Electrical Power Systems by C.L. Wadhwa: The Ultimate Resource for Power Systems
Electrical Power System by C.L. Wadhwa: A Comprehensive Book for Power Engineers
If you are looking for a book that covers all the aspects of electrical power systems, from fundamentals to advanced topics, then you should check out Electrical Power System by C.L. Wadhwa. This book is written by a renowned author who has more than 40 years of experience in teaching, research, and consultancy in power engineering. In this article, we will give you an overview of what this book is about, what topics it covers, and why it is useful for students and professionals alike.
electrical power system by cl wadhwa pdf zip
Overview of the book
Electrical Power System by C.L. Wadhwa is a comprehensive textbook that presents an exhaustive exposition of the various dimensions of electrical power systems. The book covers both basic and advanced topics, with a clear and systematic manner. The book is divided into 16 chapters, each covering a specific aspect of power systems. The chapters are as follows:
Chapter 1: Fundamentals of Power Systems
Chapter 2: Line Constant Calculations
Chapter 3: Capacitance of Transmission Lines
Chapter 4: Performance of Lines
Chapter 5: High Voltage D.C. Transmission
Chapter 6: Corona
Chapter 7: Mechanical Design of Transmission Lines
Chapter 8: Overhead Line Insulators
Chapter 9: Voltage Control
Chapter 10: Neutral Grounding
Chapter 11: Transients in Power Systems
Chapter 12: Fault Calculation
Chapter 13: Protective Relays
Chapter 14: Circuit Breakers
Chapter 15: Power System Synchronous Stability
Chapter 16: Load Flows
The book also includes a large number of solved examples, practice problems, and multiple choice questions, with answers provided at the end of the book. The book also has references to other books and papers for further reading and research.
Benefits of the book
Electrical Power System by C.L. Wadhwa is a valuable resource for anyone who wants to learn more about power engineering. Some of the benefits of the book are:
The book covers both theoretical and practical aspects of power systems, with a balance between analytical and numerical methods.
The book explains the concepts and principles in a simple and lucid language, with diagrams, tables, and graphs to illustrate the points.
The book provides a comprehensive coverage of the topics, from basic to advanced, with a logical and coherent sequence.
The book updates the readers with the latest developments and trends in power systems, such as HVDC transmission, FACTS devices, renewable energy sources, and smart grids.
The book is suitable for undergraduate and postgraduate students of electrical engineering, as well as for AMIE, GATE, and other competitive examination candidates. The book is also useful for practicing engineers and consultants who want to refresh their knowledge or learn new skills.
Fundamentals of Power Systems
In this chapter, we will introduce some of the basic concepts and definitions related to power systems. A power system is a network of electrical components that generate, transmit, distribute, and utilize electrical energy. The main components of a power system are:
Power stations or generating units: These are the sources of electrical energy, such as thermal, hydro, nuclear, solar, wind, etc.
Transmission lines: These are the conductors that carry high voltage electricity from the generating units to the load centers or substations.
Substations: These are the points where the voltage level is stepped up or down using transformers, and where switching and protection devices are installed.
Distribution lines: These are the conductors that carry low voltage electricity from the substations to the consumers or loads.
Loads: These are the devices that consume electrical energy, such as lighting, heating, cooling, motors, appliances, etc.
Some of the parameters that describe a power system are:
Voltage: This is the potential difference between two points in an electric circuit. It is measured in volts (V).
Current: This is the rate of flow of electric charge in an electric circuit. It is measured in amperes (A).
Power: This is the rate of doing work or transferring energy in an electric circuit. It is measured in watts (W).
Energy: This is the capacity to do work or transfer heat in an electric circuit. It is measured in joules (J) or watt-hours (Wh).
Resistance: This is the opposition to the flow of current in an electric circuit. It is measured in ohms (Ω).
Reactance: This is the opposition to the change of current or voltage in an electric circuit due to capacitance or inductance. It is measured in ohms (Ω).
Impedance: This is the total opposition to the flow of current or voltage in an electric circuit due to resistance and reactance. It is measured in ohms (Ω).
Power factor: This is the ratio of real power to apparent power in an electric circuit. It indicates how efficiently a load utilizes electrical energy. It ranges from 0 to 1.
Performance of Overhead Lines
In this chapter, we will discuss how overhead lines perform under different operating conditions. Overhead lines are one of the most important components of a power system, as they carry bulk power over long distances. However, they also have some limitations and losses that affect their performance. Some of the factors that influence the performance of overhead lines are:
Line constants and calculations
Mechanical design of lines
The mechanical design of lines involves the selection of suitable conductors, supports, and accessories for overhead lines. The main objectives of mechanical design are to ensure the safety, reliability, and economy of the lines. Some of the factors that affect the mechanical design of lines are:
Conductor size and material: The conductor size and material determine the current carrying capacity, resistance, weight, and cost of the line. The most common materials used for conductors are copper, aluminum, and steel.
