Real-time Distribution Network Research Articles

Optimal Switch Insertion for Power Loss Reduction and Reliability Enhancement in the Nigeria Conventional Distribution Networks: A Case Study

This paper seeks to analyze the potentials of optimal switch insertion and relocation of the existing ones in the Nigeria conventional distribution network for reliability enhancement and power loss minimization. Maximizing customers’ satisfaction and enhancement of service reliability of the distribution network isa critical thing to utility and how to achieve it is also a major concern? Optimal switch insertion can enhance the network operation, minimize power losses in the lines, increase service restoration to blackout areas and improve the electric power supply to customers in the distribution network and increase the system reliability. The impact of optimal insertion of sectionalizing switches and optimal relocation of the existing ones for reliability enhancement and power loss reduction in real-time distribution network has been investigated. Additionally, the research examined the history of frequent power interruptions in the network and their cost implication on the system and customers alike, and as well as the benefits of eliminating frequent outages in the Nigeria distribution networks as a case study. Also, feeder ranking based on reliability indices, customer damage function (CDF), capital investment and their correlations were analyzed and established. Conclusively, the results depicted that the reliability of the network can be affected by the number of sectionalizing switches introduced by an optimal relocation of the existing ones and their locations as well as its capacity of power loss reduction in the network.

Cooperated Online Learning and Optimization Operation of the Low Voltage Distribution System Considering User Electrical Characteristics

With the acceleration of energy reform, photovoltaic, energy storage, electric vehicles, and other new loads in low-voltage distribution networks have been rapidly developed. However, the distribution network with distributed power supply has some problems, such as imprecise power flow modeling and difficult coordination between various energy sources and loads, which bring challenges to the online optimization of the distribution network load curve. In this study, a multi-time scale online load optimal operation scheme of the distribution network is proposed by using the Bayesian online learning method. This scheme transforms the online power optimization of the distribution network into a Markov decision process. The output time of different energy sources is different, and the load with different user load characteristics is optimized. The scheme can track the state of the distribution network in real time and make the optimization scheme of multi-energy output online. Finally, an example is given to verify the effectiveness of the proposed method, which has theoretical significance for promoting the diversified development of low-voltage user-side load.

Harmonics mitigated multi-objective energy optimization in PV integrated rural distribution network using modified TLBO algorithm

This paper presents an optimal operation of PV integrated distribution network to address the multiple issues such as harmonics, voltage variation, poor power factor, and power losses. A real time rural distribution network is modeled on ETAP (industrial software) to obtain un-optimized parameters and component settings, and, then the DHPF is embedded in TLBO algorithm to obtain the optimal parameters and component settings considering various constraints such as node voltage, conductor thermal loading (ampacity), transformer taps and inverter harmonic generation limits. The optimal parameters so obtained are validated again on real time distribution network and assessed in comparative reference context with the un-optimized base case. The results show that TLBO gives the best operation of the distribution network, particularly flat voltage profile, improved power factor, reduced power losses and mitigated harmonics.

Research on Fault Monitoring Technology of Distribution Network Based on Fuzzy Association Rules Mining

In order to monitor the operation status of distribution network in real time and ensure the security and stability of distribution internet of things, a fault monitoring method based on fuzzy association rule mining was proposed. Fuzzy association rules mining was used to build the normal state parameter model of distribution network. The degree of interest index replaced the traditional index, aiming to improve the association degree between the rule parameters and form an effective expert knowledge base. According to the rules in the expert knowledge base, the normal state data of distribution network were obtained by fuzzy reasoning. Further, the state similarity function between the monitoring states and the normal states was used as the state judgement index. When the similarity is lower than the threshold, the fault alert should be triggered. Taking the single-phase ground fault data of distribution network simulated by MATLAB Simulink as an example, it was verified that the proposed method can effectively monitor the single-phase ground fault.

