Overhead conductors used for long distance power transmission and inter-city connections which include bare hard drawn copper conductors, All Aluminum Conductors (AAC ), All Aluminum Alloy Conductors (AAAC), Aluminum Conductors Steel Reinforced (ACSR), Aluminum Conductors Aluminum Clad Steel Reinforced (ACSR/AW), Aluminum Conductors Aluminum Alloy Reinforced (ACAR), Aluminum Alloy Conductors Steel Reinforced ( AACSR), galvanized Steel Earth wires (GSW) and Alumoweld Earthwires (AW).

Standards:

ASTM B232 (Concentric-Lay-Stranded Aluminum Conductors, Coated-Steel Reinforced [ACSR].)

ASTM B230 (Aluminum 1350–H19 Wire for Electrical Purposes.)

ASTM B498 (Zinc-Coated (Galvanized) Steel Core Wire for Use in Overhead Electrical Conductors.)

ASTM B500 (Metallic Coated or Aluminum Clad Stranded Steel Core for Use in Overhead Electrical Conductors.)

ASTM B606 (High-Strength Zinc-Coated (Galvanized) Steel Core Wire for Aluminum and Aluminum-Alloy Conductors, Steel Reinforced.)

ASTM B802 (Zinc-5% Aluminum-Mischmetal Alloy-Coated Steel Core Wire for Aluminum Conductors, Steel Reinforced [ACSR].)

ASTM B803 (High-Strength Zinc-5% Aluminum-Mischmetal Alloy-Coated Steel Core Wire for Use in Overhead Electrical Conductors.)

 

 

Conductor:

Concentric-lay-stranded conductor made from round aluminum 1350-H19 (extra hard) wires and round, coated steel core wire(s).

 

 

 

Electrical properties:

Density @ 20^oC                                                                 Aluminium: 2.703 kg/dm

Galvanised Steel: 7.80 kg/dm

Temperature coefficient @20^oC                                 Aluminium: 0.00403(^oC)

Resistivity @ 20^oC                                                            Aluminium: should not exceed 0.028264

Linear Expansivity                                                            Aluminium 23 x 10 (^oC)

Galvanised Steel: 11.5 x 10(1/^oC)

Service Condition:

Ambient Temperature:                                                  -5^oC – 50^oC

Wind pressure:                                                                 80-130km/m^2

Sesmic Acceleration                                                        0.12 – 0.05g

Isokeraunic Level                                                             10-18

Relative Humidity                                                             5-100%

Types of Conductors

As it is already mentioned above, aluminum conductors have an edge over copper conductors considering combined factors of cost, conductivity, tensile strength, weight etc. Aluminum conductors have completely replaced copper conductors in overhead power lines because of their lower cost and lower weight. Though an aluminum conductor has larger diameter than that of a copper conductor of same resistance, this is an advantage when ‘Corona’ is taken into consideration. Corona reduces considerably with increase in the conductor diameter. Following are four common types of overhead conductors that are used for overhead transmission and distribution to carry generated power from generating stations to the end users. Generally, all types of conductors are in stranded form in order to increase the flexibility. Solid wires, except for very small cross sectional area, are very difficult to handle and, also, they tend to crystallize at the point of support because of swinging in winds.

1. AAC : All Aluminum Conductor
2. AAAC : All Aluminum Alloy Conductor
3. ACSR : Aluminum Conductor, Steel Reinforced
4. ACAR : Aluminum Conductor, Alloy Reinforced

 

Max DC Resistance	Nominal Breaking load	Weight			Approx. Overall Diameter	Stranding Wire Diameter		Area				Name of Conductor
		Total	ST	AL		ST	AL	Total	ST	AL
Ω/km	kgf	Kg/km	Kg/km	Kg/km	mm	mm	mm	mm2	mm2	mm2	Nominal
2.63987	421	43	14	29	4.5	1/1.50	6/1.50	12.37	1.77	10.60	–	Mole
1.3414	806	85	27	58	6.33	½.11	62.11	24.48	3.50	2098	–	Squirrel
1.06645	980	106	34	72	7.08	12.36	6/2.36	30.62	4.37	26.25	25	Gopher
0.88545	1157	128	41	87	7.77	12.59	6/2.59	36.88	5.27	31.61	30	Weasel
0.76306	1343	148	48	101	8.37	12.79	6/2.79	42.79	6.11	3668	–	Fox
0.65997	1553	171	55	116	9	1/3.00	6/3.00	49.48	7.07	42.41	40	Ferret
0.52927	1873	214	69	145	10.05	1/3.35	6/3.35	61.70	8.81	52.88	50	Rabbit
0.44341	2223	255	82	173	10.98	1/3.66	6/3.66	73.64	10.52	63.12	–	Mink
0.42001	5378	483	288	175	12.95	7/2.59	12/2.59	100.10	36.88	63.22	–	Shrunk
0.3709	2627	303	97	206	11.97	1/3.99	6/3.99	87.52	12.50	75.02	–	Beaver
0.36195	6240	537	334	203	13.95	7/2.79	12/2.79	116.16	42.79	73.36	70	Horse
0.35334	2774	320	103	217	12.3	¼.10	6/4.10	92.42	13.20	79.21	–	Recon
0.33353	2930	339	109	230	12.66	¼.22	6/4.22	97.90	13.99	83.92	–	Otter
0.29332	3341	386	124	262	13.5	¼.50	6/4.50	111.33	15.90	95.42	–	Cat
0.26661	3665	424	136	288	14.16	¼.72	6/4.72	122.43	17.50	104.98	–	Hare
0.26811	3333	394	106	288	14.15	7/1.57	6/4.72	118.53	13.55	104.98	100	Dog
0.26316	4194	451	160	291	14.57	7/1.93	7/4.39	126.43	20.48	105.96	–	Hyena
0.21432	4157	492	132	360	15.81	7/1.75	6/5.28	148.21	16.84	13137	–	Leopard
0.21443	4684	510	156	364	15.89	7/1.91	26/2.54	151.80	20.06	131.74	–	Coyote
0.21717	3116	420	58	362	15.25	1/3.05	18/3.05	138.81	7.31	131.51	–	Cougar
0.21273	5916	602	239	363	16.52	7/2.36	30/2.36	161.85	30.62	131.23	–	Tiger
0.17663	7061	725	288	437	18.13	7/2.59	30/2.59	194.93	36.88	158.05	150	Wolf
0.1900	3460	506	69	437	16.75	1/3.35	18/3.35	167.46	8.81	158.65	150	–
0.15221	8137	841	334	507	19.53	7/2.79	30/2.79	226.20	42.79	183.40	175	Lynx
0.15501	3983	558	80	508	18.05	1/3.61	18/3.61	194.47	10.24	184.23	175	–