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Explore power transmission — components, line design, conductors, and techniques for efficient high-voltage energy transfer over long distances.
Let us try to understand why transmission of electricity requires a high-voltage transmission system. This is essential before discussing the details of an electrical transmission system, Requirement of Electrical Transmission System All the generating stations generate electric power at a low voltage level. Because generating electrical power at a low voltage level is economical. Actually, … Read more
Power Transmission Utilities use lattice-structured transmission towers for extra high voltage transmission lines and ultra-high voltage transmission lines, normally above 33 kV or including 33 kV lines. They use galvanized iron or GI angles with nuts and bolts to erect the electrical transmission towers. The height of these towers ranges from 20 to 40 meters, … Read more
ACSR means Aluminum Conductor Steel Reinforced. ACSR is the most standard choice for high‐voltage overhead transmission lines. An ACSR consists of mainly two parts. It has multiple layers of pure aluminum strands for carrying current. It also has a central core of galvanized steel to provide tensile strength to the conductor. The aluminum strands are … Read more
Type Tests as per IS 398 Part-5 Routine Tests on ACSR Conductors These tests are performed as per IS 398 Part-5 Acceptance Tests on ACSR Conductors as per IS 398 Part-5
Power Transmission Challenges The main drawback of conventional ACSR (Aluminum Conductor Steel Reinforced) conductors is their limited thermal capacity. These conductors are typically designed to operate at a maximum temperature of 75°C. Although some modern variants can withstand up to 85°C, exceeding these temperature limits by increasing current leads to higher thermal expansion, which in … Read more
A Gap-type HTLS conductor is a special type HTLS conductor. It exhibits a separate high strength low elongation steel core surrounded by layers of thermal resistant aluminum alloy strands. The typicality of a gap type HTLS conductor is, it maintains a deliberate annular gap between the core and the first layer of aluminum alloy strands. … Read more
The electricity demand increasing tremendously from last few decades. The increasing demand of lands and few government policies are the constraints in expanding transmission infrastructure. Hence there is no way other than increasing the ampacity of the existing transmission networks. This increases the need for High-Temperature Low-Sag (HTLS) conductors. Among the various HTLS conductors, INVAR … Read more
Insulators Used in Overhead Transmission Lines In overhead transmission lines, insulators support the conductor on metallic tower structures. At the same time, they electrically isolate the high-voltage conductor from the metallic body of the supporting towers. In high-voltage overhead transmission lines, engineers typically install insulator strings at the tip of the cross arms of towers. … Read more
Before we discuss the use of disc insulators in high-voltage transmission lines, let’s understand the need for such insulators. Transmission lines operate at very high voltages such as 66 kV, 132 kV, 220kV, 400 kV, even 765 kV and more. So, the conductors used in these systems are also very heavy. To maintain proper ground clearance, we suspend these … Read more
Engineers prefer to use silicone rubber composite insulators for transmission lines in areas with high pollution levels. In other words, these areas are among the most heavily polluted. These insulators normally have a creepage distance of 31 mm/ kV. The disc insulators used in heavily polluted areas also have a creepage distance of 31 mm/kV. … Read more
Power stations generate electric power. Electrical power transmission lines transmit the generated power to far places. The resistance and reactance of the line cause a voltage drop in the power. The Voltage Regulation of Transmission Line is the change in voltage between the sending and receiving ends. What is Voltage Regulation? We express the Voltage … Read more
Skin effect is a phenomenon that occurs in conductors. It mainly occurs while a conductor carries alternating current. Actually, when an alternating current tries to flow through the outer layer of the conductor. The inner portion of the conductor carries much lower current than the outer surface. As a result, the current distribution across the … Read more
Before entering the topic of line differential protection, or simply differential protection of a transmission line, we shall first recall our concept of differential protection. Actually, the differential protection used for a transmission line is called line differential protection. We have already heard about the differential protection of transformers, busbars, etc. The same principle is … Read more
A Digital Teleprotection Coupler (DTPC) is often referred as a Digital Protection Coupler (DPC). It serves as a high-speed, reliable interface for transmitting protection commands between substations over a communication medium (OPGW). Typically it is used for carrier protection of transmission lines. Working Principle First, a protective relay such as a digital distance relay or … Read more