TOWER DESIGN PROCEDURE TOWER DESIGN BASIS .pptx

TOWER DESIGN BASIS

1. 400KV DOUBLE CIRCUIT CHALINZE – MKURANGA VIA KINYEREZI TRANSMISSION LINE TOWER DESIGN METHODOLOGY AND PHILOSOPHY 30/MAY/2024

2. INTRODUCTION The works covered by these technical specifications and the Employer’s requirements form part of the 400kV Chalinze – Mkuranga Via Kinyerezi transmission line project. The project consists construction of 136 km long, 400 kV double circuit triple bundle AAAC SORBUS conductor transmission line (400kV transmission line using 3 SORBUS conductor per phase (AAAC – 61/3.71 wires)), using one (1) OPGW with capacity for 48 optical fibers and one (1) Overhead Ground Wire (ACSR - 95/55 with Inner Core Aluminium Clad Steel) strung on lattice steel towers from New 400kV Chalinze substation to New Mkuranga substation via Kinyerezi substation in Dar es Salaam City. The project consists of engineering design, procurement, manufacturing, inspection, site delivery & storage, construction & erection, start-up field tests, system testing, and work related for the commissioning of the 400 kV transmission line, including all temporary works.

3. GIST Over View Tower Nomenclature Tower Components Tower Anatomy Employer’s Requirements Design Concepts Tower Loading Standards For Loading Analysis & Design_PLS Tower

4. Towers constitute vital component of a very as they perform the important transmission lines function of supporting the power conductors and overhead ground wires at the required distances above the ground level maintaining the appropriate inter- conductor spacing within permissible limits under all operating conditions. Transmission line towers are used to transmit electricity from power generation station to utilities /Sub- stations. Over View

5. Tower Nomenclature Sr. No. TOWER DESIGNATIONS DEVIATION 1 NS (Normal Suspension) t ower 0- 2 2 LA (Light Angle) t ower – At angle points / Used as a Section Tower 0- 15 3 MA ( Medium Angle ) Tower - At angle points / used as a Transposition 15°- 30° 4 HA (Heavy Angle) 30 °- 7 0° 5 DE (Dead End/ Terminal Tower) °- 9 0° 6 TP (Transposition) Tower 0°- 2

6. Tower Components

7. Tower Anatomy

8. Design Requirements (Employer Requirements) Voltage Requirements/System System highest voltage for equipment /power frequency - (420 / 50 kV/Hz ) . Nominal voltage (400 kV). Conductors . Phase conductor ( AAC-SORBUS) Earth wire ( ACSR 95/55) OPGW ( similar to AL/ACS 95/55) Design Wind Speed 39m/s (3s gust) Design Temperatures Maximum ambient temperature (+40 °C) Conductor temperature (+10 - +80 °C) Everyday temperature (+27 °C) Line Data Number of circuits (2) Number of conductors per phase (3) Number of OPGW (1) Number of OHGW (1) Total approximate length of lines (136 km) Minimum Partial factors for load actions For permanent actions (1.2) For variable actions (1.3) For construction and maintenance loads (1.5) Minimum Partial factors for material strength. Structural steel sections, plates, etc. for towers (1.25) Bolts (1.25) Concrete (1.5)

9. Design Requirements (Employer Requirements) cont’d Maximum slenderness Ratios (L/r) to EN50341-1-J Main leg, stub, and main compression members in cross-arm (120). All other members having computed stresses (200). Redundant members without computed stresses (250). Tension members only (300). Minimum thickness (t) and size of steel members of towers. Main leg, stub, and main compression members in cross-arm ( ≥ 6mm). All other members having computed stresses ( ≥ 5mm). Redundant members without computed stresses ( ≥ 5mm). Gusset plates ( ≥ 6mm). Minimum angle bars: equal angle sections (L45x45xt). Minimum Partial factors for load actions For permanent actions (1.2) For variable actions(1.3) For construction and maintenance loads(1.5) Insulators. Insulator Type for Suspension string Cap and Pin. IEC designation (U210BS, IEC 60305). Insulator Type for Tension string Cap and Pin IEC designation (U210B, IEC 60305).

10. Sag Tension Configuration Clearances Design Concepts Sag – Tension Calculation Fixing configuration by providing minimum required clearances Loading Calculation. Loading Combination. Analysis & Design Detailing Prototype testing of towers

11. Tower Configuration Clearances considered while design of Tower Ground Clearance Live Metal Clearance Mid Span Clearance Shielding Angle Clearances. Minimum clearance between phase conductors D pp (4.2 m) Minimum clearance to earthed parts D el (3.3m) Minimum Vertical Clearances Normal ground (10.00m) Roads and streets (12.00m) Rivers (no ships) (11.00m) Minimum Horizontal Clearance. Highway and Main roads (30m) Energy Pipeline (30m)

12. Towers are analyzed for loads applied in all three directions namely Transverse ( FX ), Vertical ( FY) and Longitudinal (FZ) direction of the line. Transverse loads consists of – ( Loads acting perpendicular to TL LINE ) Wind on Conductor Wind on Insulator Component of Wire Tension in Transverse Direction (Deviation Load) Wind on Tower Body Vertical Load consists of – Weight of Wire Weight of Insulator Weight of Line man & Tools Self Weight of Tower Longitudinal Load Consist of – ( Loads acting parallel to TL LINE ) Component of Unbalanced pull of the wire in the longitudinal direction. Loading Calculations:

13. Type of loading conditions Reliability Condition Maximum design load experience by the tower Security condition Accidental loading due to broken wire condition Safety Condition. Erection and Maintenance loading condition Loading Calculations:

