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In this article, we are going to discuss the dead tank CT or 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 … Read more
A current transformer (CT) reduces high currents to small, usable values. We utilize CTs for metering and protection purposes. Proper CT selection ensures accuracy, safety, and reliable protection. Identify the Purpose of CT Metering CT A metering CT measures current for billing and monitoring. Therefore, it must work accurately within the tolerable upper limit of … Read more
An induction disc relay is a variety of electromagnetic relays. It belongs to one of the most primitive forms of conventional electromechanical protection relays. Its basic construction and working principle are quite simple. Basic Construction of Induction Disc Relay There is an electromagnet. The system current or a current proportional to the system current flows … Read more
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
What is Insulation Resistance? Insulation resistance measures how well an insulating material stops leakage current. We measure this blocking ability in Ohms (Ω). Furthermore, good insulation has very high resistance. In contrast, poor insulation allows current to leak. Obviously, this leakage can cause electric shocks, equipment damage, and fire hazards. Basic Formula of Insulation Resistance … 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
A wire wound resistor consists of a winding of resistive wire wrapped around a non-conductive cylinder. This is the oldest type of resistor. Although we use wire wound resistors these days. Because these resistors provide high accuracy, better stability. Also, they can handle much more power than other types of resistors available for fixed resistor … Read more
What is a Carbon Composition Resistor? A carbon composition resistor is a simple electronic component. Engineers use it to control current flow in circuits. This resistor contains carbon particles mixed with clay material. Construction and Manufacturing Manufacturers follow a simple process to make these resistors. First, they mix fine carbon powder with ceramic clay. The … Read more
Let us discuss the effect of temperature on resistance. When the temperature of a conductor increases, its resistance also increases. This relation is linear. In other words, the change in resistance is directly proportional to the change in temperature. Mathematical Relationship If R1 is the initial resistance of a particular resistor or conductor at T1 … Read more
In this article, we are going to discuss the theory behind a condenser bushing. We have mainly focused on how the capacitor grading improves the voltage distribution along the thickness of the insulation. We also call it a capacitor graded bushing. There are mainly two types of condenser bushings. These are the OIP bushing and … Read more
We also refer to a resin-bonded paper bushing or a synthetic resin-bonded paper bushing, respectively, as SRBP or RBP bushings, in short form. Before entering the actual discussion of resin-bonded paper bushings, let us understand the meaning of resin-bonded paper. What is the meaning of resin-bonded? We all know that paper is a cellulose material, … Read more
A Numerical Protection Relay: Modern Power System Protection A numerical protection relay is a breakthrough in power system protection technology. Unlike electromagnetic relays and static relays, this relay uses microprocessor-based technology. It combines digital signal processing, advanced algorithms, and communication systems. Today, numerical protection relays form the backbone of modern power system protection schemes. What … 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
We will discuss here in details the concept of Arc Voltage, Recovery Voltage, Restriking Voltage, RRRV Basic Concept of Arc Voltage, Recovery Voltage, Restriking Voltage, RRRV When contacts of a circuit breaker open under current carrying condition, electric arcs form in the gap between the contacts. This is due to ionization of the surrounding medium. … Read more
The Buchholz Relay is a gas-actuated protection relay. It is a mechanical relay. All oil-immersed transformers that have a conservator tank should be equipped with a Buchholz relay. A Buchholz relay can detect both slow-developing faults and major transient faults occurring within the transformer. It provides an early warning (alarm) for slow-developing faults and initiates … 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
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
An Oil Surge Relay, or OSR, is a type of mechanical relay. It operates in response to a sudden oil surge. Need for Separate Diverter Tank Every modern power transformer includes an On-Load Tap Changer (OLTC). During tap-changing operations, some arcing always occurs at the diverter switch contacts. It is desirable to change tap positions … 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
We are going to discuss here in this article a clear idea about SOTF Protection. Sometimes it becomes necessary to open a circuit breaker just after closing. This is due to the presence of a fault during the closing of the circuit breaker. This type of condition may arise due to different reasons. Such as … Read more