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

Rated Insulation Levels

Understanding Rated Insulation Levels in High-Voltage Systems High-voltage equipment needs strong insulation to work safely, reliably, and efficiently. Rated insulation levels show how much stress the insulation can handle, such as lightning strikes, sudden electrical surges, or power overloads. To ensure everything works consistently everywhere, organizations like the IEC and Indian Standards (IS: 13118) have … Read more

Testing of a Vacuum Circuit Breaker

Type Tests for a 36kV Class Vacuum Circuit Breaker (VCB) As per IS: 13118, these type tests include: These tests are intended to ensure that the circuit breakers perform reliably, safely, and efficiently under various operating conditions. Routine Tests for a 36kV Vacuum Circuit Breaker (VCB) As per IS: 13118, the routine tests include the … Read more

Questions on 33KV Circuit Breaker – A Complete Session

What type of circuit breaker is generally used for the 36KV class? Ans: The 36KV class circuit breaker is normally an outdoor type Vacuum Circuit Breaker (VCB). Why is VCB Preferred in 33KV Outdoor Systems Over SF6 Circuit Breakers? Ans: VCBs offer a more economical approach for 33KV systems compared to SF6 circuit breakers. It … Read more

Online Partial Discharge Measurement of GIS

What is a partial discharge in an insulation system? A partial discharge (PD) in an insulator system is a localized electrical discharge that occurs when the electric field within the insulation exceeds its dielectric strength in specific areas, without completely bridging the insulating material between conductors. When high voltage is applied to an insulation system, … Read more

What is Accuracy Limit Factor of Current Transformers?

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

Testing of High Voltage Isolators

Type Tests of Isolators as per IS 9921 (Part 4) – 1985 The type tests of isolators are conducted to ensure that the isolators meet the performance criteria under standard operating conditions. According to IS 9921 (Part 4) – 1985, the type tests of isolators can be broadly categorized into the following: These type tests … Read more