scholarly journals A Novel Machine Learning-Based Short-Circuit Current Prediction Method for Active Distribution Networks

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3793 ◽  
Author(s):  
Zheng ◽  
Wang ◽  
Jiang ◽  
He
Keyword(s):  
Distribution Systems ◽  
Large Scale ◽  
Short Circuit ◽  
Distribution Network ◽  
Prediction Method ◽  
Short Circuit Current ◽  
Distribution Networks ◽  
Test System ◽  
High Penetration ◽  
Active Distribution Networks

The traditional mechanism models used in short-circuit current calculations have shortcomings in terms of accuracy and speed for distribution systems with inverter-interfaced distributed generators (IIDGs). Faced with this issue, this paper proposes a novel data-driven short-circuit current prediction method for active distribution systems. This method can be used to accurately predict the short-circuit current flowing through a specified measurement point when a fault occurs at any position in the distribution network. By analyzing the features related to the short-circuit current in active distribution networks, feature combination is introduced to reflect the short-circuit current. Specifically, the short-circuit current where IIDGs are not connected into the system is treated as the key feature. The accuracy and efficiency of the proposed method are verified using the IEEE 34-node test system. The requirement of the sample sizes for distribution systems of different scale is further analyzed by using the additional IEEE 13-node and 69-node test systems. The applicability of the proposed method in large-scale distribution network with high penetration of IIDGs is verified as well.

scholarly journals Online Estimation of Short-Circuit Fault Level in Active Distribution Network

2020 ◽  
Vol 10 (11) ◽  
pp. 3812
Author(s):  
Xiaohui Wang ◽  
Peng Wang ◽  
Yunbo Wang ◽  
Fang Shi
Keyword(s):  
Equivalent Circuit ◽  
Short Circuit ◽  
Distribution Network ◽  
Estimation Method ◽  
Short Circuit Current ◽  
Distribution Networks ◽  
Measurement Unit ◽  
Online Estimation ◽  
Active Distribution Network ◽  
Short Circuit Fault

The potential short-circuit current in active distribution network features time-variance with the increasing distributed generations. This feature makes the online estimation of fault level necessary. In this paper, a novel online estimation method is proposed to be implemented by either phasor measurement unit (PMU) or the measurements from protection relays. The equivalent circuit of the radial distribution network with distributed generators (DGs), e.g., wind turbines and photovoltaic cells, is derived with necessary simplifications. The natural disturbances downstream are used to evaluate the parameters of the equivalent circuit so that the potential fault level can be estimated in advance of the actual fault occurrence. A fuzzy logic identifier is presented to rank the confidence of the measurements incurred by the disturbance and to distinguish the qualified disturbance to launch the estimation. The mechanism based on multi-measurements and confidence indices was applied, to improve the accuracy. A typical distribution network in the United Kingdom (UK) with DGs was taken, as an example, to validate the proposed method under various load fluctuation. The results confirm the effectiveness of the proposed method, which is suitable for online estimation of short-circuit fault level in active distribution networks.

Protection System Monitoring in Electric Networks with Embedded Generation Using Petri Nets

2008 ◽  
Vol 9 (6) ◽  
Author(s):  
Vito Calderaro ◽  
Vincenzo Galdi ◽  
Antonio Piccolo ◽  
Pierluigi Siano
Keyword(s):  
Petri Nets ◽  
Distribution Systems ◽  
Short Circuit ◽  
Distribution Network ◽  
Distribution Networks ◽  
Protection System ◽  
Electric Networks ◽  
Embedded Generation ◽  
Network Operation ◽  
Monitoring Architecture

The connection of distributed generation (DG) essentially changes the distribution network operation and creates a range of well-documented effects varying the voltage levels and short circuit currents. Among others, DG can alter protection system operations in distribution networks, leading to the failure of reclosing, the disconnection of the healthy feeder or the prevention of a protection operation. This paper proposes a procedure, based on Petri nets and supported by a centralized monitoring architecture, for monitoring failures of the protection systems in radial distribution networks. Some case studies applied to a real Italian distribution network proved the effectiveness of the proposed procedure that can therefore represent an effective solution to improve distribution systems reliability in the presence of DG.

scholarly journals Impacts of Placement of Wind Turbine Generators with Different Interfacing Technologies on Radial Distribution Feeder Fuse-Fuse Protection Coordination Scheme.

