Industrial Distribution Network Research Articles

Ground Fault in Medium-Voltage Power Networks with an Isolated Neutral Point: Spectral and Wavelet Analysis of Selected Cases in an Example Industrial Network Modeled in the ATP-EMTP Package

The paper presents some case spectral analysis of zero-sequence voltages and currents in an example industrial power distribution network. The network layout is based on typical power delivery networks in underground coal mines. Ground fault simulations have been made using an ATP/EMTP program. Due to the high environmental risks, the reliability of the protection relay operation related to their selectivity plays an important role. This paper tries to find the reasons for nonselective operation and unnecessary tripping in extensive mine cable networks, particularly with large power sources of higher-order harmonics. It was found that in transient states—due to the decaying oscillations occurring in complex RLC circuits—the results of short time measurements of the criterion values for ground fault protective relays can be overestimated (particularly for small values of ground resistance) and lead to nonselective tripping of a healthy cable line. Therefore, it might be advisable to increase the integration time used for measuring rms values. Also, if there is a significant level of higher harmonics in the industrial network generated by high-power converters, it should be noted that the higher harmonics of the ground fault current and currents measured by ground fault protection relays assume much higher values, which may also cause nonselective tripping. In this case, it may be advisable to use higher harmonic filters in the measuring circuits and to select a sufficiently high sampling frequency in the digital protective relays.

A set of Non-Synthetic test systems of European LV Rural, LV urban and hybrid MV/LV industrial distribution networks

The process of electrification and digitalisation that the electricity distribution sector is currently undergoing is a true revolution, imposing more changes in recent years than in dozens of previous years. The electrification process involves the deployment of more and more so-called flexible devices in the distribution network, such as electric vehicles, heat pumps, photovoltaic systems with or without electrical storage. Electrification will bring obvious benefits such as decarbonisation of the energy system and reduction of dependence on fossil fuels, but it is also true that it will put the distribution grid under stress never seen before. The introduction of digital twins for the real-time management of distribution networks, the precise calculation of hosting capacity at each point of the network, the analysis of safety in protections, etc., is already a reality even in low-voltage networks. Some of these methodologies involve the use of precise mathematical models of distribution networks, and this is precisely what is presented in this article. A set of 3 test networks of European type networks, generated with real data representing a 100% urban low voltage distribution system, a 100% rural low voltage distribution system and a mixed medium/low voltage system representing a network in an industrial/commercial environment. As part of the work, OpenDSS models of these networks are attached, which can be of great value to the research community in many types of studies.

Evaluation of Passive Filters for the Management of Harmonics in Industrial Electrical Distribution Networks

Es necesario gestionar armónicos para obtener calidad energética en sistemas de distribución. Por lo cual, este artículo tuvo como objetivo evaluar el uso de filtros pasivos como alternativa viable para la gestión armónica en redes de distribución eléctricas en media tensión con alta carga industrial, mediante el análisis de Índices de Distorsión Armónica Total que fueron calculados y graficados con el software Matlab. Así, primero se propuso un caso de estudio con base en la red de distribución IEEE 34 nodos, para posteriormente, definir cuatro escenarios de simulación que permiten la integración de bancos de condensadores, reactancias de rechazo y fuentes de armónicos. Partiendo de un diseño matemático se analizó el flujo de carga armónico diario para cada hora, y se propusieron mecanismos de diseño de reactancias de rechazo como complemento a las soluciones tradicionales de corrección de factor de potencia basadas en bancos de condensadores. Los resultados mostraron que, el uso de los filtros pasivos LC pueden ser altamente efectivos para la gestión de distorsión armónica de tensión, pero insuficientes para la eliminación de distorsión armónica de corriente. Sin embargo, esta clase de filtros sí muestran completa eficacia en la limitación de amplificación de armónicos (tanto de tensión, como de corriente) al utilizar bancos de condensadores para la corrección de factor de potencia en sistemas con problemáticas de armónicos. Concluyendo que los filtros pasivos LC con reactancias de rechazo mitigan armónicos de voltaje así se tengan bancos de condensadores y fuentes de armónicos, lo que los convierte en la forma más factible, eficaz y económica de obtener calidad energética.

Optimal selection of single tuned passive filters to enhance post‐fault voltage recovery and power quality in a renewable integrated microgrid

AbstractThe harmonic currents produced by nonlinear loads and renewable energy sources (RES) like PV and wind energy have had a growing impact on industrial distribution networks in recent times. Along with harmonic distortions, lack of adequate reactive power support in a heavily loaded renewable‐rich industrial network has made the operation vulnerable to fault‐induced delayed voltage recovery (FIDVR). Due to poor post‐fault voltage recovery, an industrial microgrid is exposed to cascading loss of distributed generators (DGs). Dynamic var sources are being used to prevent cascade tripping. However, they may result in deterioration of the network's THD scenarios. Single tuned passive filters are widely used to suppress harmonic contents. The goal of this work is to design filters so that these become capable to lower overall harmonic distortion while also minimizing the risk of blackouts caused by inadequate post‐fault voltage recovery. To determine the allocation and rating of single tuned passive filters in a renewable‐penetrated industrial microgrid, an optimization model is developed. To show the feasibility and efficacy of the proposed formulation, simulations are performed on a modified IEEE 43 bus system. The findings suggest that the proposed design methodology produces effective solutions to minimize the necessity of additional reactive power sources.

