Electric Delivery Research Articles

An adversarial model for attack vector vulnerability analysis on power and gas delivery operations

Power systems often rely on natural gas pipeline networks to supply fuel for gas-fired generation. Market inefficiencies and a lack of formal coordination between the wholesale power and gas delivery infrastructures may magnify the broader impact of a cyber-attack on a natural gas pipeline. In this study we present a model that can be used to quantify the impact of cyber-attacks on electricity and gas delivery operations. We model activation of cyber-attack vectors that attempt to gain access to pipeline gas compressor controls using a continuous-time Markov chain over a state space based on the gas operator Industrial Control System firewall zone partition. Our approach evaluates the operating states and decision-making in the networks using physically realistic and operationally representative models. We summarize these models, the sequence of analyses used to quantify the impacts of a cyber-incident, and propose a Monte Carlo simulation approach to quantify the resulting effect on the reliability of the bulk power system by the increase in operational cost. The methodology is applied to a case study of interacting power, gas, and cyber test networks.

The impact of airspace regulations on unmanned aerial vehicles in last-mile operation

Utilizing autonomous unmanned aerial vehicles (drones) in the last-mile delivery of parcels is regarded as the ultimate disruptive technology that might significantly reduce the GHG emissions in the freight sector. This study estimates the CO2e emissions for UAVs under different policies compared to diesel and electric ground delivery modes. First, the international UAV flight regulations are synthesized and classified into three groups representing varying degrees of policy strictness. Second, utilizing real-word delivery demand data, full-day parcel-delivery operations of a three-digit postal code area in both urban and rural contexts are simulated for UAVs and ground delivery modes. The results show that in general, UAVs produce significantly lower emissions compared to ground delivery per parcel-km and up to 35% compared to electric vehicles. However, UAV emissions are highly dependent on the fuel mix used in electricity generation. In urban contexts, UAV policy strictness can increase GHG emissions by up to 400%.

DSO–TSO Coordination of Day-Ahead Operation Planning with the Use of Distributed Energy Resources

Growing penetration of uncoordinated Distributed Energy Resources (DERs) in distribution systems is contributing to the increase of the load variability to be covered at the transmission system level. Forced, fast and substantial changes of power plants’ output powers increase the risk of their failures, which threatens the reliable and safe delivery of electricity to end users in the power system. The paper handles this issue with the use of DERs and proposes a bilevel coordination concept of day-ahead operation planning with new kind of bids to be submitted by Distribution System Operators (DSOs) to the Transmission System Operator (TSO). This concept includes the extension of the Unit Commitment problem solved by TSO and a new optimization model to be solved by DSO for planning a smoothed power profile at the Transmission–Distribution (T–D) interface. Both optimization models are described in the paper. As simulations show, the modified 24-h power profiles at T–D interfaces result in a reduction of the demand for operation flexibility at the transmission system level and, importantly, result in a decrease of the number of conventional power plants that are required to operate during a day. Additionally, it has been proved that the modified profiles reduce the congestions in the transmission network. Hence, the concept presented in the paper can be identified as an important step towards the transformation of power systems to low-emission and reliable systems with high share of DERs.

Should we inject hydrogen into gas grids? Practicalities and whole-system value chain optimisation

Injection of hydrogen into existing natural gas grids, either partially or as a complete conversion, could decarbonise heat and take advantage of the inherent flexibility that gas grids provide in a low-carbon future. However, hydrogen injection is not straightforward due to the differing properties of the gases and the need for low-cost, low-carbon hydrogen supply chains. In this study, an up-to-date assessment of the opportunities and challenges for hydrogen injection is provided. Through value chain optimisation, the outlook for hydrogen injection is considered in the context of a national energy system with a high reliance on natural gas. The optimisation captures the operational details of hydrogen injection and gas grid flexibility, whilst also modelling the wider context, including interactions with the electricity system and delivery of energy from primary resource to end-use. It is found that energy systems are ready for partial hydrogen injection now and that relatively low feed-in tariffs (£20–50/MWh) could incentivise it. Partial hydrogen injection could provide a stepping stone for developing a hydrogen infrastructure but large scale decarbonisation of gas grids requires complete conversion to hydrogen. Whether this solution is preferable to electrification in the long term will depend on the value of the gas grid linepack flexibility and the costs of expanding electricity infrastructure.

