Feeder Test Research Articles

Power Quality Study in Distribution Networks with High Penetration of Renewable Energies using Real-Time Simulation

Introduction: The power supplied to the load through the distribution network comes mainly from conventional energy sources. However, a transformation is being made towards sustainable and efficient electricity networks, which incorporate distributed renewable energy sources and closer to consumption. This process has led to the investigation of the effects that the inclusion of distributed energy resources brings, which have shown power quality issues. However, more studies are required to show more detailed effects and the use of new tools such as real-time simulation. Objective: This paper uses real-time simulation to evaluate the impact on the power quality produced by integrating distributed energy resources (DER) into a distribution network. Method: The IEEE 13-node test feeder system was used to evaluate voltage harmonics, current harmonics, flicker, and DC injection based on the IEEE 1547-2018, IEEE 519-2014, and the NTC 5001-2008 standards. The feeder test system was implemented in the Hypersim software and used to run real-time simulations. Results: The results show that integrating distributed energy resources into the network produces a high impact on the current harmonics of the network. Conclusions: The DC injection phenomenon presents a medium impact, and flickers and voltage harmonics present a lower impact.

Mosquitoes do not Like Bitter.

Chemical repellents play a crucial role in personal protection, serving as essential elements in reducing the transmission of vector-borne diseases. A biorational perspective that extends beyond the olfactory system as the classical target may be a promising direction to move. The taste system provides reliable information regarding food quality, helping animals to discriminate between nutritious and potentially harmful food sources, often associated with a bitter taste. Understanding how bitter compounds affect feeding in blood-sucking insects could unveil novel molecules with the potential to reduce biting and feeding. Here, we investigated the impact of two naturally occurring bitter compounds, caffeine and quinine, on the feeding decisions in female Aedes aegypti mosquitoes at two distinctive phases: (1) when the mosquito explores the biting substrate using external taste sensors and (2) when the mosquito takes a sip of food and tastes it using internal taste receptors. We assessed the aversiveness of bitter compounds through both an artificial feeding condition (artificial feeder test) and a real host (arm-in-cage test). Our findings revealed different sensitivities in the external and internal sensory pathways responsible for detecting bitter taste in Ae. aegypti. Internal detectors exhibited responsiveness to lower doses compared to the external sensors. Quinine exerted a more pronounced negative impact on biting and feeding activity than caffeine. The implications of our findings are discussed in the context of mosquito food recognition and the potential practical implications for personal protection.

Integrating discrete wavelet transform with neural networks and machine learning for fault detection in microgrids

Microgrids are essential for integrating renewable energy sources into the power grid. However, fault detection is challenging due to bidirectional energy flow. Traditional relay-based systems struggle in microgrids, primarily because of limited fault currents from grid-connected renewable energy inverters. To address these challenges, this paper proposes a new methodology for fault detection and classification in a renewable microgrid. The main contributions encompass two key aspects. Firstly, it enhances fault detection performance in microgrids characterized by nonlinear relationships, including photovoltaic, hydrokinetic, and variable electric load systems. Secondly, the combination of the discrete wavelet transform with various types of neural networks and supervised learning techniques provides a robust methodology for fault detection and classification. The proposed approach is evaluated using an IEEE-5 feeder test bed representing a realistic ring network configuration. The results show that the radial basis function neural network model exhibited promising outcomes, yielding a low prediction error of 1.31 e-31, highlighting its practical potential for enhancing system reliability and performance. Furthermore, various test cases were conducted by altering the ground resistance to train the neural networks, demonstrating the effectiveness of this neural network in accurately identifying fault conditions. Additionally, this research achieved promising outcomes with other models, including support vector machine and nonlinear autoregressive with external input, emphasizing the adaptability of these models in fault detection.

