Operating High Variable, Renewable Generation Power Systems Lessons Learned from Ireland and Northern Ireland

Transcription

1 Operating High Variable, Renewable Generation Power Systems Lessons Learned from Ireland and Northern Ireland 16 th September 2015

2 Overview 2

3 EirGrid s Role EirGrid is the Transmission System Operator and Market Operator * Note: In Ireland ESB owns the transmission and distribution system 3

4 Power System of Ireland and Northern Ireland 9000 MW of conventional plant Relatively large units (several > 400 MW) 2800 MW of Windfarms Peak Demand of ~6800 MW Valley Demand ~2300 MW Total annual demand ~36 TWh DC HVDC Interconnection: 1000 MW NI & GB: Moyle (500 MW) IE & GB: EWIC (500 MW) 4

5 2020 RES-E Targets 5

6 Ireland Fuel Statistics Fuel Mix 2010 Other RES 1.1% NR Waste Wind 0% Hydro 9.7% 2.1% Imports 1.6% Coal 14.3% Peat 7.8% Oil 2.1% Other RES 1.8% Wind 16.3% Hydro 2.1% Fuel Mix 2013 Imports NR Waste 7.6% 0.2% Coal 17.2% Peat 8.8% Oil 0.7% Gas 61.3% Gas 45.4% Figures courtesy of Sustainable Energy Authority of Ireland 6

7 Changing Portfolio: Changing System Needs Changing Generation Mix Installed Capacity MW Wind Hydro Pumped Thermal CCGT OCGT Coal Unknown Year 7

8 Facilitation of Renewables 8

9 Key Finding 1: Frequency Control and Impact of ROCOF Relays The management of frequency following the loss of the largest unit will become progressively more difficult at high penetration of wind. In addition the use of ROCOF relays, currently employed on all distribution connected windfarms, further threatens frequency stability. 9

10 Key Finding 1: Frequency Control Mitigation Measures: Impact on Disabling RoCoF 10

11 Key Finding 2: Single Largest Contingency may change With large amounts of wind power, a transmission fault of 100ms has the potential to result in a MW reduction greater than that of the largest single in feed, potentially resulting in serious frequency events. Faults with wind reductions > 400MW Winter Maximum, 75% Wind - Post fault wind MW reductions 100% 90% percentage of faults causing power imbalance above 400 MW 80% 70% all cases with zero export (0X)!!! 60% 50% 40% 30% 20% 11% 10% 3% 0% 0% 0% 0% 0% SMIN 0% WMIN load level SMAX WMAX 69% 10% 6% 0% W25 W0 22% W75 W50 53% W100 wind level 11

12 Key Finding 3: Dynamic Stability Issues Moderate amounts of wind power increase dynamic stability, but at high levels of wind power penetration, dynamic stability deteriorates significantly 12

13 Key Finding 4: Voltage and Reactive Power Control The management of both steady state and dynamic reactive control becomes difficult with the addition of significant amounts of wind. Requirement for significant reactive support in base case Modelling showed over compensated system can lead to voltage collapse at high per unit voltages Dynamic Response from all generators necessary to manage stability issues 13

14 Normal Operating Period Frequency (Hz) Example of Incident Generator Trip Reserve Time (mins) Recovery Period 14

15 Frequency Response: Inertia 60,000 Inertia Duration Curves Inertia ,000 Synchronous Inertia (MW s) 40,000 30,000 20,000 10, % 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Percentage of hours in the year 15

16 Frequency Response: Inertia 60,000 Inertia Duration Curves Inertia ,000 Inertia 2020 Synchronous Inertia (MW s) 40,000 30,000 20,000 10,000 Insecure region 0 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Percentage of hours in the year 16

17 Reactive Power Synchronised 6,000 Reactive Power Duration Curves (Lagging) 2010 outturn 5, base case Reactive Power Capability (Mvar) 4,000 3,000 2,000 1, % 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Percentage of hours in the year 17

18 Reactive Power Synchronised 6,000 Reactive Power Duration Curves (Lagging) 2010 outturn 5, base case 2020 with wind contribution Reactive Power Capability (Mvar) 4,000 3,000 2,000 1, % 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Percentage of hours in the year 18

19 Facilitation of Renewables Fundamental issues Frequency Stability Loss of largest infeed RoCoF capability and protection Short term frequency variations Frequency Stability Temporary loss of wind power due to network faults Conventional Generator Reserve performance Fundamental issues that need further analysis Voltage Stability Voltage Control Issues that can be mitigated Fault Levels Transient Stability Network Loading Small Signal Stability Non-issues according to modelling Power balance fluctuations and frequency regulation Windfarms controllability and reactive power capability New operating procedures including embedded windfarms 19

20 DS3 Programme 20

21 Background Operations and DS3 Delivering a Secure Sustainable System 2011 Programme established Meeting the RES Policy Objectives efficiently while maintaining system security Detailed Technical Analysis All Island Grid Study Facilitation of Renewables Ensuring a Secure Sustainable System Holistically considering technical, commercial and regulatory needs of the system Engaging with all industry stakeholders 21

22 DS3 Shaping the System of the Future Grid Code Performance Monitoring Frequency Voltage DSM System Services Renewable Data ROCOF WSAT Control Centre Tools 22

23 Real-Time Operational Limits and Impact on RES-E Maximum Allowable Real Time Wind Level Wind Curtailment Levels 23

24 Challenges and Responses Facilitating up to 75% Renewables in real-time requires change Challenges System Stability Resource Variability Uncertainty New connections Changed power flows Infrastructure: Network and Interconnectors Operational:DS3 and Smart Grids 24

