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ETAP Power System Analysis Online Course For Electrical Engineer

(Real Industrial Projects Based Training Program)

Course Objective

This course is designed to provide hands-on practical exposure using ETAP for real-world electrical systems such as substations, industrial plants, and renewable energy integration.

🔰 Module 1: ETAP Basics & Interface (Beginner Level)

Topics:

Introduction to ETAP & Applications

Interface, Toolbar, Project Setup

Standards: IEC vs ANSI
Base Values & Per Unit System Practical:

Create first SLD
Add basic components Assignment:

Develop SLD of a simple 11 kV system

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⚙️ Module 2: Equipment Modeling & SLD Development

Topics:

Transformers, Cables, Motors, Generators

Circuit Breakers, CT, PT

Busbars & Loads
Data input (real industrial parameters) Practical:
Model industrial plant SLD Assignment:
Build full plant electrical system

⚡ Module 3: Load Flow Analysis (Power Flow Study)

Topics:

Load Flow Methods (Newton-Raphson)

Voltage Profile Analysis

Loss Calculation
Power Factor Improvement Practical:
Load flow on industrial system Real Case:

Voltage drop problem in plant

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Assignment:

Improve voltage profile

⚡ Module 4: Short Circuit Analysis

Topics:

Fault Types (3-phase, L-G, L-L)
IEC 60909 / ANSI standards
Fault Current Calculation
Breaker Rating Selection Practical:
Fault analysis at different buses Assignment:

Select correct breaker rating

🔒 Module 5: Protection & Relay Coordination

Topics:

Overcurrent Protection

Time Current Curves (TCC)

Relay Coordination

Differential Protection

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Practical:

Relay setting in ETAP
Curve plotting Assignment:
Achieve selectivity

🔥 Module 6: Arc Flash Study & Safety

Topics:

Arc Flash Theory

IEEE 1584

Incident Energy Calculation
PPE Category Practical:
Arc flash simulation Assignment:

PPE calculation

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📊 Module 7: Harmonic Analysis & Power Quality

Topics:

Harmonics sources

THD calculation

Filters design (Passive/Active)
IEEE 519 Practical:
Harmonic analysis in VFD system Assignment:
Design harmonic filter

🏗️ Module 8: Substation Design (33/11 kV Project)

Topics:

Substation layout

Equipment selection

Protection scheme
Earthing design Practical:
Complete substation modeling in ETAP

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Assignment:

Design full 33/11 kV substation

🏭 Module 9: Industrial System Design Project

Topics:

Plant load calculation
Motor load analysis
Distribution system Practical:
Full industrial plant design Assignment:

Submit plant study report

Course Deliverables

ETAP Project Files
Calculation Sheets
Design Templates
Industrial Case Studies
Certification (Tips Engineer Zone)

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🔰 Module 1: ETAP Basics & Interface (Detailed Learning)

1. Introduction to ETAP & Applications

What is ETAP?

ETAP is a powerful electrical engineering software used to:

Design electrical systems
Simulate real power networks
Analyze faults and performance

Where it is used?

Substations (33/11 kV, 132/33 kV)
Industrial plants (steel, cement, oil & gas)
Solar & renewable energy systems
Utility power systems

Why ETAP is important?

In real industry:

Before installing equipment → engineers simulate in ETAP
To avoid failures → load flow + fault study is done
For safety → arc flash study is mandatory

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□ 2. Interface, Toolbar & Project Setup

Step 1: Open ETAP

Click → New Project
Enter:

Project Name (e.g., “11kV_System”)
Frequency (50 Hz for India)
Standard → IEC

Step 2: Understand Interface Main Sections:

One-Line Diagram (SLD) Window → where you draw system
Toolbar → contains all electrical components
Project View → shows project files
Output Window → results & errors

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Step 3: Toolbar Components (Very Important)

You will use these daily:

Bus
Transformer
Cable
Load
Circuit Breaker
Generator

These are same as real electrical equipment

3. Standards: IEC vs ANSI

IEC (India, Europe)

Units: kV, kA
Used in most Indian projects

ANSI (USA)

Different fault calculation methods

What to choose?

Always select IEC for:

India
Gulf countries
Most industrial projects

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4. Base Values & Per Unit System

What is Base Value?

Reference value used in calculations Example:
Base Voltage = 11 kV
Base Power = 10 MVA

What is Per Unit System?

Formula:

Per Unit = Actual Value / Base Value

Why important?