Discussion on “Mitigation of Fault Induced Delayed Voltage Recovery (FIDVR) by PV-STATCOM”

The authors of [1] presented a novel controller for PV-STATCOM. The theory posits dynamic modulation of PV inverters’ active/reactive power through non-unitary power factor operation. The proposed approach is applied to mitigate the effects of fault-induced delayed voltage recovery (FIDVR) experienced in power systems with high penetration of solar PVs and induction motor loads. The structure of the proposed control algorithm is based on 4 modes: 1) normal operation, 2) active power control, 3) reactive power control, and 4) ramp-up active power process. The methodology is tested and comprehensively validated on a radial distribution network (RDN) for numerous scenarios of LLL-G faults, X/R ratios, and night-time operation. For clarity, the authors’ insights on the following technical points are appreciated: 1)The authors meticulously adhered to many standards (IEEE std. 1547-2018, German grid code - BDEW and NERC) to formulate the PV-STATCOM and RDNs’ operational constraints. As per the IEEE std. 1547-2018, the PV inverter design is recommended to be oversized by 11% to address numerous operational challenges [2]. Did the authors consider this standard for the solar farm placed at Bus 3 of the RDN as depicted in Fig. 1? 2)In [Section IV-A (3 and 4)], the authors introduced the values of variables “$k_2$” and “$k_1$” as 1.1 and 0.96 that were used in Mode 2 and Mode 3 for active and reactive power control of the PV-STATCOM respectively as depicted in Fig. 2. What is the selection criteria and/or the range(s) of these variables? Will these values be the same under different RDN scenarios or different RDN networks (for instance, IEEE 34 feeder test system)? 3)In [Section VII], the authors comprehensively presented in-depth analytical case studies for the proposed PV-STATCOM. Most of these studies considered only a single solar farm. Practically, the active-reactive power coordination strategies through PV inverters mostly consider high PV penetration (at each bus) in RDNs [3]. Therefore, how will the proposed PV-STATCOM framework coordinate with more than one solar farm? 4)In [Section VII-E], the author validated the economical dominance of the proposed PV-STATCOM over conventional STATCOM in terms of equivalent size. Nevertheless, the operation of PV inverters as STATCOM negatively affects the inverter lifetime and hence impacts their economical significance [4]. In this respect, is the inverter of the PV-STATCOM economically dominant for long-term operation as well? 5)In [Section VII-G], the authors presented 5 cases to study the voltage recovery rate of the proposed PV-STATCOM based on different fault locations. These faults are LLL-G (for 100 ms) induced at various distances from the substation and the PV solar farm, high voltage side, and low voltage side of the 138/12.6 kV transformer. Considering these 5 cases, will the obtained recovery time be different if the PV-STATCOM was placed at different bus of the study system considered. In other words, is the placement of PV-STATCOM optimal? 6)Finally, the authors proposed a novel application of PV-STATCOM in the field of PV-integrated power network. Voltage stability requirement is one of the key parameters that affects the permissibility of integrating high-scale, inertia-less, and unpredictable PVs in a power network [5]. Therefore, with the proposed PV-STATCOM configuration, what is the maximum achievable hosting capacity of the RDN under consideration?

The Circulating Cooling in Liquid Nitrogen for Superconducting Cables -Including Verification Railway Feeder Test-

The Circulating Cooling in Liquid Nitrogen for Superconducting Cables -Including Verification Railway Feeder Test-

Optimal Coordinated Charging and Routing Scheme of Electric Vehicles in Distribution Grids: Real Grid Cases

The government policies and benefits led to the surge in penetration of Plug-in Hybrid Electric Vehicles (PHEVs) and Battery Electric Vehicles (BEVs) into both public and private sectors. Power Grids are dynamic with load and generation varying, and wide spread adoption of PHEVs can jeopardize and endanger the operation and security of the distribution grids due to overloading and congestion. This paper develops two optimization models, one is for the routing algorithm of Battery Electric Vehicles (BEVs) to find the minimum energy consumption for Personal Rapid Transit (PRT) system in a collegiate environment. The other optimization model is for charging a maximum number of PHEVs interfaced with American Electric Power (AEP) utility system. Mixed Integer Linear Programming (MILP) is used to determine the charging schedules of PHEVs to minimize the power system overloading. MILP is also used to find the optimum charging schedule of BEVs to satisfy the passenger demand of the transit system. Different charging strategies have been developed, and their effects on distribution system voltage profile and losses have been illustrated. We used the real-time data for the PRT routing algorithm. PHEV customers are categorized into different real-world Demand Response (DR) participants capable of flattening the load curve. A time series simulation of a distribution feeder test system is performed to show the feasibility of the proposed methods. Case studies on AEP system and West Virginia University transportation system were carried out. The simulation results demonstrate the effectiveness of our proposed optimization framework in reducing system peak load and satisfying the demand while utilizing minimum number of BEVs.

