CIGRE Working Group (WG) C4.603: Analytical techniques and tools for power balancing assessments

Transcription

1 CIGRE Working Group (WG) C4.603: Analytical techniques and tools for power balancing assessments Main objective: Critical assessment of existing modelling methods and tools for analyzing power balancing issues in order to provide recommendations for future developments

2 WG C4.603: Analytical techniques and tools for power balancing assessments Scope of work Power balancing includes all power system control and operational aspects ranging from secondary (active) power control up to management of reserves and intra-hour power (balancing) markets. Relevant application areas for the analytical techniques and tools in question include the analysis of: Secondary and tertiary control (active power balance) Reserves management (how to assess the need for reserves) Benefits and challenges with larger control areas and multi-national balancing markets.

3 WG C4.603: Analytical techniques and tools for power balancing assessments Background / motivation Two main drivers are influencing operation of the transmission systems: Rapid development of wind power Opening to competition of regional electricity markets as part of larger power markets crossing national borders and interconnections. Creating new challenges in predicting power flows and managing imbalances and congestions in the transmission networks. increasing challenges related to balancing control and management of fast reserves. Few tools and analytical techniques readily available for the analysis of power balancing issues, ranging from secondary and tertiary generation control to the organisation of markets for balancing and reserves management. New methods and analysis tools are therefore needed to address the new challenges in transmission system operation.

4 WG C4.603: Analytical techniques and tools for power balancing assessments Main activities Overview of balancing control practices and balancing markets. This activity will serve as an introduction and a background for identifying the need for new analytical tools. Previous and ongoing work under study committees C1, C2, C5 and C6 may provide valuable input to this overview. Review existing analytical techniques and tools for the assessment and analysis of balancing control problems. Collection and description of relevant application examples. Identify and describe the need for new models and tools based on existing knowledge. Recommend areas for further research and development to gain new knowledge.

5 First meetings Minneapolis, July 25 (IEEE PES GM) Paris, August 25, (Cigre Session)

6 Balancing and reserves - overall aim : Balancing: Control and stabilise the power system subject to: variable and uncertain (renewable) power generation, matching a variable and uncertain demand, and managing outages/contingencies (N-1,..) Tools are needed to: Identify the requirement for reserves Quantify the need for control in terms of Power capacity (MW) Energy / duration (MWh) Response time Design and analyse the performance of the control systems Analyse the additional cost of balancing 6

7 Preliminary thoughts on how to identify and describe tools: How can we classify the different balancing problems that needs to be analysed? How can we classify the different tools? Can we summarise the findings of the WG in a table: Problems Tools and methods? And by this identify the need for further developments (new models and tools) 7

8 Tasks and time-scales in operation Degree of automation Increasingly market based - Primary frequency control - Inertia - Intra-day markets - Real-time balancing markets (tertiary contr - AGC (secondary control) -Long term markets and contracts -Day-ahead markets Main challenge due to increased variability (wind power in particular) sec. min. hour day week month/year 8

9 Tasks and time-scales in operation Degree of automation Increasingly market based - Primary frequency control - Inertia - Intra-day markets - Real-time balancing markets (tertiary contr - AGC (secondary control) -Long term markets and contracts -Day-ahead markets Main challenge due to increased variability (wind power in particular) sec. min. hour day week month/year Power system simulators? Market models, Unit committment,.. 9

10 Example: Analysis tool developed from power system simulators A method for analysis of primary and secondary control The fast dynamics in the power system is neglected The focus is the dynamics in the minute area Last (MW) Production Load + exchange Produksjon Last + utveksl :00 7:00 8:00 9:00 10:00 Time Tid (h) Stepwise Power Flow (SPF)

11 Control stages in power system operation Frequency [Hz] f Reserves activated [MW] R f Primary Secondary Tertiary 0.0 P 0 1 min. 15 min. 1 hour Time System frequency bias / response: B = P f [MW/Hz]

12 Frequency control in the Nordel power system 50.1 Frequency (Hz) :00 05:30 06:00 06:30 07:00 07:30 08:00 Time Primary control response Scheduled (according to day-ahead market) Frequency control (balancing) 12

13 Implementation of SPF model for the study of primary and secondary control behaviour P = P wind (t) - P load (t) P load (T), P gen (T) P load (T+1), P gen (T+1) Unit/load droops, δ i Frequency Bias, B(δ) Regulating power (RP) Sum of unit droops, δ ι Frequency bias, B [MW/Hz] Unit/load droops f = P / B(δ) P gen = f(δ, f) f < f lim => RP Power flow t = t+1 13

14 Load increase Regulating power activated at 30 min Frekvens (Hz) Tid (min) 14 Regulerstyrke (MW/Hz) Tid (min)

15 Example: Analysis tool developed from market models Input: - Plant description - Production costs - Transmission system - Demand, Ex-&Import curves - Hydro inflow, wind speeds Reserve requirements - Control area - Balancing area - Total area System imbalance - Demand forecast error - Wind forecast error Step: Day-ahead market - Day-ahead disptach - Water values - Area prices Reserve procurement - Resource redispatch - Water values - Area prices System balancing Output: - Total production cost - Optimal generation dispatch - Transmission dispatch - Reserve procurement cost - Availability of regulating reserves - System balancing cost - Regulating resource exchange EMPS or PSST IRiE Flow based Power-market Simulator IRiE Integrated Regulating power market in Europe 15

16 Thank you for your attention! If you want to contribute:

17 Wind power variations Characteristic of wind power variations: High amplitude low frequency variations Lower amplitude high frequency variations Uncertainty of wind power related to the variability Different solutions are needed to balance wind Day (100%) Hour (30%) Apt, J., The spectrum of power from wind turbines, Journal of Power Sources, 2007 Minute (7.5%) 17

18 Secondary/tertiary control Example on balance management January 8, 2005 a strong storm crossed over Denmark The wind farms of western Denmark at first produced close to rated power, but then started to cut out due to the excessive wind speed (+ 25 m/s) the wind production were reduced from about 2200 MW to 200 MW in a matter of 10 hours Data for DK1, west Denmark 2003 MW Central power plants 3,516 Decentralised CHP units 1,567 Decentralised wind turbines 2,374 Offshore wind farm Horns Rev A 160 NO1 +/-1000 MW DC DK1 AC DC DK2 670/630 MW SE Maximum load 3,780 Minimum load 1,246 Germany 800/1200 MW

19 MWh/h January 2005 Exchange DK1 -> NO1 Balancing power (NO1) Windpower DK Hour Source: NORDPOOL The case demonstrates that the existing real-time balancing market can handle large variations in (wind) generation and demand

20 Norwegian hydro as the European energy battery potential and challenges 20

21 An early stage senario for offshore Multiterminal HVDC System Control and stability of MTDC grids? Offshore load Grid 1 Primary and secondary control? Wind farm How to exchange balancing services? Grid 2

22 1. Introduction Report content (first outline) Motivation for the work Scope 2. Power balancing assessments Main definitions (what do we cover how do we define the different terms) Balancing control problems (Define and classify the different balancing problems that needs to be analysed) 3. Analytical techniques and tools Description of available tools and analytical techniques Overview and classification of the tools (e.g. in a table) 4. Recommendations Identify and describe the need for new models and tools based on the findings above (and summarised in the table) Recommend areas for further research and development to gain new knowledge 5. Conclusions and references 22