Grid Code Frequency Response Working Group Requirements for System - - PowerPoint PPT Presentation

Grid Code Frequency Response Working Group Requirements for System Inertia

Antony Johnson, System Technical Performance

Overview

Summary or Work to Date Pre / Post fault Wind Curtailment Manufacturer Engagement Further Work

Summary of Work Completed to Date

Additional Study work Spread Sheet Digsilent Power Factory BM Dashboard – Network Operations The effect of Inertia on the Transmission System Manufacturer Engagement Assessment of manufacturer capabilities Power Recovery Patents Further Work

Spread Sheet Results – Effect of Inertia – 1800 MW Loss 1

• The spread sheet calculation has been developed to demonstrate the effect of inertia:-
• Key Points

25 GW load 23.2GW of Coal 3.6 GW of Pumped Storage (Response) 50% Delivery of Pumped Storage – ie 1.8GW Generation Loss = 1.8GW Demand Reduction – 2%/Hz Zero Secondary Response Provided – Beyond Study Timescales

Spread Sheet Results – Effect of Inertia – 1800MW loss 2

8.9 49.45 1800 0.107168 12 8.9 49.42 1800 0.11524 11 8.8 49.37 1800 0.124625 10 8.7 49.33 1800 0.13567 9 8.7 49.28 1800 0.148875 8 8.5 49.22 1800 0.16492 7 8.3 49.14 1800 0.1848 6 8.1 49.05 1800 0.2102 5 7.85 48.94 1800 0.2437 4 7.6 48.8 1800 0.2898 3 7.1 48.62 1800 0.3575 2 6.6 48.37 1800 0.466 1 5.75 47.99 1800 0.67 Time to Min Frequency (s) Min Frequency (Hz) Loss (MW) ROCOF (Hz/s) H Equivalent (MWs/MVA)

A summary of the Requirement / Issue

Time (s) Time (s) Frequency (Hz) 49.2 Hz Power (MW) 12s 2s 0s

• 4s
• 4s

0s ~8s PNom PDeload PTemp (5-10% PNom) Additional power delivered by synchronous machines – area under the curve is the kinetic energy released by the rotating mass Primary response delivered by de-loaded machines Power output of decoupled Wind Generation – Ideally such plant should behave like that of a synchronous plant through a controlled action 1) Initial Rate of change of frequency limited by stored energy of the rotating mass (ie the size of the inertia) 2) Primary Response acts within 10 seconds and sustained for a further 20 to contain and start correcting frequency deviation Recovery in Kinetic Energy following restoration of System Frequency

Deadband

High Level Requirements (1)

Power (MW) PNom PIncrease (Max ~10% PNom) 0s 10s Time (s) Active power decay to be proportional to the rate of change of frequency PIncrease (MW) 0.003 df/dt (Hz/s) 0.1 PIncrease Max ~10 PNom ~200ms Time of Machine loss triggered by df/dt (Power injection determined by df/dt – Full power required in approximately 200ms from initiation of df/dt) Additional Power increase if available Mandatory requirement Recovery in Kinetic Energy permitted following injection of Active Power to the Network

High Level Requirements (2) – Detail of initial Short term Power Injection

Power (MW) PNom PIncrease (Max ~10% PNom) 0s Time (s) ~200ms Actual controlled power

• utput of Power Park

Module including delay time Profile Required – ie up to 10% of PNom to be delivered in 200ms

High Level Requirements (2)

Time (s) PIncrease (MW) 0.003 0.1 PIncrease Max 10 PNom 0.05 Power (MW) PNom PIncrease (~10% PNom) 0s 10s Time (s) Time of Machine loss triggered by df/dt (Power injection determined by df/dt) PNom 0s 10s Time of Machine loss triggered by df/dt (Power injection determined by df/dt) Power (MW) PIncrease (~5% PNom) df/dt (Hz/s) Active power decay to be proportional to the rate of change of frequency (df/dt) Active power decay to be proportional to the rate of change of frequency (df/dt) Additional Power increase if available Mandatory requirement

Power Injection Capability and Recovery

Courtesy of Enercon – Taken from Figures 6 and 7 of Reference [1]