Micro-synchrophasor based special protection scheme for distribution system automation in a smart city

IntroductionAspects of power system protection which contributes to mal-operations and blackouts can be improved by supervision of system behavior and response based analysis rather than condition-based or event-based analysis using wide area measurements based on synchrophasor technology. The paper explores the application of micro-Phasor Measurement Unit for time synchronized real-time distribution network monitoring and agile decision support schemes for system prognosis and control.Case descriptionThe scheme is proposed as part of a project on “Power System Voltage Stability Analysis using synchrophasors in Distribution System of Kerala Grid” at Kerala State Electricity Board Ltd. An actual grid occurrence during the severe tropical cyclone Ockhi, is considered as the base case which motivated the work.Discussion and evaluationA voltage stability index (VSI) based special protection scheme (SPS) for radial distribution network at a proposed smart city is presented in the present study. The proposed special protection scheme on actual implementation can use data from proposed local micro-Phasor Measurement Unit. The PMU is proposed to be placed at one of the key nodes of the distribution system network in the city.ConclusionThe VSI is derived using local phasor values and is used to initiate a Special Protection Scheme for N-1 contingency at the key node, so as to ensure availability of the most essential feeder which provides supply to a hospital campus housing several health institutes of prime importance. The voltage stability index derived is tested and SPS is validated using real-time grid data.

Planning and real-time management of smart grids with high PV penetration in Italy

For planning and development and in real-time operation of smart grids, it is important to evaluate the impacts of photovoltaic (PV) distributed generation. This paper presents an integrated platform, constituted of two main components: a PV simulator and a real-time distribution network simulator. The first, designed and developed following the microservice approach and providing Representational State Transfer web services, simulates real-sky solar radiation on rooftops and estimates the PV energy production. The second, based on a digital real-time power systems simulator, simulates the behaviour of the electricity network under the simulated generation scenarios. The platform is tested on a case study based on real data for a district of the city of Turin, Italy. In the results, the authors show possible applications of the platform for power flow forecasting during real-time operation and for detecting possible voltage and transformers’ capacity problems during planning due to high penetration of renewable energy sources. In particular, the results show that the case study distribution network, in the actual configuration, is not ready to accommodate all the generation capacity that can be installed, as, in certain hours of the day and on certain days of the year, the capacity of some transformers is exceeded.

Adaptive Weight-Based Self Reconfiguration of Smart Distribution Network With Intelligent Agents

This work proposes an improved restorative algorithm for distribution systems with load priority consideration. The proposed algorithm takes into consideration about the optimization of the network while continuous monitoring for changes in system load conditions with a prevention mechanism for network reconguration with respect to small load changes. A simple adaptive, weight-based self reconfiguration algorithm is proposed with distributed generators for load sharing and reducing congestion in the lines. Individual node load priority is proposed at the time of restoration rather than taking priority of node to be restored. The proposed method is based on distributed computing with multiagent systems, implementation, and validation in laboratory scale distribution network in real time with low cost hardware. Results are also validated with the IEEE-33 bus distribution system.

Dynamic reconfiguration of distribution networks considering the real‐time topology variation

Network reconfiguration is a vital analysis process for optimising and controlling distribution systems (DSs). Given a stable initial DS, the distribution feeders can be reconfigured by changing the status of the switches to improve the operational performance. Owing to the fault trip, equipment maintenance, and system extension, the removal or addition of a branch can change the structure of the initial topology. This study proposes a dynamic reconfiguration method that considers the real-time initial topology variation. The method combines the dynamic topology analysis with network reconfiguration to address the optimisation problem of the real-time distribution network. A set of independent topological parameters represents the initial topology of a DS. After the changes in the initial topology are detected, the dynamic topology analysis is used to restore network connectivity and identify out-of-service areas. Then the real-time initial topology is obtained by updating the topological parameters. In accordance with network reconfiguration, the optimal configuration is identified to reduce power loss and improve the voltage profile of the real-time distribution network. Illustrative examples verify the effectiveness of the proposed method.

Research on Integrated Parameter Measurement and Control System of Low Voltage Distribution Network

In order to ensure the safe operation of the distribution network and to understand the operation of the distribution network, it is necessary to monitor the various operating parameters of the distribution network in real time and to send the various measurement parameters to the dispatching and monitoring center in time. So the low-voltage distribution network integrated parameter measurement and control has been widely used. This paper introduces a design method of combining two sets of reactive power compensator and distribution network measuring and controlling device into one part. The distribution network measurement and control, power factor correction and reactive power compensation are realized. In a word, the system has simple structure, high precision, and strong anti-interference ability, among other advantages, with great market potential.

