Feeder Circuit Research Articles

Stabilizing Voltage and Managing Power Loss in Medium Voltage Distribution Systems Through Strategic Maneuvers

Repairs and maintenance on the electrical power system often require power outages. To ensure safety and security during maintenance, limiting the extent of these outages is essential. This study aims to analyze the impact of network maneuvers on voltage drop and power loss in feeders in Medan, Indonesia. The research involves simulating the feeder circuit under various maneuver scenarios using ETAP 19.0.1 software to analyze voltage drop and power loss in the 20 kV distribution network. The end voltage on the backup feeder decreased from 20.31 kV before maneuvering to 20.10 kV after maneuvering. Despite the maneuvers causing an increase in voltage drop from 0.724 kV (3.24%) to 1.080 kV (4.23%) and in active power losses from 152.59 kW (2.29%) to 226.92 kW (3.02%), both remained within the acceptable standard of 5%. To mitigate the voltage, drop, the study proposes uprating the conductor by replacing the existing AAAC conductor with an XLPE-insulated cable. This upgrade can increase the end voltage from 20.09 kV to 20.49 kV, thus improving the overall performance of the feeder during maintenance activities.

Low-pressure gasoline direct injection system development and emissions analysis for a reciprocating two-stroke engine

This study presents the design and construction of an electronic low-pressure gasoline direct injection system for two-stroke engines, with the objective to study engine performance and the emission of exhaust polluting gases, maintaining the expectations of this type of engine. The investigation includes a test bench with an incorporated engine and the required control devices for this, as well as a gas analyzer Class 0, a computerized data acquisition and several tools for displaying and process all the electronic signals from the engine in real time. In order to manage this system, a custom electronic injection control unit has been designed and built, which allows to control the fuel injection timing and duration. This unit uses the signal from an inductive sensor installed in the crankshaft as a reference and synchronization point. Additionally, modifications have been made to the fuel feeder circuit and the electronic of the test engine, as well as to some parts of the mechanism in order to adapt them to this technology. The implementation of the engine tests is described, and the performance and operational points of the original system and those of the new injection system are evaluated.

Performance Analysis of Reluctance Coil Launchers Driven by Distributed Feeder Circuit

Performance Analysis of Reluctance Coil Launchers Driven by Distributed Feeder Circuit

Medium-Voltage Circuit Breakers and Contactors Are Not the Same: Neither are Their Protection Methods

Many standards and specifications related to medium-voltage (MV) motor and feeder circuits continue to center around the improper generic use of IEEE Device 52 as a circuit identifier for the switching device used within various points of power systems. IEEE Device 52 is defined as a device that is used to close and interrupt an ac power circuit under normal conditions or to interrupt this circuit under fault or emergency conditions. While many of the present standards include detailed protection and coordination recommendations that are centered only on the protective and control settings for circuit breakers (CBs), the protection schemes for CBs and fused contactor-controlled motors are documented in IEEE Standard 3004.8. This article clarifies some key differences between MV contactors and MV CB ratings. It also compares the appropriate protection variations and requirements between the two devices, highlighting the dangers to personnel and equipment if misapplied. Recommended protective device functions for motor protection for fused contactor-controlled or breaker-controlled motors are presented with companion drawings.

Data-Driven Fast Uncertainty Assessment of Distribution Systems With Correlated EV Charging Demand and Renewable Generation

When multiple uncertain resources (e.g., renewable energy and EV charging stations) are integrated into distribution systems, the uncertainties of correlated power supplies and demands pose a challenge for reliable grid operation. This challenge is compounded by the fact that this correlation cannot be modeled by standard pair copulas, e.g., Gaussian, Clayton, and Frank, as observed from the actual measurement data. To address these issues, this paper proposes a data-driven approach based on Gaussian Mixture Model (GMM) and Polynomial Chaos Expansion (PCE) for efficient grid impact studies with multiple correlated uncertain resources. The GMM is applied to segment these uncertain resources into multiple clusters, and the joint probability density within each cluster is approximated by multivariate Gaussian functions. The result is a feasibility for applying Gaussian Copula iteratively to handle the nonlinear correlation and the avoided construction of polynomial bases from arbitrary probability distributions for improved performance. Subsequently, the k-medoids clustering is utilized to strategically select experimental samples of PCE for the fast uncertainty quantification. The high efficiency and accuracy of the proposed approach has been demonstrated with real-world distribution feeder circuits together with actual measurement data from EV charging stations and solar farms.

