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 sup and A. bet wit con t0= Th tra ma hor B. bet C. act con app cal wh wh DV Engineerin www.etasr pports), the tra d the temperat The Catenary When a perf tween two ho th L be the spa nductor, t0 the =WC, ∅ the an hen if we co ansmission line ay be termed rizontal tensio So: S S = S = Y=Point p(A Y = Y = Y = Sag Calculat By using (6) Y - C Sag is maxim Dmax D = For the whol Substituting tween the poin Wind Effect o On transmiss ting horizontal nductor with plied from a p lculated with i WW = P.D.1 WW = P. (D + here WW = We With the effe hich is termed Vertical = D ng, Technology r.com ansmission lin ture. ry Curve fectly flexible orizontal supp an distance, W e tension at th ngle between th onsider a tra e up to the poi d as S. Thre on t0=WC, the C sin C ( ! A + A,B) measured C cos C (1 + ! C + tions we get: C = = Dx mum when A = x = le conductor l S = A A = L/2 to nt o and the su and l = L on Line Sag sion lines, the lly and is mea length 1 m a point P horizo ice and withou without ice ef + 2t) .1 with ic eight of the con ect of wind th as vertical sag y & Applied Sci Abbasi ne tension, the wire of unifo ports [8] it wi W the weight p he dip of the c he tension and avelling point int O (sag poi ee forces are weight i.e. W ! ⋯ above the orig ! ⋯ = sag is A + get the length upport end a or for the le e wind is usu asured in (kg/m and diameter ntally [8], the ut ice effect as ffect ce effect nductor in Kg/ e sag makes a g and is equal t ience Research et al.: An Inves weather cond orm weight is ill form a cat per unit length conductor in k d the horizonta t p(A, B) o int), then this l acting on S S and the tens (1) (2) (3) gin vertically. (4) (5) (6) (7) (8) (9) h of the cond r b. evel supports. ually assumed m2). If we cons D and wind en the wind eff : /m2 an angle θ vert to h V stigation of Tem ditions s hung tenary of the kg i.e. al axis. n the length S: the sion t. ductor to be sider a being ffect is tically A. sag and too dist line tran grid [11 The hor the ana the Fig. on A A. tem and (Ta B. win con are C. con tem Vol. 8, No. 3, 20 mperature and II Modeling and The ETAP 12 g and tension o d distribution l to perform sa tribution lines es [10]. For sim nsmission line d station (Pak ] is shown in e selected co rizontal. Load Newton Raph alyzed using th different para 1. The transm IV Four different ACSR conduc Case 1 Five differen mperature i.e. d the correspo able II). Case 2 In Case 2, the nd speed is hi nductor tension shown in Tab Case 3 In case 3, th nsidered with a mperature resul 018, 3009-3012 Wind Impact o II. SYSTEM d Load Flow A 2.6 [9] softwa of ACSR trans line sag and ag and tension to ensure ade mulation setup e between Ta kistan). The m Figure 1. Th onductor is A flow analysis hson Method 1 he sag and ten ameters used. mission line mode V. RESULT t cases of temp ctors with leve nt span length 5 oC with win onding values e temperature igher (50 N/m n changes whi ble III. e maximum o a wind speed o lts to larger sa 2 on ACSR Trans IMPLEMENTAT Analysis are is used fo mission line. E tension modu n calculation fo quate operatin p, the model se arbela and Sh model and its e tower heigh ACSR and th is performed 10 (Figure 1). sion library [1 el and its load flo TS AND DISCUS perature and w el supports. hs are analyze nd speed 25 N s of tension a is the same w m2). Due to th ile sag is hardl operating temp of 25 N/m2. As g (Table IV). 3010 smission Line S TION r the estimatio ETAP transmi ule is an impo or transmission ng condition fo elected is a 50 heikh Moham load flow ana hts are set to 1 e configuratio in ETAP base The losses are 12]. Figure 2 s w analysis. SSION wind are consid ed under mini N/m2 using A and sag are sh with Case 1 bu he wind effect ly affected. Re perature (50 o s shown, the h Sag … on of ission ortant n and or the 00 kV mmadi alysis 16 m. on is ed on e then shows dered imum ACSR hown ut the t, the esults oC) is higher Engineerin www.etasr TAB Spa (m 100 150 200 250 300 TAB Spa (m 100 150 200 250 300 ng, Technology r.com Fig. 2. ETAP BLE II. OPER an ) Wind spe (N/m 2 ) 0 25 0 25 0 25 0 25 0 25 BLE III. OPER an ) Wind spe (N/m 2 ) 0 50 0 50 0 50 0 50 0 50 y & Applied Sci Abbasi editors for differ RATING TEMPERAT eed ) Sag 1.03 2.31 4.1 6.41 9.23 RATING TEMPERAT eed ) Sag 1.03 2.31 4.1 6.41 9.23 ience Research et al.: An Inves ent temperature a TURE 5 OC Tension 1967 1951 1927 1889 1825 TURE 5 OC Tension 2023 2007 1982 1943 1877 h V stigation of Tem and wind effects o Vol. 8, No. 3, 20 mperature and on ACSR conduct TABL Span (m) 100 150 200 250 300 TABL Span (m) 100 150 200 250 300 018, 3009-3012 Wind Impact o tor for finding sag LE IV. OPERA n Wind spee (N/m 2 ) 25 25 25 25 25 LE V. OPERA n Wind spee (N/m 2 ) 50 50 50 50 50 2 on ACSR Trans g of different span ATING TEMPERATU ed Sag T 1.24 2.79 4.96 7.76 11.17 ATING TEMPERATU ed Sag T 1.24 2.79 4.96 7.76 11.17 3011 smission Line S ns URE 50 OC Tension 1625 1541 1433 1294 1119 URE 50 OC Tension 1672 1585 1474 1317 1152 Sag … 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. 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