Figure 6 - Power Control including Rotational Speed – Note black dotted lines with extrapolated additional values additional to original figure quoted by Enercon ~4.5s ~14s ~16.1s ~45% ~34.58% ~29.26% ~22s ~3.5s Figure 7 - Power Control excluding Rotational Speed – Note black dotted lines with extrapolated additional values additional to original figure quoted by Enercon ~14s ~20.35s ~47.9% ~39.2% ~20.7%

Power Injection Capability and Recovery

Courtesy of Vestas – Taken from Figure 8 of Reference [3]

Figure 8 - Wind Power with Inertia emulation – Note black dotted lines with extrapolated additional values additional to original figure quoted by Vestas 0s 0.7 ~ 0.81 ~3.6s ~6.1s ~0.67 ~13.75s

Power Injection Delivery

Courtesy of Vestas – Taken from Figure 3 of Reference [2]

Manufacturer Engagement

High level principles and concepts were issued to a wide range of manufacturers at the end of June 2010 Ongoing dialogue Early stages but issues include Power Recovery Recovery time Variations in wind speed Patents Impact of response on the Power System Further modelling work required

Study Results (1) – Spread Sheet Without Energy Recovery

Study Results (1) – Spread Sheet – H = 0 Without Energy Recovery

Study Results (2) – Spread Sheet – H = 0 With Energy Recovery

Study Results (2) – Spread Sheet With Energy Recovery

Study Results (3) – Spread Sheet With Energy Recovery

Study Results (3) – Spread Sheet – H = 0 With Energy Recovery

Frequency Control Capability

Frequency Trace, 26-May-2003

49.4 49.5 49.6 49.7 49.8 49.9 50 50.1 50.2 50.3 50.4 00:33:00 00:34:00 00:35:00 00:36:00 00:37:00 TIM E (GM T) FREQUENCY(Hz) 49.4 49.5 49.6 49.7 49.8 49.9 50 50.1 50.2 50.3 50.4 FREQUENCY (Hz) FREQUENCY TARGET FREQ

Primary Response 0 - 30 secs Secondary Response 30 secs - 30 mins

Example of a Secured Incident 26 May 2003 (1175 MW loss)

Further Work Required

• Finalise modelling to determine settings based on the minimum needs of the

Transmission System taking energy recovery into account

• Compare model results

Spread Sheet Digsilent Power Factory BM Dashboard

• Understand manufacturers Capabilities in more detail

Power Recovery, Recovery Time, Impact on the Transmission System Effect of Wind Speed

• Finalise Settings

Maximum value of PIncrease / Time duration Exponential decay requirements / Power recovery Deadband settings Active Power injection during lower rates of change of system frequency

• Legal drafting
• Timescales

References / Further Information

• [1] Contribution of Wind Energy Converters with Inertia Emulation to frequency control

and frequency stability in Power Systems – Stephan Wachtel and Alfred Beekmann – Enercon – Presented at the 8th International Workshop on Large Scale Integration of Wind Power into Power Systems as well as on Offshore Wind Farms, Bremen Germany, 14 – 15 October 2009.

• [2] Variable Speed Wind Turbines Capability for Temporary Over-Production – German

Claudio Tarnowski, Philip Carne Kjaer, Poul E Sorensen and Jacob Ostergaard

• [3] Study on Variable Speed Wind Turbine Capability for Frequency Response - German

Claudio Tarnowski, Philip Carne Kjaer, Poul E Sorensen and Jacob Ostergaard

• [4] GE Energy – WindINERTIATM Control fact sheet – Available on GE Website at :-

http://www.ge-energy.com/businesses/ge_wind_energy/en/downloads/GEA17210.pdf

• [5] Transmission Provider Technical Requirements for the Connection of Power Plants to

the Hydro-Quebec Transmission System – February 2006

• [6] Amendment Report SQSS Review Request GSR007 Review of Infeed Loss limits –

Prepared by the SQSS Review Group for Submission to the Authority – 10th September 2009 available at:- http://www.nationalgrid.com/NR/rdonlyres/EF5C0829-1C5E-4258-8F73-70DC62C43F49/36936/SQSS1320Reportv10_final.pdf