14. Reliability Condition Transverse Load : Wind Load on Conductor/Earthwire Wind Load on Insulator Mechanical Tension of Conductor/Earth wire due to deviation Wind Load on Tower Body Loading Calculations:

15. Vertical Load : Self weight of Structure. Weight of Conductor and Earth wire Weight of Insulators and other Accessories Ice load in case ice effect. Longitudinal Load : Wind load on Structure in case of Oblique wind condition. Wind load on Insulator in case of Oblique wind for Suspension towers. Mechanical tensions in Longitudinal directions in case of Dead End Terminal Towers. Loading Calculations: Reliability Condition

16. Security Condition Loading Calculations: Transverse Load : Wind Load on Conductor/Earth wire Wind Load on Insulator Mechanical Tension of Conductor/Earth wire due to deviation(intact condition) Wind Load on Tower Body

17. Vertical Load : Self weight of Structure. Weight of Conductor and Earth wire Weight of Insulators and other Accessories Ice load in case ice effect. Longitudinal Load : Wind load on Structure in case of Oblique wind condition. Wind load on Insulator in case of Oblique wind for Suspension towers. Mechanical tensions due to failure in Longitudinal directions. Loading Calculations: Security Condition

18. Loading Calculations: Safety Condition Transverse Load : Mechanical Tension of Conductor/Earth wire due to deviation Vertical Load : Self weight of Structure. Weight of Conductor and Earth wire Weight of Insulators and other Accessories Weight of Line man with tools Additional loads due stay wires uses during stringing time. Longitudinal Load : Mechanical tensions due to stay wires uses in stringing time.

19. Standards for Load Calculation Loads are calculated as per the guide lines furnished in specification/standard Standards for Calculation of Loads EN 50341 ASCE -10 IEC – 826 The loads are calculated for following Conditions Reliability / Working condition Security / Broken wire condition Safety / Erection & maintenance Condition

20. ANALYSIS & DESIGN_PLS TOWER

21. MODELING IN PLS TOW ER G ENERAL DATA PR I M ARY JOINTS s e c o n d a r y JOINTS ADD G R O UPS MEMBER ADDIT I O N G R UPI N G MEMBERS BRIEF & FLOW CHAT Tower is idealized as 3- D space structure and analysis is carried out by finite element software PLS Tower The critical compression and tension in each member group is found out Required FOS is provided in input file to find out ultimate force Members and Connections are designed for these forces Several iterations are carried to find out the optimum weight of tower The design out put is indicated in a drawin g called Basic Tower Configuration & Electrical Clearance Diagram

22. G ENERA L DATA G ENERAL DATA DESIGN CHECK DESIGN CHECK OPTIONS Note: All the details in the general data need to be filled in accordance to the project requirements

23. PRIMARY JOINTS AND SECONDARY JOINTS A tower model is built by inserting angle or round members between joints and connecting other components to existing joints. There are key joints which must be located by their coordinates (Primary joints), other joints that are located by straight line interpolation or extrapolation between key joints (Secondary joints).

24. PRIMARY JOINTS AND SECONDARY JOINTS Create a joint label Add the symmetry of the joint Enter the co ordinates of the joint , mentioning in X,Y,Z in a c c o r d a n c e t o t h e PLs c o - ordinate system Enter the displacement restraint and rotation restraint if applicable or else it can be declared Free PRIMARY JOINTS After the primary joint is created , a secondary joint can be Added between 2 Primary joints A secondary joint can also be added by providing ratio of member length at which it should be added after the members have been created SECONDARY JOINTS

25. GROUPING In the grouping table , We have to add the Group labels and the group description according to the requirement in modeling . These should be such that it could define the members assigned to the respective group Then we have to provide the Angle type and size for the respective group Assign the Element type and also the group type Using the Geometry / Groups , we can Find the information of any group , Find the members of respective group Modify any group type Modify any element type Rename any group Delete any unused groups

26. MEMBER ADD In the member table , We have to add the member labels and the group label according to the groups defined for each member type . The member symmetry needs to be entered. The origin joint and the end joint between which the member needs to be added has to be entered . The eccentricity code , Restraint code and rati os of RLX , RLY and RLZ needs to be entered according to the requirement Bolt type i.e. diameter of bolt used needs to be entered according to the technic al specific ations . No. of bolts and no. of she ar planes needs to be added in accordance to the member angle and design requirement .

27. LOAD FILE Loads can be inputted in two ways Vector loads(LCA file) : In this the LCA file is created and each individual c a s e l o a d s i s i n p ut t e d o n e b y o n e . Batch import : In this the loads of all the cases are given all at a time in point loads column . In this the load cases and loads with joint label will be given as an input . Loading tree report : A report is generated with all the loads imported . R e m o v e L C A / L I C / EIA fi le r e f e r e n ce s : Thi s i s u s e d t o r e m o v e a l l t h e references , so that we can freshly import any loading without any stance of previous loading left .

28. DESIGN After the model is generated and loads have been inputted , The model is c h e ck e d usi n g M o d e l / Ch e c k . Then once the check is successful with errors , The mo d e l is run usi n g M o d e l / Run. This w ill g e n e r a t e a D e f o r me d geometry RUN ANALYSIS Af t e r t h e mo d e l is run successfully then it is analyzed using M o d e l / G e n e r a t e A n a l y sis results report Then an Analysis report will be generated. Then you have to design section as per the requirement given in specification .

29. T h a n k YOU