Conductor spacing and configuration: The conductor spacing and configuration affect the inductance, capacitance, corona loss, and interference of the line. The most common configurations are single-phase, three-phase, and double-circuit.
Support type and height: The support type and height determine the sag, tension, clearance, and strength of the line. The most common types of supports are poles, towers, and pylons.
Insulator type and number: The insulator type and number provide the electrical insulation and mechanical support for the conductors. The most common types of insulators are pin, suspension, strain, and post.
Accessories and fittings: The accessories and fittings include the devices that connect, protect, and control the line. Some examples are splices, joints, clamps, connectors, dampers, arresters, switches, etc.
Corona and insulation
Corona is a phenomenon that occurs when the electric field around a conductor exceeds a critical value. It causes a partial ionization of the air around the conductor, resulting in a bluish glow, hissing noise, ozone formation, and power loss. Corona can also cause interference with communication systems and damage to insulation. Some of the factors that influence corona are:
Voltage level: Corona increases with increasing voltage level.
Conductor size and shape: Corona decreases with increasing conductor size and smoothness.
Conductor spacing: Corona decreases with increasing conductor spacing.
Air density and humidity: Corona decreases with increasing air density and humidity.
Insulation is the material or device that prevents the flow of current between conductors or between conductors and ground. Insulation is essential for maintaining the safety and reliability of power systems. Some of the factors that affect insulation are:
Voltage level: Insulation increases with increasing voltage level.
Insulation type and material: Insulation varies with different types and materials of insulation.
Ambient conditions: Insulation decreases with increasing temperature, moisture, pollution, etc.
Aging and deterioration: Insulation decreases with aging and deterioration due to thermal stress, mechanical stress, chemical reaction, etc.
Voltage Control and Neutral Grounding
In this chapter, we will discuss how voltage control and neutral grounding are implemented in power systems. Voltage control is the process of maintaining or adjusting the voltage level in a power system within acceptable limits. Neutral grounding is the process of connecting the neutral point of a power system to earth or to a reference potential. Both voltage control and neutral grounding are important for ensuring the quality, stability, and protection of power systems. Some of the methods and devices used for voltage control and neutral grounding are:
Voltage regulation and compensation
Voltage regulation is the ratio of the change in voltage at a given point in a power system to the change in load at that point. Voltage regulation indicates how well a power system can maintain its voltage level under varying load conditions. Voltage compensation is the technique of injecting reactive power into or absorbing reactive power from a power system to improve its voltage regulation. Some of the devices used for voltage compensation are:
Generators: Generators can adjust their terminal voltage by changing their excitation current or field flux.
Transformers: Transformers can adjust their output voltage by changing their tap settings or phase angle.
Capacitors: Capacitors can inject reactive power into a power system by storing electric charge.
Reactors: Reactors can absorb reactive power from a power system by storing magnetic flux.
Synchronous condensers: Synchronous condensers are synchronous motors that operate at no load and can inject or absorb reactive power by varying their excitation current or field flux.
Static VAR compensators: Static VAR compensators are power electronic devices that can inject or absorb reactive power by switching capacitors, reactors, or thyristors.
Neutral grounding methods and devices
Neutral grounding is the method of connecting the neutral point of a power system to earth or to a reference potential. Neutral grounding serves several purposes, such as:
Limiting the overvoltages due to lightning, switching, or resonance.
Facilitating the detection and isolation of faults.
Reducing the risk of electric shock and fire hazards.
Improving the power quality and reliability.
Some of the methods and devices used for neutral grounding are:
Solid grounding: Solid grounding is the direct connection of the neutral point to earth with a low resistance. Solid grounding provides the best protection against overvoltages and faults, but it also causes high fault currents and ground potential rise.
Resistance grounding: Resistance grounding is the connection of the neutral point to earth through a resistor. Resistance grounding limits the fault currents and ground potential rise, but it also reduces the sensitivity of fault detection and increases the transient overvoltages.
Reactance grounding: Reactance grounding is the connection of the neutral point to earth through a reactor. Reactance grounding limits the fault currents and transient overvoltages, but it also reduces the sensitivity of fault detection and increases the resonance overvoltages.
Resonant grounding: Resonant grounding is the connection of the neutral point to earth through a capacitor or a tuned circuit. Resonant grounding cancels out the capacitive current of the system and provides zero sequence impedance. Resonant grounding eliminates the fault currents and overvoltages, but it also requires careful tuning and maintenance.
Ungrounded or isolated neutral: Ungrounded or isolated neutral is the absence of any connection between the neutral point and earth. Ungrounded or isolated neutral avoids any fault currents and ground potential rise, but it also causes high overvoltages and difficulty in fault location.
