High Voltage Circuit Breaker – Air, Oil, SF6 & Vacuum Types

A High Voltage Circuit Breaker (HVCB) is a crucial component in power transmission and distribution networks. Its primary role is to protect electrical equipment by interrupting fault currents within the system. Beyond safeguarding equipment, HVCBs are vital for maintaining the integrity of the power grid. They isolate faults effectively, ensuring that adjacent systems remain unaffected … Read more

Current Ratings of an Electrical Equipment

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

Stage Inspection of a Transformer

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

Parameters of a Transformer (10MVA 66/11KV Transformer)

The clearance requirements for HV and LV terminals in the air are as follows:For 66 kV side, the phase-to-phase and phase-to-earth clearance should be 700 mm, and 660 mm respectively.For 12 kV side, the phase-to-phase and phase-to-earth clearance should be 280 mm, and 140 mm respectively. The following points should be noted for designing winding … Read more

Instrument Safety Factor or Instrument Security Factor (ISF)

ISF (Instrument Security Factor)

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

What is Accuracy Limit Factor of CT? Complete Details

ALF (Accuracy Limit Factor)

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

Rated Short Circuit Making Current and Breaking Current 

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

Zero Current Crossing Method in A Circuit Breaker

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

Small Inductive Current Interruption by Circuit Breakers

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

GAP-Type HTLS Conductors

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