess harmonic performance of all wind and solar plants Request design study reports that assess risk, and if necessary mitigation, for wind and solar plants located near series compensated lines © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 46 / Table of Contents Executive Summary Introduction Reactive Power and Voltage Control Performance During and After Disturbances Active Power Control Capabilities Harmonics and Subsynchronous Interaction Models for Facility Interconnection Studies Communications Between Variable Generation Plants and Grid Operators Appendices Chapter 6: Models for Facility Interconnection Studies Generator Interconnection Request FERC LGIP or other applicable procedure Interconnection Study NERC FAC-002-0, FERC LGIP or other applicable procedure GO provides initial collector system model to Transmission Owner Data can be preliminary Generator Owner signs Interconnection Agreement and facility is put in-service FERC LGIP or other applicable procedure GO provides dynamic model and final collector system model to Transmission Owner before System Impact Study starts Generator Owner provides Transmission Owner and Regional Reliability Org with “as built” data MOD-10-0, MOD-12-0 FAC-002 Generator Owner performs model & performance validation testing FERC Order 661-A FERC Order 661-A Transmission Owner develops Facility connection requirements and requests models and data from the Generator Owner at each process stage FAC-001-0 © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 48 / Chapter 6: Models for Facility Interconnection Studies Specific Recommendations  Preliminary model data may be used for the initial feasibility study of a variable generator interconnection project  The best model available should be used for the final System Impact Study or Facilities Study These models can be user-written and require non-disclosure agreements  The detailed dynamic model must be accurate over the frequency range of 0.1 to Hz Time constants in the model should not be less than ms  The detailed dynamics model must have been validated against a physical or type test  Verification of detailed model performance should be confirmed during commissioning to the extent possible The following tests shall be performed:  Primary/secondary voltage control  Low voltage and high voltage ride through  Power factor/reactive power capability  Power ramping and power curtailment © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 49 / Chapter 6: Models for Facility Interconnection Studies Specific Recommendations Verification of the non-propriety model accuracy may be performed by simulation tests compared with the detailed model performance At the end of the commissioning tests, the Generator Owner shall provide a verified detailed model and a non-proprietary model, ideally in IEEE, IEC or other approved format, for ongoing regional studies © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 50 / Table of Contents Executive Summary Introduction Reactive Power and Voltage Control Performance During and After Disturbances Active Power Control Capabilities Harmonics and Subsynchronous Interaction Models for Facility Interconnection Studies Communications Between Variable Generation Plants and Grid Operators Appendices Chapter 7: Communications between Variable Generators and Grid Operators Meteorological Data, Unit Status, etc Grid Operator Power Limit, Voltage Schedule, etc P, Q, V, Unit Status, Meteorological Data, etc Forecasted Power Output, etc Forecast Provider Variable Generation Plant (Wind or Solar) © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 52 / Chapter 7: Communications between Variable Generators and Grid Operators Specific Recommendations Variable generation plants should send a minimum set of monitoring data to the grid operation via the grid’s SCADA network Variable generation plants should receive and execute command signals (power limit, voltage schedule, ramp rate limit, etc.) sent from the grid operator via the SCADA network Variable generation plants should have trained on-call plant operators that can receive calls from the grid operator 24/7 and immediately execute verbal commands The plant operators would not need to be located at the plant provided they have secure remote control capability for the plant © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 53 / Chapter 7: Communications between Variable Generators and Grid Operators Monitoring Signals from Wind Plant to Grid Operator (Similar signals would be required for Solar Plants) • Active power (MW) • Average plant wind speed • Reactive power (MVAr) • Plant main breaker (binary status) • Voltage at POI • Plant in voltage regulation mode (binary status) • Number of turbines available (or total MW rating of available turbines) • Number of turbines running • Number of turbines not running due to low wind speed • Number of turbines not running due to high speed cutout • Maximum and minimum reactive power capability of plant • Plant in curtailment (binary status) • Plant up ramp rate limiter on (binary status) • Plant down ramp rate limiter on (binary status) • Plant frequency control function on (binary status) • Plant auto-restart blocked (on/off) • Total available wind power (equal to production unless curtailed) © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 54 / Chapter 7: Communications between Variable Generators and Grid Operators Control Signals from Grid Operator to Wind Plant (Again, similar concept for solar plants) • Plant breaker trip command • Engage up ramp rate limiter (on/off) • Engage down ramp rate limiter (on/off) • Engage frequency control function (on/off) • Block auto-restart (on/off) Forecast Provider Power Limit, Voltage Schedule, etc • Maximum power output limit (MW, for curtailment) Forecasted Power Output, etc