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Introduction to Power System Protection

Learn the fundamentals of power systems and the mechanisms involved in protecting them with this free online course.

Publisher: NPTEL
In this free online diploma course, you will learn the fundamentals of power protection, the features of current-based relaying schemes, and the processes involved in the protection of transmission lines. For a power system network to operate efficiently, its protection is very essential. Therefore, the knowledge attained in this course will help you to improve your skills in this field and will form an invaluable addition to your résumé.
Introduction to Power System Protection
  • Duration

    5-6 Hours
  • Students

  • Accreditation






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In this free online course, you will acquire the essential skills and knowledge on the protection of power systems networks. Power system protection is the aspect of electrical power engineering that deals with the safeguarding of an electrical power system from faults. Faults can cause extensive damage to equipment and result in interruption of power supply, hazards to personnel, and loss of revenue to power supply companies. Basically, power protection systems work by isolating the components that are faulty and leaving the rest of the system in operation. You will start by learning the distinction between power protection devices and switchgear, and the roles they play in the power protection system. You will then discover the different types of faults and their effects on the power system components. The various types of protective relays will then be introduced, including the thermal relays, attracted armature relays, induction relays, and balanced beam relays. Furthermore, you will learn about the materials used to make these relays, the application of the relays, their advantages, and disadvantages. You will then be introduced to the universal torque equation.

Next, you will delve into current based relaying schemes wherein the overcurrent protection of transmission lines will be covered in detail. You will study the various types of overcurrent protection relays, which include the instantaneous overcurrent relay, definite minimum time overcurrent relay, inverse time overcurrent relay, and the inverse definite minimum time overcurrent relay. The plug setting (PS) and time dial settings (TDS) of overcurrent relays will also be explained. You will then consider how to calculate the PS and TDS through worked examples for each type of overcurrent relay. In addition, the application of the overcurrent relay will be discussed, together with its advantages and disadvantages. Moreover, the discrimination philosophy of relays will be considered. Here, you will study the current discrimination, time discrimination, and current-time discrimination. Too, the directional and non-directional types of relays will be presented to you. Thereafter, you will be introduced to the distance relay, how it works, and its characteristics. You will also learn about the classification of relays into phase and ground relays. The effect of fault resistance on the performance of distance relay will be covered in detail, alongside the effect of a power swing.

Finally, you will learn about fault distance measurement, and the stepped distance characteristic as part of distance relays. You will then explore the reach of distance relays, and the various types of distance relay comprising the impedance relay, reactance relay, mho or admittance relay, ohm or angle impedance relay, offset mho relay, and more. Power system protection is an essential aspect of power system networks. If you are considering a career path in power system networks, or you are a professional seeking to refresh or enhance your knowledge and skill in power system protection, then this course is the one for you. Therefore, begin this course and build your knowledge and skill on power system protection. Start this course today!

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