Fuse failure supervision (supervision functions)

February 19th, 2018 | Make a comment | Posted in Electrical distribution

Ahmed H. wanted to tell us about Supervision functions- especially Fuse failure supervision. Enjoy!

fuse failure supervision

What is fuse failure supervision?

Fuse-failure supervision is a function used to supervise the operation of the fuses responsible for protecting the secondary circuit of the potential transformer, which delivers the reduced voltage to the protection relay and voltmeters.

In relay codes and substation automation, the fuse-failure supervision function can be identified by the following symbols,
Read the rest of this entry »

Current and auto transformers (working principle)

February 12th, 2018 | Make a comment | Posted in Electrical distribution

As we know transformers are device for converting one AC voltage to the another AC voltage with same frequency. One transformer is made of core, primary windings and secondary windings.

In general there are two main classes voltage and power transformers. Let Milan – one of the members of the Electrical Engineering Community Blog tell us about it.

Principle of one classic transformer

Picture 1. Principle of one classic transformer

Read the rest of this entry »

Sympathetic tripping in electrical power systems

February 9th, 2018 | Make a comment | Posted in Electrical distribution

megaphone-red
New article by Carlos who sometimes sends us his essays. If you too want to be published in the blog, do not hesitate to send us a mail.

Introduction

Several industries and utilities have experienced circuit breakers tripping due to undesirable relay operations, producing blackouts and a decrease in their expected incomes. This situation has raised a lot of concern in managers, grid operators, and reliability and protection engineers who have carried out root cause analysis to determine the origin of the missoperation of the protection systems.
Read the rest of this entry »

AC aircraft brushless generators with constant speed drive unit

February 6th, 2018 | Make a comment | Posted in Electrical distribution

megaphone-darkblue

As Milan talked earlier, aircraft generators are essential part of aircraft electrical system. Briefly, he mentioned two main types of AC generators, one is constant frequency and another is variable frequency generators.

Now, he’s going to dive deeply in working principle of one most common generator – brushless generator.

Standard generators are bitten from brushless

Classic use of brushes and slip rings for passing excitation current to AC windings made huge problems due to brush consumption and during the time rotating surface make traces on rotor of generator. Also, power that is conveyed is smaller that in brushless type.
Read the rest of this entry »

Electrical System Protection : how can we use relays?

February 1st, 2018 | Make a comment | Posted in Electrical Safety

In this article your fellow electrical engineer Yasser is going to explore the different types of relay and the devices that relays protect…

We used to consider circuit breakers as the devices that protect the electrical systems, however circuit breakers are only the muscles they just isolate and protect when they get the orders. Relays are the brains, the devices that sense the faults and compare the value to the predefined values, and send the signals to breakers to take the actions.

What is Relay?

First of all we need to define the relay. It’s the device that protects the electrical systems against abnormal conditions like over and under voltage, over load and short circuit to ensure the safety of equipment from damage and personnel from shocks.

Relay circuit

Figure.1 Relay circuit | ieeexplore.ieee.org

Read the rest of this entry »

Electrical engineering Community is proudly powered by WordPress
Entries (RSS) and Comments (RSS) and license Creative Commons License