Automated Transmission Line Impedance Calculation Project

Transcription

1 Automated Transmission Line Impedance Calculation Project Paul Myrda Technical Executive Project Information Webcast March 2015

2 Background Can we use LIDAR / GIS data to improve or automate the transmission line impedance calculation process? 2

3 First Step Data Needed Span lengths Tower geometry Conductor positions Conductor properties Conductor Attachments. more Data Available in LIDAR Yes Yes Yes No But we can get it elsewhere Yes Yes Data is in LIDAR but more useful data is actually in GIS 3

4 Provided Data in XML Conductor Attributes Type and span length. No bundle information. Transmission Line Discontinuities Build type and span length Unique ID numbers are given for all the data provided Operating Voltages Tower Characteristics Height Base elevation Sample XML Data structure_list_report rownum="11"> <rowtext/> <struct_number> </struct_number> <station units="ft">693.81</station> <line_angle units="deg">5.89</line_angle> <ahead_span units="ft">977.12</ahead_span> <height_adjust units="ft">0.00</height_adjust> <offset_adjust units="ft">0.00</offset_adjust> <orient_angle units="deg">180.00</orient_angle> </structure_list_report> 4

5 Potential Data Gaps Conductor Clearance Tower height is provided but not the height (ground clearance) of the actual conductor, we need tower drawings to determine points of attachment. Designed / survey route center line clearance data may be needed. Transmission Line Discontinuities Need to know where line segments are joined, originate, and terminate Transpositions Conductor Geometry, Arrangement, and Attachment Physical conductor specs are provided, however we still need Data is actually in GIS information relating to conductor attachment points, arrangement and geometry, specifically how the phases are arranged geometrically, and if they consist of one or multiple wires (if multiple need bundle bracket dimensions). 5

6 Sample Tower Configuration struct_number set_no phase_no set_label wire_attach_point_x units4 wire_attach_point_z units SW ft ft SW ft ft TW ft ft TW ft ft Outlier 6

7 Calculating Sequence Impedances of Overhead Lines Support Provided by Sean McGuinness GOP

8 Typical Single Circuit Tower Geometry LIDAR GIS measurements: Phase and shield wire conductor relative position Conductor position both at tower and along span X1, B1 important for load flow X1, X0 important for short circuit 8

9 Positive Sequence Impedance ln Message: Phase conductor spacing increases X 1 Phase conductor spacing decreases C 1 Phase conductor spacing unlikely to vary in service 9

10 Zero Sequence Impedance j 3ln Message: Phase conductor spacing decreases X 0 Phase conductor spacing unlikely to vary in service 10

11 Summary GIS measurements provide conductor positions along entire route Can help improve calculation of X1, X0, B1, B0 X1, B1 important for load flow X1, X0 important for short circuit Most helpful measurements: Phase conductor spacing Distance between phase conductor and shield wire The longer the line, the bigger the impact of impedance errors on the overall network simulation result 11

12 Conclusion Can we use GIS data to improve or automate the transmission line impedance calculation process? 12

13 Automated Transmission Line Impedance Calculation Benefits Improve network model impedance process and accuracy Reduce manpower required to calculate and maintain network models Simplify overall impedance model creation through data reuse Phase I Complex Line Impedance Calculation Process based on a complex transmission line which has multiple mutually coupled lines and other complexities. Phase II Improved Line Impedance Calculation Process includes terrain variations, conductor sag and other parameters that may affect the actual line impedance and the accuracy of the actual impedance value. Price of Project The cost of the project is $100K and it qualifies for tailored collaboration or self-directed funding. A minimum of 5 participants are needed. Target participation is 8. 13

14 Together Shaping the Future of Electricity 14