Simplifies complex calculations
Used in:

Load Flow
Short Circuit

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🔧 Practical: Create First SLD (Step-by-Step)

Objective:

Create a simple 11 kV system

Step 1: Add Bus

Select Bus from toolbar
Place it on screen
Rename → “11kV Bus”
Set voltage → 11 kV

Step 2: Add Source (Grid)

Add Utility / Grid
Connect to bus

Step 3: Add Transformer

Drag transformer
Set:

Rating → 10 MVA
Voltage → 33/11 kV

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Step 4: Add Load

Add Static Load / Motor Load
Connect to 11 kV bus
Example:

Load = 5 MW

Step 5: Add Circuit Breaker

Place between:

Bus & Transformer
Bus & Load

Final SLD Structure:

Grid → CB → Transformer → CB → 11 kV Bus → Load

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📂 Assignment (Very Important for Learning)

Task:

Create SLD of simple 11 kV system

Requirements:

1 Incoming source
1 Transformer (33/11 kV)
1 Bus (11 kV)
2 Loads (e.g., 2 MW + 3 MW)
Circuit breakers

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⚙️ Module 2: Equipment Modeling & SLD Development (Detailed)

Objective

Learn how to model real electrical equipment in ETAP and create a complete industrial plant SLD (Single Line Diagram).

1. Equipment Modeling (Core of ETAP)

In real projects, wrong data = wrong results

So this module is most important for accuracy

A. Transformer Modeling

What you enter in ETAP:

Rating (MVA) → e.g., 10 MVA
Voltage → 33/11 kV
Impedance (%Z) → e.g., 8%
Vector Group → Dyn11
Cooling → ONAN / ONAF

Industry Tip:

% Impedance directly affects fault current
Always take data from:

Transformer nameplate
Vendor datasheet

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B. Cable Modeling

Parameters:

Cable type (XLPE / PVC)
Size (e.g., 240 sq.mm)
Length (important for voltage drop)
Installation type (tray / buried / air)
Resistance & Reactance

Why important?

Affects:

Voltage drop
Losses
Short circuit current

C. Motor Modeling

Input Data:

Power → kW (e.g., 500 kW)
Voltage → 11 kV / 415 V
Power factor
Efficiency
Starting method (DOL / Star-Delta / VFD)

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Industry Insight:

Motors are major load in industries
Starting current = 5–7 times rated current

D. Generator Modeling

Parameters:

Capacity (MVA)
Voltage level
Subtransient reactance (Xd")
Power factor

Use Case:

Backup DG system
Captive power plant

2. Switchgear & Measurement Devices

A. Circuit Breaker (CB)

Key Inputs:

Rated Voltage
Breaking Capacity (kA)

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Type → VCB / SF6

Role:

Protect system during faults

B. Current Transformer (CT)

Input:

Ratio (e.g., 1000/1 A)
Accuracy class (5P10, 0.2)

Use:

Measurement + Protection

C. Potential Transformer (PT)

Input:

Voltage ratio (e.g., 33kV/110V)

Use:

Voltage measurement

3. Busbars & Load Modeling

Busbar

Voltage level (11 kV / 33 kV)

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Short circuit rating

Acts as common connection point

Load Types in ETAP:

Static Load (kW, kVAR)
Motor Load
Lumped Load

Load Input Example:

Active Power = 5 MW
Power Factor = 0.85 lag

4. Data Input (Real Industrial Practice)

Where to get data?

Equipment datasheets
Site survey
Vendor drawings
Electrical BOQ

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Golden Rule:

“Garbage In = Garbage Out” Always verify:

Voltage levels
Ratings
Units

🔧 Practical: Model Industrial Plant SLD

Objective:

Create a real plant electrical system

Example Plant:

33 kV incoming supply
10 MVA transformer
11 kV distribution
Motors + loads

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Step-by-Step SLD Creation

Step 1: Create 33 kV Source

Add Utility/Grid
Set:

Voltage = 33 kV
Short circuit level

Step 2: Add Circuit Breaker + CT/PT

Place CB between source & bus
Add CT/PT for protection

Step 3: Create 33 kV Bus

Name: BUS-33KV-01

Step 4: Add Transformer

33/11 kV, 10 MVA
Connect to bus

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Step 5: Create 11 kV Bus

Name: BUS-11KV-01

Step 6: Add Feeders Add:

