ROSE - Real Time Analysis Tool for Enhanced Situational Awareness

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1 ROSE - Real Time Analysis Tool for Enhanced Situational Awareness Marianna Vaiman V&R Energy Copyright V&R Energy Systems Research, Inc. All rights reserved. WECC JSIS Salt Lake City, UT October 15 17,

3 What is ROSE? Region Of Stability Existence - ROSE defines the range of phasor measurements or other system parameters For which the system may securely operate in terms of the accepted N-k security criteria Addresses the problem of utilizing the PMU data to increase the situational awareness of the operators and improve stability and reliability of the electric grid For steady-state analysis: voltage stability, voltage constraint (voltage range and/or pre-to post contingency voltage drop) and thermal overloads may be simultaneously monitored, enforced and visualized on the boundary Hybrid approach Combines model-based (State Estimator data) and measurement-based (PMU data) computations Uses full power system model (no collapsing of buses)! Copyright V&R Energy Systems Research, Inc. All rights reserved. 3

Utilizing PMU Data to Make nearly Instantaneous System Operational Decisions ROSE uses PMU and State Estimator data for on-line calculation and visualization of the current operating point and its

4 Utilizing PMU Data to Make nearly Instantaneous System Operational Decisions ROSE uses PMU and State Estimator data for on-line calculation and visualization of the current operating point and its proximity to the stability boundary Additionally, SCADA data may be used to update the boundary Figure, see Relationship between the current operating point and the boundary defines health of power system network state: Each point on the boundary corresponds to a nose point on the P-V curve, or a thermal or voltage constraint being violated Copyright V&R Energy Systems Research, Inc. All rights reserved. 4

5 Current Use of PMU to Identify Steady- State Stability Limit ROSE provides the framework for utilizing PMU measurements in order to: Improve state estimation; Continuously monitor the electric grid: Identify system stability limits under normal and contingency conditions; Alarm the operator about the impending crisis before a new State Estimator (SE) case arrives; Invoke optimal remedial actions to prevent a blackout. Copyright V&R Energy Systems Research, Inc. All rights reserved. 5

An operator is alarmed if the operating point and the boundary are moving towards each other in terms of: Alarming the Operator MW/MVAr/MVA margin across the interface or load pockets Phase angle

6 An operator is alarmed if the operating point and the boundary are moving towards each other in terms of: Alarming the Operator MW/MVAr/MVA margin across the interface or load pockets Phase angle difference between two nodes (buses) For multiple PMU installations, ROSE identifies two most critical phase angles, and displays the current operating condition and the boundary on the plane of the most critical phase angles and other user-defined parameters Copyright V&R Energy Systems Research, Inc. All rights reserved. 6

7 Preventing System Collapse If the operating point and the boundary are moving towards each other, automatically identify (recommend to the operator) minimal optimal preventive actions before the new SE case arrives and before the system collapse Available optimal mitigation measures are MW, MVAR re-dispatch, ULTC settings, phase shifter settings, switching CAP banks, line switching, load curtailment Identifies two types of measures: Corrective measures for each contingency Preventive (global) measures for all contingencies Copyright V&R Energy Systems Research, Inc. All rights reserved. 7

region of stability existence and the maximum transfer capability for the specific interfaces ROSE at the limit

9 POM Suite/ROSE ver Boundary-based approach shown on the plane of two phase angles Determines the relationship between the region of stability existence and the maximum transfer capability for the specific interfaces ROSE at the limit value of stressing The operating point is on the boundary ROSE for the base case conditions Remedial actions are invoked at the limit value Copyright V&R Energy Systems Research, Inc. All rights reserved. 9

10 ROSE ver Tested with ISO NE on ISO s 12,000-bus SE snapshots under a CEATI project Combined SE and PMU data: For buses where PMUs were installed, measurements supplied by the devices are used: Fixed voltage angle and reactive power consumption ( AQ Load bus ) introduced in CEATI report and IEEE paper published in 2010 M. Y. Vaiman, M. M. Vaiman, S. Maslennikov, E. Litvinov, X. Luo, "Calculation and Visualization of Power System Stability Margin Based on PMU Measurements", SmartGridComm 2010, pp: 31-36, /SMARTGRID For all other buses, power flow equations are solved and approximate values of bus voltage magnitudes and angles are determined. The 2-D ROSE boundary was constructed by changing the values of two phase angles while other parameters were fixed: For different levels of stressing; Under contingency conditions; While simultaneously monitoring voltage, thermal and steady-state stability limits; Remedial actions were invoked; Displayed on the planes of phase angles and real powers. Copyright V&R Energy Systems Research, Inc. All rights reserved. 10