A Novel Integrated Real-time Simulation Platform for Assessing Photovoltaic Penetration Impacts in Smart Grids

For future planning and development of smart grids, it is important to evaluate the impacts of PV distributed generation, especially in densely populated urban areas. In this paper we present an integrated platform, constituted by two main components: a PV simulator and a real-time distribution network simulator. The first simulates real-sky solar radiation of rooftops and estimates the PV energy production; the second simulates the behaviour of the network when generation and consumption are provided at the different buses. The platform is tested on a case study based on real data for a district of the city of Turin, Italy.

An Approach for Online Assessment of Rooftop Solar PV Impacts on Low-Voltage Distribution Networks

Assumption-based offline analysis tools may not be able to provide sufficient and accurate information for the corrective decision making to mitigate solar photovoltaic (PV) impacts in the future distribution grids. This is mainly due to the increasing penetration level of intermittent power generation resources and also the fluctuating behavior of consumer demand. Online assessment tools can assist to manage PV impacts and aid to mitigate those on a real-time basis. This paper proposes an approach for online assessment of rooftop PV impacts on low-voltage (LV) networks using real-time network data. A variable-width sliding window will be used to provide the analysis an outcome-based online data. The width of the sliding window can be varied according to user input so that the changes in network behavior caused by PV integration can be investigated conveniently. Several numerical indices are proposed in this paper to assess solar PV impacts on the LV networks. This approach also uses the online data to develop real-time distribution network models for a dynamic “what-if” analysis. The usefulness of the proposed online assessment approach is verified using an Australian LV distribution feeder.

Initial Designs of an on-Chip EMI Sensor Array

The purpose of the on-chip EMI sensor array (OCEMISA) is to measure the 2-dimension profile of the EMI voltage in the on-chip power distribution network in real time. The feedback signal from a senser cell should reflect only its local EMI. Signals have to be grouped carefully. This paper presents two different designs of the OCEMISA. In the first design, sensor cell generates regular pulses as feedback. The time domain waveform is monitored. In the second design, the supply noise generated by the sensor cell is utilized as feedback. The spectrum is monitored. Designs are implemented with FPGA for validation check. Measurement results show that feedback signals faces synchronization and instability problems. Those problems come from the IC process variation and are influenced by the feedback scheme. With the presentation and analysis of those problems, the paper is intent to provide optimization directions to make OCEMISA practical.

Intelligent system for automatic reconfiguration of distribution network in real time

In normal operation, the reconfiguration of distribution network can reduce losses, balance loads and improve quality indicators. The increasing use of remote controlled equipment in power systems leads the development of more efficient techniques for automatic reconfiguration of network, being particularly important in Smart Grid applications. This paper presents a methodology and system for automatic reconfiguration of distribution network in real time. The optimization of the network performance is based on a heuristic method and multicriterial analysis. This work relies on the Analytic Hierarchic Process (AHP) method to define weights for the optimization criteria and to determine the best sequence of switching for the network. In addition, the analysis of the technical feasibility of connecting feeders in parallel during the reconfiguration is also considered, focusing on determining transient constraints. The method assumes that only the remote controlled switches are analyzed. The developed algorithms are integrated into a supervisory system, which allows real time measurements and commands to the equipment. The proposed methodology is tested in a real network of a power utility and results are presented and discussed.

Switched Ethernet in Synchronized Distributed Control Systems Using RTnet

We adopt a model of a real-time distributed network where the synchronization is done by an external timing network that triggers the acquisitions. A Switched Ethernet is used to send the synchronously sampled data from nodes to nodes to perform the distributed control algorithm. In order to guarantee low latencies and jitter, the traffic on the Switched Ethernet must be carefully analyzed to be able to correctly model closed-loop systems and potentially identify events that might lead to large delays or even packet losses. In this paper we discuss the most relevant results from a testbed control network with synchronous data acquisition nodes. A switched Gigabit Ethernet is adopted and each node uses RTnet running in a RTAI/Linux Operating System. To resolve the problem of timing uncertainties at the data link layer, we propose a new custom solution based on a TDMA discipline.