Power transmission is mainly based on overhead transmission lines with conductors being supported by transmission towers. Transmission lines are subjected to environmental stress (temperature changes, winds, snow etc), have an impact on the surrounding areas (visual pollution, building restrictions) and experience heavy losses due to resistive, magnetic and capacitive effects. Thus, proper modeling and installation of these conductors are necessary. The conductors are generally installed in a catenary shape to minimize the capacitive effects and to balance the tension. This paper presents an investigation on the sag and tension behavior under different temperature and wind of ACSR (Aluminum Conductor-Steel Reinforced) lines. Four different cases of temperature and wind are tested to calculate sag and tension. Simulation setup is done in ETAP (electrical transient and analysis program). Results are recorded and discussed

B. Noor

F. W. Karam

M. A. Aman

M. Z. Abbasi

S. Farooqi

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Engineering, Technology & Applied Science Research Vol. 8, No. 3, 2018, 3009-3012 3009    www.etasr.com Abbasi et al.: An Investigation of Temperature and Wind Impact on ACSR Transmission Line Sag …  An Investigation of Temperature and Wind Impact on ACSR Transmission Line Sag and Tension  Muhammad Zulqarnain Abbasi Electrical Engineering Department IQRA National University Peshawar, Pakistan Babar Noor Electrical Engineering Department IQRA National University Peshawar, Pakistan Muhammad Aamir Aman Electrical Engineering Department IQRA National University Peshawar, Pakistan Sidra Farooqi Electrical Engineering Department IQRA National University Peshawar,Pakistan Fazal Wahab Karam  Electrical Engineering Department COMSATS University Abbottabad Pakistan  Abstract—Power transmission is mainly based on overhead transmission lines with conductors being supported by transmission towers. Transmission lines are subjected to environmental stress (temperature changes, winds, snow etc), have an impact on the surrounding areas (visual pollution, building restrictions) and experience heavy losses due to resistive, magnetic and capacitive effects. Thus, proper modeling and installation of these conductors are necessary. The conductors are generally installed in a catenary shape to minimize the capacitive effects and to balance the tension. This paper presents an investigation on the sag and tension behavior under different temperature and wind of ACSR (Aluminum Conductor-Steel Reinforced) lines. Four different cases of temperature and wind are tested to calculate sag and tension. Simulation setup is done in ETAP (electrical transient and analysis program). Results are recorded and discussed.  Keywords-ACSR; overhead; line; transmission; conductors; span; sag; temperature; variation I. INTRODUCTION  Overhead transmission lines are used to carry electrical power over long distances [1]. The performance of these transmission lines depends on their well-engineered modeling which is one of the major issues issue during the design stage. [2]. If the support structures are at the same height (which is rarely the case, however it provides a simplified base to study other parameters), then the sag is the height difference between the conductor’s lowest point and the height of the supporting points [3]. During the design (and construction) phase many parameters are to be considered. Among them, the calculated tension, the safety distances (clearances), the location of rural areas etc. Thus, mechanical modeling as well as geospatial data are usually employed [4]. The design stage results to certain routing, placement of towers, tower types, conductor sag and tension throughout the route [5]. Different types of conductors are used for the transmission of electrical energy e.g. AAC (All Aluminum Conductor), AAAC (All Aluminum Alloy Conductor), HTLS (High Temperature Low Sag), ACSS (Aluminum Conductor, Steel-Supported), ACSR (Aluminum Conductor-Steel Reinforced) with ACSR being probably the most usual choice for transmission lines. ACSR has a galvanized steel core that carries the mechanical load and outer strands made of high purity aluminum that carry the current [6]. To meet changing necessities, ACSR is accessible in an extensive variety of steel substance - from 7% by weight for the 36/1 stranding to 40% for the 30/7 stranding. Early ACSR outlines, for example, 6/1, 30/7, 30/19, 54/19 and 54/7 stranding, included high steel content, 26% to 40%, with accentuation on quality because of the fear of vibration fatigue. Today, for bigger sizes, the most utilized standings are 18/1, 45/7, 72/7, and 84/19, involving a scope of steel substance from 11% to 18%. For the modestly higher quality 54/19, 54/7, and 26/7 standings the steel substance is 26%, 26% and 31%, respectively. The high-quality ACSR 8/1, 12/7 and 16/19 standings are commonly utilized in special cases (e.g. intersections) [6].  