Motor 1 → 500 kW
Motor 2 → 1 MW
Static Load → 2 MW

Step 7: Add Cables

Connect all loads using cables
Enter length & size

Final SLD Structure:

33 kV Grid → CB → Bus → Transformer → 11 kV Bus → Feeders → Loads

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📂 Assignment: Build Full Plant Electrical System

Task:

Design complete industrial plant SLD

Requirements:

System must include:

1 Incoming (33 kV)
1 Transformer (33/11 kV)
1 Main Bus (11 kV)
Minimum 3 Loads:

1 Motor (500 kW)
1 Motor (1 MW)
1 Static Load (2 MW)

Circuit breakers for all feeders
Cables with proper data

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⚡ Module 3: Load Flow Analysis (Power Flow Study)

Objective

Learn how to use ETAP to:

Analyze voltage at every bus
Calculate power flow & losses
Identify system problems
Improve overall system performance

1. Load Flow Methods (Newton-Raphson)

What is Load Flow?

Load flow (power flow) calculates:

Voltage magnitude (kV)
Voltage angle (°)
Active power (kW)
Reactive power (kVAR)

For every bus in the system

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Newton-Raphson Method (Most Important)

Why used?

High accuracy
Fast convergence
Used in real industrial software

Basic Concept:

It solves power equations:

P = V × I × cosθ Q = V × I × sinθ

Iterative method:

Guess initial voltage
Correct step-by-step
Reach accurate solution

In ETAP:

You don’t calculate manually — but you must:

Understand results
Validate system behavior

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2. Voltage Profile Analysis

What is Voltage Profile?

Voltage at different buses:

Should be within ±5% of rated value Example:
11 kV system → acceptable range:

o 10.45 kV to 11.55 kV

Problems:

Undervoltage → motors overheat
Overvoltage → insulation damage

In ETAP:

After load flow:

Check each bus color:

Normal

Problem

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3. Loss Calculation

Types of Losses:

Cable losses (I²R)
Transformer losses
Reactive power losses

Formula:

Loss = I² × R

Why important?

Reduces efficiency
Increases electricity bill
Affects system design

ETAP Output:

Total system losses (kW)
Loss per branch

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4. Power Factor Improvement

What is Power Factor?

PF = kW / kVA

Problem:

Low PF (<0.9):

High current
Higher losses
Penalty from utility

Solution:

Capacitor Bank
Synchronous condenser

Target:

Maintain PF ≥ 0.95

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🔧 Practical: Load Flow on Industrial System

Objective:

Run load flow on your Module 2 plant model

Step-by-Step in ETAP:

Step 1: Open Your SLD

Ensure:

All components connected
No red errors

Step 2: Go to Load Flow Mode

Click → Load Flow Analysis

Step 3: Set Parameters

Method → Newton-Raphson
Tap changer → Auto (if transformer present)

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Step 4: Run Simulation

Click → Run

Step 5: Analyze Results

Check:

Bus voltage
Line loading (%)
Transformer loading
Losses

Real Case: Voltage Drop Problem in Plant

Problem Scenario:

Plant load increases
Voltage at 11 kV bus drops to:

9.8 kV (Too low )

Causes:

Long cable length
Heavy motor load
Low power factor

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Solutions (Industry Approach):

Solution 1: Increase Cable Size

Reduce resistance → less voltage drop

Solution 2: Add Capacitor Bank

Improve PF
Reduce reactive current

Solution 3: Adjust Transformer Tap

Increase output voltage

Solution 4: Load Distribution

Shift load to another feeder

Assignment: Improve Voltage Profile

Task:

Fix voltage issues in given plant system

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Given:

11 kV system
Voltage at bus = 10 kV (low)

You must:

Run load flow
Identify weak buses
Apply solutions:

Capacitor
Tap change
Cable improvement

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⚡ Module 4: Short Circuit Analysis (Fault Study)

Objective

Using ETAP, you will learn to:

Calculate fault current at different locations
Select correct circuit breaker ratings
Ensure system safety & protection

1. Fault Types (Very Important)

A. 3-Phase Fault (Symmetrical Fault)

All three phases shorted together

Characteristics:

Highest fault current
Most severe fault

Use:

Used for equipment rating selection

B. Line-to-Ground (L-G Fault)

One phase touches ground

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Characteristics:

Most common fault (≈70%)
Lower current than 3-phase

C. Line-to-Line (L-L Fault)

Two phases short together

Characteristics:

Moderate fault current

D. Double Line-to-Ground (L-L-G)

Two phases + ground

Summary Table:

Fault Type	Severity	Occurrence
3-Phase	Highest	Rare
L-G	Medium	Most common
L-L	Medium	Less common

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2. Standards: IEC vs ANSI

IEC Standard (IEC 60909)

Used in India & most countries
Provides:

Initial fault current (Ik")
Peak current (Ip)
Breaking current

🇺🇸 ANSI Standard

Used in USA
Different calculation approach

What to use?

