Journal of Advanced Zoology
ISSN: 0253-7214
Volume 44 Issue S-2 Year 2023 Page 4119:4124
SUBSTATION MONITORING USING IoT
Bandi Narasimha Rao
Department of Electronics and Communication Engineering, National Institute of Technology, Warangal, India.
narasimharaobandi5@gmail.com
Article History Abstract:
Received: 15 April 2023 In the current era of automation, ensuring the safe supply of electricity to consumers is
Revised: 10 June 2023 crucial, and monitoring and controlling substations play a vital role in this task.
Accepted: 07 July 2023 However, the risk of blackouts, brownouts, and fires is on the rise due to outdated
distribution grid configurations and the lack of automation systems to monitor critical
conditions within substations. Substations comprise various electronic components like
transformers, breakers, and relays, making them susceptible to issues like overheating,
transformer fluid leakage, and insulation breakdown. The conventional approach of
manual system checks is both imprecise and time-consuming, especially for substations
in urban areas. To address these challenges, we propose a cost-effective, user-friendly
substation monitoring system that operates in automatic mode, eliminating the need for
manual labor and reducing electricity loss. Our system offers various ways to display the
results, ensuring that multiple individuals can monitor and control the parameters for
safety and protection reasons. Notably, the uniqueness of our system lies in its ability to
simultaneously display results on both desktop and mobile devices. To validate the
system's performance in real-time monitoring, data logging, and controlling, we have
successfully tested it on the CAYENNE platform. The positive outcomes of this test
CC License affirm the effectiveness of our proposed system.
CC-BY-NC-SA 4.0
Introduction:
The basic variable related with the Substation protection, Control and Monitoring include current, voltage,
frequency, time, power factor and temperature.Electrical energy is transmitted from large generating stations to
distant load centers through a series of substations. Each substation requires specific measurements, supervision,
control, and protection functions. A control room is present in every substation, housing relay and control panels.
These control-relay panels oversee the various circuit breakers, tap changes, and other devices. In smaller
independent substations, operators can perform supervision and normal service operations with the assistance of
analog and digital control systems on-site. The breakers can be remotely operated from the control room. In case of
faults or abnormal conditions, protective relays take automatic action, operating the breakers to ensure the safety and
stability of the system. Generally, in substations the primary control is of two types and these are,
Routine operations are carried out by operators through manual commands.
The system operates automatically through the actions of protective relays and control system.
In conventional substation control, the three functions - protection, control, and monitoring - are not
completely integrated. However, in modern interconnected systems, these functions are interconnected
using digital processing devices and power carrier links to achieve seamless integration.
In traditional hard wired systems are relays and circuit breaker operate during abnormal operating conditions. The
routine and emergency control functions are performed at individual ‘Unit’ level systems with the held of substation
equipment such as circuit-breaker, tap changes etc. Control and monitoring functions are performed by separate
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SUBSTATION MONITORING USING IoT
equipment installed on respective panels. Each substation control room operated almost independently all
instructions are received from Control Centre via Power Line carrier telephone communication link.
With the present trend and availability of powerful microcontrollers a low price, the protection, control and
monitoring system in substations have undergone a radical change. The system architecture now includes,
microcomputer based digital system control protection and monitoring systems installed in (1) load centers (2) Sub-
station control room (3) Generating station control room. The control and protection systems are integrated and there
is interaction and information transfer by means of communication channels.
As technology continues to advance rapidly, internet connectivity is expanding, even to remote areas. As a result,
the Internet of Things (IoT) has gained immense popularity as a transformative technology. The primary objective of
IoT is to create a better living environment by monitoring various activities, including energy management. Through
IoT, innovative and smart solutions can be developed to address various problems and significantly conserve energy.
Electricity has become an indispensable part of people's lives, and it serves as a fundamental requirement for both
individuals and industries in a country. The effective utilization of electrical energy is vital for a country's
development. Given the growing population and industrialization, energy plays a crucial role in the current scenario.
However, meeting the escalating energy demands has become challenging, particularly because a significant portion
of the energy is generated from non-renewable sources.
Therefore, in this context, energy conservation and monitoring are of utmost importance to address the ever-
increasing demand for energy and promote sustainable practices, especially considering the reliance on non-
renewable energy sources [1].
In contemporary society, the Internet of Things (IoT) technology [2] is gaining widespread adoption. It involves
integrating small and intelligent objects with computational capabilities, utilizing various existing technologies like
Wi-Fi, Bluetooth, and sensors. As a result, numerous hardware and software platforms have been developed to
facilitate the creation and deployment of objects and services following the principles of IoT.
