Fault Location, Isolation And Service Restoration Research Articles

Implementation of a software defined FLISR solution on an active distribution grid.

The resiliency of the distribution grid is of increasing concern to the distribution system operator (DSO) due to factors such as climate change and the resulting faults caused by inclement weather conditions, leading to service disruption to consumers. Loss of service negatively affects key performance indicators (KPI) of the DSO, such as customer minutes lost (CML) and customer interruptions (CI), leading to financial penalties imposed by the regulator. In this paper we propose a software-driven Fault Location, Isolation and Service Restoration (FLISR) solution, leveraging modern software and communication technologies married with the DSO's existing infrastructure, to aid fault detection and resolution, with the aim of reducing CMLs & CIs and curtailing the financial penalties incurred. The proposed FLISR solution was trialled in an area of south-east Ireland which sees a higher count of service loss as compared to more inland areas, providing an ideal environment to gauge the effectiveness of the solution. It was found that the solution generated outputs that could potentially lead to the resolution of fault events faster than the current systems in place by the DSO. Based on the results gathered from operating the FLISR solution on an active grid, it has demonstrated that leveraging modern software technologies in tandem with existing grid infrastructure benefits the DSO with reference to grid management and operations and the customer in terms of quality of service site.

Generic microgrid controller with self-healing capabilities

Generic Microgrid Controller (GMC) specifications, developed at the University of California, Irvine (UCI) to support the standardization of microgrid controllers and guide IEEE standards were applied to the UCI Microgrid (UCIMG) for testing and deployment. While transition and dispatch capabilities of GMC were simulated and demonstrated, response of the controller to internal faults while islanded or to inadvertent trip of generation were not addressed previously. The present study adds self-healing capabilities to the GMC for islanded microgrid operations with the goal to enhance reliability of serving critical loads, and resiliency of the system. To verify and assess self-healing attributes as well as impacts on reliability and resiliency while islanded, the self-healing capability was simulated on the UCIMG model developed on MATLAB Simulink. The model was enhanced with recently deployed redundancies including two new switchyards and redundant lines, and was then divided into sections to (1) focus on critical and high priority loads, and (2) reduce the number of nodes and computational requirements. Our study explores the resiliency of a real system microgrid platform using the FLISR (fault location, isolation and service restoration) approach as the self-healing capability as part of the microgrid controller. This expert systems approach with precalculated and predetermined sequence makes it a practical and simple solution which can be implemented without having to deal with computational limits of the controller and time constraints. Results show that, even with a fault-induced circuit outage during islanded operation, critical loads can be served by interconnected circuits and rapidly dispatched switching, thereby minimizing the loss of critical and noncritical loads, and increasing reliability and resiliency.

Implementation of a software defined FLISR solution on an active distribution grid

Background: The resiliency of the distribution grid is of increasing concern to the distribution system operator (DSO) due to factors such as climate change and the resulting faults caused by inclement weather conditions, leading to service disruption to consumers. Loss of service negatively affects key performance indicators (KPI) of the DSO, such as customer minutes lost (CML) and customer interruptions (CI), leading to financial penalties imposed by the regulator. Methods: In this paper we propose a software-driven Fault Location, Isolation and Service Restoration (FLISR) solution, leveraging modern software and communication technologies married with the DSO's existing infrastructure, to aid fault detection and resolution, with the aim of reducing CMLs & CIs and curtailing the financial penalties incurred. Results: The proposed FLISR solution was trialled in an area of south-east Ireland which sees a higher count of service loss as compared to more inland areas, providing an ideal environment to gauge the effectiveness of the solution. It was found that the solution generated outputs that could potentially lead to the resolution of fault events faster than the current systems in place by the DSO. Conclusions: Based on the results gathered from operating the FLISR solution on an active grid, it has demonstrated that leveraging modern software technologies in tandem with existing grid infrastructure benefits the DSO with reference to grid management and operations and the customer in terms of quality of service site.

Formal specification and verification of fault location, isolation and service restoration of local topology model based on distributed processing for active distribution network

Active distribution network (ADN) technology, as an important trend of the future smart distribution grid, is able to effectively absorb distributed energy resource (DER), to reasonably optimise grid-load operation characteristics, and to safely support the reliability of power supply. Through enhancing energy utilisation efficiency and friendly interaction with user access, ADN technology is also able to comprehensively improve the power supply reliability of the distribution network. However, distributed feeder automation (FA), as an important part of ADN technology, will also meet new problems and challenges with the access of DER in the distribution network. The formal method can analyse the correctness and effectiveness of a distributed fault processing algorithm from mathematical logic, which provides an important theoretical basis for distributed fault processing. The focus herein is on the formal description and verification of topology modelling in fault location, isolation, and service restoration (FLISR) based on distributed processing. By abstracting and simplifying the complex power system features, the adaptability of the formal method is solved. The logical correctness of the topology model in FLISR based on distributed processing is verified. Finally, the distributed local topology model and algorithm is verified through a formal method using an actual ADN example.

