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Electrical equipment is designed to handle different types of current, and there are mainly three types of current ratings that apply to it: Normal Current Rating, Short Circuit Current Rating (for a specific time period), and Dynamic Current Rating. Let’s explain these in simple terms: Normal Current Rating The normal current rating of electrical equipment … Read more
RIP bushing is a kind of condenser bushing or capacitor-graded bushing. The full form of RIP bushing is Resin Impregnated Paper Bushing. The working principle of an RIP bushing is similar to that of an OIP bushing, and construction-wise, they are almost similar. The only difference is that in an OIP bushing, we use oil … Read more
What is a Transformer Breather? A transformer breather (silica gel breather) is a simple device that keeps moisture out of the transformer. We fit it to the pipe coming out from the transformer conservator tank. When the transformer heats up, the oil expands. When it cools down, the oil contracts. This creates a breathing action. … Read more
An ammeter is connected in the secondary circuit of a current transformer. The ammeter measures the current through the primary of the current transformer. Impact of Fault Current on Secondary Current Now, suppose a fault occurs in the system. Consequently, a large fault current starts flowing through the primary of the current transformer. If the fault current … Read more
Current transformers (CTs) play a crucial role in power systems, especially in protection and metering applications. The Accuracy Limit Factor (ALF) is one of the key parameters that determines the performance of current transformers. This article provides an in-depth understanding of the ALF. The article covers its significance and its impact on the reliable operation … 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
This zero current crossing method is only applicable to alternating current circuit breaker. We all know that an alternating current naturally passes through zero at regular intervals (every half-cycle of the AC waveform). This method safely interrupts the alternating current at the natural zero-crossing of its waveform. Working Principle of a CB based on Zero … Read more
Normal Short Circuit Rating of Circuit Breaker Engineers design high voltage circuit breakers to handle very high short-circuit currents. Manufacturers build these breakers to interrupt extremely high fault levels effectively. They typically rate circuit breakers for short-circuit breaking capacities such as 25kA, 31.5kA, 40kA, or even 50kA and more. Such ratings define their ability to … Read more
Power Transmission Challenges The main drawback of conventional ACSR (Aluminum Conductor Steel Reinforced) conductors is their limited thermal capacity. These conductors are typically designed to operate at a maximum temperature of 75°C. Although some modern variants can withstand up to 85°C, exceeding these temperature limits by increasing current leads to higher thermal expansion, which in … Read more
A Gap-type HTLS conductor is a special type HTLS conductor. It exhibits a separate high strength low elongation steel core surrounded by layers of thermal resistant aluminum alloy strands. The typicality of a gap type HTLS conductor is, it maintains a deliberate annular gap between the core and the first layer of aluminum alloy strands. … Read more
The electricity demand increasing tremendously from last few decades. The increasing demand of lands and few government policies are the constraints in expanding transmission infrastructure. Hence there is no way other than increasing the ampacity of the existing transmission networks. This increases the need for High-Temperature Low-Sag (HTLS) conductors. Among the various HTLS conductors, INVAR … Read more
What is LBB Protection? Local Breaker Backup (LBB) Protection is a special protection scheme. This protection isolates a fault from the electrical power system when a circuit breaker fails to do so. When a fault occurs at a particular point in a power system, the primary protection relay associated with that part of the system detects … Read more
Current transformers (CTs) play a critical role in protection and metering. The proper operation of protection relays depends on CT accuracy to detect faults. Additionally, the accuracy of CT is more important for metering purposes. However, when a CT experiences core saturation, its secondary output no longer represents the true replica of the primary current. … 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
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
What is Normal Current Rating? This is the current represented in its RMS value. Electrical equipment can carry this current continuously without being overheated and without losing its desired performance. According to IC 62271, the definition of normal current rating of electrical equipment is the rated normal rms current that the electrical equipment can carry … Read more
In addition to the normal current rating of a circuit breaker (which is the current it can handle continuously during regular operation), there are two important categories of short-circuit current ratings that define how the circuit breaker performs during fault conditions: Rated Short Circuit Breaking Current The short-circuit breaking current of a circuit breaker consists … Read more
Discover the First Pole to Clear Factor. How does the highest restriking voltage in the first-clearing pole, divided by phase-to-ground recovery voltage, impact circuit breaker performance?123 characters (approx) In an AC system, the phase difference between the currents of each phase is \(120^\circ\). This means the current of one phase is \(120^\circ\) apart from the … Read more
A high voltage circuit breaker plays a crucial role in power systems by protecting electrical equipment from damage due to electrical faults in the system. One of the key challenges in circuit breaker design is dealing with the transient recovery voltage (TRV), a phenomenon that occurs immediately after current interruption. When a fault current gets … Read more