Power distribution companies strive to maximize profits by ensuring a dependable and continuous power supply.
The critical components of power distribution include transformers, substation transformers [3], and high-voltage
wires. Substation transformers are equipped with various functionalities such as overcurrent protection [4], ground
protection, and other differential power protection [5]. The monitoring and control of substations are essential tasks
in the age of automation to guarantee the secure delivery of electricity to consumers.
The potential for blackouts, brownouts, and fires is on the rise due to outdated distribution grid configurations
(substations) and the lack of automation systems to monitor critical conditions within substation systems.
Substations contain various electronic components like transformers, breakers, and relays, which are susceptible to
problems such as overheating, transformer fluid leakage, and internal insulation breakdown. The conventional
approach involves periodic manual system checks that lack accuracy. Moreover, physically inspecting substations in
urban areas is more difficult and time-consuming, adding to the complexity of related tasks.The substation can
experience several significant faults, such as:
Under and over voltage fault.
Fault due to overload.
Fault due to reduction of oil level.
Elevated temperature of the transformer.
The significance of substation protection becomes evident considering the various risks these faults pose to both the
transformer and the environment. However, traditional methods for substation protection have proven to be slow,
resource-intensive, and costly. To overcome these limitations, this research article proposes a user-friendly, cost-
effective system that offers real-time monitoring and data logging of the system's performance, enabling timely
actions to prevent losses.
The primary objectives of the proposed system are as follows:
Measure transformer parameters.
Protect the substation transformer from overrating of voltage, current, temperature, and empty oil level.
Implement automatic voltage control of the substation through multi-taping.
Utilize IoT-based monitoring, controlling, and data logging.
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By achieving these objectives, the proposed system aims to enhance the efficiency and reliability of substation
protection while reducing operational complexities and costs.
Literature survey:
Authors in [6] proposed a frame work for measuring voltage, current and oil level of transformer using IoT and
LoRa technologies. LCD is used for presenting the measured parameters.Arduniois used for collecting the inputs
and provides results equally.
A smart monitoring system is proposed to measure various parameters of the substation such as voltage and current
using Arduino controller. The collected parameters are transmitted to end user for monitoring purpose. It also
calculates power factor and frequency using the detector of reference value of zero [7].
For providing the safe electricity to consumers, the authors in [8-10] proposed a efficient substation monitoring
system.They proposed a low cost system and reduces the interference of manual labour.
An energy monitoring system is proposed in [12-14], which calculates the energy consumed by the load connected
to circuit. It makes use of IoT based Arduino controller for measuring the energy.
Substation monitoring system:
To implement a condition-based maintenance scheme, the initial step involves monitoring, which entails gathering
essential parameters from an asset. The collected data plays a crucial role in conducting comprehensive analyses,
determining the asset's condition, and making informed decisions regarding maintenance to prevent breakdowns and
faults. Monitoring substations can be complex due to the large number of features involved. Depending on the asset
and the required diagnosis, monitoring can be conducted either online, offline, or a combination of both. This
process necessitates the use of suitable sensor data collection and software. Moreover, substations are often
constructed using assets from various manufacturers, which adds to the complexity of the monitoring process.
The benefits of employing IoT for substation monitoring and control are as follows:
System for wireless monitoring and control.
Swift control action.
Automated control action.
Precise system operation.
Detection of various types of constraints.
Implementation of relays for system protection.
Prevention of system instability.
Ensuring uninterrupted power supply.
Proposed Substation Monitoring system:
Substation transformers are at risk of damage from various factors, including exceeding temperature limits, low oil
levels, heavy loads, and high current transfers. As the temperature increases, the likelihood of internal damage to the
transformers also rises, making thorough inspection and monitoring crucial.
In our proposed system (refer to fig. 1), the controller incorporates a sensing mechanism to monitor diverse
substation parameters, including voltage, frequency, current, oil level temperature, and humidity. The processing
system connects to a digital display, enabling real-time monitoring of parameter values and relevant technical
procedures at the substation.
The microcontroller is designed to detect heavy loads and overcurrent streams in the internal windings, which could
potentially lead to equipment failure. The Arduino IDE (ESP32) [5] is programmed to continuously monitor the
transformer and update the parameters at regular intervals.Utilizing the built-in IoT module, the Arduino IDE
captures the substation parameter values and transfers them to a web page and mobile phone, ensuring remote access
and monitoring of the data.