Disrupting the power grid via EV charging: The impact of the SMS Phishing attacks

Abstract Electric vehicle (EV) is a paradigm shift for automotive, power industries, and people. EV penetration increases due to environmental concerns. Growing demand shows that reliable smart grid integration is essential to successful EV adoption. EV adds various stochastic processes to the smart grid management ranging from consumer behavior, the vehicle type to battery state of charge. As with every new technology, EVs introduce new security concerns both for the power grid and charging infrastructure. Having a holistic view and understanding consumer behavior is important to address security issues. Regulative bodies and researchers consider cyber-threats and provide security architecture for EV charging systems. However, phishing attacks and their impact on the system have been overlooked up to now. In this study, we investigate how people’s charging behavior can be guided to disturb EV connected grid with mobile phone SMSs, so-called SMiShing attacks. We demonstrated the attack on the IEEE European Low Voltage Feeder Test System. Simulation results show that SMiShing attacks targeting the EV system may result in disruptions on the power system and should not be overlooked for reliable EV transition.

Reliability and protection in distribution power system considering customer-based indices

A stable and reliable electric power supply system is a pre-requisite for the technological and economic growth of any nation. Nigeria's power supply has been experiencing incessant power interruptions caused by a failure in the distribution system. This paper developed a system planning approach as part of the key mitigation strategies for improved reliability and protection of the distribution network. The developed algorithm is tested using 33kV feeder supplying electricity to Kaura-Namoda, Zamfara State, Nigeria. A customer-based reliability index was used as a tool to evaluate the reliability assessment of the feeder test system. The result showed that alternative 3 gives better results in terms of improvement of the system average interruption duration index (SAIDI), which in turn gives the minimum interrupted energy. Also, it is found that a greater number of sectionalizing switches do not give better results. It is very important to place the sectionalizing switches at a strategic location. If it is located at such points that will facilitate to sectionalize the faulty sections faster and to make the supply available to the unfaulty part of the network. Hence the utility company should apply this mitigation algorithm for system reliability improvement, depending on their needs and requirements. Thus, utilities can optimize network performance and better serve customers by adopting mitigation strategies in addressing trouble-prone areas to achieve a stable and reliable supply
 Keywords: distribution system; reliability; reliability indices; system performance evaluation; protection system; mitigation algorithms and sectionalizing switches

An Efficient Backward/Forward Sweep Algorithm for Power Flow Analysis through a Novel Tree-Like Structure for Unbalanced Distribution Networks

The increase of distributed energy resources (DERs) in low voltage (LV) distribution networks requires the ability to perform an accurate power flow analysis (PFA) in unbalanced systems. The characteristics of a well performing power flow algorithm are the production of accurate results, robustness and quick convergence. The current study proposes an improvement to an already used backward-forward sweep (BFS) power flow algorithm for unbalanced three-phase distribution networks. The proposed power flow algorithm can be implemented in large systems producing accurate results in a small amount of time using as little computational resources as possible. In this version of the algorithm, the network is represented in a tree-like structure, instead of an incidence matrix, avoiding the use of redundant computations and the storing of unnecessary data. An implementation of the method was developed in Python programming language and tested for 3 IEEE feeder test cases (the 4 bus feeder, the 13 bus feeder and the European Low Voltage test feeder), ranging from a low (4) to a very high (907) buses number, while including a wide variety of components witnessed in LV distribution networks.

The Effect of SMiShing Attack on Security of Demand Response Programs

Demand response (DR) is a vital element for a reliable and sustainable power grid. Consumer behavior is a key factor in the success of DR programs. In this study, we focus on how consumer reaction to Short Messaging Service (SMS) messages can disturb the demand response. We present a new type of threat to DR programs using SMS phishing attacks. We follow a holistic approach starting from a risk assessment focusing on DR programs’ notification message security following the Smart Grid Information Security (SGIS) risk methodology. We identify threats, conduct impact analysis, and estimate the likelihood of the attacks for various attacker types and motivations. We implemented deterministic and randomized attack scenarios to demonstrate the success of the attack using a state-of-the-art simulator on the IEEE European Low Voltage Feeder Test System. Simulations show that the attack results in local outages, which may lead to large-scale blackouts with the cascading effect on the power system. We conclude that this is a new type of threat that has been overlooked, and it deserves more attention as mobile devices will continually be part of our lives.

