In electrical power systems, electric power is generated, transmitted, and distributed in the form of alternating current. The electrical power is generated at a power generating station which is located far away from the consumer's load. The generated power is then transmitted and distributed through an electrical network to the load ends. But it is also important to note that power is generated at a lower voltage, transmitted at a higher voltage, and distributed at a lower voltage again. This voltage variation is for many technical and economic reasons. For changing this voltage at many locations in the power system, ... Read More

In electrical power systems, an instrument transformer is used in measurement and protection applications. A current transformer is nothing but a specially designed voltage step-up and current step-down electrical transformer which is used to reduce the high currents in power lines to a safe value for metering and protection applications. In practice, a current transformer is referred to as a CT. Depending on the application, there are two main types of current transformers (CTs) namely, metering current transformer and protection current transformer. Both types of current transformers are different from each other in many aspects. The primary difference between ... Read More

An indoor substation is one in which the entire substation is built inside a building, whereas an outdoor substation is a substation in which the equipment are installed in an open environment. Read this article to understand all the important differences between indoor and outdoor substations. Let us start this article with a brief overview on electrical substations, indoor substations, and output substations. What is a Substation? A substation or electrical substation is an arrangement of electrical equipment for changing the voltage levels of electric supply for transmission, distribution, and utilization purposes. Basically, a substation is used for the following ... Read More

AIS and GIS are the two most widely used switchgear technology in the field of electrical substations. AIS stands for Air Insulated Switchgear and GIS stands for Gas Insulated Switchgear. A substation in which the insulation between phases is provided by the atmospheric air is called an air insulated substation or AIS substation. On the other hand, a substation in which the insulation within phase and between phases is provided by SF6 gas is known as a gas insulated substation or GIS substation. The primary difference between AIS substation and GIS substation is that an AIS substation uses the atmospheric ... Read More

Oil circuit breakers (OCBs) are used for performing the following two important functions - Switching of electric supply Protection of electrical system They are called oil circuit breakers because in this type of circuit breakers, insulating/dielectric oil is used for quenching the arc. In this article, we will learn about the basics of oil circuit breakers and their different types. What is an Oil Circuit Breaker? An oil circuit breaker is an electrical switch in which an insulating or dielectric oil is used for arc quenching. As we know, when a fault occurs in the electrical system, we ... Read More

A protective relay is an electrical switch which can automatically operate when a fault or any other abnormal conditions occur in the electrical system. It sends a signal to turn on the alarm or indicator or trip a circuit breaker to separate the faulty part from the healthy section. The primary function of a protective relay in an electrical circuit or system is to sense the fault and initiate the operation of a circuit breaker to which it is connected. A protective relay is one of the most important components of an electrical protection system, as it is entirely ... Read More

A power system is an interconnected network of electrical components such as alternators, transformers, transmission and distribution lines, and electrical loads. Each of these components are sensitive to different types of faults or abnormal conditions. For example, a transformer can burn due to overloading or short-circuit. Therefore, it is desirable to implement such systems that can protect these highly expensive electrical equipment from damage. This practice of implementing protection systems for power system or its components is referred to as power system protection. In this article, we will explain in detail the components, important terms, and the importance of power ... Read More

An MCB or Miniature Circuit Breaker is a type of circuit breaker or an automatic electric switch used to provide protection against different types of electric faults like short-circuit, overcurrent, overload, etc. Therefore, MCB is considered an electrical protection device. MCBs are primarily used in low-voltage electrical circuits like house wiring, commercial wiring, etc. They are not commonly used in high-voltage industrial applications. The main function of an MCB is to protect an electric circuit from damages due to flow of excessive current. This article is meant for explaining the following major concepts related to MCB (Miniature Circuit Breaker) ... Read More

In electrical engineering, a relay is an electromagnetic or an electronic switch that can automatically operate if any abnormal conditions occur in the circuit. The primary functions of a relay are to monitor the circuit, sense the fault, and initiate the tripping of the circuit if a fault occurs in the system. Read this article to learn the operation of a relay. Let's start with some frequently used terms related to the operation of a relay. Relay Operation Terminology The following are some key terms related to the operation of a relay in power system. Operating Force or Torque - ... Read More

In the field of electrical engineering and power systems, a fault is an abnormal condition that can result in damages to the circuit. Hence, a fault is nothing but a defect in the power system. When a fault occurs in a power system, we need a "power system protection" scheme that can isolate the faulty part from the healthy part. In this article, we will learn about basic definition of a fault in power system, its main causes and effects. So, let’s get started with the basic definition of the electrical fault in power system. What is a Fault in ... Read More