Contents

1 Introduction
2 Objectives
3 Hardware Implementation
- 3.1 Block Diagram
4 Working Principle
5 Software Implementation
6 OVER VIEW
7 CONTACT INFORMATION
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Introduction

Transformers are a vital part of the transmission and distribution system. Monitoring transformers for problems before they occur can prevent faults that are costly to repair and result in a loss of service. An innovative design to develop a system for monitoring the voltage, current and temperature, and to protect the system from the mentioned parameters based on GSM is described in this project.
The proposed design is developed for the user to easily recognize the distribution transformer that is suffered by any problems detect all operating parameters operation, and send to the monitoring center in time. It leads to online monitoring of key operational parameters of distribution transformers which can provide useful information about the health of transformers which will help the utilities to optimally use their transformers and keep the asset in operation for a longer period. This will help to identify problems before any serious failure which leads to a significant cost savings and greater reliability.

Objectives

The Transformer Management System has the following major objectives:

•To take voltage and current reading to get an accurate picture of electricityconsumption.

•To measure the real power, apparent power and power factor to trackpower usage.

•To measure the on-board temperature to diagnose possible problems.

•To save all the data in the cloud for later use and analytics.

•To keep track of whether a transformer is functioning or not.

Hardware Implementation

Block Diagram

The following block diagram illustrates the device components of our system.

The Transformer Management System consists of these major components:

•Micro-controller (1)

•Voltage Transformers (3)

•Current Transformers (3)

•Voltmeters (3)

•Ammeter (3)

•Frequency Measurement (3)

•Temperature Sensor (1)

•GSM Modem Module (1)

•Backup Power Supply (1

Working Principle

The device basically performs three major functions: i) measure the voltage and current in each phase, ii) measure the transformer oil temperature, iii) send measurements to central server. A brief summary of the device’s working is given below:

Voltage-Current Measurement

For each phase, the voltage transformer(VT) and current transformer (CT) step-down the voltage and current respectively. The on-board voltmeter measures the voltage and the on-board ammeter measures the current flowing through the wires. Along with these two inputs, the device receives a frequency line which helps identify the start and end of cycles as well has lets us measure the frequency. These lines are fed into the micro-controller for further processing.

Ambient Temperature Measurement

The board contains a temperature sensor that measures the ambient temperature inside the transformer. This data is sent to the micro-controller for further processing.

Data Transmission

After the micro-controller processes all the voltage, current and temperature data, the information is sent to the central server via a GSM Modem module through the GSM mobile network.

Software Implementation

Features

The Transformer Management System has the following features:

•Voltage and Current Measuring Capability

•Temperature Measuring Capability

•OTA Updates•Device Provisioning

•Provision for Logs•Constant Connection with Server

•Realtime Dashboard with Charts

•Provision for Measurement History

Data Flow Diagram

The following flow chart illustrates the data flow of our system.

Working

Device To Server

Initialize Sequence

When the device first boots, an initialization sequence is run which checks whether all necessary components are functioning as intended. This includes the NVS, connection with GSM module, web socket connection, and readings from voltmeter and ammeter.

–If a new device is initialized, the NVS is set with default database configurations. A certified technician may then set identifying information about the device, such as its geolocation, device ID etc. via a Bluetooth service. When the device reboots, it access the informationin it’s NVS to inform the server about its status.

–The GSM connection is established via a UART connection to aGSM Modem with a PPPOS protocol. The websocket module issimilarly configured by attaching it to a NETIF provided my theGSM connection.

–The readings from the voltmeter, ammeters and op-amp are supplied via an analog to digital converter on the micro-controller.

Measure

The measurement task handles the measurement and calculation of power factor. The reading from the op-amp frequency line is first read to calculate the frequency of AC supply. The appropriate memory is allocated based on the number of samples per cycles. The voltmeter and ammeter readings are then read and stored in the memory buffer. The rms voltage, rms current, rms power, average power and power factor is then calculated. The resulting output is sent to a queue to be sent to the server .This operation is repeated for all 3 phases. The temperature data is also measured and forwarded to the send data queue.

Send Data

For two way communication a persistent web socket is established between device and the server. The device checks whether the queue has any data to be sent. If data is found, the web socket connection sends the data with its appropriate header.

Receive from device

Server will receive data from unique web socket established to the device .It identifies which web socket connection the data came from, and forwardsit to be database to be stored.

Store in Database

Received data by the server is then stored in the database server for safe and a well backed up and in scale-able fashion.

Display in dashboard

The dashboard provides an quick and easy way to check the status of all active transformers and verify their working state. The data received from the device is displayed as a table and charts for the end user to see. The user may then track Temperature, RMS Voltage, RMS Current, Active Power, Reactive Power and Power Factor for every active transformer with a device installed in it.

Server to Device

User Actions

The user may select user actions from a drop down menu from the UI to be sent to individual devices installed in the transformers. These actions include OTA Updates, Balance Query Requests, Log Request and Factory Restore.

–OTA Updates Over the Air updates for adding features, debugging and making device perform better over time.

–Balance Query Requests Request Balance Amount from the GSM module’s SIM.

–Log Request Request Log file stored in device.

–Factory Restore Restore device to factory state.

Handle Action Request

The server takes in the requests from the UI and sends action commands to each device depending on the action. For example, a Balance Query Request might invoke a function in the remote device and return the result when a valid response is received. An OTA update, however, would require the user to upload and select a valid update file to be sent for update.

Receive Commands

Device will receive commands from server via web socket and commands are handled accordingly by handlers in device.