11 ROSE ver Results presented at the NASPI OITT Meeting on June 8 9, 2010 in Vancouver, Canada The ROSE boundary is shown on the plane of two phase angles The operating point moves in the direction in which the boundary shrinks The point lies on the boundary This is a limiting contingency It has the smallest margin Copyright V&R Energy Systems Research, Inc. All rights reserved. 11

12 The effect of remedial actions on increasing the boundary for the limit case Using remedial actions to increase the region beyond the limit case ROSE ver Copyright V&R Energy Systems Research, Inc. All rights reserved. 12

Same algorithms for off-line and real-time analysis Model-based & measurement-based State Estimator Integrated voltage and transient stability analyses Boundary-based solution Automatic analysis

13 Same algorithms for off-line and real-time analysis Model-based & measurement-based State Estimator Integrated voltage and transient stability analyses Boundary-based solution Automatic analysis of cascading outages Automatic remedial actions to mitigate steady-state & transient stability violations ROSE ver.2013 Copyright V&R Energy Systems Research, Inc. All rights reserved. 13

14 Requirements to Deploy ROSE Standard hardware and software Microsoft Windows Server 2003/2008, Windows 7.NET Framework IIS Standard input State Estimator data: Node-breaker or bus-branch PMU stream in C Customizable Detailed specification Contact person(s) Copyright V&R Energy Systems Research, Inc. All rights reserved. 14

15 Next Release ROSE Adding PMU-only analysis to supplement hybrid-based analysis: Used when SE case doesn t arrive or system quickly approaches the limit; Linear state estimation creating very fast a new emergency case. Includes voltage stability analysis, phase angle limit computation, etc. using measurement-based case. 2. Decreasing run-time: Distributed computations; Parallel computations. 3. Integrated analysis: Integrated steady-state, transient and small-signal stability: On a hybrid (measurement- and model-based) model. Both steady-state and transient stability limits are displayed on the ROSE boundary. Copyright V&R Energy Systems Research, Inc. All rights reserved. 15

16 Next Release ROSE Steady-state stability analysis: Conventional scenario-based analysis: Implemented in current ROSE version. Scenarios developed by ROSE in real-time: Based on the user-defined input of which interface/path flows to optimize; Non-scenario based analysis: Moving from a set of scenarios to global monitoring of system stressing: Determine the actual direction of system; Determine system limit in this direction. Advanced voltage stability: Determine and visualize areas affected by steady-state instability: After stressing; Post-contingency. What is between stable and unstable regions? How to increase stable region? Copyright V&R Energy Systems Research, Inc. All rights reserved. 16

17 Next Release ROSE Transient stability analysis: Automating the process of creating real-time dynamic models, if they are not available Constructing dynamic security region: Hybrid approach: The boundary is determined using the model; The current operating point is computed using PMU data. Monitored criteria - rotor angle deviation, transient voltage dip, damping, frequency. When one the monitored criteria is violated, automatic remedial actions for transient stability preservation are invoked. ROSE determines which PMU(s) is critical for each fault. Use of Prony method for analysis of PMU data: Prediction: Identify the onset of a wide-area event before it happens; Analysis of the event when it starts : determine that an event has already started Fast Fault Screening (FFS) methodology: To very quickly determine and rank the most severe faults in the system. Copyright V&R Energy Systems Research, Inc. All rights reserved. 17

18 Next Release ROSE Small-signal stability analysis: ROSE includes four approaches: Eigenvalue analysis; Galerkin approach; Modal analysis; PMU-based computations. PMU data is used for: The analysis of dynamic characteristics of the system and Detection of unhealthy changes in these characteristics, such as increase in the amplitude of oscillations, change in frequency, phase angles, voltage magnitude Separating local and inter-area oscillations Copyright V&R Energy Systems Research, Inc. All rights reserved. 18

WISP Project Copyright 1997-2013 V&R Energy

WECC-ROSE Real-Time Mode WECC-ROSE has three inputs: State Estimator data Node-breaker model PMU data in C37.

