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What is the definition of the rated voltage of a lightning arrester? As per IS 3070, the definition of the “rated voltage of a Lightning Arrester” is given below.The maximum permissible r.m.s. value of power-frequency voltage between the line and earth terminal under temporary over-voltage conditions for a duration of 10 seconds as established in … Read more
What are the short circuit withstand levels for 400kV, 220kV, and 132kV transformers? Ans: 400 kV transformers must withstand 63 kA for 1 second. 220 kV transformers must withstand 50 kA for 1 second and 40 kA for 3 seconds. 132 kV transformers must withstand 40 kA for 1 second and 31.5 kA for 3 … 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
We also refer to a Gas Insulated Switchgear (GIS) as a Gas Insulated Substation. Why is GIS the Future of High-Voltage Power Systems? There are several reasons for preferring a Gas-Insulated System (GIS) over an Air Insulated System (AIS). Constructional Details of Gas Insulated Substation (GIS) A GIS consists of several key modules, each performing … Read more
The Selective DC Scheme in circuit breaker control circuits is a specialized design used to enhance reliability and ensure fail-proof operation in power system protection and control. In a Selective DC Scheme, multiple (normally two) DC supplies are taken to ensure that control circuit of CB remains functional even if one of the supplies fails. … Read more
In electrical power systems, circuit breakers play a crucial role in protecting equipment and ensuring the stability of the grid. However, improper operation of breakers can lead to major faults and unsafe conditions. One critical issue in breaker operation is multiple closing attempts before clearing a fault. This can occur due to a continuous closing … Read more
Power transformers are critical to electrical systems, and their failure can lead to major disruptions. Sweep Frequency Response Analysis (SFRA) is a powerful diagnostic tool used to detect mechanical and electrical issues inside a transformer before they cause serious problems. It helps identify winding movement, core displacement, insulation failure, and structural deformations by analyzing how … Read more
The Nitrogen Injection Fire Protection System (NIFPS) prevents and extinguishes fires in oil-filled transformers. Thereby, it safeguards critical power infrastructure. We also commonly call it the Nitrogen Injection Fire Prevention & Extinguishing System (NIFPES). This system operates on a “drain and stir” principle, effectively mitigating fire hazards through a coordinated sequence of actions. Working Principle … Read more
XLPE stands for Cross Linked Polyethylene. This is a type of polymer insulation widely used in electrical power cables, especially in high voltage (HV) and extra-high voltage (EHV) applications. It is derived from polyethylene but has been chemically modified to improve its thermal, mechanical, and electrical properties. Key Features of XLPE Cross-Linking Process: In standard … Read more
A Milliken conductor is a specialized type of stranded electrical conductor. We primarily use this type of conductor in high-voltage (HV) and extra-high-voltage (EHV) power cables. Its design reduces the skin effect and, the proximity effect. Therefore, it improves current distribution in large cross-sectional conductors, typically those exceeding 800 mm² (e.g., 1000, 1200, 1600, 2000, … Read more