Basic Electrical and Instrumentation Engineering

Sivaraman Palanisamy, Sharmeela Chenniappan, A. Thaiyal Nayagi, R. Mahendran

• Publisher: Wiley-Scrivener
• Year: 2020
• ISBN:
  9781119765127
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Electrical Engineering & Telecommunications
• Index: Technology & Engineering

Electrical and instrumentation engineering is changing rapidly, and it is important for the veteran engineer in the field not only to have a valuable and reliable reference work which he or she can consult for basic concepts, but also to be up to date on any changes to basic equipment or processes that might have occurred in the field. Covering all of the basic concepts, from three-phase power supply and its various types of connection and conversion, to power equation and discussions of the protection of power system, to transformers, voltage regulation, and many other concepts, this volume is the one-stop, "go to" for all of the engineer's questions on basic electrical and instrumentation engineering.

There are chapters covering the construction and working principle of the DC machine, all varieties of motors, fundamental concepts and operating principles of measuring, and instrumentation, both from a "high end" point of view and the point of view of developing countries, emphasizing low-cost methods.

A valuable reference for engineers, scientists, chemists, and students, this volume is applicable to many different fields, across many different industries, at all levels. It is a must-have for any library.

1
Introduction to Electric Power Systems

The main parameters in electrical systems are voltage and current. The product of voltage and current gives a third parameter called power, and power consumed over some time duration is called energy [1]. The electric power system consists of power generation, transmission and distribution system [2]. Power is generated from two main sources, namely conventional energy sources and non-conventional energy sources. The conventional energy sources are non-renewable which gets depleted over a period of time, while non-conventional energy sources are non-depleting sources [3, 10, 30]. Most large-scale power plants are located in areas where the raw materials are available locally and generated power is transmitted over long distances for distribution. An electrical conducting medium is required in order to transfer the power from generating station to load center. This conducting medium is called as transmission system. Transformers and transmission lines are the main components of the transmission system; they are used to transfer the power from generating station to consumers (customers) at various operating voltage levels. Generation voltage of the conventional power plant typically ranges from 6.6 kV to 22 kV, and transmission voltage typically ranges from 110 kV to 765 kV. High voltage is stepped down to various voltage levels for different consumers depending upon the requirements and installed capacity.

1.1 Introduction

In general, electrical power used for commercial and residential purpose is mostly Alternating Current (AC). An AC voltage or current has the magnitude and direction which changes periodically with respect to time, unlike the Direct Current (DC) supply, which has constant magnitude with respect to time. Figure 1.1 shows the waveform of AC (voltage and current) and Figure 1.2 shows the waveform of DC (voltage and current).

Figure 1.1 Waveform of AC.

Figure 1.2 Waveform of DC.

Types of AC supply system:

The AC supply system is classified into two types based on the number of phases:

• • Single-phase power supply
• • Three-phase power supply

A. The single phase supply

The single-phase power supply is used to power all the single-phase loads in the systems. Generally, single-phase power supply is derived from a three-phase, four-wire circuit. The single-phase voltage level varies from country to country. The general single-phase supply voltage is 220 V, 230 V, 240 V in low voltage systems (in Asian countries). Most of the single-phase supply systems are 2W systems as shown in Figure 1.11.

B. Three-Phase Power Supply

The three-phase power supply is used to power certain loads which need the poly-phase supply for their operation. Here phase means branch circuits or winding and poly means many. Such loads in any applicati...