Optimal allocation of protection and control devices in smart distribution systems: Models, methods, and future research

The fundamental goal of the distribution system operator (DSO) is to serve its customers with reliable and low-cost electricity. Failures in power distribution systems are responsible for 80% of customer service interruptions. The emergence of smart distribution system (SDS) with advanced distribution automation (DA) and communication infrastructure offers a great opportunity to improve reliability, through the automation of fault location, isolation, and service restoration (FLISR) process. DA includes the installation of protection and control devices (PCD). The use of PCD makes fault management more efficient, reduces average outage duration per customer in case of faults, reduces costs due to unsupplied energy, and improves distribution system reliability. Although the use of PCD remarkably enhances distribution system reliability, it is neither economical nor affordable to install them in all potential locations. To obtain the optimal allocation of PCD (OAPCD), an optimisation problem has to be formulated and solved. Several models and methods have been suggested for the OAPCD in SDSs. Herein, an overview of the state-of-the-art models and methods applied to the OAPCD in SDSs are introduced, identifying the contributions of reviewed works, identifying advantages and disadvantages, classifying and analysing current and future research directions in this area.

A FLISR approach for distribution networks integrated distributed generators

The penetration of distributed generators (DG ) into the distribution etworks (DN) greatly improves the reliability of electricity supply and reduces power loss. However, the operation of these DGs can also make the protection of distribution etwork more complex. This paper will examine the effects of two DG types on the protection of DN by analyzing the solution called Fault Location, Isolation and Service Restoration (FLISR). The FLISR approach considers DGs as auxiliary sources for the post-fault restoration plans in order to minimize the number of interrupted customers and unserved energy. Moreover, the combination of setting value of the overcurrent relay and the statuses of switching device and the loss voltage warning signal are used to detect and identify types of incidents in the distribution etwork with DGs. A two-constrained objective function will be solved to find possible plans for fault isolation and service restoration. There are six performance indices (PIs) selected for post-fault service restoration processing. The simulation results for the 22kV distribution network with integrated DG were performed by using E-terra software to validate this FLISR approach. To be concluded, the FLISR approach well adapt to the integration of DG into the DN and also helps to identify risks from false protection-coordination. On the other hand, it also helps to quickly detect and identify types of incidents as well as evaluate service restoration plans after incidents of distribution etwork with DG less than two minutes.

Service restoration enhancement by FIs deployment in distribution system considering available AMI system

Service restoration is considered as one of the most staple functions of distribution automation, which executes the fault location, isolation and service restoration (FLISR) function in case of contingency occurrence. The first part of the FLISR function is the fault location that can be improved through fault indicators (FIs) employment in electricity distribution system (EDS). On the other hand, the advanced metering infrastructure (AMI) is widely proliferated in EDSs in order to gather the consumers' consumption data for the operational purposes. In this study, FIs are deployed in the EDS considering available AMI data, using a metaheuristic optimisation method. The economic objective function of the optimisation problem consists of the total customers' interruption cost and the total cost of FI deployment. In addition, the technical objective function of the problem is the system average interruption duration index. In order to investigate the effectiveness of the proposed method, it is implemented on bus number four of the Roy Billinton test system. The results show that the number of deployed FIs reduces when the electric utility uses the proposed method.

Advanced Applications in an Advanced Distribution Management System: Essentials for Implementation and Integration

For more than a decade, the distribution utility industry has recognized and increasingly accepted the concept of an advanced distribution management system (ADMS). In a nutshell, an ADMS combines the functional domains of distribution supervisory control and data acquisition (SCADA) system, the outage management system, switching management, and distribution network analysis and optimization into a single seamless system. The distribution network analysis and optimization functions are referred to as advanced applications. However, surprisingly few distribution utilities have successfully implemented an ADMS with advanced applications. Even fewer have system operators making full use of such applications. Numerous small-scale pilot projects have been executed and completed where the value of such advanced applications as fault location isolation and service restoration (FLISR) and integrated volt/volt-ampere reactive optimization (IVVO) have been positively confirmed. Successful systemwide operational deployments of advanced applications, however, are much less common. There are multiple reasons for this, including insufficient numerical robustness of advanced applications to provide solutions under a wide variety of system conditions. Other reasons include model-magnitude, complexity, and data-quality issues.

Data-Driven Fault Location Scheme for Advanced Distribution Management Systems

There is now an increased interest among electric utility companies to implement advanced distribution management system (ADMS) software platform in their regular operational activities. ADMS provides smart grid functionalities, such as conservation voltage reduction, demand response, fault location, isolation, and service restoration (FLISR), etc. The ADMS platform improves power quality, increases reliability and resiliency, and manages the integration of distributed energy resources (DERs) effectively. This paper proposes a fault location scheme as a part of the FLISR program based on measurement from wireless sensors and smart meters deployed throughout the feeder. Sensors and smart meters use wireless sensor network and advanced metering infrastructure (AMI), respectively. The fault location scheme also considers the bi-directional power flow complexities with the integration of PV-based DERs at the edges of the grid. Initially, a modified depth first search is utilized to reduce the search space to find the faulty zone(s) bounded by two sensor buses; next, a voltage profile analysis is conducted in the specified zone(s) to find the actual faulty section(s). To demonstrate the robustness, the entire algorithm is tested in a utility scale feeder with various loading, DER penetration, and fault resistance condition using Monte-Carlo method.