Economic analysis of annual load loss due to voltage sags in industrial distribution networks with distributed PVs

In an industry, analysis of load disconnection indices is essential to determine the annual economic loss because of the high cost of load interruptions. With the interconnection of PVs in modern industrial networks, this analysis gets more complicated due to controls associated with PV inverters for reactive power support. Hence, the paper proposes a unique method for such analysis that relies on dynamic simulation to calculate load disconnections. The dynamic simulation allows the integration of the voltage tolerance curve of loads and controls associated with PVs making the scenarios more realistic. The indices are determined by employing statistical experiments which account for annual variability of daily solar and load profiles with the least possible runs of dynamic simulation. The proposed method is applied to calculate load disconnection indices for an IEEE 399-1997 industrial distribution system. A comparative analysis of the cost of disconnection under a variety of solar penetration and operation scenarios is presented. Network planners and reliability engineers can potentially utilize the proposed method to identify PV inverter controls, placement, and size effects on the annual load disconnection indices due to voltage sags.

Reliability Evaluation Model of Distribution Network Based on Circuit Structure

In order to meet the electricity requirements and improve the quality of distribution networks, it is essential to improve the reliability level of the power system. This paper established several mathematical models based on circuit analysis and computer simulation to realize the evaluation of distribution network reliability. Firstly, the Sequential Monte Carlo method was utilized to simulate the indicators of series and parallel circuits, and the Entropy Weight Method was adopted to weight the indicators. Then, simulation results were comprehensively evaluated using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), and the evaluation model of distribution network reliability was obtained. The established mathematical model provided some guidance to construct an industrial distribution network and improve the reliability level of the power system.

Series FACTS controllers in industrial low voltage electrical distribution networks for reducing fault current levels

In this paper, series FACTS devices like Thyristor control series capacitor(TCSC)and Static synchronous series compensator (SSSC) with designed control logic used to reduce the fault current located in LV distribution network at the LV busbar. The electrical distribution network in small and medium scale industries such as steel plants, process and power plants is through low voltage switchgear (LVS) fed from motor control centre (MCC) switchgear through step down transformer of 11kV or 33kV /415V. The designed switchgear in the LV side for these utilities usually is at 50kA. However, the process loads are continuously increasing and sustained with additional feeders with the existing switchgear. Consequently, the fault current at the busbar of the switchgear increases which may require the replacement of entire switchgear to the new design fault current. However, upgrading the existing switchgear is not an economical solution to the industries. Alternatively reducing the fault current at the busbar is feasible. Controller design implemented for reducing the short circuit current with series FACTS devices. A study carried on 800 MW Thermal power plant Ash handling LVS in ETAP and Matlab. It is observed that the results are encouraging to use series FACTS devices effectively in the LVS.

Impact assessment of simultaneous operation of photovoltaic and cogeneration power plants on industrial distribution system

<p>Industries with co-generation plants face unprecedented problems due to penetration of renewable energy systems such as solar power on their existing distribution networks. These problems are caused by intermittent solar power. To this end, this paper provides a detailed investigation of the effects due to sudden changes in solar power on an existing industrial distribution network connected to co-generation plants. Moreover, the case studies in this work consider simultaneous operation of a large industry having co-generation captive power plant and large scale solar photovoltaic power plant. The real-time field data for the past three years are used to check the performance of solar photovoltaic power plant, load management, power quality and other concerning issues on the distribution network. In addition to the real-time data, the simulations were performed for the solar power output under different solar irradiance conditions. Moreover, these simulations are used to assess photovoltaic integration effects on a distribution system having a co-generation captive power plant. Finally, this paper put forward photovoltaic integration guidelines to industries and policymakers interested to carry out the integration studies in the future.</p>

An approach of incorporating harmonic mitigation units in an industrial distribution network with renewable penetration

