Oscillatory Stability: Extended Range & Enhanced Source Location

Transcription

1 Oscillatory Stability: Extended Range & Enhanced Source Location Ricardo Lira, MSc III International Workshop on PMU in Rio December 2014

2 ALSTOM WAMS: Deployments Worldwide Presentation title - 12/12/2014 P 2

3 India URTDSM Unified Real-Time Dynamic State Measurement Win of World s Largest WAMS Project! Customer: Power Grid Corporation of India Limited, INDIA Scope: Two Packages covering all 5 Regions of India Phasor Data Concentrator for 34 Control Centers > 1000 Phasor Measurement Units for 351 Substations Presentation title - 12/12/2014 P 3

4 WAMS Addressing the New Grid Challanges Great Britain (GB) System Renewable Generation Strong growth of renewable generation capacity Mainly wind Some solar PV Installed wind >10GW Projected ~30GW by 2020 Demand 30-60GW Changing system dynamics Installed Capacity of Wind Power Presentation title - 12/12/2014 P 4

5 Uneven GB Distribution of Wind Power Large North-South power flow (except in low wind) Major constraint Scotland- England Inertia reducing, particularly in Scotland Wind power - no inertia Interconnectors no inertia Synchronous plant closed or constrained off Large Wind Resources Largest Load Interconnectors Presentation title - 12/12/2014 P 5

6 Only 4% wind in mix at random selection rising rapidly Presentation title - 12/12/2014 P 6

7 UK Government Issues: Growing Wind Power Presentation title - 12/12/2014 P 7

8 Lack of Observability in Remote Areas North Scotland Blackout A Warning Occurred in high-wind, low load, export (evening) Protection issue at new substation But why the cascade? No PMUs there to tell us! Presentation title - 12/12/2014 P 8

9 Enhancing System Transfer Capacity: New Issues GB System Enhancements Constrained boundary Sub-sea HVDC link HVDC Series Capacitors 5-45Hz Sub-Synchronous Resonance A new problem for GB Grid Limit changes from First- Swing Transient to Post- Fault Oscillations Presentation title - 12/12/2014 P 9

10 Two Related Innovation Projects Ofgem Network Innovation Competition Projects Monitoring VISOR: VISualisation Of Real-time Dynamics Increase Scotland-England boundary transfer Manage risks with series capacitor / HVDC additions Reduce oscillation & dynamics risks, understanding GB grid better Led by ScottishPower, partners National Grid, SHE Transm., Univ. of Manchester. Alstom contracted to deliver infrastructure, design, applications and services Control EFCC: Enhanced Frequency Control Capability Address low-inertia faster frequency response to disturbance Use non-conventional fast-response capability Reduce future cost of Frequency Response ( 60M 250M ~2021) Led by National Grid, partners Alstom, Flexitricity (demand side), Centrica (wind & CCGT), Belectric (storage & PV) Presentation title - 12/12/2014 P 10

11 VISOR: A Project With Clear Business Case The B6 (Cheviot) boundary between England and Scotland is now constrained for significant periods of time, and operational cost of this constraint is in excess of 100m per annum. The current investment programmes: Series compensation project Costs 160m, Releases 1100 MW due 2015 Western HVDC Costs 1000m, Releases 2250 MW due 2016 The following diagram demonstrated the significant boundary capacity shortage post the completion of those projects Presentation title - 12/12/2014 P 11 EN NIC VISOR-2013 B6 Scheme 11 Capital Cost B6 Increment m/mw m/50mw (VISOR Equiv) Series Compensation 160m MW m Western HVDC link 1000m MW m VISOR 8m > +50MW m Avoided Investment Cost

12 Selected Applications (VISOR) Presentation title - 12/12/2014 P 12

13 VISOR Target Areas Oscillations monitoring & source location Hz Governor/frequency control 0.1-4Hz Electromechanical 4-46Hz Sub-synchronous oscillation Disturbance, islanding, blackstart enhanced detection, presentation, risk assessment, reporting Angle-based constraint definition State Estimation Linear Hybrid Model Validation Dynamic models Transmission line parameters Infrastructure Presentation title - 12/12/2014 P 13