2019 ◽  
Vol 4 (10) ◽  
pp. 59-77
Author(s):  
Kemei Peter Kirui ◽  
David K. Murage ◽  
Peter K. Kihato
Keyword(s):  
Wind Turbine ◽  
Short Circuit ◽  
Renewable Energy Sources ◽  
Distribution Network ◽  
Short Circuit Current ◽  
Electrical Energy ◽  
Distribution Networks ◽  
Turbine Generators ◽  
Wind Turbine Generators ◽  
Coordination Scheme

The ever increasing demand on the electrical energy has led to the diversification on the electrical energy generation technologies especially from the renewable energy sources like the wind and the solar PV. Micro-grids powered by distributed generators utilizing renewable energy sources are on the increase across the globe due to the natural abundance of the resources, the favorable government policies and the resources being environmentally friendly. However, since the electrical power distribution networks have always been passive networks, the connection of the distributed generations (DGs) into the network has associated several technical implications with distribution network protection and Over-Current Protective Devices (OCPDs) miss-coordination being one of the major issues. The need for a detailed assessment of the impacts of the wind turbine generation (WTGs) on the distribution networks operations has become critical. The penetration of the WTGs into a distribution network has great impacts on the short circuit current levels of the distribution network hence eventually affecting the OCPDs coordination time margins. The factors which contribute to these impacts are: The size of the WTG penetrating the distribution network, the location at which the WTG is connected on to the network and the Type of the WTG interfacing technology used. An important aspect of the WTGs impacts studies is to evaluate their short circuit current contribution into the distribution network under different fault conditions. The magnitudes of these short circuit currents, both the three phase and the single-line-to-ground (SLG) faults, are needed for sizing the various Over-Current Protective Devices (OCPDs) utilized in protecting the distribution network. The sizing of the OCPDs entails among other procedures coordinating them with both the upstream and the downstream OCPDs so that there is sufficient time margin between their Time Current Characteristic (TCC) curves. For Fuse-Fuse protection coordination, the ANSI/NEC rules stipulate that a minimum of 0.025seconds or more time margin should be maintained between the primary/downstream fuse and the secondary/upstream/back-up fuse. Due to the topological and operational differences between the different types of WTGs interfacing technologies, the electrical generators design industry has divided wind turbine generators into four different types labeled as Type I, Type II, Type III and Type IV. This paper presents a detailed study of the impacts brought upon by integrating wind turbine generators on a conventional Fuse-Fuse protection coordination scheme. A conventional Fuse-Fuse protection coordination scheme was modeled in Electrical Transients Analysis Program (ETAP) software and WTG with different interfacing technologies connected. A study of the impacts brought by the integration of the WTGs on Fuse-Fuse Miss-coordination was performed. IEEE 13 Node Radial Distribution Test Feeder was used for the study.

scholarly journals Robust Fault Protection Technique for Low-Voltage Active Distribution Networks Containing High Penetration of Converter-Interfaced Renewable Energy Resources

Processes ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 34 ◽  
Author(s):  
Shijie Cui ◽  
Peng Zeng ◽  
Chunhe Song ◽  
Zhongfeng Wang
Keyword(s):  
Renewable Energy ◽  
Low Voltage ◽  
Short Circuit ◽  
Renewable Energy Sources ◽  
Distribution Network ◽  
Distribution Networks ◽  
Fault Current ◽  
Fault Protection ◽  
High Penetration ◽  
Small Fault