Overhead transmission lines are subjected to a variety of environmental stresses during their lifetime. Sag or dip is considered in order to keep tension as low as possible. Sag is conversely corresponding to the transmission line tension [6]. As the ground level varies in hilly areas so, the sag also does not remain constant [7].Wind is a main common factor to most transmission lines and thus wind impact is often investigated (e.g. [6]). The minimum distance of a conductor from the ground is set by each county (and usually it also depends on the installations found-or to be constructed- under the line) but some usual distances are shown in Table I. TABLE I.  VOLTAGE WITH GROUND CLEARANCE LEVEL Voltage Level Clearance to Ground Less than 66kV 20 feet 66kv to 110kv 21 feet 110kv to 165kv 22 feet Greater than 165kv 23 feet  II. MECHANICAL DESIGN OF A TRANSMISSION LINE  The sag of a transmission line depends on the following factors: the conductor’s weight, the span (distance between the    supandA. betwitcont0=ThtramahorB. betC. actconappcalwhwhDVEngineerinwww.etasrports), the tra the temperatThe CatenaryWhen a perfween two hoh L be the spaductor, t0 theWC, ∅	the anen if we consmission liney be termedizontal tensioSo: SS = S = Y=Point p(AY = Y = Y = Sag CalculatBy using (6) Y - CSag is maximDmaxD =For the wholSubstituting ween the poin	 	Wind Effect oOn transmissing horizontalductor with lied from a pculated with iWW = P.D.1 WW = P. (D +ere WW = WeWith the effeich is termed ertical = Dg, Technology.com nsmission linure.  Curve ectly flexible rizontal suppn distance, W tension at thgle between thnsider a tra up to the poi as S. Thren t0=WC, the C	sin 	  C ( 	 !A +  ,B) measured C cos 	  C (1 + !C +  ions we get:  =  = Dx um when A = = 	  	 e conductor l S = AA = L/2 to t o and the su and l = L 	n Line Sag ion lines, thely and is mealength 1 m aoint P horizoce and withouwithout ice ef 2t) .1 with icight of the conct of wind thas vertical sag  & Applied SciAbbasi e tension, thewire of unifoorts [8] it wi the weight pe dip of the ce tension andvelling pointnt O (sag poie forces are weight i.e. W  	 ! 	⋯    above the orig  	 ! 	⋯            sag is  + 	 get the lengthpport end a or for the le wind is ususured in (kg/mnd diameter ntally [8], thet ice effect asfect e effect ductor in Kg/e sag makes a and is equal tence Researchet al.: An Inves weather condrm weight isll form a cater unit lengthonductor in k the horizonta p(A, B) ont), then this lacting on SS and the tens(1) (2) (3) in vertically.(4) (5) (6) (7) (8) (9)  of the cond b. vel supports.ally assumed2). If we consD and wind n the wind eff: m2 n angle θ verto  Vtigation of Temitions  hung enary of the g i.e. l axis. n the ength : the ion t. uctor to be ider a  being ect is ically A.sagandtoodistlinetrangrid[11Thehorthe anatheFig. on AA.temand(TaB.winconare C.contemol. 8, No. 3, 20perature and IIModeling andThe ETAP 12 and tension o distribution l to perform saribution lines s [10]. For simsmission line station (Pak] is shown in  selected coizontal. LoadNewton Raphlyzed using thdifferent para1.  The transmIVFour differentCSR conducCase 1 Five differenperature i.e. the correspoble II). Case 2 In Case 2, thed speed is hiductor tensionshown in TabCase 3 In case 3, thsidered with aperature resul18, 3009-3012Wind Impact oI. SYSTEM  Load Flow A.6 [9] softwaf ACSR transline sag and g and tensionto ensure adeulation setup between Taistan). The mFigure 1. Thnductor is Aflow analysis son Method 1e sag and tenmeters used. ission line mode.  RESULT cases of temptors with levet span length5 oC with winnding values temperature gher (50 N/m changes while III. e maximum o wind speed ots to larger sa n ACSR TransIMPLEMENTATnalysis re is used fomission line. Etension modu calculation foquate operatin, the model serbela and Shodel and its e tower heighCSR and this performed 0 (Figure 1). sion library [1 l and its load floS AND DISCUSerature and wl supports. s are analyzed speed 25 N of tension ais the same w2). Due to thle sag is hardlperating tempf 25 N/m2. Asg (Table IV). 