Electrical Control & Protection Systems

In this lecture the student will learn about all of the symbols & terms that we will be using in this course, and introduces them to the differences between primary & secondary systems.

We will then look in detail at how the different elements of the secondary protection connect together.

After the first module in which we looked at the equipment's that we use for the protection system, in this module we look at the basic principles behind protection systems.

By the end of this section you will understand some of the principles behind protection systems including the importance of clearing a fault quickly whilst keeping as much of the healthy system connected as possible

In this section we will look at three phase currents.

Before you can start designing a protection system you need to understand in detail how the electrical network behaves when it is operating normal, only then can you design a system that reacts quickly and decisively when things go wrong.

In this section we will look at the other main primary measuring device that we use, which are voltage transformers.

In the same way as we looked at current transformers we will learn how voltage transformers operate and how they should be connected to the secondary protection system.

In this next section we will look at one of the key primary equipment's that we use which are current transformers.

We will show all of their key features and how they operate during normal and fault situations, this will allow you to understand all of the parameters that you will find on a CT rating plate.

In this next section we will leave the theory behind and start looking at the practical side of protection systems, by looking at how we use current transformers, connect them together and feed the protection and control circuits..

In this section we will start looking at the theory of secondary protection systems, by introducing some of the basic principles behind fault detection.

Our aim is to detect faults quickly and accurately so that we minimise the impact on the equipment and network, and keep as many customers connect as possible

This section shows what happens to the voltages and currents for each of the different types of fault.

In this module we will look in detail at protection panels & wiring.

These house all of the protection and control equipment's that we use, and it is interesting to study how they are constructed, and look at some of the equipment's that they contain, some of which only appears in protection systems

In this section we will look at circuit breaker controls.

Circuit breakers are the main device that we use to switch the electricity around the network and for disconnecting faults as they occur.

In this section we will see look at the different types of circuit breaker and how the secondary protection system interacts with the breaker controls circuits.

Welcome to the first module on overcurrent protection. Overcurrent protection is the most widely used protection device that we use on the distribution and transmission network and appears on the most simple and complicated systems.

In this module you will learn the basic principles behind instantaneous overcurrent protection and see how an overcurrent relay can be used to provide a basic overload function.

This is the second module on one of the most important protection relays that we use on the network, overcurrent protection

In this section we will introduce some practical examples of how to use all of the available features of overcurrent relays.

It is obviously impossible to cover every single network configuration, but hopefully by the end of this section you will have learned some basic principles that can be applied to any situation.

Earth fault protection is one of the most widely used protection systems.

In this module we will show how the earth fault relay works and how it can be connected to the current transformers to generate the current information that we need. We will then finish by introducing the earth fault connections required to protect a transformer from internal & external faults.