With the decentralization of the electricity market and the plea for a carbon-neutral ecosystem, more and more distributed generation (DG) has been incorporated in the power distribution grid, which is then known as active distribution network (ADN). The addition of DGs causes numerous control and protection confronts to the traditional distribution network. For instance, two-way power flow, small fault current, persistent fluctuation of generation and demand, and uncertainty of renewable energy sources (RESs). These problems are more challenging when the distribution network hosts many converter-coupled DGs. Hence, the traditional protection schemes and relaying methods are inadequate to protect ADNs against short-circuit faults and disturbances. We propose a robust communication-assisted fault protection technique for safely operating ADNs with high penetration of converter-coupled DGs. The proposed technique is realizable by employing digital relays available in the recent market and it aims to protect low-voltage (LV) ADNs. It also includes secondary protection that can be enabled when the communication facility or protection equipment fails to operate. In addition, this study provides the detail configuration of the digital relay that enables the devised protection technique. Several enhancements are derived, as alternative technique for the traditional overcurrent protection approach, to detect small fault current and high-impedance fault (HIF). A number of simulations are performed with the complete model of a real ADN, in Shenyang, China, employing the PSCAD software platform. Various cases, fault types and locations are considered for verifying the efficacy of the devised technique and the enabling digital relay. The obtained simulation findings verify the proposed protection technique is effective and reliable in protecting ADNs against various fault types that can occur at different locations.

scholarly journals Optimal Conductor Size Selection in Distribution Networks with High Penetration of Distributed Generation Using Adaptive Genetic Algorithm

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2065 ◽  
Author(s):  
Zhenghui Zhao ◽  
Joseph Mutale
Keyword(s):  
Genetic Algorithm ◽  
Distributed Generation ◽  
Distribution Systems ◽  
Distribution Network ◽  
Distribution Networks ◽  
Adaptive Genetic Algorithm ◽  
Optimization Approach ◽  
Optimization Strategy ◽  
Size Selection ◽  
High Penetration

The widespread deployment of distributed generation (DG) has significantly impacted the planning and operation of current distribution networks. The environmental benefits and the reduced installation cost have been the primary drivers for the investment in large-scale wind farms and photovoltaics (PVs). However, the distribution network operators (DNOs) face the challenge of conductor upgrade and selection problems due to the increasing capacity of DG. In this paper, a hybrid optimization approach is introduced to solve the optimal conductor size selection (CSS) problem in the distribution network with high penetration of DGs. An adaptive genetic algorithm (AGA) is employed as the primary optimization strategy to find the optimal conductor sizes for distribution networks. The aim of the proposed approach is to minimize the sum of life-cycle cost (LCC) of the selected conductor and the total energy procurement cost during the expected operation periods. Alternating current optimal power flow (AC-OPF) analysis is applied as the secondary optimization strategy to capture the economic dispatch (ED) and return the results to the primary optimization process when a certain conductor arrangement is assigned by AGA. The effectiveness of the proposed algorithm for optimal CSS is validated through simulations on modified IEEE 33-bus and IEEE 69-bus distribution systems.

scholarly journals Modeling and Validation of a Directional Overcurrent Relay as an Island Interconnection Device

2020 ◽  
Author(s):  
Wandry R. Faria ◽  
Jonas V. Souza ◽  
Rodrigo B. Otto ◽  
Benvindo R. Pereira Jr.
Keyword(s):  
Power Systems ◽  
Power Flow ◽  
Distribution Systems ◽  
Short Circuit ◽  
Electrical Power ◽  
Distribution Networks ◽  
Test System ◽  
Electrical Power Systems ◽  
Distributed Generators ◽  
Overcurrent Relay