Experiences developing large-scale synthetic U.S.-style distribution test systems

This paper describes computational, data management, and other experiences developing large-scale, realistic‑but-not-real U.S.-style distribution test systems for the Smart-DS project. These test systems cover entire metropolitan areas and include everything from low-voltage secondaries to sub-transmission for hundreds or thousands of feeders making them as much as three orders of magnitude larger than existing single feeder test systems. Lessons learned with automation and data handling are shared to aid data set users and synthetic test grid creators.

PN Inference Based Autonomous Sequential Restoration of Distribution System Under Natural Disaster

Potential challenge during a disaster is the wide range of disturbance caused to the power system network. The article attempts to develop a systematic procedure to progressively restore the network by recognizing the alive network. During disaster there is manpower shortage and poor road connectivity around the affected area. Hence, an autonomous priority-based restoration policy is required for critical load restoration. The main idea of the proposed article is to develop an autonomous system, which is decision-based restoration system by identifying the network component still available after disaster followed by reconfiguration confirming the proposed load pickup procedure. Because of the inherent capability of implementing the condition-based state transition of switches and parallel processing, a petri net (PN) based methodology has been used in the article to integrate alive parts, which further assists in identifying the best switching schedule of circuit breakers for autonomous load restoration. The primary contribution of the article is to develop an encapsulated algorithm using PN as a modeling platform of components as well as empowering the same by introducing the game-theory-based concept in the formulation of different microgrids integrated with distributed generators during extreme weather events. The verification of effective autonomous restoration is then realized by using the available delivery capability and design verification of the framed microgrids, and the comparison with different restoration strategies adopted by other authors. The studies are carried out with the IEEE 34, 37, and 123-bus feeder test systems for implementation and validation of the proposed article along with the comparison with other published works.

AACO technique for solving multiobjectives in electrical distribution system

The multi objectives in electrical distribution system are service restoration and minimization of Ohmic losses. These objectives can be achieved by artificial ant colony optimization through reconfiguration. Service restoration is also a major aspect for reliable service. If any fault occurs in the system, faulted zone is isolated from healthy system. This originates discontinuity in power supply. To maintain the continuity in power supply there is a necessity to provide service to these loads from adjacent healthy feeders through reconfiguration without infringement of radiality, load balance and critical parameters. In distribution system Ohmic losses are 30 to 40 percent. In order to minimize these losses, there is a need for reconfiguration of the system and perform the power flow analysis to get bus voltages, branch currents and power losses (i.e. real or Ohmic or copper loss and reactive power loss). A direct load flow analysis is adopted in the proposed work. In this paper four feeder test system used for service restoration and IEEE 33 bus, IEEE 69 bus test systems for minimization of Ohmic losses have been obtained.

Intelligent Expert System for Power Quality Improvement Under Distorted and Unbalanced Conditions in Three-Phase AC Microgrids

This paper presents an expert system (ES) based on decoupled power/current decomposition and the ${k}$ -nearest neighbor pattern recognition method to identify and choose the correct mitigation solution for power quality improvement in three-phase ac microgrids under non-sinusoidal current and voltage operations. By using power/current terms, load conformity factors and a ${k}$ -nearest neighbor classifier, the proposed ES achieved 99.98% classification accuracy. Simulation studies were carried out in a PSCAD/EMTDC environment, where the IEEE 13-bus feeder test system was in a grid connected microgrid mode. The obtained results indicate that the proposed ES is robust and able to easily select an appropriate/adequate compensation solution.

A Projection-Based Decomposition Algorithm for Distributed Fast Computation of Control in Microgrids

We present a novel algorithm for the computation of optimal predictive storage and reactive power control in microgrids operating in grid-tied mode. This algorithm is based on the dual decomposition method, but local constraints are handled by means of primal projections. The use of projections significantly increases the speed of convergence of the approach with respect to the dual decomposition algorithm, which uses dual variables for the local constraints of the problem. Convergence of the algorithm to an optimizer is shown for a general class of quadratic programs, which includes a storage and reactive power control problem. In addition, a distributed implementation of the algorithm which is based on the Jacobi overrelaxation is presented. Simulations compare the algorithm performance with that of a purely dual decomposition approach over a set of standard distribution feeder test cases acting as grid-connected microgrid proxies.