Power supply arm protection scheme of high-speed railway based on wide-area current differential

When fault occurs on cross-coupling autotransformer (AT) power supply traction network, the up-line and down-line feeder circuit breakers in the traction substation trip at the same time without selectivity, which leads to an extended power failure. Based on equivalent circuit and Kirchhoff’s current law, the feeder current characteristic in the substation, AT station and sectioning post when T–R fault, F–R fault, and T–F fault occur are analyzed and their expressions are obtained. When the traction power supply system is equipped with wide-area protection measurement and control system, the feeder protection device in each station collects the feeder currents in other two stations through the wide-area protection channel and a wide-area current differential protection scheme based on the feeder current characteristic is proposed. When a short-circuit fault occurs in the power supply arm, all the feeder protection devices in each station receive the feeder currents with time stamp in other two stations. After data synchronous processing and logic judgment, the fault line of the power supply arm can be identified and isolated quickly. The simulation result based on MATLAB/Simulink shows that the power supply arm protection scheme based on wide-area current differential has good fault discrimination ability under different fault positions, transition resistances, and fault types. The verification of measured data shows that the novel protection scheme will not be affected by the special working conditions of the electrical multiple unit (EMU), and reliability, selectivity, and rapidity of relay protection are all improved.

Evaluation of Electric Power Losses on 33/11 kV Distribution Feeder Networks in Uyo Urban, Nigeria Using Loss Factor Approach

No matter how carefully a power system is designed, grid inefficiencies or load losses would happen, causing power unbalance between distribution and major load centers. It is therefore fundamental to clearly determine and identify electric power system losses for network improvement because of their financial-economic value to distribution companies and consumers. In this work, relevant data including monthly loading, feeder route length, and cross-sectional area of four 11 kV feeders namely, Aka, Ibrahim Babangida, Udo Udoma, and Idongesit Nkanga secretariat-dedicated feeders were obtained from the Port Harcourt Electricity Distribution (PHED) company technical office, Uyo, Nigeria for four years (January 2018 to December 2021) for the 33/11 kV Akwa Ibom State Secretariat Injection Substation and distribution feeder circuits. Average load, maximum load, load factor, loss factor, power losses in the feeders and total power loss in the system were computed and the results which were shown graphically revealed grid inefficiencies and power imbalance or losses which increased slightly on a yearly basis. The losses are due to heat dissipation, lack of maintenance of the power system components, transformer overloading, copper losses, core losses, lengthy feeder routes, and location/aging of the transformers. Suggestions were made in order to reduce further losses in the network.

Current Breaking Test of the Superconducting Feeder on Tram-Train Running

To introduce the superconducting feeder cable for commercial operation of a railway system, it is required to establish technologies for safety and reliability. The behavior of the superconducting cable must be determined for the case in which the superconducting cable fails in the feeder system for railways. The superconducting cable can be introduced so that it is installed along with the existing feeder cable or so that only the superconducting cable is installed to be used as the feeder line. For this time, at first only, the superconducting cable was used to establish a circuit for feeder to the electric railcar without using the existing feeder circuit to conduct the power-transmission test and current breaking test. Then, the superconducting cable was installed along the existing feeder line to establish a circuit that is capable of feeder via both feeder lines to conduct the same tests. In both tests, it is confirmed that no problem occurs in the train and the superconducting cable system when it encounters the current breaking. For the parallel feeder system, it is found that the current path is transferred to the existing feeder line and the system is continuously capable of operating the train stably when the current is broken in the superconducting cable.

Research on state monitoring method of subway DC traction power supply line

In the subway traction power supply system, it is necessary to detect the line state and confirm that there is no short circuit on the line before closing the feeder circuit breaker. In this paper, the existing rules and principles of line test are summarized, the simulation model of subway traction power supply system and locomotive is established, and the results of line test under various conditions are studied. Aiming at the problems existing in the current line test, a new solution is proposed. Furthermore, by calculating temperature rise of the test resistor, the selection method of the test resistor is given.