Fault Analysis and Protection
In this chapter, we will discuss how faults are analyzed and protected in power systems. A fault is an abnormal condition in a power system that causes a deviation from the normal operation. Faults can be classified into two types: symmetrical faults and unsymmetrical faults. Symmetrical faults are faults that involve all three phases equally, such as three-phase short circuits. Unsymmetrical faults are faults that involve one or two phases unequally, such as single-phase or phase-to-phase short circuits, or phase-to-ground faults. Faults can cause serious problems in power systems, such as:
Voltage drop and power loss.
Equipment damage and fire hazards.
System instability and blackout.
Interference with communication systems.
Therefore, it is essential to analyze and protect power systems from faults. Some of the methods and devices used for fault analysis and protection are:
Fault types and calculations
Fault types are determined by the location, duration, impedance, and polarity of the fault. Fault calculations are performed by applying Kirchhoff's laws, Ohm's law, symmetrical components, or matrix methods to find the fault currents, voltages, impedances, and powers. Fault calculations are useful for designing protective devices, selecting equipment ratings, evaluating system performance, etc. Some of the steps involved in fault calculations are:
Drawing the single-line diagram of the system.
Converting all quantities to per unit values.
Determining the pre-fault conditions.
Applying the fault at a given point.
Solving for the fault currents, voltages, impedances, and powers.
Comparing the results with the equipment ratings and protection settings.
Protective relays and circuit breakers
the rest of the system. Protective relays and circuit breakers work together to provide fast and reliable protection for power systems. Some of the functions and types of protective relays and circuit breakers are:
Overcurrent protection: This function protects the system from excessive currents due to overloads or short circuits. The types of overcurrent relays are instantaneous, inverse-time, directional, differential, etc.
Distance protection: This function protects the system from faults that occur at a certain distance or impedance from the relay location. The types of distance relays are impedance, reactance, mho, quadrilateral, etc.
Differential protection: This function protects the system from faults that cause a difference in current or voltage between two points. The types of differential relays are current differential, voltage differential, percentage differential, etc.
Pilot protection: This function protects the system from faults that occur on long transmission lines or interconnections. The types of pilot relays are wire-pilot, carrier-pilot, microwave-pilot, etc.
Frequency protection: This function protects the system from abnormal frequency variations due to load-generation imbalance or islanding. The types of frequency relays are underfrequency, overfrequency, rate-of-change-of-frequency, etc.
Voltage protection: This function protects the system from abnormal voltage variations due to faults, load changes, or voltage regulation. The types of voltage relays are undervoltage, overvoltage, directional overvoltage, etc.
Directional protection: This function protects the system from faults that occur in a certain direction with respect to the relay location. The types of directional relays are directional overcurrent, directional distance, directional power, etc.
Power protection: This function protects the system from abnormal power flows due to faults, load changes, or power swings. The types of power relays are reverse power, underpower, overpower, etc.
Oil circuit breakers: These circuit breakers use oil as the arc quenching and insulating medium. They are suitable for low and medium voltage applications.
Air circuit breakers: These circuit breakers use air as the arc quenching and insulating medium. They are suitable for low and medium voltage applications.
SF6 circuit breakers: These circuit breakers use sulfur hexafluoride gas as the arc quenching and insulating medium. They are suitable for high voltage applications.
Vacuum circuit breakers: These circuit breakers use vacuum as the arc quenching and insulating medium. They are suitable for medium and high voltage applications.
Power System Stability and Control
In this chapter, we will discuss how power system stability and control are achieved in power systems. Power system stability is the ability of a power system to maintain synchronism and voltage balance under normal and disturbed conditions. Power system control is the process of regulating and adjusting the power system parameters to maintain or improve its stability and performance. Some of the methods and devices used for power system stability and control are:
Synchronous stability and voltage stability
Synchronous stability is the ability of a power system to maintain synchronism among its generators under small or large disturbances. Synchronous stability depends on the balance between the mechanical input power and the electrical output power of each generator. Synchronous stability can be classified into two types: steady-state stability and transient stability. Steady-state stability is the ability of a power system to maintain synchronism under small disturbances that do not cause significant changes in the system state. Transient stability is the ability of a power system to maintain synchronism under large disturbances that cause significant changes in the system state.
Voltage stability is the ability of a power system to maintain acceptable voltage levels at all buses under normal and disturbed conditions. Voltage stability depends on the balance between the reactive power demand and supply of each bus. Voltage stability can be classified into two types: static voltage stability and dynamic voltage stability. Static voltage stability is the ability of a power system to maintain acceptable voltage levels under steady-state conditions or small disturbances that do not cause significant changes in the system state. Dynamic voltage stability is the ability of a power system to maintain acceptable voltage levels under dynamic conditions or large disturbances that cause significant changes in the system state.
Some of the methods and devices used for improving synchronous stability and voltage stability are:
Excitation systems: Excitation systems are devices that control the field current or flux of the generators to regulate their terminal voltage and reactive power output. Excitation systems can be classified into three types: static excitation systems, brushless excitation systems, and rotating excitation systems.
Power system stabilize