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A voltage transformer is a type of instrument transformer. We also call it a potential transformer. It reduces high voltage to a lower and measurable value according to its turns ratio. We need to measure the voltage in extra-high-voltage (EHV) systems. However, a normal measuring instrument cannot measure such high voltages directly. So, a voltage … Read more
Circuit breakers are essential protective devices of electrical power systems. A circuit breaker safeguards electrical circuits from abnormal conditions such as overloads and faults. Among different tripping arrangements, the shunt trip mechanism is the most popular method for ensuring safe and reliable operation in high-voltage systems. In this article, we will explain the theoretical working … Read more
A miniature circuit breaker, or MCB, is an essential protective device in low-voltage electrical systems because it protects the circuit from both overload and short-circuit faults. Let us explore the constructional details and the working of an MCB. Introduction to MCB An MCB has two main functions. We can use it as a toggle switch … Read more
Before entering the article on the transformer vector diagram or the transformer phasor diagram, we may recall our concept of an ideal transformer. For a basic idea of an ideal transformer, you may also read our article on the emf equation of a transformer. Considering Core Losses for Transformer Vector Diagram Now, we shall consider … Read more
A power transformer has high cost, large size, and complex design. So, identifying defects at the final stage of manufacturing can lead to significant delays, expenses, and operational challenges. Therefore, standards always recommend performing different tests and inspections during various stages of manufacturing. That means the standards always prefer to perform stage inspections of a … Read more
In this article, we are going to discuss the dead tank current transformer, commonly referred to as a dead tank CT. Dead tank current transformers are not popular for very high-voltage systems like 220 kV and above. Utilities often use dead tank CTs in 33 kV systems. They prefer this design at 33 kV because … Read more
A live tank current transformer (Live Tank CT) is a high-voltage current transformer. Here we place the entire current transformer at the top of the device. If we imagine a current transformer, the primary of the current transformer is nothing but the line conductor. Because of that, we connect the primary in series with the … 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
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
Definition of Making Current The rated short circuit making current of a circuit breaker is the maximum peak current that the circuit breaker can close without any damage. It is the maximum peak current that a circuit breaker can make safely. Definition of Breaking Current The rated short circuit breaking current, on the other hand, … Read more