3010  mission Line SION r the estimatioTAP transmile is an impor transmissiong condition folected is a 50eikh Mohamload flow anats are set to 1e configuratioin ETAP baseThe losses are2]. Figure 2 sw analysis. SION ind are considd under mini/m2 using And sag are shith Case 1 bue wind effecty affected. Reerature (50 o shown, the hag … n of ssion rtant  and r the 0 kV madi lysis 6 m. n is d on  then hows ered mum CSR own t the , the sults C) is igher      Engineerinwww.etasrTABSpa(m100150200250300TABSpa(m100150200250300 g, Technology.com Fig.  2.   ETAP LE II.  OPERn ) Wind spe(N/m2) 25  25  25  25  25 LE III.  OPERn ) Wind spe(N/m2) 50  50  50  50  50  & Applied SciAbbasi editors for differATING TEMPERATed  Sag 1.03 2.31 4.1 6.41 9.23 ATING TEMPERATed  Sag 1.03 2.31 4.1 6.41 9.23 ence Researchet al.: An Invesent temperature aURE 5 OC  Tension 1967 1951 1927 1889 1825 URE 5 OC Tension 2023 2007 1982 1943 1877  Vtigation of Tem  nd wind effects o ol. 8, No. 3, 20perature and n ACSR conductTABLSpan(m)100150200250300TABLSpan(m)10015020025030018, 3009-3012Wind Impact oor for finding sagE IV.  OPERA  Wind spee(N/m2) 25 25 25 25 25 E V.  OPERA  Wind spee(N/m2) 50 50 50 50 50  n ACSR Trans of different spanTING TEMPERATUd Sag T1.24 2.79 4.96 7.76 11.17 TING TEMPERATUd Sag T1.24 2.79 4.96 7.76 11.17 3011  mission Line Ss RE 50 OC  ension 1625 1541 1433 1294 1119 RE 50 OC ension 1672 1585 1474 1317 1152 ag … Engineering, Technology & Applied Science Research Vol. 8, No. 3, 2018, 3009-3012 3012    www.etasr.com Abbasi et al.: An Investigation of Temperature and Wind Impact on ACSR Transmission Line Sag …  D. Case 4 In Case 4, temperature is set to 50 oC but the wind speed is set to 50 N/m2. The conductor tension increases while sag is hardly affected (Table V). V. CONCLUSION A significant factor in overhead transmission line design is sag and tension calculation which is performed considering the potential environmental stresses that the transmission line is expected to suffer throughout its life time. The most common environmental stress factors are wind and temperature. Their impact is investigated in this paper, considering a part of an actual transmission line in Pakistan modeled in ETAP. Four different cases are considered and results show that an increase in temperature has a direct impact on sag whereas an increase in wind has a direct impact on tension.  REFERENCES [1] J. Quintana, V. Garza, C. Zamudio, “Sag-tension calculation program for power substations”, 42nd Annual Conference of the IEEE Industrial Electronics Society, IECON 2016, Florence, Italy, pp. 3889–3893, IEEE, 2016 [2] M. Keshavarzian, C. H. Priebe, “Sag and tension calculations for overhead transmission lines at high temperatures-modified ruling span method”, IEEE Transactions on Power Delivery, Vol. 15, No. 2, pp. 777–783, 2000 [3] V. K. Mehta, R. Mehta, Principles of Power Systems, S. Chand, New Delhi, India, 2011 [4] D. Pylarinos, I. Pellas, “Incorporating Open/Free GIS and GPS Software in  Power Transmission Line Routine Work: The Case of Crete and Rhodes”, Engineering, Technology & Applied Science Research, Vol. 7, No. 1, pp. 1316-1322, 2017 [5] M. T. Bedialauneta, I. Albizu, E. Fernandez, A. J. Mazon, S. de Arriba, “Monitoring the tension and the temperature in an overhead line”, 16th IEEE Mediterranean Electrotechnical Conference (MELECON), Yasmine Hammamet, Tunisia, pp. 245–248, IEEE, 2012 [6] F. I. Oluwajobi, O. S. Ale, A. Ariyanninuola, “Effect of sag on transmission line”, Journal of Emerging Trends in Engineering and Applied Sciences, Vol. 3, No. 4, pp. 627–630, 2012 [7] Southwire Company, Overhead conductor manual, Southwire Company, Carrollton, Georgia, USA, 2007 [8] A. K. Akhani, Mechanical design of overhead transmission lines, available at: http://top10electrical.blogspot.gr/2014/12/mechanical-design-of-overhead.html, 2014 [9] ETAP, “Line Sag & Tension Analysis”, available at: etap.com/product/line-sag-tension [10] C. J. Soni, P. R. Gandhi, S. M. Takalkar, “Design and analysis of 11 kv distribution system using ETAP software”, 2015 International Conference on Computation of Power, Energy Information and Commuincation, Chennai, India, pp. 0451–0456, IEEE, 2015 [11] M. Aien, R. Ramezani, S. Mohsen Ghavami, “Probabilistic load flow considering wind generation uncertainty”, Engineering, Technology & Applied Science Research, Vol. 1, No. 5, pp. 126-132, 2011 [12] M. A. Aman, S. Ahmad, A. Asar, B. 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An Investigation of Temperature and Wind Impact on ACSR Transmission Line Sag and Tension

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An Investigation of Temperature and Wind Impact on ACSR Transmission Line Sag and Tension

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