Always select IEC 60909 for:

India
Industrial projects

3. Fault Current Calculation

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Basic Concept:

Fault current depends on:

System voltage
System impedance

Formula:

Fault Current (Isc) = Voltage / Impedance

Important Terms:

Ik" (Initial Symmetrical Current)

Used for breaker selection

Ip (Peak Current)

Used for mechanical strength

Example:

System Voltage = 11 kV
Impedance = low

Fault current becomes very high (danger )

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🔌 4. Circuit Breaker Rating Selection

Breaker must handle:

Breaking Capacity (kA)
Making Capacity (Peak current)
Thermal withstand

Rule:

Breaker rating must be: Breaker Capacity ≥ Fault Current

Example:

Fault current = 25 kA

Select breaker:

31.5 kA (safe choice)

Wrong Selection:

Breaker explodes
System damage

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🔧 Practical: Fault Analysis in ETAP

Objective:

Perform fault analysis on industrial system (Module 2 SLD)

Step-by-Step:

Step 1: Open SLD

Ensure:

All data correct
No errors

Step 2: Go to Short Circuit Mode

Click → Short Circuit Analysis

Step 3: Select Standard

Choose → IEC 60909

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Step 4: Select Fault Type

3-phase
L-G
L-L

Step 5: Run Simulation

Step 6: Analyze Results

Check:

Fault current at each bus
Breaker duty
Equipment rating

🏭 Practical Case: Fault Analysis at Different Buses Example System:

33 kV Bus
11 kV Bus

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Observations:

At 33 kV Bus:

Lower fault current

At 11 kV Bus:

Higher fault current (closer to load)

Why?

Lower voltage side → lower impedance → higher current

Assignment (Important for Mastery)

Task:

Perform short circuit analysis of plant system

Requirements:

Run:

3-phase fault
L-G fault

Record:

Fault current at each bus
Breaker ratings

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🔒 Module 5: Protection & Relay Coordination

Objective

Using ETAP, you will learn:

How to protect electrical systems from faults
How to set relays properly
How to achieve selective tripping (only faulty section trips)

1. Overcurrent Protection (Most Common Protection)

□ What is Overcurrent Protection?

When current exceeds a set limit → relay sends signal → breaker trips

Types:

Instantaneous (High Fault)

Trips immediately (no delay)

Time-Delayed (Backup Protection)

Trips after some time delay

Real Example:

Motor feeder fault → only that feeder should trip

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Relay Parameters:

Pickup Current (Ip)
Time Dial Setting (TDS)
Curve Type (Standard inverse, very inverse)

2. Time Current Curves (TCC)

What is TCC?

Graph between:

Current (X-axis)
Time (Y-axis)

Purpose:

To ensure proper coordination between relays

Example:

Feeder relay → fast trip
Main relay → slower trip

So feeder trips first

Key Rule:

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Downstream relay must trip before upstream relay

3. Relay Coordination (Most Important Concept)

What is Coordination?

Ensuring:

Only faulty section trips
Rest system remains ON

Without Coordination:

Entire plant shutdown
Production loss

Coordination Chain Example:

Load → Feeder Relay → Bus Relay → Transformer Relay → Grid Relay

Fault at load → only feeder should trip

Coordination Margin:

Typically: 0.3 to 0.5 sec delay between relays

4. Differential Protection (Advanced Protection)

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What is Differential Protection?

Compares:

Current IN = Current OUT

If mismatch:

Fault inside equipment → trip immediately

Used For:

Transformer protection
Generator protection

Advantage:

Fastest and most accurate protection

Practical: Relay Setting in ETAP

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Objective:

Set relay parameters and check coordination

Step-by-Step:

Step 1: Open Your SLD

Ensure:

o Short circuit study completed (Module 4)

Step 2: Add Relay to Circuit Breaker

Select breaker → assign relay

Step 3: Enter Relay Settings Example:

Pickup current = 1.2 × full load current
Curve type = Standard inverse
Time dial = adjust for coordination

Step 4: Open TCC Curve

Go to → Star View / TCC
Select multiple relays

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Step 5: Plot Curve

You will see:

Multiple curves (feeder, transformer, etc.)