Fault Location, Isolation, and Service Restoration (FLISR) Technique using IEC 61850 GOOSE

Fault Location, Isolation, and Service Restoration (FLISR) Technique using IEC 61850 GOOSE

Application of IEC 61850 for distribution network automation with distributed control

IEC 61850 was originally conceived as a communication standard within a substation, but is being extended to cover other areas of the power system such as distribution automation (DA). IEC TC57 Working Group 17 has set up a task force to study the information exchange required for automating the distribution network. A draft technical report IEC 61850-90-6 is available, which presents different use cases of DA, produces the information models and proposes the configuration method. This paper presents one of the use cases which applies distributed control on an open-loop distribution feeder. The system consists of a number of smart terminal units (STUs) to monitor and control substation circuit breakers, sectionalizing switches and tie switches within the feeder. The STUs work together in a distributed manner to achieve fault location, isolation and service restoration (FLISR) of the feeder. The data model for this use case is presented. New logical nodes are introduced. Standardizing the data model allows interoperability between vendors, makes integration of new devices easier, and forms the basis of a smart distribution network. Another important aspect is the configuration of the system. The configuration process of a new DA system is introduced in this paper.

Reliability Improvement of Power Distribution Systems using Advanced Distribution Automation

Towards the complete vision of smarter distribution grid, advanced distribution automation system (ADAS) is one of the major players in this area. In this scope, this paper introduces a generic strategy for cost-effective implementation and evaluation of ADAS. Along with the same line, fault location, isolation and service restoration (FLISR) is one of the most beneficial and desirable applications of ADAS for self-healing and reliability improvement. Therefore, a local-centralized-based FLISR (LC-FLISR) architecture is implemented on a real, urban, underground medium voltage distribution network. For the investigated network, the complete procedure and structure of the LC-FLISR are presented. Finally, the level of reliability improvement and customers’ satisfaction enhancement are evaluated. The results are presented in the form of a comparative study between the proposed automated and non-automated distribution networks. The results show that the automated network with proposed ADAS has a considerable benefit through a significant reduction in reliability indices. In addition, it has remarkable benefits observed from increasing customers’ satisfaction and reducing penalties from industry regulators.

Improving performance of underground MV distribution networks using distribution automation system: A case study

Abstract Towards the complete vision of smart distribution grid, this paper presents a generic framework and strategy for the implementation of distribution automation system (DAS). Fault location, isolation and service restoration (FLISR) is one of the most beneficial and desirable applications of DAS for self-healing and reliability improvement of distribution networks. FLISR is implemented on an actual, urban, underground medium voltage (MV) distribution network based on substation-centralized scheme, called SC-FLISR. The complete structure and procedure of SC-FLISR are introduced. The fully automation level is defined to be implemented in such network. To examine the level of reliability improvement and customers’ satisfaction enhancement, a reliability assessment study is applied for the proposed automated distribution network. The results presented in this paper emphasize that the proposed automated network has a high reliability level compared to non-automated network, where the results indicate clearly that reliability indices such as SAIDI and AENSI are reduced significantly.

Distributed processing based fault location, isolation, and service restoration method for active distribution network

Active distribution network (ADN) is a solution for power system with interconnection of distributed energy resources (DER), which may change the network operation and power flow of traditional power distribution network. However, in some circumstances the malfunction of protection and feeder automation in distribution network occurs due to the uncertain bidirectional power flow. Therefore, a novel method of fault location, isolation, and service restoration (FLISR) for ADN based on distributed processing is proposed in this paper. The differential-activated algorithm based on synchronous sampling for feeder fault location and isolation is studied, and a framework of fault restoration is established for ADN. Finally, the effectiveness of the proposed algorithm is verified via computer simulation of a case study for active distributed power system.

Multiagent-Based Distribution Automation Solution for Self-Healing Grids

A multiagent-based distribution automation solution is proposed to be used in the distribution of self-healing grids to solve the service restoration part of the Fault Location, Isolation and Service Restoration (FLISR) task. The solution reduces the grid topology to an undirected weighted graph and executes a distributed implementation of Prim's minimum spanning tree algorithm to solve the problem. The solution is compliant with state-of-the-art standards within smart grids, including but not limited to IEC61850. To test the performance of the algorithm, a testbed is assembled consisting of a physical dc grid model and several Arduino microcontrollers and Raspberry Pi computers. The test results show that the proposed algorithm can handle complex FLISR scenarios.

Distributed Energy Resource Impacts on FLISR Scheme in Distribution System

The key distribution automation (DA) application for implementing a self-healing smart distribution network is the fault location isolation and service restoration (FLISR) application. With DGs introduce significantly more variability into distribution system power flows, it has a great impact to FLISR. Based on summarizing the existing FLISR scheme, this paper analyses the influence of fault detection and service restoration with large-scale DGs.