A PRACTICAL GUIDE TO PERFORMING WIDE-AREA COORDINATION ANALYSIS

Transcription

1 A PRACTICAL GUIDE TO PERFORMING WIDE-AREA COORDINATION ANALYSIS November 10, 2015 Author and Presenter: Bipasha Barman, P.E. POWER Engineers Other Authors: Jason Clack, P.E. POWER Engineers Vernon Padaca, P.E. POWER Engineers

2 Challenging.. 2

3 3

4 Presentation Overview Intro to Wide-Area Coordination Methodology Data Management Short-Circuit Model Evaluation Criteria Approach Selection Analysis Conclusions 4

5 Introduction to Wide-Area Coordination Definition: Wide-area coordination (WAC) analysis is the evaluation of protective device selectivity and sensitivity at a system level (multiple layers of adjacent terminals) with a goal of improving system reliability.

6 Background Reasons to Perform a WAC Study Increase System Reliability Responsive Action to Unexplained Outages Meet Regulatory Requirements 6

7 WAC Analysis vs. Protection Evaluation

8 Methodology (Part 1) 8

9 Methodology (Part 2) 9

10 Planning Stage Define Scope of Analysis System Boundaries Operating Conditions Protective Devices and Elements 10

11 Data Management More Data Required for WAC Analysis Establish File/Folder Structure Consider Using Revision Control Software Use for Living Documents 11

12 Short-Circuit Model Determine If System Model Exists Yes -> Is model complete and up-todate? Gain Familiarity with Software Package Automation Tools? Additional Data Required? 12

13 Short-Circuit Model Typical Data Needed Protective Device Settings CT and VT Ratios Single-Line & Three-Line Drawings System Boundary Source Equivalents Ratings & Impedances for Apparatus 13

14 Evaluation Criteria Document Serves as Starting Point for Evaluation Not Intended to Standardize Protection Sections to Include: Description of Study Boundaries Operating Configurations Contingencies Selected Approach Evaluation Criteria by Protection Type Critical Notes and Assumptions 14

15 Evaluation Criteria Document Define General Trip Times to Use as Rule of Thumb: 15

16 Evaluation Criteria Document Define Criteria in Terms of Ranges: Z1P MIN = 60% Z LINE Z1P MAX = 80% Z LINE Z1P PREF = 70% Z LINE 16

17 Considerations for Approach Selection Factors Driving Approach Selection: System Topology Schedule Constraint Variables: Operating Scenarios Protection Schemes Protective Elements 17

18 Approach Selection 18

19 Subset Boundaries Example Establish Criteria for Subset Boundaries 19

20 Operating Scenarios Develop Strategy with Focus on Selectivity Goal is to Define Maximum, Normal and Minimum Fault Levels Factors: Weak or Strong Source Seasonal Generation N-1 Contingencies 20

21 Protective Element Evaluation Sequence Develop Strategy with Focus on Selectivity Determine Sequence of Evaluating Protective Elements Primary Then Backup Elements Underreaching Then Overreaching 21

22 Coordination Analysis: Flowchart (Pt. 1) Focus on Selectivity 22

23 Coordination Analysis: Flowchart (Pt. 2) Focus on Selectivity 23

24 Ways to Gain Efficiency Automate Calculation Tools Streamline Short-Circuit Analysis Utilize Coordination Checking Tool 24

25 Automated Tool Develop Calculation Spreadsheet Input Data 25

26 Automated Tool Develop Calculation Spreadsheet Line Data Sequence Impedance Maximum Torque Angle 26

27 Automated Tool Calculate Results Fault Analysis Input Programmed Cells = Z1Line 1.2 = Apparent Z

28 Automated Tool Utilize to Calculate Final Setting Evaluate: Existing Preferred Recommended 28

29 Streamlining Short-Circuit Analysis Defining Points of Fault Placement Line Apparatus Fault Type Balanced Faults Unbalanced Faults 29

30 Automated Coordination Checking Tool Overcurrent/Distance Coordination Select Primary Relay Program its Backup Relay Group Select Type of Faults and their Placement Enter Desired CTI Check Coordination Against the Relays Serving as Backup Against the Relays that it Backs up 30

31 Automated Coordination Tool Reports Miscoordination Flags the Elements Margin of Violation Fault Type Improve Coordination Adjust Time Dial, Pickup and Curve Adjust Reaches, Timers Re-evaluate Coordination 31

32 Coordination Challenge Example - Looped System Time-Delayed Directional Overcurrent Ground Elements 32

33 Solution to Coordination Challenge Overcurrent Coordination Checking Tool Helped: Decide Close-in SLG Fault Placement Strategize Mitigation Set Pickups at 30% of the Smallest Ground Fault at the Remote Bus Choose Time Dials to Trip after 39 cycles

34 Conclusions WAC Analysis is Not Trivial. The Following Helps to Improve Project Outcome: Careful Upfront Planning Documenting Evaluation Criteria Keeping Files Organized Establishing a Systematic Approach Using Automated Tools

35 Questions Bipasha Barman, P.E. POWER Engineers (208)

36 Challenges Larger Scale Study Collecting and Managing Data More Upfront Planning Required to Be Efficient 37

37 Presentation Overview Intro to Wide-Area Coordination Methodology Data Management Short-Circuit Model Evaluation Criteria Approach Selection Analysis Conclusions 38