Step 6: Adjust Settings

Ensure:

Curves do not overlap
Proper time gap maintained

Practical: Curve Plotting (Visualization)

Goal:

Ensure:

Feeder trips first
Transformer trips later

Correct Coordination:

Curves separated properly

Wrong Coordination:

Curves overlap → system failure risk

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Assignment: Achieve Selectivity

Task:

Design relay coordination for plant system

Given System:

33/11 kV transformer
3 feeders

You must:

Assign relays to:

Feeders
Transformer

Set:

Pickup current
Time delay

Plot TCC curves

Target:

Achieve selectivity:

Fault at feeder → only feeder trips

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Module 6: Arc Flash Study & Safety

Objective

Using ETAP, you will learn to:

Analyze arc flash hazards
Calculate incident energy
Define safe working distance
Select proper PPE (Personal Protective Equipment)

1. Arc Flash Theory

What is Arc Flash?

An arc flash is a sudden electrical explosion caused by:

Short circuit
Equipment failure
Human error

Effects:

Extreme heat (up to 20,000°C )
Blast pressure
Serious injury / death

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Where it happens?

Switchgear panels
MCC panels
Substations
Transformer terminals

Real Example:

Technician opens 11 kV panel → internal fault → arc flash → severe burn

2. Standard: IEEE 1584

What it provides:

Formula for incident energy calculation
Arc flash boundary
PPE categories

Why important?

Mandatory for:

Industrial safety compliance
Electrical design projects

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3. Incident Energy Calculation

What is Incident Energy?

Energy received by a person at a distance from arc

Unit:

cal/cm²

Concept:

Incident Energy ∝ Fault Current × Time × Distance

Key Factors:

Fault current (from short circuit study)
Clearing time (relay + breaker)
Working distance

Example:

Fault current = high
Trip time = slow

Incident energy becomes dangerously high

4. PPE Category (Safety Gear Selection)

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□ PPE = Personal Protective Equipment

PPE Levels:

Category	Energy Range	Protection
0	< 1.2 cal/cm²	Basic clothing
1	1.2–4 cal/cm²	FR shirt
2	4–8 cal/cm²	FR suit
3	8–25 cal/cm²	Full suit
4	25–40 cal/cm²	Heavy suit

Rule:

Higher energy → higher protection

🔧 Practical: Arc Flash Simulation in ETAP

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Objective:

Calculate arc flash hazard for plant system

Step-by-Step:

Step 1: Complete Short Circuit + Relay Study

Required input for arc flash

Step 2: Switch to Arc Flash Mode

Click → Arc Flash Analysis

Step 3: Enter Data

Working distance (e.g., 600 mm)
Enclosure type
Electrode configuration

Step 4: Run Simulation

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Step 5: Analyze Output

Check:

Incident Energy (cal/cm²)
Arc Flash Boundary
PPE Category

Real Case: High Arc Flash Risk

Scenario:

11 kV panel
Fault current = 25 kA
Trip time = 0.8 sec

Result:

Incident energy = very high
PPE Category 4 required

Solution:

Reduce relay operating time
Use faster breaker
Improve protection coordination

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Assignment: PPE Calculation

Task:

Calculate PPE requirement for system

Given:

Incident Energy = 10 cal/cm²

You must:

Identify PPE category
Suggest safety measures

Answer:

PPE Category 3 required

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📊 Module 7: Harmonic Analysis & Power Quality

Objective

Using ETAP, you will learn to:

Identify harmonic sources
Calculate THD (Total Harmonic Distortion)
Design harmonic filters
Improve overall power quality

1. Harmonics Sources

What are Harmonics?

Harmonics are distorted waveforms caused by non-linear loads.

Instead of pure sine wave → distorted wave

Common Sources in Industry:

VFD (Variable Frequency Drives)
UPS systems
Rectifiers / Converters
LED lighting
Computers / SMPS

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Example:

Ideal waveform → smooth sine
With VFD → distorted waveform

Problems Caused:

Overheating of cables
Transformer losses increase
Equipment malfunction
Nuisance tripping

2. THD Calculation (Total Harmonic Distortion)

What is THD?

