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Surya 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
Before discussing the types of sheath bonding used in high voltage cable let us recall our knowledge regarding sheath and cause of induced voltage and current in the sheath of a HV cable. Actually, all types of bonding are used to limit the unwanted, induced voltage and current in a cable sheath. What is a … Read more
Single Bus System with Bus Sectionalizer Often, engineers adopt a single bus bar with a sectionalizing arrangement. Because it is cheap and simple. The figure just below shows a single bus bar with a sectionalizing arrangement. The scheme works best when the incoming and outgoing circuits are distributed evenly across the sections. When a single … 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
Spring-spring mechanism is the most commonly used circuit breaker operating mechanism today. It offers many advantages. Manufacturers use this as the simplest and most economical mechanism in circuit breakers. It also provides high reliability. This mechanism is much more compact than hydraulic or pneumatic mechanisms. Previously, engineers widely used spring-spring mechanisms for 11 kV indoor … 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
Before entering the minimum oil circuit breaker (MOCB), let us recall our knowledge about the older version of the oil circuit breaker and which is the bulk oil circuit breaker. In a bulk oil circuit breaker,(BOCB) we use oil as the insulating medium. Also, we use oil as the arc-quenching medium. So, to serve both … Read more
When it comes to high-voltage power systems, current transformers (CTs) play a critical role. It has a vital role in measurement and protection. CTs come in two main designs—Live Tank and Dead Tank. While both serve the same fundamental purpose, they differ significantly in construction. Live tank and dead tank CTs differ mainly in insulation. … Read more
The High Impedance Bus Differential Protection is a very interesting subject to study. A busbar is a critical component in a power substation. It ensures the proper connection of all incoming and outgoing feeders to a single voltage level system. Obviously, if a fault occurs on the bus itself and does not promptly clear, it may cause permanent damage to the … Read more
A Comprehensive Analysis of Nanocrystalline Core A critical component of a CT is its magnetic core, which significantly influences its performance, accuracy, and efficiency. Accuracy is the most essential property of a current transformer. Traditionally, Cold-Rolled Grain-Oriented (CRGO) silicon steel has been the material of choice for these cores. Nowadays, a superior alternative is available … Read more
Rated Voltage: 36kV Rated Insulation Level:
Type Tests of a 33/0.415KV Station Service Transformer There are mainly three standards we follow for testing of a Station Service Transformer. These are IS : 1180 part 3 – 2021, CEA Guideline and CBIP Manual. Type Tests According to IS : 1180 part 3 – 2021 According to the latest version of IS 1180 … Read more
In the early days, less 1910 or the early 20th century, most utilities used a bulk oil circuit breaker (BOCB) for high-voltage switching during that time. Earlier air circuit breakers served the purpose of switching high voltage and very high voltage current. But after the 19th century, engineers realized that mineral oil, or specially treated … Read more