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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
The current transformer is a kind of transformer that steps down currents. From the name “current transformer,” we can understand that it deals with current. The available instruments for measuring and protection purposes in the market are of a few amperes range. The ammeters, energy meters, wattmeters, and various protection relays are rated for only … Read more
Introduction to M2 Class Circuit Breakers The M2 class of circuit breaker belongs to a special class defined by IEC 62271-100. This means these circuit breakers require minimal maintenance and can operate mechanically for an extended lifespan. If a breaker performs at least 10,000 mechanical operations without any even minor damage, it comes under M2 … Read more
The C2 Duty Cycle Test confirms a circuit breaker capable of capacitive switching operations. Even a few tens or hundreds of amperes of capacitive current may cause unexpectedly high transient recovery voltage. That is not a healthy condition for the insulation of the system. A circuit breaker interrupts capacitive current when it cuts unloaded transmission … 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
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
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
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
Here, in this post, we have discussed the DC Control Circuit of an SF6 Circuit Breaker. Selective DC Supply for High‑Voltage Circuit Breakers A circuit breaker’s control power always uses DC. In high‑voltage installations (132 kV and above), designers often choose a selective DC supply. In this scheme, two separate DC sources, Supply 1 and Supply 2, feed … 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