Master the Essentials: Electrical Systems – Theory & Design Calculations (more contents will be added weekly)

What you will learn

### Fundamentals of Electrical Circuits: Understand Ohm’s Law, Kirchoff’s Laws, and Thevenin’s Theorem to analyze and solve electrical circuits.

### AC Circuit Analysis: Master the analysis of AC circuits with resistive, inductive, and capacitive components, calculating power and power factor.

### Three-Phase Systems: Learn the principles of three-phase circuits, including connections, power measurement, and power factor correction.

### Harmonics and Mitigation: Grasp the concept of harmonics, their effects, and strategies to mitigate harmonics in electrical systems.

### Energy Measurement: Explore various energy measurement methods, including electromechanical, electronic, and smart energy meters.

### HT and LT Distribution: Differentiate between high-tension (HT) and low-tension (LT) distribution systems and their applications.

### Per Unit System Basics: Learn the concept of the per unit system and its importance in power system analysis.

### Switchgear and Protection: Explore the role of switchgear in electrical systems and the importance of protection devices.

### Distribution System Types: Understand radial, ring, and mesh distribution systems in electrical power networks.

### Fault Current Calculation: Calculate three-phase fault current and MVA using per unit values for power system protection.

### Types of Circuit Breakers: Understand various circuit breaker types, including air, vacuum, and SF6 circuit breakers.

### Switchboard and Switchgear Assemblies: Learn about high and low voltage switchgear assemblies.

### Protection Systems: Understand the purpose of protection systems and their components, including relays and transformers.

### Protection Schemes: Explore protection schemes, including overcurrent, earth fault, and differential protection.

### Transformer Basics: Learn about distribution transformers, their types, and protection methods.

### Cable Joints and Terminations: Explore methods for joining and terminating cables in electrical installations.

### Earthing Systems: Learn about substation and system earthing, including the role of earthing conductors and circuit protective conductors (CPC).

### Cable Construction and Types: Understand the construction, insulation materials, and specifications of electrical cables.

### Electrical Installation Design Sequence: Understanding steps in designing electrical installations, ensuring a systematic approach to the process.

### Determine Load Characteristics: Analyzing and calculating electrical load requirements for installations, considering equipment and load diversity.

### Determine Supply Characteristics: Identifying and assessing power supply characteristics, such as voltage levels, frequency, and reliability.

### Electrical Installation Outline: Creating an initial plan for installations, detailing the placement of components, circuits, and connections.

### Power Distribution Design: Planning the distribution of electrical power, addressing cable routing, conductor sizing, and selecting distribution equipment.

### Use Standard Final Circuits: Incorporating standard final circuits into designs, ensuring compliance with relevant regulations and standards.

### Isolation and Switching Requirements: Defining requirements for isolation and switching mechanisms, prioritizing safety and functionality.

### Final Assessment and Client Review: Conducting a comprehensive evaluation of the design and reviewing it with the client for alignment.

### Design calculations

### Electrical design

### Departure from Local Electrical Standards: Addressing deviations from local standards, documenting and justifying any departures appropriately.

### Fault calculations

### Cable sizing

### Shock protection

Ohm’s Law

Radial Distribution System

Electrical Installation Design Sequence

Description

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### Electrical Circuit Theory and Analysis

