IoT BASED OVERCURRENT PROTECTION IN DISTRIBUTION SYSTEMS

This project focuses on enhancing fault detection and location on a 240V distribution network to minimize power outages. It introduces a system consisting of a main unit mounted on the distribution line, interfaced with a GSM SIM800L model to relay fault information to a cloud service acting as the substation. The main unit, equipped with current and voltage sensors, gathers real-time data and analyzes it to detect faults. In case of an overcurrent fault, additional parameters such as the fault's location relative to the main unit are reported. A hardware implementation confirmed the system's ability to identify overcurrent faults and estimate their location on the distribution line. It features a liquid crystal display (LCD) to show voltage, current, and line status, along with a buzzer to alert of detected faults.IntroductionPower systems encompass power generation, transmission, and distribution systems. Distribution systems play a vital role in transmitting power from generating points to distribution points 1. However, distribution lines incur significant losses compared to other power system classes. The vulnerability of modern power infrastructure to various natural and malicious events affects overall performance and stability. With growing demand for power, faults in distribution lines remain a challenge, affecting supply to consumers. Traditional fault detection methods are slow and laborious, relying on circuit indicators and manual processes 2. Engineers face difficulty in precisely locating faults, necessitating a shift towards automated fault detection systems interfaced with high-performance data communication networks. This modern approach aims to expedite fault detection, reduce downtime, and ensure uninterrupted power supply to consumers amidst increasing demand and extensive distribution line networks 1. Problem StatementThe demand for power across various sectors in Ghana is rapidly increasing, leading to a corresponding rise in problems associated with distribution lines. Detecting the exact location of faults in these lines has proven challenging, resulting in prolonged downtime and damage to infrastructure 3. To address this issue, a reliable and efficient fault detection system is essential to maintain power system stability. This project introduces an Internet of Things (IoT) based fault detection and location system designed to accurately detect and locate faults in distribution lines. By optimizing performance procedures, this system aims to preserve the lifespan of distribution lines, protect household devices, and reduce the frequency of power outages experienced by consumers 3. Implementing an IoT-based fault detection system, integrated with a GSM model, will address the crucial challenge of delivering real-time information promptly. This system will send overcurrent fault status or normal operation status in real-time to a cloud service, including information about the faulted side of the distribution system. By eliminating the need for manual fault identification processes, engineers can avoid trial-and-error methods, leading to quicker fault resolution. Ultimately, reducing the duration of power outages endured by consumers.ObjectiveThe below outline the objectives of this project:1. To detect and locate over-current faults in distribution lines with the implementation of an IoT mounted system.2. To intimate fault information to a cloud service.3. To protect loads from the effects of over-current by disconnecting the loads from the faulted line.Scope of WorkImplementing an IoT-based fault detection system, integrated with a GSM model, will address the crucial challenge of delivering real-time information promptly. This system will send overcurrent fault status or normal operation status in real-time to a cloud service, including information about the faulted side of the distribution system. By eliminating the need for manual fault identification processes, engineers can avoid trial-and-error methods, leading to quicker fault resolution. Ultimately, reducing the duration of power outages endured by consumers.Literature ReviewIn 4, an algorithm was presented for detecting single-phase ground faults (SPGF) in resonant ground (RG) systems. This method combines a neutral voltage displacement technique with a mathematical morphology algorithm to identify SPGF. By comparing pre-fault and post-fault voltages and analyzing the slope of neutral voltage displacement, faulty phases and feeders can be determined. This technique successfully localized faults on long feeders and detected faults within 15ms using local voltage and current information.The paper described in 5 proposes a Fault Detection and Localization (FDL) system comprising a master device located in a control room and slave devices installed on poles for fault detection. The master device communicates with slave devices via GSM using short message service (SMS). Equipped with a graphical user interface (GUI), the master device consists of a personal computer with a modem to facilitate communication.The equipment described in 6 consists of a transmitter and a current transformer (CT) detector designed for fault detection. Signals detected by the CT detector are transmitted to the distribution lines, while current signals are monitored through the fault loop. If a signal is detected and relayed to the transmitter, it indicates an earth fault in the distribution line; otherwise, no earth fault is present. When the CT detector identifies a fault, both an LED and a buzzer are activated to emit light and sound respectively, signalling an earth fault. By gradually determining the fault location using this principle, the faulty feeder can be successfully detected.The method discussed in 7 determines the fault position by analyzing the voltage and current of the faulted line, relying on the impedance of the distribution line per unit length. Two impedance-based methods are employed: the single-ended impedance method and the double-ended impedance method. The single-ended method offers a simple and rapid fault location process without requiring extensive communication. It finds applications in power systems due to its solid sequence value and high resistance to faults, despite challenges posed by non-homogeneous loads and tapping.Electric Faults in AC Distribution SystemsA fault-free electrical system is an ideal that does not exist in reality due to the inevitability of electrical faults. These faults, including overcurrent, over-voltages, and short circuits, pose significant threats to power systems' continuous operation. Overcurrent faults, in particular, involve abnormally high currents flowing through conductors due to various causes such as mechanical effects, insulation failures, or atmospheric conditions. These currents can lead to thermal damage and mechanical stresses on system components, resulting in irreversible damage and safety hazards. Protective systems comprising relays and automatic circuit breakers are crucial for detecting faults and isolating faulted parts to minimize service disruptions. Planning and operating power systems must account for short circuits by estimating worst-case currents to design system components to withstand overcurrent and define circuit breaker breaking capacities. Adjusting relay settings ensures efficient detection of fault conditions, highlighting the importance of protective devices in maintaining power system reliability 3. Brief Introduction of Proposed WorkThis project proposes a technique for recording voltage and current values of a distribution line using voltage and current sensors respectively. A predetermined threshold current value is set, and if the measured current exceeds this threshold, the microcontroller classifies the fault as an overcurrent fault, triggering a buzzer to indicate its presence. If the measured current falls within a specified range, the system is classified as being in a normal operating state. Additionally, the project involves interfacing a microcontroller with a GSM SIM800L module, which will be embedded in the circuitry to send the distribution line's state to a cloud service. The block diagram for the proposed system for fault detection, location, and protection is illustrated in Figure 2.7.METHODOLOGYThe objective of this project is to design a system for detecting overcurrent in distribution systems, comprising two main components: the fault detection system and the centralized processing system. The fault detection system, positioned at a specific distance from the distribution line, simultaneously measures current and voltage levels in real-time. This setup enables the centralized processing system to accurately estimate the side of the line where the fault occurred. When a fault occurs, the fault detection system reports abnormal current and voltage to the centralized processing system for analysis. The main unit then analyzes this data to determine the type of fault and identify the side of the line where the fault occurred. Block DiagramThe figure below shows a block diagram for the proposed system.