14 Full Oscillation Detection Concepts Benefits 4-46Hz: Sub-Synchronous Oscillations (SSO) from series capacitors, torsional modes, control interaction, etc. to identify precursors Hz: Manage governorfrequency control stability risk by oscillation detection & angle-based SSO Early warning Avoid network tripping Natural frequencies for model tuning and scenario selection Assess system tests of control tuning and control tuning effect Identify & correct plant malfunction or misconfiguration quickly Governor Control Hz Electromech & V. Control 0.1 4Hz Sub-Synch Osc 4 46Hz Detection & early warning Source Location for identifying contributions (unique Alstom) Geographic View presents participation and contributions Analysis information for scenario selection, problem location, modelling Presentation title - 12/12/2014 P 14

15 Sub-Synchronous Oscillation (SSO) Monitoring Sub-Synchronous Oscillations Series capacitors & inductance LC natural frequency. Interacting series caps, thermal gens, windfarms, HVDC weak/strong resonance Windfarms Thermal Generators Series Capacitors Novel Analysis & Early Warning 1. Measure LC natural frequency variability 2. Real-time detect weak resonance AVOID TRIPPING HVDC SSO Applications 200Hz streaming from integrated DFR/PMU/SSO Outstation captures 4-45Hz Frequency, amplitude, damping analysis DOES NOT REPLACE model studies and SSO protection; COMPLEMENTS by identifying pre-cursors for user info & alerts using network data. Presentation title - 12/12/2014 P 15 RA33x Acquisition Unit RPV311 Central Unit

16 SSO Monitoring Speed, Voltage, Addresses Monitoring needs complements protection Centralised approach required for interpretation Continuous oscillation analysis, proven for multi-mode frequency, amplitude, damping Extensive capability for Real-time early warning Off-line analysis of system behaviour Studies, reporting and analysis an integral part Presentation title - 12/12/2014 P 16

17 Sub-Synchronous Oscillation (SSO) SSO Outstation Integrated SSO, PMU, DFR, TWFL new PMU&SSO locations coincide (SPT) 64-channel with fibre-connect transducers for whole substation Integrated monitoring useful for ongoing SSO management process during- and post-visor RA33x Acquisition Unit RPV311 Central Unit SSO Application 200Hz Waveform data chosen from R&D and data trials Uses Async System feature infrastructure; not new start Simple SSO Outstation requirement Differentiate between LC and Torsional oscillation Approach successfully trialled on Torsional Oscillation data Multi-mode non-resonant information available Novel Analysis & Early Warning 1. Measure LC natural frequency variability 2. Real-time detect weak resonance AVOID TRIPPING Presentation title - 12/12/2014 P 17 Other SSResonance monitors focus on single mode, large amplitude resonant condition only not suitable for analysis info & early warning

18 Source Location Need for Reliable Source Location in Managing Oscillations Oscillation Identification long established Real-time control-room measures on known modes since 1998 (GB inter-area 0.5Hz) Monitoring reveals previously unseen behaviour and risks Oscillation behaviour can be complex Many plants, loads, controllers participating over wide area Issues not replicated in models e.g. interaction/resonance, plant malfunction, forcing Decisions on actions (real-time or planning) require information to identify sources Applicable to interconnection (is source in my area?) Largest amplitude is an unreliable indicator Assume incomplete observability (especially currents) New method yields Source Identification using Sparse Voltage Bus Measurements 0.26Hz 100MW (1 line) 30 mhz 12 minutes Presentation title - 12/12/2014 P 18

19 Oscillation Phase Relations for a Single Machine P and δ lag ω by about 90, determined by damping. E.g. damping ratio 20%, angle lags and power lag speed by Power (P) in phase with speed (ω) produces positive damping. Power out of phase with speed produces negative damping. Presentation title - 12/12/2014 P 19

20 2-Machine Example Equal Damping Contributions More Damping Contribution from Generator 1 More Damping Contribution from Generator 1 Lagging generator contributes more damping than leading generator Leading generator is source Presentation title - 12/12/2014 P 20

