An IoT-based transmission line monitoring and protection system built using ESP32, designed to detect abnormal line conditions and automatically isolate the protected line through a remotely controlled breaker unit.

The system consists of two ESP32 units:

ESP32 #1 — Protection Unit: Monitors current, vibration, tilt and GPS data, performs fault detection, hosts a live monitoring dashboard, and transmits fault information using ESP-NOW.
ESP32 #2 — Breaker Unit: Receives the fault information through ESP-NOW and controls a relay to isolate the line.

📌 Project Overview

Transmission lines can be affected by conditions such as conductor disconnection, excessive current, pole tilting and abnormal mechanical vibration.

This prototype provides a multi-sensor approach for detecting these conditions and automatically responding to faults.

System Flow

Sensors
   │
   ▼
ESP32 Protection Unit
   │
   ├── Fault Detection
   ├── GPS Location
   ├── Web Dashboard
   └── ESP-NOW Communication
              │
              ▼
       ESP32 Breaker Unit
              │
              ▼
            Relay
              │
              ▼
       Line Isolation

🔧 Hardware Components

Component	Purpose
ESP32 × 2	Protection and breaker control
ACS712	Line current measurement
SW420	Vibration detection
SW520D	Pole tilt detection
NEO-8M GPS	Fault location tracking
Relay Module	Line isolation
DC Load	Transmission-line prototype test load

🛡️ Protection Unit

The Protection Unit continuously monitors the transmission-line model and evaluates the connected sensors.

Features

ACS712 current measurement
Automatic ACS712 zero-point calibration at startup
SW420 vibration monitoring
SW520D tilt monitoring
NEO-8M GPS location tracking
Multi-fault classification
Local Wi-Fi Access Point
Real-time web dashboard
AJAX-based live telemetry
Fault/event history
Google Maps location integration
ESP-NOW communication with the Breaker Unit

The Protection Unit checks the sensors at regular intervals and sends the detected fault status to the Breaker Unit.

⚡ Current Monitoring

The ACS712 current sensor is calibrated during startup with the load turned OFF.

The prototype was tested with approximately:

Load connected    → ~16 A
Load disconnected → ~0 A

This allows the system to identify a significant drop in current as a possible line-disconnection condition.

Current Threshold Configuration

The current limits are configurable according to the user's own load and sensor calibration.

The values currently included in this repository are the values used for the prototype:

LOW_CURRENT_THRESHOLD  = 16.40 A
HIGH_CURRENT_THRESHOLD = 18.01 A

Interpretation

Condition	Interpretation
Below low-current threshold	LINE SNAP
Between configured limits	NORMAL
Above high-current threshold	OVERCURRENT

Important: The threshold values are not universal. When adapting this project to a different load or transmission-line model, calibrate the ACS712 and configure the minimum and maximum current limits accordingly.

🚨 Fault Detection

The Protection Unit supports the following fault classifications:

0 → NO FAULT
1 → LINE SNAP
2 → TILT FAULT
3 → VIBRATION FAULT
4 → OVERCURRENT
5 → MULTIPLE FAULTS

If multiple fault conditions occur simultaneously, the system reports:

MULTIPLE FAULTS

with the active fault conditions included in the status message.

📡 ESP-NOW Communication

The two ESP32 units communicate using ESP-NOW.

The Protection Unit sends a compact message containing:

fault → Whether a fault is active
type  → Fault classification

Communication Flow

┌─────────────────────┐
│ ESP32 Protection    │
│      Unit           │
│                     │
│ Sensor Monitoring   │
│ Fault Detection     │
└──────────┬──────────┘
           │
           │ ESP-NOW
           ▼
┌─────────────────────┐
│ ESP32 Breaker Unit  │
│                     │
│ Fault Reception     │
│ Relay Control       │
└──────────┬──────────┘
           │
           ▼
        RELAY
           │
           ▼
    LINE ISOLATION

🔌 Breaker Unit

The Breaker Unit receives the fault message from the Protection Unit.

When a fault is detected, the relay is switched to the tripped state.

The relay used in the prototype is active-LOW:

LOW  → Relay ON  → Breaker CLOSED
HIGH → Relay OFF → Breaker TRIPPED

The Breaker Unit prevents repeated tripping and waits for manual inspection/reset after a fault.

Breaker Unit behavior

Fault received
      ↓
Fault identified
      ↓
Breaker trips
      ↓
Relay switches OFF
      ↓
Line isolated
      ↓
Manual inspection/reset

📍 Pin Configuration

ESP32 Protection Unit

Component	ESP32 Pin
ACS712 Current Sensor	GPIO 34
SW420 Vibration Sensor	GPIO 26
SW520D Tilt Sensor	GPIO 27
NEO-8M GPS RX	GPIO 16
NEO-8M GPS TX	GPIO 17

The GPS module uses HardwareSerial 2.

ESP32 Breaker Unit

Component	ESP32 Pin
Relay Module	GPIO 26

🌐 Live Web Dashboard

The Protection Unit hosts a local web dashboard through its Wi-Fi Access Point.