Chemical vs. mechanical microstructure evolution in drying colloid and polymer coatings

Colloidal based films have been widely developed for a wide range of applications including chemical and electrical barrier coatings, photonic materials, biomaterials, and pharmaceutical oral drug delivery. Many previous studies investigate methods to generate uniformity or desired stratification of the final components with a desired microstructure. Few studies have been able to investigate this microstructure in-situ during drying. This experimental study directly tracks fluorescent colloids that are either stable in suspension or have attractive interactions during the drying process using high speed laser scanning confocal microscopy to obtain details of microstructural evolution during drying. The colloidal microstructure in stable suspensions evolves continuously during drying. Microstructures in these systems have a signature Voronoi polyhedra distribution that is defined by lognormal curve having a constant standard deviation that only depends on its chemical composition. Those formulations having strongly attractive constituents have microstructure that is heterogeneous and non-monotonic due to the mechanics associated with internal convection and capillary forces. Toward the end of drying, the influence of the mode of microstructure rearrangements remains evident.

Important factors to daily vehicle routing cost of battery electric delivery trucks

This study investigates the effects of key technological and operating factors on daily routing of battery electric truck (BET) in urban goods delivery. The key factors are service area, number of customers, battery capacity, number of charging stations, vehicle capacity, and charging rate. A primary cost metric used is daily vehicle routing cost (DVRC), which is defined as the sum of driver salary associated with driving time and idling time for en-route battery recharging activities, and electricity (energy) cost. It is estimated with a proposed green EVRP (G-EVRP) model. Overall, BET works with the economies of scale. However, BET may be better suited for a market place with high number of customers (customer density) at a city or a county scale but often technologically or financially constrained at a regional (intercity) scale. For a given network size and number of customers, battery capacity must be carefully chosen to minimize the BET DVRC. Vehicle capacity affects the number of vehicles needed to dispatch and the optimal fleet size is a compromise between the level of consolidation and that of en-route recharging activity. Little effect is found in number of charging stations on BET daily routing in the study setting as optimal routing strategies typically result in either zero or very low en-route recharging activity level.

International experiences of criminal violence and delivery of urban basic services: the case of electricity

We investigate the impact of criminal violence on the delivery of an urban basic service, electricity, through a comparison of international experiences. We find that the structure of criminal violence matters more than its level. If the violence is of an unorganized nature, or if local criminal organizations take no interest in electricity theft, service providers may be able to deliver electricity through regulated commercial relationships with local residents, even in areas of high violence. Where criminal organizations seek to profit from electricity theft, regulated commercial delivery of electricity will be extremely limited or impossible, even when those organizations maintain overt violence at low levels. Successful experiences of regulated commercial delivery involve using technology to reduce opportunities for theft as well as practices to improve customer relationships, sometimes supplemented by community engagement. But a necessary condition for success remains physical access to the area by the service provider’s personnel.

External Electrode Temperature Monitoring of Lithium Iron Phosphate Batteries Based on Fiber Bragg Grating Sensors

Lithium-ion (Li-ion) batteries have become a promising candidate for the electrical energy storage and power delivery solutions. Thermal management is a key tool to improve performance and safety of Lithium-ion batteries. Currently, the common method is using electric sensors to monitor the thermal behaviour of batteries. In this work, an optical fiber sensor was proposed for temperature measurement of cells. The proposed sensor consists of a metal ring and a fiber Bragg grating (FBG). The FBG sensor calibration test shows a good linearity and high sensitivity. The FBG sensors were gloved on the external electrodes to monitor the temperature variation during charge/discharge cycles, and the PT100 sensors were attached on the electrodes as a comparison. Comparison test illustrates the response of proposed FBG sensors has a good agreement with PT100 sensors. It provides that the proposed FBG sensor can be used to monitor the temperature variation of cells, which provides a promising tool to improve the thermal management and safety of Li-ion batteries.