21 Identifying Sources of Oscillations Example Leading phase indicates less damping contribution. The source is the location with the lowest damping contribution (possibly negative). To find the source of an oscillation: 1. Divide into opposing groups. The group leading by less than 180 is the group containing the source. 2. Find the most leading location within the leading group Gen 1 Gen2 Gen3 Gen Gen 1 & 2 are the leading group. 330 Gen 2 leading within group Gen 2 is the Source Presentation title - 12/12/2014 P 21

22 Real System Case from ISO-NE Undamped 0.9 Hz oscillations after disturbance, 10 minutes PMU19 PMU30 PMU31 PMU34 Angle Oscillations Angle Oscillations (Degrees) (Degrees) Angle Oscillations (Degrees) Time (seconds) Amplitude and Phase differences in time domain signals. Group of PMUs 19,30,31 leads PMU 34 by less than 180 source group is PMUs 19, 30, 31 Within source group, phase PMU31 PMU30 PMU19. PMU31 is source Time from start of oscillations(seconds) Presentation 0 title - 12/12/ P liability and is subject to change without notice. Reproduction, Time use or disclosure from to third start parties, of without oscillations(seconds) express written authority, is strictly prohibited.

23 Most Leading Locations Within Group 1 Phase (Degrees) PMU19 PMU23 PMU30 PMU31 Within Group 1, PMU31 is leading small or negative damping near PMU31. If PMU31 was not available, PMU30 would be indicated, which is near PMU31, but much lower mode amplitude. Correct conclusion would be reached without PMU Time from start of oscillations(seconds) Correct Conclusion to Nearest PMU, even without Large Amplitude Presentation title - 12/12/2014 P 23

24 Application to Large Interconnection Largest Group Change Largest Contribution Change Group 2 Contributions Group 1 Contributions Group 1 Contribution Presentation title - 12/12/2014 P 24 Reference time Current / selected time Reference Current

25 Application to Large Interconnections Concern Are there significant oscillations in interconnection? Is my system involved? Can the oscillation be controlled within my area? What measures can I take? Operationally Planning & control design Solution Alarm on unusually large or poorly damped oscillations Check high level geographic interconnection source location view Compare contributions inside & outside system action if source(s) within system Identify specific source plant(s) in detailed measurements Change V/VAR dispatch, P dispatch if necessary. Inform plant. Improve PSS, SVC-POD control design at key plant(s). Confirm wide-area response after commissioning Presentation title - 12/12/2014 P 25 Approach can be applied to a large interconnection by sharing a high-level sparse set of voltage phasor measurements

26 Frequency, Damping, PHASE Application to PSS tuning Identify damping contribution with different PSS settings Network Switch PSS Enabled FLJ PSS Disabled SIG-PSS Switching Tests (opening) Presentation title - 12/12/2014 P 26 Mode Frq Damping SIG-FLJ Phase Change PSS OFF % PSS #1 ON % PSS #2 ON % that ALSTOM it is complete or All correct rights reserved. or will apply Information to any particular contained project. in this This document will depend is indicative on the technical only. No representation and commercial or circumstances. warranty is given It is or provided should be without relied on PSS liability #3 and is subject ONto change without notice. Reproduction, 0.33 use or disclosure to third 6.3% parties, without express written authority, is strictly prohibited. Group Contribution Improves SIG-PSS OFF, #2 FLJ SIG-PSS #1, #3

27 Conclusions Presentation title - 12/12/2014 P 27

28 Key Messages (1) Leading Projects GB: VISOR Project Co-ordinated GB Transmission Licensee Collaboration OFGEN founded (GB regulator) Targeting operational & analysis decision-making Extending technology boundaries Applicable to other interconnections US: PG&E DOE funds (general WAMS improvement) ALSTOM PhasorAnalytics Dynamic Transient Simulation (DTS) Presentation title - 12/12/2014 P 28

29 Key Messages (2) Dynamics Monitoring Ehnacements Full Range of Monitoring ALSTOM unique solution Use of phasors not enough to cover higher frequencies >5 Hz Requires the use of WMU (Waveform Measurement Unit) New function in Reason DFR/PMU device RA33x Acquisition Unit RPV311 Central Unit Oscillatory Source Location Enhancement to the monitoring Enabled infomormation for RT operations Uses only voltage phasors (easy to implement in competitive markets) Proven solution (US ISO-NE) Presentation title - 12/12/2014 P 29

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