21 WECC-ROSE Real-Time Mode WECC-ROSE has three inputs: State Estimator data Node-breaker model PMU data in C RAS status points WECC-ROSE output includes: Tabular results which are archived Visualization Alarms SE-based alarms PMU-based alarms Architecture Copyright V&R Energy Systems Research, Inc. All rights reserved. 21

22 ROSE Implementation at WECC WECC-ROSE is used for steady-state stability analysis: Model-based analysis: Utilizes node-breaker based State Estimator (SE) case from EMS every 5 minutes; Full non-collapsed model; Runs multiple user-defined scenarios; Real-time RAS; Computations performed for each scenario are: Determining interface limits; Performing PV-curve analysis; Performing QV-curve analysis. An alarm is issued if the current system state in terms of interface flows is close to the limit Copyright V&R Energy Systems Research, Inc. All rights reserved. 22

23 ROSE Implementation at WECC (cont) WECC-ROSE is used for steady-state stability analysis Model-based and PMU-based (hybrid) analysis: PV-curve analysis is performed on the pre-contingency SE case on selected buses for each scenario Current operating point is determined using the PMU data for each scenario for selected buses Measurements for selected buses for each scenario are compared vs. computed values An alarm is issued if the current operating point is close to the limit values computed by WECC-ROSE Copyright V&R Energy Systems Research, Inc. All rights reserved. 23

24 User Perspective on WECC-ROSE Flexibility of WECC-ROSE tool: Ability to have very flexible scenario input files Gives WECC RC lots of flexibility to define different types of scenarios Adding RAS via flexible scripting Simplicity in use: Very complex software but easy to use, interpret the results and learn Speed: Very fast application Multiple levels of off-line analysis using POM capabilities: Fully integrated into the POM Suite Detailed analysis, automatic remedial actions, boundary-based solution, prediction of cascading outages for off-line studies Copyright V&R Energy Systems Research, Inc. All rights reserved. 24

User Interface in Real-Time Scenario summary and alarming Results of model-based computations

26 Work since Last JSIS Meeting Testing of control devices Preparing to roll out ROSE Off-Line version: Site license for POM, OPM, BOR and PCM applications at both RC locations Extensive IT-related work Copyright V&R Energy Systems Research, Inc. All rights reserved. 26

ROSE Integration at ISO NE Copyright 1997-2013 V&R

29 ROSE Analysis at ISO NE Both 1-D or 2-D ROSE boundaries are computed; Each point on the boundary corresponds to thermal overload, voltage violation, or voltage collapse ROSE uses a hybrid approach: The boundary is updated every 3 min using State Estimator data; Current operating point is updated every second using PMU data. Multiple Stressing scenarios are analyzed Remedial actions are determined in real-time: Including remedial actions for unstable post-contingency conditions; Input data design provide flexibility and minimizes data maintenance Trending of results in Real Time and Historical Trend Visualization on the plane of interface flows (MW) and phase angles (degrees) Copyright V&R Energy Systems Research, Inc. All rights reserved. 29

ROSE Client at ISO NE Copyright 1997-2013 V&R

32 Work since Last JSIS Meeting Parallel and distributed computations: Ability to run more scenarios within a 3-min interval. Especially important when running with remedial actions. Near future work: Compute alternative sets of remedial actions for the same post-contingency violation. Determining PMUs that accurately represent system stress. Copyright V&R Energy Systems Research, Inc. All rights reserved. 32

33 Acknowledgement Saad Malik and Sergio Rodriguez, WECC RC, and Slava Maslennikov, ISO NE For contributing to this presentation, providing prints screens and diagrams Copyright V&R Energy Systems Research, Inc. All rights reserved. 33

34 Conclusion ROSE increases situational awareness of the operators by: Allowing them to accurately and timely predict steady-state instability, and Compute system stability margins in real-time environment by using phasor quantities collected by PMUs Alarms before a new State Estimator case arrives Automatically identifies optimal mitigation measures for the use by the operators in order to prevent collapse PMU-based only analysis was added ROSE demonstration at the next JSIS meeting? Copyright V&R Energy Systems Research, Inc. All rights reserved. 34

Linear State Estimation

Linear State Estimation Marianna Vaiman, V&R Energy marvaiman@vrenergy.com WECC JSIS Meeting Salt Lake City, UT October 15 17, 2013 Copyright 1997-2013 V&R Energy Systems Research, Inc. All rights reserved.