Planning with justice: Using spatial modelling to incorporate justice in electricity pricing – The case of Tanzania

Universal electrification by 2030 is an important goal of Sustainable Development Goal (SDG) 7. Electricity provision no longer relies only on centralized grid expansion, but also on off-grid and mini-grid systems. Although this technological diversity holds promise, the technologies differ both physically and institutionally in electricity delivery. These differences raise equity and justice concerns around how they are implemented. For example, how can electricity be kept affordable for all consumers when access is provided by various technologies operated under different business models? This paper addresses this aspect of affordability and sheds light on how the SDG7 target could be met more equitably and fairly. We use a novel analytical methodology to apply two different principles of justice – equality and equity – to incorporate affordability into electricity pricing. Using a geospatial electrification model and Tanzania as a case study, we first arrive at price levels based on the principle(s) of justice. Then, we produce location-specific recommendations for subsidy levels needed to ensure those price levels. We find that the equity approach benefits a bigger section of the population than the equality approach. Moreover, the former costs significantly less per capita than the latter. Having said that, the equity approach is complex and therefore harder to implement. The methodological framework proposed in this study acts as a proof-of-concept for examining concerns around distributive justice using quantitative energy modelling tools and drawing policy relevant insights for energy planning in developing countries. Additionally, by focusing on the spatial aspects of energy access and the issue of fairness, the study also contributes to the growing conceptualizations of energy justice.

Renewable energies evaluation and linking to smart grid

To tackle the widespread challenges encountered during the management of power flow in electrical networks, the integration of smart grid (S.G) is proposed as a viable solution to address the environmental and economic concerns. In order to enhance overall functionality of the electric power delivery system, operation of the smart grid is governed by data-driven algorithms where various sensors and smart meters are used to collect this data. On other hand, the fluctuating cost of fossil fuels and its negative impact on the environnement has incentivized the exploitation of renewable energies in the smart grid. In the present paper, a hybrid Photovoltaic/Wind (PV/Wind) is suggested to supply a smart grid. The objective of this study is to asses the feasibility of a smart grid supplied solely by renewable energy sources. Conceptual standings of this newly suggested model are validated by simulations.

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The actual direction of maritime and inland water transport is alternative energy supply by the optoelectronic means. The study of brushless electromotor with electric energy delivery by the laser ray with using the fiber optic elements and photoelectronic transformers for the robotic digital complex for management and control of small-displacement surveying vessel motion is perspective. The connection between energy and information transmitted in the dynamic electromechanical transformers of the robotic digital complex is examined in the paper. It has been showed that the information and energy methods for processing the same experimental data lead to the identical results, namely, measuring information and energy are transmitted simultaneously through the measuring and information channel. Based on the conducted researches of brushless motor model and patents for inventions obtained by the Admiral Makarov State University of Maritime and Inland Shipping, a four-propellers robotic digital complex for managing and controlling the small-displacement self-propelled electric propulsion surveying vessel motion. The robotic small - displacement surveying vessels in conjunction with the base automatic surveying posts, combined by the atmospheric radio-optical and terrestrial fiber-optic communication channels, can be the basis of terrestrial segment of the digital measuring and information network of the Russian inland waterways.

Evaluation of Human Body Characteristics for Electric Signal Transmission Based on Measured Body Impulse Response

Human body communications (HBCs) have recently emerged as an innovative alternative to the current radio frequency communications for realizing wireless body area networks (WBANs) using the human body as a transmission channel without wired or wireless connections. This article addresses the provision of reliable modeling of the human body as a passage of the electric signal delivery based on the impulse response measurement through the proposal of a measurement setup and signal processing techniques applicable to wearable devices for healthcare and biosignal acquisition. In the experiments, customized impulse signals were applied to the body using battery-powered devices isolated to the earth ground for the operating environments of wearable devices. The impulse responses passed through the body were measured by considering 52 measurement conditions determined by the device locations from the head to ankle and the body postures. Body channel transfer functions (BCTFs) for the respective conditions were derived by an adaptive filter approach using an iterative algorithm to minimize the mean squared error between the measured and modeled impulse responses. The channel analysis parameters, such as mean path loss, root-mean-square delay spread, and mean and maximum excess delays, were analyzed based on the measured body impulse responses. In addition, the practical bit-error-rate performance for HBC based on the BCTFs reproducing intersymbol interference effects caused by the delay spreads of the body channels was explored to verify communication reliability in terms of the transmitter structures adopting digital transmission, sorts of human body channels, data rates, and operating frequencies.

