Learn Electrical Engineering
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
Type Tests of SF6 Circuit Breakers as per IS-13118: Routine Tests on SF6 Circuit Breaker as per IS-12729. Acceptance Tests on SF6 Circuit Breaker
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
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
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
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, proximity effect. Therefore, it improves current distribution in large cross-sectional conductors, typically those exceeding 800 mm² (e.g., 1000, 1200, 1600, 2000, 2500, … Read more
Conductor of an EHV Cable This is the main part of the cable. The one and only purpose of a cable is to carry electric current. The conductor performs that task. The conductor of an EHV XLPE cable is normally stranded. It is needless to say that the stranding is done to reduce the skin … Read more
Measuring soil resistivity is essential before designing a grounded earthing system for a substation. Because this measurement determines how well the ground can dissipate fault currents. If the soil resistivity is high, the grounding system needs some changes. It requires denser earthing mesh and more conductive electrodes. A well-designed earthing system prevents intolerable voltage buildup. … Read more
Sheath Voltage Limiters (SVL) As I have already told, in high-voltage cables, the metallic sheath plays an important role in protecting the conductor from external physical, environmental and electromagnetic influences. But due to electromagnetic induction of the current flowing through the main conductor, a voltage is developed along the sheath, especially in long cable runs. … Read more