Design And Analysis Of Over Voltage Protection System In A Distribution Network
The design and analysis of an overvoltage protection system in a distribution network involve developing mechanisms to safeguard against excessive voltage levels, which can potentially damage electrical equipment and disrupt operations. This process encompasses the creation of protective devices and strategies to mitigate overvoltage events, ensuring the reliability and safety of the distribution network. Through comprehensive analysis and simulation, engineers evaluate various factors such as voltage transients, load fluctuations, and system faults to devise effective protection measures. These measures may include the implementation of surge arrestors, voltage regulators, and coordination schemes to detect and suppress overvoltage conditions promptly. Additionally, the analysis entails assessing the performance of the protection system under different scenarios, considering parameters like response time, coordination effectiveness, and cost-efficiency. By integrating advanced technologies and methodologies, the design and analysis aim to enhance the resilience and stability of the distribution network, safeguarding critical infrastructure and optimizing operational performance.
Overvoltage happens in a condition where the voltage is increased and exceed its design limit. This situation may lead to harmful damage to machines or related equipment that connected to the system. Overvoltage can exist in a form of transient, voltage spike or permanent, depending on its duration. Along with increasing importance of power quality the effect of overvoltage protection to short interruptions and voltage dips is of great importance. With advanced reliability analysis tool integrated to network information system, the effect of protection can be studied. This study is aimed at carrying out an analysis of over voltage protection system in a distribution network.
Cover page
Title page
Approval page
Dedication
Acknowledgement
Abstract
CHAPTER ONE
INTRODUCTION
1.1 Background of the project
1.2 Problem statement
1.3 Aim and Objective of the project
1.4 Significance of the study
1.5 Scope and limitation
CHAPTER TWO
LITERATURE REVIEW
2.1 Review of the study
2.2 Overvoltages and overvoltage protection
2.3 Causes of over voltage in power system
2.4 Lightning, switching and temporary over voltage
2.5 Effects of over voltages on power systems
2.6 Review of overvoltage protection
2.7 Methods of protection against lightning
2.8 Insulation coordination
CHAPTER THREE
Methodology
3.1 Modelling of the evaluated system
CHAPTER FOUR
4.0 simulation results and discussion
CHAPTER FIVE
5.1 Conclusion
5.2 Recommendation
References
INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Protection systems are vital components of any power system. Its goal is to detect and isolate faults when they occur. By doing so, safe operation of power systems can be achieved, extensive equipment damage can be avoided and the areas affected by faults can be minimized.
The overvoltage protection of distribution networks is quite challenging task. The traditional reason for overvoltage protection has been prevention of failure of expensive components like transformers. Along with increasing importance of power quality the effect of overvoltage protection to short interruptions and voltage dips is of great importance. This means that overvoltage protection should be deeply modeled and analysed as part of reliability based network analysis. For example, selection of using surge arresters instead of spark gaps in transformer protection is not necessary based on the transformer itself but the consequences of short interruption and voltage dips due to arcs in spark caps. This paper presents different types of strategies which can be applied in overvoltage protection planning but focusing mainly on the use of surge arresters which is been modeled in this work.
1.2 PROBLEM STATEMENT
Power distribution systems are directly linked to customers. Thus the distribution system plays an important role in the overall power system reliability and the perceived reliability to customers. By improving distribution protection systems such that sustained outage times can be reduced, power system reliability can be enhanced.
For every power distribution system lightning discharges are one of the most significant disturbances, since it can give origin to overvoltage and consequent influences on the quality of the power supply. Among several consequences of the incidence of any lightning discharge, one of the most significant is the transference of voltage surge between primary and secondary windings of any power distribution transformer. The degree of transference basically depends on the frequency response of the transformer (Cabral et al, 2010) as well as on its grounding impedance. Thus, several studies have been carried out by analyzing transferred or induced voltages due to lightning discharges through grounding systems (Visacro et al, 2012).
This work studies the analyses of such kind of overvoltage require the utilization of reliable modeling to represent all the elements involved in this process. In this work distribution transformer modeling is considered using surge arrester.
1.3 AIM AND OBJECTIVE OF THE PROJECT
This work is aimed carrying out an analysis of over voltage protection system in a distribution network.
The objective of this work is:
• Provide a solution to voltage in a power system.
• To presents a model for the analysis of overvoltage in power distribution network caused by lightning discharges.
• To carry out a simulation of overvoltage protection scheme using surge arrester.