Electrical Field-Assisted Gene Delivery from Polyelectrolyte Multilayers.

To sustain gene delivery and elongate transgene expression, plasmid DNA and cationic nonviral vectors can be deposited through layer-by-layer (LbL) assembly to form polyelectrolyte multilayers (PEMs). Although these macromolecules can be released for transfection purposes, their entanglement only allows partial delivery. Therefore, how to efficiently deliver immobilized genes from PEMs remains a challenge. In this study, we attempt to facilitate their delivery through the pretreatment of the external electrical field. Multilayers of polyethylenimine (PEI) and DNA were deposited onto conductive polypyrrole (PPy), which were placed in an aqueous environment to examine their release after electric field pretreatment. Only the electric field perpendicular to the substrate with constant voltage efficiently promoted the release of PEI and DNA from PEMs, and the higher potential resulted in the more releases which were enhanced with treatment time. The roughness of PEMs also increased after electric field treatment because the electrical field not only caused electrophoresis of polyelectrolytes and but also allowed electrochemical reaction on the PPy electrode. Finally, the released DNA and PEI were used for transfection. Polyplexes were successfully formed after electric field treatment, and the transfection efficiency was also improved, suggesting that this electric field pretreatment effectively assists gene delivery from PEMs and should be beneficial to regenerative medicine application.

How the excitation system parameters and the generator protection settings affect the reliability of electricity delivery from distributed generation facilities

The paper analyzes the causes of disruptions in electricity delivery to critical users in power areas that operate distributed generation facilities (DG), hereinafter referred to as DG areas. Statistics is shown to be affected by the types of the excitation systems (ES) chosen for the DG generators, as well as by the relay protection (RP) settings as configured when designing the facilities. The paper dwells upon the specifications of the ES’s used in low-power generators, their effective applications, as well as the consequences of disturbances in the power area or in an external grid. It is proven herein that RP settings as configured by generator manufacturers are often suboptimal, which jeopardizes their further operation, prevents the operator from aligning these settings to those of the grid RPs, and results in unnecessary disconnections. The paper also details upon calculating the parameters of DG-enabled grids in the common software suits, as well as on how to make a list of effective contingencies. It further gives recommendations on grouping the calculation problems by initial disturbance to optimize the number of projected scenarios. The authors prove that ES selection and generator RP configurations must be appropriate if DG facilities are to deliver electricity reliably.

Intelligent based technique for under voltage load shedding in power transmission systems

<p>The increasing demand of electric power energy and the presence of disturbances can be identified as the factors of voltage instability condition in a power system. A secure and reliable power system should be considered to ensure smooth delivery of electricity to the consumers. A power system may experience undesired event such as voltage instability condition leading to voltage collapse or cascading collapse if the system experiences lack of reactive power support. Thus, to avoid blackout and cascaded tripping, load shedding is the last resort to prevent a total damage. Under Voltage Load Shedding (UVLS) scheme is one of the possible methods which can be conducted by thepower system operators to avoid the occurrence of voltage instability condition. This paper presents the intelligent based technique for under voltage load shedding in power transmission systems. In this study, a computational based technique is developed in solving problem related to UVLS. The integration between a known computational intelligence-based technique termed as Evolutionary Programming (EP) with the under-voltage load shedding algorithm has been able to maintain the system operated within the acceptable voltage limit. Loss and minimum voltage control as the objective function implemented on the IEEE 30-Bus Reliability Test System (RTS) managed to optimally identify the optimal location and sizing for the load shedding scheme. Results from the studies, clearly indicate the feasibility of EP for load shedding scheme in loss and minimum voltage control in power system.</p>