25 Constraints vs. Curtailment Constraint 1 % Individual Wind Curtailment Constraint 2 Curtailment Installed Wind 25

26 Effect of SNSP on Curtailment 25% 50% SNSP DS3 5% 75% SNSP Illustrative SNSP curves 26

27 IRE & NI: Dispatch Down by Hour of Day 27

28 Today: Enabling 50% in Real Time 1. Active and reactive control of windfarms 2. Best in class wind forecasting 3. On-line real-time dynamic assessment 4. Enforcement of standards on all generators 28

29 SNSP Early SNSP (%) /1/15 3/1/15 5/1/15 7/1/15 9/1/15 11/1/15 29

30 Wind Generation Early Wind Generation (MW) Wind Available Hourly Wind Actual Hourly 30

31 Example Exporting When Wind/Load > 50% 31

32 Tomorrow: Enabling 75% Additional System Services 2. RoCoF to 1 Hz/s over 500 ms 3. Revised Operational Policies 4. New Control Centre Tools 32

33 Driver for System Services RoCoF Low System Inertia Lack of Synchronising Torque Frequency Nadirs System Ramping Capability Voltage Dip Induced Frequency Dips Reactive Power Shortfall 33

34 Incentivising the Portfolio: Market Signals Incentivising performance of plant Financial Mix will move to higher capital lower variable cost technologies Obtaining the plant mix that matches the system requirements and achieves the policy objectives Ancillary Services Capacity Payments Energy Payments Today Ancillary Services / System Services Capacity Payments Fixed Costs Energy Payments Variable Costs Tomorrow 34

35 DS3 System Services Frequency Products Inertial Response Reserve Ramping SIR POR TOR1 RR FFR SOR TOR2 Ramping 0 5s 5 90s 90s 20min 20min 12hr time Synchronous Inertial Response Fast Frequency Response Fast Post Fault Active Power Recovery Ramping Margin 35

36 DS3 System Services Voltage Products Transient Voltage Response Voltage Regulation Network Dynamic Reactive Power Steady-state Reactive Power Network Adequacy Grid 25 ms s s min min hr Dynamic Reactive Power Steady state Reactive Power 36

37 RoCoF Move to New Standard Current standard: 0.5 Hz/s Proposed standard: 1.0 Hz/s measured over 500 ms Differing industry perspectives Wind farms no issues DSOs require LoM protection changes Conventional generators have concerns 37

38 RoCoF Implementation Project Generator Studies Project TSO DSO Implementation Project Alternative / Complementary Solutions Project Plan A Plan B 38

39 Realising Potential of DSO Generation Transmission 110kV TSO DSO Engagement Distribution 33kV 39

40 Voltage Control DSO implemented TSO-DSO agreed changes at Cauteen wind farm cluster Interim measure to improve voltage stability in the area Wider reactive compensation studies underway Value of DSO windfarms: significant off setting of transmission reactive compensation requirements 2025 Power Factor of TYPE B Wind Farms MVAr Required WP 0.95 Leading 145 WP 0.98 Leading 105 WP Unity Power Factor 55 WP Voltage control ±

41 Operational Policies Policy v1.0 Pilot Widespread Implementation v2.0 41

42 DS3: Operational Control Process 42

43 Control Centre Tools New Tools Existing Control Centre Tools 2011 Regulation, Ramping, Voltage Trajectory Tools Delivered WSAT, Short Circuit, Wind Dispatch, Synchrophasor Blue Sky Thinking

44 Ramping Example 44

45 Ramping Load Generation Ramping Requirement 45

46 Ramping Concept Demand / Wind (MW) Demand Wind Net Demand 0 00:00 06:00 12:00 18:00 00:00 Time of Day 46

47 Ramping Concept Demand / Wind (MW) Demand Wind Net Demand 0 00:00 06:00 12:00 18:00 00:00 Time of Day 47

48 Ramping Concept Demand / Wind (MW) Demand Wind Net Demand 0 00:00 06:00 12:00 18:00 00:00 Time of Day 48

49 Ramping Concept Demand / Wind (MW) Demand Wind Net Demand 0 00:00 06:00 12:00 18:00 00:00 Time of Day 49

50 Ramping Concept Net Demand (Dispatchable Generation) Uncertainty Net Demand :00 15:00 16:00 17:00 18:00 19:00 20:00 Time of Day 50

51 Ramping Concept Net Demand (Dispatchable Generation) Uncertainty Net Demand Ramping Duty :00 15:00 16:00 17:00 18:00 19:00 20:00 Time of Day 51

52 Ramping Concept Net Demand (Dispatchable Generation) Uncertainty Net Demand Ramping Duty :00 15:00 16:00 17:00 18:00 19:00 20:00 Time of Day 52

53 Ramping Concept Net Demand (Dispatchable Generation) Uncertainty Net Demand Ramping Requirement Uncertainty Ramping Duty :00 15:00 16:00 17:00 18:00 19:00 20:00 Time of Day 53

54 Ramping Margin (RM1, RM3 & RM8) 54

55 Summary 55

56 Complementary Progress Essential Industry System Services RoCoF 75% SNSP Operational Tools Operational Policies 56

57 DS3 Programme Summary Regularly operating at 50% SNSP and 65% wind/load RoCoF workstream progressing System Services underway but significant design and implementation issues need to be worked through Need to maximise contribution from embedded generation DSO/DNO input key Operational policy and tools need to be developed in parallel in a considered manner 57

58 Energy sector is going through a period of remarkable transition EirGrid s experience can be leveraged to benefit other power systems USA Europe 58

59 Sowing the Seeds of solution 59