Diversity in mixed species groups improves success in a novel feeder test in a wild songbird community

Mixed-species groups are common and are thought to provide benefits to group members via enhanced food finding and antipredator abilities. These benefits could accrue due to larger group sizes in general but also to the diverse species composition in the groups. We tested these possibilities using a novel feeder test in a wild songbird community containing three species that varied in their dominant-subordinate status and in their nuclear-satellite roles: Carolina chickadees (Poecile carolinensis), tufted titmice (Baeolophus bicolor), and white-breasted nuthatches (Sitta carolinensis). We found that chickadees and titmice were more likely to obtain seed from the novel feeder with greater diversity of species composition in their mixed-species flocks. For successful chickadee flocks, furthermore, the latency to obtain seed from the novel feeder was shorter the more diverse their flocks were. These results in a natural setting indicate that diversity, per se, can benefit individuals in mixed-species groups in biologically meaningful contexts such as finding food in novel places.

Solar Photovoltaic Generators with MPPT and Battery Storage in Microgrids

Maximum power point tracking (MPPT) of a photo voltaic system with different temperature and insolation conditions used for Micro grids can be explained in this paper. The different steps of the design of this controller are presented together with its simulation and the feasibility of control methods to be adopted for the operation of a micro grid when it becomes isolated. Normally, the micro grid operates in interconnected mode with the medium voltage network; however, scheduled or forced isolation can take place. In such conditions, the micro grid must have the ability to operate stably and autonomously. An evaluation of the need of storage devices and load to take off strategies is included in this paper. Solar photovoltaic (PV) energy has witnessed double-digit growth in the past decade. The penetration of PV systems as distributed generators in low-voltage grids has also seen significant attention. In addition, the need for higher overall grid efficiency and reliability has boosted the interest in the microgrid concept. High-efficiency PV-based microgrids require maximum power point tracking (MPPT) controllers to maximize the harvested energy due to the nonlinearity in PV module characteristics. This paper proposes an approach of coordinated and integrated control of solar PV generators with the maximum power point tracking (MPPT) control and battery storage control to provide voltage and frequency (V-f) support to an islanded microgrid. The simulation studies are carried out with the IEEE 13-bus feeder test system in grid connected and islanded microgrid modes. The MPPT of a Photovoltaic System for Micro Grid operation is successfully designed and simulated by using MATLAB/Simulink Software in this paper.

Guest Editorial

Guest Editorial

Optimal Use of Existing Distribution Feeders to Accommodate Transportation Electrification

An analytical method that can be used to study the optimal topology and maximum capacity of the existing distribution network to accommodate electric vehicle (EV) charging demands is presented in this paper. In order to facilitate a large number of EV integrations, the feeder reconfiguration problem is formulated as a discrete nonlinear optimization problem that finds optimal feeders' tie switch locations and their on/off schedule to minimize operation costs and comply with the system operation constraints. A novel stochastic dynamic programming technique is adopted to solve the problem that includes various uncertainties associated with feeder baseline and EV charging loads. Simulation results obtained from an 84-bus feeder test system have indicated that for a case with 20% EV penetration to a 70% capacity utilization feeder area, a 10.78% reduction of operation cost and a 14.4% decrease in maximum feeder utilization can be obtained by distribution feeder reconfiguration.

Coordinated V-f and P-Q Control of Solar Photovoltaic Generators With MPPT and Battery Storage in Microgrids

The microgrid concept allows small distributed energy resources (DERs) to act in a coordinated manner to provide a necessary amount of active power and ancillary service when required. This paper proposes an approach of coordinated and integrated control of solar PV generators with the maximum power point tracking (MPPT) control and battery storage control to provide voltage and frequency (V-f) support to an islanded microgrid. Also, active and nonactive/reactive power (P-Q) control with solar PV, MPPT and battery storage is proposed for the grid connected mode. The control strategies show effective coordination between inverter V-f (or P-Q) control, MPPT control, and energy storage charging and discharging control. The paper also shows an effective coordination among participating microresources while considering the case of changing irradiance and battery state of charge (SOC) constraint. The simulation studies are carried out with the IEEE 13-bus feeder test system in grid connected and islanded microgrid modes. The results clearly verify the effectiveness of proposed control methods. The simulations are carried out in Matlab and Simpowersystems.