The dashboard provides real-time information about:

Current load
Pole tilt
Wire vibration
GPS status and coordinates
Overall system status
Fault classification
Fault history
Node information
ESP-NOW status
Google Maps location

The dashboard uses AJAX telemetry updates, allowing sensor information to be updated without reloading the complete webpage.

Dashboard Preview

Add your cropped dashboard image to the repository, for example:

Images/dashboard_fault_detection.jpg

Then display it in this section using:

![Live Dashboard](https://raw.githubusercontent.com/winstonbabu-byte/Smart-Transmission-Line-Protection/main/Images/dashboard_fault_detection.jpg)

📍 GPS Location

The NEO-8M GPS module provides latitude and longitude information for the monitored node.

When a valid GPS fix is available, the dashboard displays:

Latitude
Longitude

and provides a Google Maps location link.

When a GPS fix is unavailable, the dashboard displays:

NO FIX

📊 Dashboard Monitoring

The dashboard provides a SCADA-style interface containing:

┌──────────────────────────────────────────────┐
│              LINE SHIELD                     │
│     Smart Transmission Line Protection       │
├──────────────────────────────────────────────┤
│              SYSTEM STATUS                   │
├────────────┬────────────┬──────────┬─────────┤
│ Current    │ Pole Tilt  │Vibration │   GPS   │
│            │            │          │         │
├────────────┴────────────┴──────────┴─────────┤
│ Diagnostics Matrix │ Event Log │ Node Data   │
└──────────────────────────────────────────────┘

The system also maintains a live fault history for detected abnormal conditions.

💻 Software Requirements

Development Environment

Arduino IDE
ESP32 Board Package

Protection Unit Libraries

#include <WiFi.h>
#include <WebServer.h>
#include <TinyGPS++.h>
#include <HardwareSerial.h>
#include <esp_now.h>

Breaker Unit Libraries

#include <WiFi.h>
#include <esp_now.h>

Install the required ESP32 board support and the TinyGPS++ library before compiling the Protection Unit.

🚀 Installation & Setup

1. Clone or download the repository

Download the repository to your computer.

2. Open the Protection Unit code

Open:

ESP32_Protection_Unit/
└── protection_unit.ino

3. Configure the Wi-Fi Access Point

Configure your own Wi-Fi credentials:

const char* ssid = "LineShield_AP";
const char* password = "YOUR_AP_PASSWORD";

4. Configure the ESP-NOW receiver

Set the receiver MAC address to the MAC address of your Breaker Unit ESP32.

5. Upload the Protection Unit

Connect the first ESP32 and upload:

ESP32_Protection_Unit/protection_unit.ino

Keep the current-sensor load OFF during startup so that the ACS712 zero-current point can be calibrated.

6. Upload the Breaker Unit

Connect the second ESP32 and upload:

ESP32_Breaker_Unit/breaker_unit.ino

7. Start the system

Power both ESP32 units and connect to the Protection Unit's Wi-Fi Access Point.

The Protection Unit provides the local dashboard for monitoring the system.

🧪 Testing

The prototype was tested using a DC load connected to the monitored line.

Normal condition

Load connected
      ↓
Current ≈ 16 A
      ↓
System monitors the line

Line disconnection

Load disconnected
      ↓
Current drops toward ≈ 0 A
      ↓
LINE SNAP detected
      ↓
Fault transmitted using ESP-NOW
      ↓
Breaker Unit receives fault
      ↓
Relay trips

Other test conditions include:

Pole tilt
Vibration
Overcurrent
Multiple simultaneous faults

📁 Repository Structure

Smart-Transmission-Line-Protection/
│
├── ESP32_Protection_Unit/
│   └── protection_unit.ino
│
├── ESP32_Breaker_Unit/
│   └── breaker_unit.ino
│
├── Images/
│   └── dashboard_fault_detection.jpg
│
└── README.md

📈 Project Status

Implemented

ACS712 current monitoring
Automatic current-sensor calibration
Line-snap detection
Overcurrent detection
Pole-tilt detection
Vibration detection
Multiple-fault detection
GPS integration
ESP-NOW communication
Relay-based breaker control
Local Wi-Fi Access Point
Real-time web dashboard
AJAX live telemetry
Fault history/event log
Google Maps integration

🚀 Future Improvements

Possible future improvements include:

Remote breaker reset
Cloud-based monitoring
Long-range communication
Improved fault-location analysis
Multiple transmission-line nodes
Centralized monitoring of multiple poles
Secure ESP-NOW communication
Improved hardware packaging and enclosure
More advanced current-sensor calibration
Remote monitoring from outside the local network

👨‍💻 Project Information

Project: Smart Transmission Line Protection System

Platform: ESP32

Programming: C/C++ with Arduino Framework

Communication: ESP-NOW

Monitoring: Local Web Dashboard

Sensors: ACS712, SW420, SW520D, NEO-8M GPS

Application: Transmission-line fault monitoring and automatic protection

⭐ Project Highlights

This project combines embedded systems, IoT, wireless communication, sensor fusion, fault detection, GPS tracking and web-based monitoring into a single transmission-line protection prototype.

The two-node architecture separates fault detection from breaker control, allowing the protection and isolation functions to operate on independent ESP32 controllers.