What you will learn

Ohm’s Law

Application of Ohm’s Law in Series Resistors Connection

Application of Ohm’s Law in Parallel Resistors Connection

Example of a DC Circuit Analysis using Ohm’s Law

Kirchoff’s Laws

Example of Circuit Analysis using Kirchoff’s Laws

Thevenin’s Theorem

Example of Circuit Analysis using Thevenin’s Theorem

Maximum Power Transfer Theorem

Sine Wave of Single Phase AC Voltage

AC Circuit With Pure Resistance Load

Power in Pure Resistive Load

Examples of Resistive Loads

Power Loss in Conductor

AC Circuit With Pure Inductive Load

Power in Pure Inductive Load

Example of Inductive Loads

AC Circuit with Pure Capacitive Load

Power in Pure Capacitive Load

Example of Capacitive Loads

Summary on Resistive, Inductive and Capacitive Circuit

Analysis on Series RLC Circuit

Analysis on Parallel RLC Circuit

Active, Reactive and Apparent Power in AC Circuit

Power Triangle

Power Factor and Relationship to Reactive Power

Example on Series RLC Circuit and Power Calculation

Effect of High Reactive Load to Power Loss

Phasor and Complex Number for AC Circuit Calculation

Three Phase AC Waveforms

Advantages of Three Phase AC

Basic Structure of a 3-Phase Circuit

Star(Y) source to Star(Y) load

Star(Y) source to Delta(∆) load

Delta(∆) source to Star(Y) load

Delta(∆) source to Delta(∆) load

Phase Voltage and Line Voltage

Relationship between Phase Voltage and Line Voltage for Y Connected Load

Current for Y Connected Load

Current for ∆ Connected Load

Conversion of ∆ source/load to Y source/load or Vice Versa

Calculation of 3 Phase Y source to Y load Circuit

Example Calculation of 3 Phase Y source to Y load Circuit

Power in a 3 phase Balanced AC Circuit

Example Power in a 3 phase Balanced AC Circuit

Calculation of ∆-Y, Y-∆ and ∆-∆ connections

Power Factor Correction

Example of Power Factor Correction

AC Current Measurement

AC Voltage Measurement

AC Power Measurement

Single, Two and Three Wattmeter Method

Power Analyzer

Energy Measurement

Electromechanical Induction Type Energy Meters

Electronic Type Energy Meters

Smart Energy Meters

Electrical Tariff

Introduction of Power System Harmonics

Triplen Harmonics

Where Do Harmonics Come From?

Example of Distorted Waveform

Total Harmonic Distortion (THD)

RMS value of a Total Waveform with Harmonics

Power and Power Factor with Harmonics

Effects of Harmonics on Generator

Effects of Harmonics on Transformer

Effects of Harmonics on AC Induction Motors

Effects of Harmonics on Cables

Effects of Harmonics on Circuit Breakers and Fuses

Effects of Harmonics on Lightings

Harmonic Standards and Mitigation Strategies

Harmonic Mitigation by Delta-Delta and Delta-Wye Transformers

Harmonic Mitigation by Isolation Transformers

Harmonic Mitigation by Passive Harmonic Filters

Harmonic Mitigation by Active Harmonic Filters

### Fundamental of Distribution and Protection Systems

What you will learn

Radial Distribution System

Ring Distribution System

Mesh Distribution System

Example of High Tension Distribution System

Example of LT Distribution System

Per Unit System

Selection & Calculation of Base Values of Per Unit System

Calculation of Per Unit Value

Establishing Uniform Base Values in Per Unit for Efficient Calculations

Purpose of Three Phase Fault Calculation

Derivation of Three Phase Fault Current

Derivation of Three Phase Fault MVA

Example of Three Phase Fault Current Calculation

Circuit Switching and Switchgears

Arcing Phenomena

Switching of Alternating Current Circuit

Electrical Specifications of Switching Devices

Switches, Switch-fuses and Fuse-switches

Rewirable Fuses

High Rupturing Capacity Fuse

Circuit Breakers – Essential Components in Electrical Systems

Miniature Circuit Breakers and Moulded Case Circuit Breakers

Air Circuit Breakers

Vacuum Circuit Breakers

SF6 Circuit Breakers

Switchboards

High Voltage Switchgear Assemblies

Low Voltage Switchgear Assemblies

Switchgear Isolation and Re-energization Procedures

Safety Precautions for Working with High Voltage Switchgear

Purpose of Protection Systems

Discrimination in Protection Systems

Earth Leakage Protection

Current Transformers

Voltage Transformers

Protection Relays

Protection Schemes

Combined Overcurrent and Earth Fault Protection

Differential Protection

Differential Protection of Feeders

Differential Protection of Transformers

Plug Setting of Protection Relays

Time Multiplier Setting of Protection Relays

Normal Inverse 3 10 IDMTL curve

Example of PS and TMS Settings of IDMTL Relays

Distribution Transformers

Mineral Oil-Filled Transformer, Silicon Oil Filled Transformer and Dry Type Tran

Terminal Markings of Transformers

Phase Shift in Transformers

Transformer Protection

Construction of Cables

Conductors and Applications

Cables Insulation Materials and Applications

Cable Types and Specifications

Cable Joints and Terminations

Substation Earthing and System Earthing

Earthing Conductor

Circuit Protective Conductor (CPC)