Circuit and working
The IoT-based system for substation monitoring and control involves the measurement of various electrical
parameters using diverse sensors, including the ACS712 current sensor, AC voltage sensor, DHT11 (digital
humidity and temperature) sensor, and frequency sensor.
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To determine the total current consumption, the ACS712 current sensor is connected in series with the mainline,
while the voltage sensor is connected in parallel to measure the overall voltage flowing through the system.
Frequency sensors are utilized to count the number of current cycles per second. Additionally, the DHT11 sensor,
operating at 5V DC, is employed to measure humidity and temperature within the substation.
The data from all the sensors is collected and processed by a microcontroller powered by a 5V DC supply. The
microcontroller displays the parameter values on a serial display. Moreover, the microcontroller is programmed and
integrated with the ESP module (Wi-Fi module). This allows real-time data transmission from the microcontroller to
a mobile device or PC connected to the same network via the Internet, enabling remote access and real-time
monitoring of the substation's parameters.Below are the hardware specifications utilized in the system model.
Step-down transformer:
The device serves as a high-to-low voltage converter [6], transforming high primary voltages into lower secondary
voltages. The transformer's primary winding contains more turns than the secondary winding. In the proposed
model, a step-down transformer is used to supply 12V DC to the voltage sensor, as depicted in Figure 3.
Relay:
The relay acts as a switch that responds to applied pulses on its coil, allowing it to open or close as needed for the
circuit. In our proposed model, we utilize a 5V DC single-pole double-throw (SPDT) relay [7]. This relay is
essential for protection and control purposes and can be operated either through the Arduino or via the internet.
In our prototype, each phase at the input side of the transformer is equipped with a dedicated relay to streamline and
enhance control and protection using internet connectivity. Initially, the relays are set in the normally open
condition, and they will switch off according to the programmed conditions for tripping assets.
Auto transformer:
An autotransformer, as depicted in Figure 5, is a transformer with a common single winding for both the primary
and secondary sides. The term "auto" signifies its ability to automatically adjust the voltage input (i/p) variation or
decrease the single winding usage. Autotransformers find application in scenarios where electrical protection
between the input and output windings is unnecessary. In our proposed model, the autotransformer features five
tapings with a difference of 25V each.
ESP-32 Micro controller:
The ESP32 is a high-performance 32-bit microcontroller featuring built-in Wi-Fi, which facilitates straightforward
implementation of IoT programs using the Arduino IDE and Arduino Wire language. This IoT module combines
both WIFI and Bluetooth functionalities, making it suitable for various applications. Additionally, it incorporates an
integrated USB interface, allowing seamless integration with any IoT product. The ESP32 serves as a versatile
physical gadget system, enabling efficient transmission of data using these modules.
Voltage sensor:
To detect over and under load conditions, voltage measurement is essential. The advantage of using this sensor lies
in its ability to easily control the voltage value through a potentiometer, allowing the creation of over and under
voltage scenarios
Current sensor:
The current sensor serves to detect the RMS current of the system and to measure over-load conditions, effectively
preventing faults that could potentially harm the load or the transformer. In the prototype, an ACS712 current sensor
[8] with a 5A rating is utilized, employing the Hall Effect to measure the AC current.
Frequency sensor:
The frequency sensor was specifically designed in PCD (Printed Circuit Design) with the assistance of a zero-
crossing detector circuit [9]. This detector operates by comparing the voltage waveform to detect when it crosses
from positive to negative, corresponding to the zero-voltage state. The sensor employs the IC LM398 comparator,
which compares the two input voltages and relays the result to the microcontroller.
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Temperature sensor:
To sense the temperature, the DHT11 [10] sensor is utilized, which can measure both humidity and temperature.
This sensor is employed to detect the overheat condition of the transformer, enabling the activation of the cooling
system to prevent any potential damages to the transformer.
Oil sensor:
The oil level in the transformer is determined using an Ultrasonic sensor. This sensor functions by sending signals
and measuring the time taken for them to be received back, allowing it to measure the length and depth of the oil.
The oil level is classified into three levels: low, medium, and full.
Data logging and IoT:
The ESP32 module is a central component of the proposed system, responsible for acquiring analog data through an
analog to digital converter (ADC). This data is then made accessible on the Wi-Fi network through a web server.
When queried using MQTT [11], the web server responds by providing the corresponding data value. Additionally,
the ESP32 module can be accessed and managed through the CAYENNE cloud [12], which serves as a storage and
data management platform.
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