An Intensive Archeological Survey of the Owl Hills-Tunstill 138-KV Transmission Line Route

Oncor Electric Delivery Company, LLC (Oncor) is planning to construct the Owl Hills—Tunstill 138-kV Transmission Line Route in Culberson, Reeves and Loving Counties, Texas. Oncor contracted with Halff Associates, Inc. to conduct an intensive pedestrian survey of 18.5 miles of new 138-kV transmission line on private property. The survey was conducted January 20-24, 2020 and a total of 102 shovel tests were excavated in areas where buried archeological deposits where expected, and two 15-meter (32.8-foot) transects underwent pedestrian survey within the 70-foot (21.3-meter) wide survey corridor, which measures approximately 157 acres. Three archeological sites (41RV208, 41RV209 and 41RV213) were identified and recorded during the archeological survey. Site 41RV208 is a prehistoric occupation containing a surface deposit of 12 lithic debitage, 6 flake tools, 6 cores, 2 groundstone fragments and 40 fire cracked rocks (FCR). The site is situated on a gravelly and deflated upland that forms the western rim of the Pecos River valley. Site 41RV209 consists of a prehistoric occupation containing a surface deposit of 12 FCR, 6 lithic debitage, 3 flake tools, 2 cores, 1 uniface, and 1 biface. This site is situated on the heavily eroded west bank of Salt Creek and has been disturbed by construction activities associated with an adjacent pipeline corridor. Site 41RV213 is an abandoned section of the Atchison, Topeka & Santa Fe (ATSF) Railway that parallels U.S. Highway 285 to the east. The section of railroad in the surveyed area has undergone extensive disturbance and consists of a narrow linear piling of fill, railroad gravels and non-descript metal debris. It is Halff’s recommendation that sites 41RV208, 41RV209 and 41RV213 are ineligible for National Register of Historic Places consideration in the surveyed area and no further cultural resources investigations are warranted for the project. While shovel testing within the lower terraces of the Pecos River valley floor resulted in negative findings, most of the shovel tests in this area did not encounter restrictive deposits soil or geologic deposits that antedate the Holocene. Therefore, the installation of the transmission line poles located along the lower alluvial terraces of the Pecos River was recommended for archeological monitoring. Halff recommends that construction of the remainder of the proposed transmission line route be allowed to proceed and that no additional archaeological investigations are recommended outside of the monitoring area. However, if the proposed transmission line route alignment changes, additional archeological survey may be necessary. In addition, should any cultural resources be discovered during the construction or maintenance activities associated with the project, work in the immediate area shall cease and the Texas Historical Commission be notified of the discovery.

Методика расчета экономической эффективности внедрения технических средств симметрирования в электротехнический комплекс с электродвигательной нагрузкой

This paper covers the key aspects of developing a method for calculating the cost-effectiveness of adopting symmetrization equipment in a motor-carrying electrical complex. Voltage asymmetry is observed in grids of any voltage class. Analysis of earlier studies into voltage asymmetry in the operational 0.4; 6; and 35-kV grids in Zabaikalsky Krai shows that GOST 32144–2013, an interstate standard for the quality of electricity, is being breached systematically on a large scale. Analyzed grids demonstrate fairly high levels of voltage asymmetry. Voltage asymmetry has negative electromagnetic and process-related effects: additional power losses, faster insulation aging, and premature electrical equipment failure. This is why, minimizing voltage asymmetry is imperative, and so is cost-effectiveness analysis of adopting symmetrization equipment in the electrical complex. The developed method is comprehensive and takes into account the cost-effectiveness components, evaluation of the effect of adopting them, as well as the variability of their applied use. The calculation method is intended to help make sound decisions on whether symmetrization equipment is necessary for a motor-carrying electrical complex. The method is meant to test the feasibility of adopting symmetrization equipment to normalize voltage in grids and improve the operational reliability of asynchronous motors. The calculation method has been tested in an electricity delivery segment in the village of Taptugary, Mogochinsky Municipality, Zabaikalsky Krai. The paper analyzes and discusses the obtained results and draws appropriate conclusions.