P, Q, V, Unit Status, Meteorological Data, etc • Voltage order (kV, setpoint for wind plant voltage regulator) Meteorological Data, Unit Status, etc Grid Operator Variable Generation Plant (Wind or Solar) © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 55 / Chapter 7: Communications between Variable Generators and Grid Operators Data Required by Forecast Providers (Again, similar concepts for solar plants) Operating Conditions Meteorological Data • Wind plant status and future availability factor •Average (scalar) wind speed • Number or percentage of turbines online •Peak wind speed (several-second duration) over measurement interval •Average wind direction • Plant curtailment status •Air temperature • Average plant power or total energy produced for the specified time intervals •Air pressure • Average plant wind speed as measured by nacelle-mounted anemometers •Relative humidity or other atmospheric moisture parameter • Average plant wind direction as measured by nacelle-mounted wind vanes or by turbine yaw orientation © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 56 / [...]... -90 63 90 - 66 0 61 .5 > 66 0 60 .6 Low Frequency Time (Sec) Frequency (Hz) 0 – 0.35 55.5 0.35 - 2 56. 5 2 - 10 57 10 - 90 57.5 90 - 66 0 58.5 > 66 0 59.4 WECC High Frequency Low Frequency Time (Sec) Frequency (Hz) Time (Sec) Frequency (Hz) 0 – 30 61 .7 0 – 0.75 57 30 – 180 61 .6 7.5 - 30 57.3 >180 60 .6 7.5 - 30 57.8 30 - 180 58.4 >180 59.4 ERCOT High Frequency Time (Sec) Frequency (Hz) 0 - 30 61 .8 30 - 540 61 .6. .. study assumptions and system performance alternatives are stated in the report • Transmission Owners/Planners, Generator Owners, and Resource Planners shall provide steady-state and dynamic model data and structures that reflects the plant design © 20 16 General Electric International, Inc All rights reserved Not for distribution without permission 24 / Solar Codes and Standards © 20 16 General Electric... develop wind and solar generation equipment that provides the highest level of economy and reliability for grid operation • Codes and standards for transmission-connected PV solar are still under development and need further revision • GE is committed to participation in development of harmonized grid codes © 20 16 General Electric International, Inc All rights reserved Not for distribution without... certain distributed energy resources and impacts on base load/cycling generation  Reactive power control  LVRT and LFRT and coordination with the IEEE Standard 1547  Under-Frequency-Load-Shedding (UFLS) and Under-Voltage-LoadShedding (UVLS)  Task Force 1-7: Reconciling Existing LVRT and IEEE Requirements  Primary focus is IEEE Std 1547 and FERC Order 66 1-A © 20 16 General Electric International, Inc... / Solar Codes and Standards • Utility-scale PV is different from rooftops – Greater impact on the grid – Needs to be a good grid citizen” • PV plants can: – Mitigate their own voltage impact – Support the grid during disturbances • Current standards (IEEE-1547, UL-1741) can be impediments to implementation of best solutions – Inflexible prohibition of DG providing voltage regulation • Will new standards... 1.Introduction 2.Reactive Power and Voltage Control 3.Performance During and After Disturbances 4.Active Power Control Capabilities 5.Harmonics and Subsynchronous Interaction 6. Models for Facility Interconnection Studies 7.Communications Between Variable Generation Plants and Grid Operators Appendices Chapter 2: Reactive Power and Voltage Control  Standards Development  Existing standards developed with synchronous... Drafting Team (GVSDT) FERC now mandates that all new reliability standards address VER International — IEC TC88/WG27 on Wind Models — IEC TC8/SC8A on Wind performance, interconnection, design and forecasting — Ontario IESO Amended Market Rules for Generation Facilities — Alberta Interconnection Requirements for Wind Generation — Chinese State Power Grid Technical Code for Wind Interconnection — Vietnamese... 20 16 General Electric International, Inc All rights reserved Not for distribution without permission 26 / Solar Standards Issues Update: IEEE 1547a now allows a distributed generator to: • Regulate the feeder voltage if capable • Ride through grid disturbances if capable This is a PERMISSIVE requirement for voltage regulation and ridethrough It is not mandated that DG must do these things © 20 16 General... Frequency (Hz) 0 - 30 61 .8 30 - 540 61 .6 >540 60 .6 Low Frequency Time (Sec) Frequency (Hz) 0–2 57.5 2 - 30 58 30-540 58.4 >540 59.4 EASTERN INTERCONNECTION High Frequency Low Frequency Freq Freq Time (Sec) Time (Sec) (Hz) (Hz) 0 – 10(90.935-1.45713*f) 61 .8 0 – 10(1.7373*f-100.1 16) 57.8 10(90.935-1.45713*f) 10(1.7373*f-100.1 16) 60 .5 59.5 Continuous - Continuous © 20 16 General Electric International, Inc... correct these gaps? © 20 16 General Electric International, Inc All rights reserved Not for distribution without permission 28 / Summary • Grid code harmonization is in the interest of all the stakeholders, including GE • There are legitimate grounds for some special or nonstandard requirements, but these should be objectively evaluated • GE continues to invest and develop wind and solar generation equipment ... Time (Sec) Frequency (Hz) 0-5 66 -90 63 90 - 66 0 61 .5 > 66 0 60 .6 Low Frequency Time (Sec) Frequency (Hz) – 0.35 55.5 0.35 - 56. 5 - 10 57 10 - 90 57.5 90 - 66 0 58.5 > 66 0 59.4 WECC High Frequency... (Hz) – 30 61 .7 – 0.75 57 30 – 180 61 .6 7.5 - 30 57.3 >180 60 .6 7.5 - 30 57.8 30 - 180 58.4 >180 59.4 ERCOT High Frequency Time (Sec) Frequency (Hz) - 30 61 .8 30 - 540 61 .6 >540 60 .6 Low Frequency... to European Grid Codes The objectives are: • To make sure generation and transmission is efficient and reliable, and • To regulate rights and responsibilities of generators, TSO’s and energy users