Due to globalization and industrial development, the need of power is increasing day by day. In addition, due to the high demand for clean energy sources, the use of renewable systems has expanded in recent years. Wind systems can take advantage of the copious and free energy provided by the wind, which is a significant benefit. However, changing incident energy from renewables generate harmonics, which may result in poor system performance. The power quality has therefore become an important issue for both the power suppliers and consumers. Power electronic devices and nonlinear loads have been used frequently in industries hence introducing harmonic distortions in the industrial power distribution network. Harmonics have adverse effects on the power quality like degradation of power generation efficiency, higher operational costs, overheating of equipment, saturation of transformer, electromagnetic interference etc. In order to solve these problems, the implementation of suitable filtration techniques and the evaluation of efficiency with harmonic reduction are crucial. Since, utilities are always aiming to improve the power quality with minimum filtering units, this paper compares the performance of two available filter implementation plan, namely the shunt active power filter (SAPF) and the single tuned filter (STF) in a renewable penetrated industrial distribution network. Based on the outcome of the comparison, a genetic algorithm (GA) based approach is proposed in this paper to determine the optimum size and position of the minimum required filtering units that improves the network’s existing harmonic scenarios. Simulation results to validate the proposed methodology are presented. According to the results, the proposed method of incorporating filtering units significantly outperformed in lowering total harmonic distortion (THD) in an industrial power distribution network with a higher renewable penetration.

Handcrafted concrete hybrids, the production of tradition and modern in the South Korea developmental state

ABSTRACT In the 1960’s and 1970’s South Korean developmental state, traditionalist and post-traditionalist architects converged upon nation building to create a unique cultural legacy in post-colonial South Korea. The employment of various architectural tectonic approaches using concrete positively re-established concepts like “Joseon” and “Craftsmanship”. Modern materials, like concrete, were pinpointed in government design guidelines as a technical medium to reconstruct tradition, while government appointed architect committee’s trips abroad established a pan-Asian framework of common challenges faced by postcolonial nations. This study investigates how handcrafted concrete architectural designs became symbols of technological innovation in the re-invention of heritage and tradition to establish a new postcolonial national identity. The hybrid approach of handcrafted technology evidences how concrete is a historical medium intrinsically tied to the existing industrial ecosystem, as a by-product of the construction of a huge industrial production and distribution network of modernist material.

Resilient operation of multi-energy industrial park based on integrated hydrogen-electricity-heat microgrids

The hydrogen-based clean energy infrastructure provides a viable option for resilience improvement against extreme events, e.g., natural disaster and malicious attacks. This paper presents a resilience-oriented operation model for industrial parks energized by integrated hydrogen-electricity-heat microgrids, which aims to improve the load survivability under contingency status. The synergies of multi-type distributed energy resources (e.g., fuel cells, hydrogen storage tanks, battery storage and heat storage unit) and the sequential operation of the industrial distribution network are analytically represented by a mixed-integer second-order conic program (SOCP) formulation. Moreover, by leveraging the information of probabilistic disaster prediction, a risk-averse receding horizon method is developed to handle the uncertainty of network contingencies, and supports the optimal decision of proactive and emergency scheduling. Numerical results on a 26-node industrial energy system demonstrate the effectiveness of the proposed model and resilient scheduling method. The synergetic operation of hydrogen-based microgrids could significantly reduce the risks of load interruption.

Harmonic mitigation technique using active three‐phase converters utilised in commercial or industrial distribution networks

Current harmonics generated by adjustable-speed drives (ASDs) are one of the main power quality concerns in commercial and industrial distribution networks due to a high number of ASDs. These harmonics affect the grid power quality, instability, resonances, and power losses. Therefore, different harmonic mitigation strategies using active front end have been proposed to tackle this issue. However, due to the cost-effectiveness, conventional front end such as diode rectifier is still recommended in industries for a broad range of three-phase power electronics systems. Thus, in this study, a new DC modulation method is proposed using three-phase diode rectifier with controlled DC-link current (boost converter) for grid harmonic elimination approach. Simulations and experiments have been carried out to validate the proposed concept that a selective harmonic can be eliminated from the grid using the developed strategy.

A Hybrid Control Strategy to Support Voltage in Industrial Active Distribution Networks

Asymmetric voltage sags often occur at the point of common coupling, which connects industrial active distribution networks to the utility grid. Distributed generations face the challenges of riding through and supporting the voltage under the grid faults. In order to tackle these challenges, a hybrid control strategy, combined with the frequency droop with passivity-based switch function, is proposed. By adopting the proposed strategy, the positive/negative sequence active/reactive power is injected to recover the voltage. The novel PBSF is enhanced by including both control components of inverter's output current and output voltage based on the Euler–Lagrange model. The novel frequency droop is applied to achieve the positive/negative sequence active/reactive power injection with a satisfied sharing accuracy among the coordinated operation of parallel connected multiple inverters. Extensive simulation and experimental results have validated the effectiveness of the proposed strategy with an effective dynamic response performance and stability.