Measure of waveform distortion

Formula:

THD (%) = √(V2² + V3² + V4² + …) / V1 × 100

Where:

V1 = Fundamental voltage
V2, V3 = Harmonic components

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Acceptable Limits:

According to IEEE 519:

Voltage THD < 5%
Current THD depends on system

If THD > limit:

System is unsafe

3. Filters Design (Very Important)

Types of Filters:

Passive Filter

Combination of:

Inductor (L)
Capacitor (C)

Tuned to specific harmonic frequency

Active Filter

Electronic device
Injects opposite harmonics

More advanced & costly

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Selection:

Type Use Case

Passive Fixed load, low cost

Active Variable load, high accuracy

4. Standard: IEEE 519

It defines:

Acceptable harmonic limits
Voltage distortion limits
Current distortion limits

Why important?

Ensures:

System reliability
Equipment safety
Utility compliance

Practical: Harmonic Analysis in VFD System

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Objective:

Analyze harmonics in industrial plant

Step-by-Step in ETAP:

Step 1: Open SLD

Include:

VFD loads
Motors

Step 2: Enable Harmonic Analysis

Switch to → Harmonic Mode

Step 3: Define Harmonic Source

Select VFD
Enter:

Harmonic spectrum (5th, 7th, 11th…)

Step 4: Run Simulation

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Step 5: Analyze Results

Check:

THD at bus
Voltage distortion
Current distortion

Real Case: Harmonic Problem in Plant

Scenario:

Multiple VFDs installed
THD = 12%

Issues:

Transformer overheating
Capacitor bank failure

Solution:

Install harmonic filter
Reduce THD < 5%

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Assignment: Design Harmonic Filter

Task:

Design filter to reduce harmonics

Given:

THD = 10%
Required THD < 5%

You must:

Identify harmonic order (5th, 7th)
Select filter type:

Passive / Active

Design parameters:

Inductance (L)
Capacitance (C)

Expected Output:

Reduced THD
Improved waveform

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⚡ Module 8: Substation Design (33/11 kV Project)

Objective

Using ETAP, you will learn to:

Design a complete 33/11 kV substation
Select correct equipment ratings
Implement protection & earthing system
Perform full system validation (load flow + fault + protection)

1. Substation Layout (Concept + Practical)

What is Substation Layout?

Arrangement of electrical equipment in:

Outdoor yard (33 kV side)
Transformer area
Indoor control room

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Layout Sections:

A. 33 kV Incoming Yard (Outdoor)

Includes:

Lightning Arrester (LA)
Isolator
CT/PT
Circuit Breaker
Busbar

Sequence:

Line → LA → Isolator → CT/PT → CB → Bus

B. Transformer Section

33/11 kV Transformer
Oil pit + Fire wall
Marshalling box

C. 11 kV Indoor Switchgear

11 kV Bus
VCB Panels
Feeders (to plant/load)

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D. Control Room

Protection panels
Relay panels
Battery & charger
SCADA

Industry Tip:

Always plan for future expansion (20–30%)

2. Equipment Selection (Very Important)

A. Transformer Selection

Example:

Load = 8 MW

Select:

10 MVA transformer

Key Parameters:

Voltage → 33/11 kV
Impedance → 8–10%
Cooling → ONAN / ONAF

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B. Circuit Breaker Selection

Based on:

Voltage level
Fault current

Example:

Fault level = 25 kA

Select:

31.5 kA breaker

C. CT/PT Selection CT:

Ratio → e.g., 800/1 A
Accuracy → 5P10

PT:

Ratio → 33kV / 110V

D. Busbar Selection

Material → Aluminium / Copper
Current rating
Short circuit withstand

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3. Protection Scheme Design

Objective:

Protect:

Transformer
Feeders
Busbar

Protection System:

Transformer Protection:

Differential Protection
REF Protection
Buchholz Relay

Feeder Protection:

Overcurrent Relay
Earth Fault Relay

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Bus Protection:

Bus differential (optional)

Coordination:

Feeder trips first
Transformer backup later

4. Earthing Design (Safety Critical)

Purpose:

Protect human life
Ensure fault current path

Components:

Earth grid (mesh)
Earth rods
Equipment earthing
Neutral earthing

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Design Target:

Earth resistance < 1 Ohm

Key Calculations:

Grid size
Step voltage
Touch voltage

🔧 Practical: Substation Modeling in ETAP

Objective:

Create full 33/11 kV system in ETAP

Step-by-Step:

Step 1: Create 33 kV Source

Utility/Grid
Set fault level

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Step 2: Add 33 kV Bus

Name: BUS-33KV

Step 3: Add Incoming Equipment

CB + CT/PT + Isolator

Step 4: Add Transformer

33/11 kV, 10 MVA

Step 5: Add 11 kV Bus

Name: BUS-11KV

Step 6: Add Feeders

3–5 feeders
Motor + load

Step 7: Add Protection

Assign relays to breakers

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Step 8: Run Studies

Load Flow
Short Circuit
Relay Coordination

📂 Assignment: Design Full 33/11 kV Substation

Task:

Design complete substation system

Requirements:

System Must Include:

33 kV incoming
Transformer (10 MVA)
11 kV bus
Minimum 3 feeders

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Equipment Data:

Transformer rating
Breaker rating
CT/PT ratios

Protection:

Transformer protection
Feeder protection

Studies Required:

Load flow
Short circuit
Relay coordination

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🏭 Module 9: Industrial System Design Project

Objective

Using ETAP, you will:

Design a complete industrial electrical system
Perform accurate load calculation
Analyze motor behavior
Build distribution network
Generate a professional plant study report

1. Plant Load Calculation (Step-by-Step)

Step 1: Identify All Loads Typical Industrial Loads:

Motors (major load)
Lighting
HVAC
Auxiliary systems

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📊 Example Plant Data:

Equipment	Rating
Motor 1	500 kW
Motor 2	1000 kW
Motor 3	750 kW
Lighting	200 kW
Utility Load	300 kW

Total Connected Load = 2.75 MW

Step 2: Apply Demand Factor

Maximum Demand = Connected Load × Demand Factor

Assume Demand Factor = 0.8

Demand Load = 2.2 MW

Step 3: Add Future Margin

Add 25% extra:

Final Load = 2.2 × 1.25 = 2.75 MW

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Final Design Load:

≈ 3 MW (Rounded for safety)

2. Motor Load Analysis (Critical Part)

□ Why Important?

Motors = 70–80% plant load

🔧 Motor Data Required:

Parameter	Example
Power	500 kW
Voltage	11 kV
PF	0.85
Efficiency	95%

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Starting Current:

Starting Current = 5 to 7 × Rated Current

Causes:

Voltage dip
Stress on system

Solutions:

Soft Starter
VFD
Proper cable sizing

3. Distribution System Design

📘 Power Flow Structure:

Grid → Transformer → 11 kV Bus → Feeders → Motors/Loads

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Step-by-Step Design:

Step 1: Source

33 kV Utility supply

Step 2: Transformer Selection

Load ≈ 3 MW

Select:

5 MVA transformer (safe margin)

Step 3: Bus Design

11 kV main bus
Rated for full load + fault

Step 4: Feeder Design

Example:

Feeder 1 → Motor Loads
Feeder 2 → Lighting
Feeder 3 → Utility

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Step 5: Cable Sizing

Based on:

Current
Voltage drop
Fault level

Step 6: Protection

Circuit breakers
Relays (overcurrent + earth fault)

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🔧 Practical: Full Industrial Plant Design in ETAP

Objective:

Create full plant system in ETAP

Step-by-Step:

Step 1: Create Grid

33 kV source

Step 2: Add Transformer

33/11 kV, 5 MVA

Step 3: Create 11 kV Bus

Step 4: Add Feeders

Motor feeder
Lighting feeder
Utility feeder

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Step 5: Add Loads

Motors + static loads

Step 6: Add Protection

Breakers + relays

Step 7: Perform Studies

Load Flow
Short Circuit
Relay Coordination
Arc Flash

Real Industrial Case

Problem:

Voltage drop at motor bus
Transformer overload

Solution:

Increase transformer size
Add capacitor bank
Redistribute loads

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📂 Assignment: Submit Plant Study Report

Task:

Design complete industrial electrical system

Requirements:

System Must Include:

33 kV source
Transformer
11 kV bus
Minimum 3 feeders
Motors + loads

Studies Required:

Load Flow
Short Circuit
Relay Coordination
Arc Flash

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📤 Final Submission Format:

1. SLD Diagram

Complete plant diagram

2. Load Calculation Sheet

All loads + demand factor

3. Equipment Sizing

Transformer
Cable
Breaker

4. Study Results

Voltage profile
Fault current
Losses

5. Protection Scheme

Relay settings
Coordination

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6. Safety Report

Arc flash
PPE