### Overview of Electrical Installation Design Sequence

What you will learn

Electrical Installation Design Sequence

Determine Load Characteristics

Determine Supply Characteristics

Electrical Installation Outline

Power Distribution Design

Use Standard Final Circuits

Isolation and Switching Requirements

Final Assessment and Client Review

Departure from Local Electrical Standards

### Simple Electrical Installation and Final Circuits

Characteristics of the Electricity Supply

Determine Fault rating of switchgear

Coordinating Load, Protective Device, and Cable Current Carrying Characteristics

Cable Sizing for Circuits without Overload Protection

Cable Sizing for Circuits with Overload Protection

30 and 32 A Ring Final Circuits

Example: Calculating Current and Protective Device Rating for a Shower Circuit

Example: 30 and 32 Ring Final Circuits Cable Sizing

Example: Ring Final Circuit Maximum Cable Length

Requirements for Fault Protection

Determining Maximum Cable Length for Voltage Drop Limits

Example: Maximum Cable Length Calculation for Ring Circuit

Example: Maximum Cable Length Calculation for Radial Circuit

Short-Circuit Current Protection Requirements

Protective Conductors Verification using Adiabatic Equation

### Maximum Demand and Diversity Factor

Understanding Electrical Demand and Load Diversity

Example of Domestic Appliances Load Demand

Overview of Load Demand of Winter Weekday

Installation Outline and Load Identification

Current Demand in Final Circuits

Example: Determining Current Demand in a Shower Circuit

Example: Determining Current Demand in a Cooker Circuit

Example: Determining Current Demand of a Lighting Circuit

Example: Determining Current Demand of a Single Phase Motor Circuit

Diversity Between Final Circuits in Simple Installations(1)

Diversity Between Final Circuits in Simple Installations(2)

Example: Calculating Maximum Demand for a Small Office

Example: Calculating Maximum Demand for a Domestic Installation

Diversity in Multi-Dwelling Electrical Installations

Accurate Estimation of Diversity in Complex Installations

Estimating Maximum Demand and Demand Factors

Estimating Maximum Demand at Sub-Distribution Points

Tolerance in Demand Estimations

Estimating Demand on Socket-Outlet Circuits

Demand Factor g

Example: After-Diversity Demand Calculation

### Cable Sizing for Current Carrying Capacity

Common Symbols in Cable Sizing

Initial Design

Overcurrent Protection Requirements

Fault Currents

Overload Currents

Small Overloads

Current-Carrying Capacity Tables

Rating Factors Explanation

Ambient temperature rating factor Ca

Group Rating Factor (Cg)

Group Rating Factor (Cg)Continued

Cg for Mixed Single Phase and Three Phase Circuits in Shared Enclosure

Example of Cg for Three-Phase and Single-Phase Circuits in a Common Enclosure

Grouping Considerations for Lightly Loaded Circuits

Example of Grouping Involving Lightly Loaded Circuits

Grouping Factors for Cables in Ducts Buried in Ground

Ci – Rating Factor for Cables in Thermal Insulation

Example Calculation Cable Current-Carrying Capacity in Thermal Insulation

Buried Circuit Rating Factor Cc

Soil Thermal Resistivity Rating Factor Cs

Depth of laying rating factor Cd

Example Determining Minimum Cross-Sectional Area of Underground Cables

Conductor Operating Temperature and Safety Guidelines

Cable Sizing for Protection Against Overload and Short Circuit

Example of Cable Sizing for Protective Device Providing Overcurrent Protection

Cable Sizing Overcurrent Protection for Conductors in Parallel

Example Cable Sizing Overcurrent Protection for Parallel Conductors

Protection against fault current only (omission of overload protection)

Example Cable Sizing for Protection against fault current only

Motors Starting and Continuous Current