Coordinated Frequency Control Strategy for an Islanded Microgrid With Demand Side Management Capability

This paper presents a novel coordinated frequency control (CFC) scheme with demand side management capability for an islanded microgrid. The proposed CFC scheme is a communication-free coordination among fast responding devices: thermostatically controlled loads (TCLs), photovoltaic power systems, battery energy storage systems, and a slow responding diesel generator (DZ). The fast responding devices are deployed to achieve a swift frequency regulation in transient state. In steady state, these devices are returned to their normal operating condition by changing loading conditions of the DZ without employing interdevice communication. The proposed control strategy not only achieves frequency regulation in adherence to IEEE Standard 1547, but also maintains customers’ quality of service while manipulating TCLs for frequency regulation. A comprehensive study of the proposed CFC scheme is carried out on a modified IEEE 13-bus balanced industrial distribution network using MATLAB/Simulink. In addition, real-time performances of the CFC scheme have been validated experimentally using OPAL-RT simulator, and a well-programmed TMS320F28335 microcontroller. Both the simulation and experimental results demonstrate effective performance of the proposed CFC in achieving efficient frequency regulation.

Control of D-STATCOM During Unbalanced Grid Faults Based on DC Voltage Oscillations and Peak Current Limitations

The safe operation of grid-connected power converters during abnormal condition is a key issue in order to guarantee operation and to avoid undesired trips. In this paper, different control strategies for the operation of a D-STATCOM are introduced, where the reference currents are determined in such a way that not only will none of the phase currents go over the limits, but also the dc voltage fluctuations remain in safe operation limits. Fluctuating active power interchange during unbalanced condition leads to dc voltage oscillation. Severe unbalanced condition and small dc capacitor selection (to meet the size and cost constraints) intensify the dc voltage oscillation. Therefore, the contribution of this paper relies on the combination of the dc voltage oscillations and the current limit control. The effectiveness of three proposed control strategies is verified by simulating a D-STATCOM tied to an industrial distribution network. Moreover, a scaled scenario has been reproduced experimentally which shows that the results cope well with the analytical equations and the simulation results.

Practical tool to aid the planning of complex electrical industrial systems—Oil and gas industry

This paper presents an integrated computational method that supports design engineers with the elaboration of industrial distribution network projects during the conceptual and basic design phases. The method proposes various electrical topologies based on studies of electrical power flow and short circuit analysis and provides the specifications of the main electrical equipment (cables, transformers, and panels). The method also provides a technical and economic analysis of the presented solutions. In addition, the paper proposes a general method that accounts for the intrinsic thermal effects of the cables in any electrical system, which can have a significant impact on the electrical system results. An example of a complex and large scale oil refinery planning is presented.

Protection Coordination Analysis Under a Real-Time Architecture for Industrial Distribution Systems Based on the Std IEEE 242-2001

The aim of this study is to introduce real-time hardware-in-the-loop (RT-HIL) techniques to test and study different protection systems on industrial distribution networks. The advantages of this implementation consist in the possibility to emulate the theoretical coordination results accordingly to the specifications of the real-system conditions, including the limitations from the protective device; certainly, the proposed methodology incorporates the feature to evaluate multiple scenarios, special fault cases, and equipment characterization, while thoroughly grasping the behavior or response of a protection setup. Therefore, the study achieves a more appropriate and reliable protection scheme and facilitates the coordination of abridged topologies. A selected case of study based on IEEE 242-2001 was implemented on two simulation softwares in order to analyze and compare the standard configuration and results; after the models are validated, the electrical system is implemented on an RT test bench. This paper also shows computational performance assessment of the RT-HIL implementation of the protection coordination system based on the standard.

A Method for Sizing of Industrial Electrical Systems using Genetic Algorithm

This work proposes an integrated computational tool to support the designer engineer during the elaboration of projects of industrial distribution networks during the conceptual and basic design, presenting the methodology for a technical and economic analysis of electrical systems applied to oil refineries.

The Impact of Distributed Generators Placements on the Reliability of Typical Industrial Power Distribution System

Electrical Distribution systems that are radially configured with one utility power source are inherently exposed to higher rates of outages and interruptions, due to failures of system components, including: transformers, breakers and switching devices. In addition, fault conditions can also be caused by weather, animals or human error. Historically in Saudi Arabia, many industrial and residential distribution networks suffered from these problems. Large-size, growing demand and cost — with the time requirements for enhancement projects — results in distributed generation (DG) — as online or backup —playing a key role in the residential, commercial and industrial sectors of the power system. In this paper, the value of DG — installed as an online power source for typical industrial distribution network in Saudi Arabia — is quantified by reliability indices that include System Average Interruption Duration Index (SAIDI), Customer Average Interruption Duration Index (CAIDI) and Energy Not Supplied (ENS). The study outcomes will provide power system engineers with the reliability benefits of DG penetration and an approach to assessing its installations, based on different factors such as size and location.

CITING THE SOUND

Geoff Stahl addresses the manner in which the (associated) fan-base, fanzine and fringe industrial distribution networks in North America foster a shared community of taste which provides the context for the popularisation of NZ indie rock music in the region.