1.4 SIGNIFICANCE OF THE STUDY
As a student of electrical and electronic engineering, working on this project has expose my knowledge to causes and solution to over-voltage protection system in a distribution network. It has made me to understand how surge arrester can be model in a distribution network.
1.5 SCOPE AND LIMITATION OF THE STUDY
The scope of this work covers the modeling of a overvoltage protection scheme based on the use of surge arresters on a distribution network. In this work surge arresters are mounted on an additional wood crossarm, considerably closer to the transformer terminal bushings. The total length of the surge arrester connection conductors is 6 m and 1.1 m for the common practice and the alternative protection scheme, respectively.
There are different methods of carrying out a protection scheme in a power system, but in this work only the use of surge arresters was studied.
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Introduction:
In the realm of electrical engineering, ensuring the stability and reliability of distribution networks is paramount. One critical aspect of this is safeguarding against overvoltage conditions, which can result in equipment damage, service interruptions, and safety hazards. To address this challenge, the design and analysis of overvoltage protection systems play a pivotal role. This article explores the intricacies of such systems within distribution networks, delving into their design principles, analysis methodologies, and practical implications.
Definition:
An overvoltage protection system in a distribution network is a set of measures and devices implemented to detect, mitigate, and manage voltage levels that exceed predefined thresholds within the network. These systems are designed to safeguard electrical equipment, appliances, and infrastructure from damage or malfunction caused by excessive voltage. Additionally, they aim to maintain system stability, prevent service disruptions, and ensure the safety of personnel and the public.
Design Considerations:
Designing an effective overvoltage protection system involves a comprehensive understanding of the distribution network’s topology, load characteristics, and potential sources of voltage fluctuations. Key considerations in the design process include:
- Voltage Ratings: Determining the permissible voltage levels for various components within the network, considering both nominal operating conditions and transient events.
- Protection Devices: Selecting appropriate protective devices such as surge arresters, voltage regulators, and voltage limiters to intercept and dissipate excess voltage.
- Placement: Strategically locating protection devices at critical points within the distribution network to ensure optimal coverage and response times.
- Coordination: Coordinating the operation of protection devices to minimize interference and maximize system reliability.
- Sensitivity: Setting the sensitivity levels of protection devices to trigger timely interventions without unnecessarily disrupting normal operations.
Analysis Techniques:
Analyzing the performance and effectiveness of an overvoltage protection system involves employing various techniques and methodologies. Some commonly used approaches include:
- Transient Analysis: Simulating transient voltage events, such as lightning strikes or switching surges, to evaluate the system’s response and identify potential vulnerabilities.
- Fault Analysis: Assessing the impact of faults, such as short circuits or line disturbances, on voltage levels throughout the distribution network.
- Monte Carlo Simulation: Utilizing probabilistic modeling techniques to assess the likelihood of overvoltage occurrences under different operating scenarios and environmental conditions.
- Frequency Domain Analysis: Analyzing voltage waveforms and harmonic content to identify resonance phenomena and mitigate their effects on system performance.
- Cost-Benefit Analysis: Evaluating the economic implications of overvoltage protection measures, considering factors such as equipment costs, maintenance expenses, and potential revenue losses due to downtime.
Practical Implementation:
The implementation of an overvoltage protection system entails a series of steps, including:
- System Assessment: Conducting a comprehensive assessment of the existing distribution network to identify vulnerabilities, critical assets, and potential risks associated with overvoltage.
- Device Selection: Procuring and installing appropriate protective devices based on the design specifications and analysis results, taking into account factors such as compatibility, reliability, and cost-effectiveness.
- Testing and Commissioning: Rigorously testing the installed protection system under various operating conditions to verify its performance and ensure compliance with regulatory standards.
- Maintenance and Monitoring: Establishing routine maintenance procedures and monitoring protocols to detect and address any deviations or malfunctions in the protection system promptly.
- Continuous Improvement: Continuously evaluating the effectiveness of the protection system through performance monitoring, data analysis, and feedback mechanisms, and implementing necessary improvements or enhancements as required.
Conclusion:
In conclusion, the design and analysis of overvoltage protection systems in distribution networks are essential for maintaining system reliability, equipment integrity, and personnel safety. By employing sophisticated design principles, rigorous analysis techniques, and systematic implementation strategies, engineers can effectively mitigate the risks associated with overvoltage events and ensure the uninterrupted operation of electrical distribution systems. Furthermore, ongoing research and innovation in this field are crucial for developing advanced protection technologies and methodologies to address emerging challenges and enhance the resilience of distribution networks in the face of evolving threats and demands