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Power System Protection and Switchgear by Oza PDF Free
Power System Protection and Switchgear by Oza PDF Free is a book that covers the fundamentals and applications of power system protection and switchgear. The book is written by Bhuvanesh A. Oza, Nirmal-Kumar C. Nair, Rashesh P. Mehta and Vijay H. Makwana, and published by Tata McGraw-Hill Education[^1^].
The book provides a comprehensive coverage of various types of faults, protection schemes, relays, circuit breakers, and switchgear equipment. It also explains the principles of carrier-aided protection, digital protection, microprocessor-based relays, and numerical relaying[^2^]. The book also includes multiple choice questions, review questions, and references for further reading[^3^].
The book is suitable for undergraduate and postgraduate students of electrical engineering, as well as practicing engineers and professionals in the field of power system protection and switchgear[^4^]. The book can be downloaded for free from various online sources[^5^].
Types of Faults and Protection Schemes
A fault is an abnormal condition in a power system that causes a deviation from the normal flow of current. Faults can be classified into symmetrical (balanced) faults and asymmetrical (unbalanced) faults, depending on whether they involve all three phases or only one or two phases. Faults can cause damage to the power system equipment, interruption of power supply, and overvoltages and overcurrents that can affect the stability and security of the system.
Protection schemes are designed to detect and isolate the faulty section of the power system as quickly as possible, while minimizing the impact on the rest of the system. Protection schemes consist of protective relays, circuit breakers, current transformers, voltage transformers, and communication devices. Protective relays are devices that sense the fault conditions and send signals to circuit breakers to open or close the contacts. Circuit breakers are devices that interrupt or establish the current flow in a power system. Current transformers and voltage transformers are devices that measure the current and voltage in a power system and provide scaled-down values to the protective relays. Communication devices are devices that transmit and receive signals between different locations in a power system.
Numerical Relays and Microprocessor-Based Relays
Numerical relays are protective relays that use digital signal processing techniques to perform various protection functions. Numerical relays have many advantages over conventional electromechanical and static relays, such as higher accuracy, faster operation, better coordination, self-monitoring, self-testing, and communication capabilities.
Microprocessor-based relays are a type of numerical relays that use microprocessors to implement the protection algorithms. Microprocessor-based relays have a modular structure that consists of input/output modules, central processing unit (CPU), memory unit, display unit, and communication unit. Microprocessor-based relays can perform multiple protection functions in a single device, such as overcurrent, distance, differential, directional, frequency, voltage, etc. 061ffe29dd