The growing number of decentralized generators in the distribution systems and the consequent increase in the penetration level in the networks have prompted the inclusion of this scenario in researches involving the planning of electrical power systems. The planning of protection systems for distribution networks considering distributed generators requires adaptations in the approach due to modifications in characteristics of the network, such as passivity and unidirectional power flow. Furthermore, the insertion of generators in distribution networks allows the implementation of new operation methods, such as the possibility of disconnecting some loads from the main feeder and supplying them through distributed generators. The island operation can improve the service continuity indexes, as well as reduce the costs of non-supplied energy. Although the island operation is widely proposed in the literature as a means to improve the system's reliability, the simulation of a protective device to intentionally island a region and the verification of its limitations is not. In this paper, we present the modeling of a directional overcurrent relay through ATP-EMTP, and its employment as a device for island interconnection, analyzing its zone of non-operation. CIGRE 14-bus test system is used to conduct short-circuit tests with the variation of resistance and type of fault applied. Theresults show the effectiveness of the device, which is able to identify all faults with real impact on the network, placing the region in island operation in less than 20 ms.

scholarly journals Effect of Distributed Wind Generation on the Voltage Sag of Distribution Networks

2019 ◽  
Vol 8 (4) ◽  
pp. 1884-1889
Keyword(s):  
Renewable Energy ◽  
Distribution Systems ◽  
Short Circuit ◽  
Distribution Network ◽  
Distribution Networks ◽  
Voltage Regulation ◽  
Energy Resources ◽  
Wind Generation ◽  
Voltage Sag ◽  
Renewable Energy Resources

As the issue of global warming is worsening, the shift towards using renewable energy resources is becoming more of an obligation rather than an option. With the continual decline in the cost of distributed small and medium-scale renewables and government sponsored programs, the outlook of growth of these converter-based resources remain high. Renewable energy resources are connected at the end-user terminals, in close proximity to the load at the distribution network. Such connection in the locale brings perceived benefits of transmission loss reduction, increased energy efficiency and improved voltage regulation. Yet, distributed renewable generation have noticeable effects on system’s power quality. This paper investigates the impacts of distributed wind generation on the voltage sag of distribution systems. A systematic approach is constructed to capture voltage sag occurrence incidents, due to wind generation connected at distribution nodes, and trigger the dynamic voltage restorer (DVR) into active operation mode to rectify the voltage sag problem. A test feeder system is represented using MATLAB/Simulink with wind turbines connected at several nodes of the system. A model for the DVR is developed in Simulink. It was then integrated with the test feeder system. Simulation results show that the incorporation of increased proportions of wind generation into the distribution network may give rise to negative operating conflicts as far as the voltage sag is concerned. Results manifest that the DVR is capable of effective correction of the voltage sag, caused by a three phase short-circuit fault, in presence of high penetration levels of variable wind generation connected at disparate locations in the distribution network.

Criticality-Based Designs of Power Distribution Systems

2021 ◽  
pp. 150-175
Author(s):  
Sadeeb Simon Ottenburger
Keyword(s):  
Power Distribution ◽  
Smart Grids ◽  
Distribution Systems ◽  
Large Scale ◽  
Distribution Network ◽  
Distribution Networks ◽  
Urban Resilience ◽  
Power Distribution Networks ◽  
Adequate Provision ◽  
Advanced Metering

The generation and supply of electricity is currently about to undergo a fundamental transition that includes extensive development of smart grids. Smart grids are huge and complex networks consisting of a vast number of devices and entities which are connected with each other. This fact opens new variations of disruption scenarios which can increase the vulnerability of a power distribution network. However, the network topology of a smart grid has significant effects on urban resilience particularly referring to the adequate provision of infrastructures whereby the way in which a distribution network is divided into interconnected microgrids is of particular importance. Such decompositions enable the systematic protection of important infrastructures and furthermore allow new forms of resilient power supply avoiding large-scale power blackouts. Therefore, the authors introduce a concept of criticality adapted to a power system relying on an advanced metering infrastructure and thereby propose a metric for an integrated resilience assessment of power distribution networks.

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