Sustainable, Portable, and Efficient Electricity Delivery (SPEED): Design, Control, and Testing

During emergencies or natural disasters, or at remote areas, the main electrical grid might be damaged or not accessible, therefore, a sustainable electricity generation is critical for human survivals or other electricity needs. This paper presents a sustainable, portable, and efficient electricity delivery (SPEED) system for community emergency, disaster relief, and power supply at remote areas. A demonstrated system with utility-level AC power output is built up with a 180 W photovoltaics (PV) array which consists of six serial-connected solar panels, a 1.8 kWh battery pack, a SYNDEM power converter, and a data monitoring subsystem. The autonomous operation of the system is achieved by advanced control technologies for power electronic converters in both islanded mode and grid-connected mode, while providing the overcharging and overdischarging protections of the battery pack. Field testing is conducted to validate the effectiveness of the proposed SPEED system under different scenarios.

Uticaj solarne elektrane na kvalitet električne energije u niskonaponskoj distributivnoj mreži

The electric power system, as an integrated system for transmission, distribution and consumption of electricity, is one of the most complex technical and economic systems today. Customers affect on the voltage quality of power network, but the network also has an impact on customers. All disturbances in the network can disrupt operation of the network and affect on operation of the customers, as well as reduce the level of efficiency and operation life or even seriously damage network. Number of customers is increasing every day, as well as proportion of customers who generate disturbances in the network and, at the same time, are sensitive to them. These circumstances impose the need for frequent monitoring of the network, so the analysis of power quality is not unjustified cost but extremely important and profitable investment. The quality of electricity, as part of the overall quality supply of electricity customers in deregulated conditions of liberal electricity market becomes significant regulatory parameter for network operators and a significant contracting parameter on the electricity market. Network operators are obliged to establish a system of individual measurements and a system of permanent monitoring of power quality parameters to determine the state and improve the parameters to the standardized level. Technical parameters are determined by the recommendations made at the international level and may, but do not need, be legally binding. Maintaining a certain level of voltage quality at some point of the network is the responsibility of electricity distributor. This task distributor executes by limiting of negative effects of producer/customer to the network. Therefore, each electricity producer/customer is obliged to reduce own negative feedback effects (injection of higher harmonics, taking of reactive power, emissions of flickers and loads unbalances) to a prescribed, prearranged, limited values. There are many norms that describe the quality of electricity, but in Europe the best known is EN50160 (issued by CENLEC). This paper presents the approach to measuring the voltage quality at the point of electricity delivery from distributed source into distribution network from the aspect of limiting the negative feedback of distributed source on the voltage quality.

Гибридное моделирование распределенной генерации в электроэнергетических системах

As many countries seek to use distributed energy more and move away from conventional centralized electricity delivery, the functioning of grids carrying distributed generation facilities becomes a relevant matter. Adoption of distributed generation fundamentally alters the properties of distribution grids, transforming them from passive transports and distributors into active distribution systems that have novel properties and dynamic characteristics, which inevitably causes the processes at major generation nodes and remote load nodes to affect each other in the context of reverse, rapidly changing power flows. Analysis presented herein shows that the mutual influence of distributed generation facilities and in-grid processes are ambiguous, and each case calls for analysis of its own, since, while being an advantage for the grid, distributed generation has negative impact, too, which pertains to the operating parameters of various DG types and units. How DG facilities and the grid affect each other can only be found by mathematical modeling; to maximize the accuracy, such modeling has to reproduce the most complete and detailed topology of grids carrying DG facilities; however, there are known limitations of software and hardware that prevent such modeling from returning accurate results. The authors hereof propose an alternative, hybrid approach to modeling electric systems (grid) that combines digital, analog, and physical-level modeling; the approach has been implemented as the All-Mode Real-Time Grid Simulation Complex. A specialized hybrid wind-farm processor has been designed and tested as a distributed generation unit of Tomsk Electric Grids.