Distribution grid impacts of electric vehicles: A California case study

SummaryCalifornia has adopted a substantial number of electric vehicles over the last decade but there are many challenges associated with the electrification of vehicles, including how they interact with the electricity grid. We employ real-world feeder circuit level data in California from PG&E to measure the capacity of local feeders. We model the adoption of electric vehicles down to the census block and take advantage of real-world vehicle charging data to simulate the future loading on circuits throughout Northern California. In our highest adoption scenario of 6 million electric vehicles in California, we find that across PG&E's service territory, 443 circuits will require upgrades (nearly 20% of all circuits) and merely 88 of these feeders have planned upgrades in the future. The costs of these feeders are an essential part of a utility's planning process, and this work speaks to the importance of electric vehicles on local distribution networks.

Simulasi Pencegahan Blackout Akibat Gangguan Hubung Singkat Di Luar Zona Proteksi Diferensial Pada Jaringan Distribusi Closed Loop Penyulang Kompetensi dan Potensial

One way to improve the reliability of the power distribution system is to design a good protection system, which is selective, sensitive, reliable, fast, and easy. Through the simulation in this study, the protection system that has been installed will be compared, namely a closed-loop system with differential relay protection with a protection system with additional logic at the relay output, focusing on busbar disturbances belonging to customers substations. The result is that the protection system that has been installed has a drawback, namely when there is a disturbance in the busbar of the customer's substation, the two feeder circuit breakers in the loop system will trip with the required clearance time of 765 milliseconds, while after adding logic to the relay output, when it occurs there is only one feeder circuit breaker that trips while another tripped circuit breaker is at the substation with the required clearance time of 524 milliseconds, so there is only one customer who experiences a blackout.

Data-Driven Probabilistic Fault Location of Electric Power Distribution Systems Incorporating Data Uncertainties

Current distribution system outage management is to separately use digital relays at the substation for estimation of fault location and use meter information to infer the activated protection device. The lack of holistic utilization of available data in the distribution operating center results in lost opportunities for accurate fault diagnosis. To solve this issue, this study proposes a data-driven probabilistic fault location methodology based on comprehensive sensing measurement from digital relays at substations, Intelligent Electric Devices (IEDs) along primary feeders, SCADA sensors in the feeder circuit, and smart meters at customers' premises. Statistics of historical fault location accuracies by digital relays and IEDs are used to estimate fault location errors with probability in real time. Multiple-hypothesis analysis is implemented to handle the uncertainties from SCADA sensors and smart meters. The spatial correlation between the potential fault location and collected sensor data is modeled as a mixed integer linear programming (MILP) problem. By solving the proposed optimization for generated hypotheses, a list of potential fault locations with possibilities is provided to system operators in decision-making for facilitated fault isolation and service restoration. Simulation results with a utility feeder validate the efficacy of the proposed approach for fault diagnosis.

Aggregation of Voltage-Controlled Devices During Distribution Network Reduction

Quasi-steady state time-series (QSTS) simulation of distribution feeders can become computationally burdensome due to many buses and devices, long simulation horizons, and/or high temporal resolution. To reduce this burden, network reduction removes buses and shifts loads/generation to the remaining buses of the circuit to produce a smaller equivalent. However, voltage-controlled devices have traditionally limited network reduction, since their operation depends on the measurement of voltage at their local bus. This work includes the reduction of buses with voltage-controlled devices by replacing the local voltage measurement with an estimate from a fast voltage sensitivity approach, which is integrated directly into a modified QSTS simulation. Comprehensive tests on an unbalanced feeder with real operating data and volt-var controlled inverters show agreement in cumulative reactive power output between the reduced and the original feeder circuits. The maximum voltage error is 0.005 Vp.u., which is nearly identical to the error in a benchmark reduction without smart inverter voltage control. The algorithm convergences for every time step, even when reducing the frequency of which the voltage estimation was updated. While the reduction methodology is demonstrated for inverter volt-var control, since it represents a frequent use case, it can be extended to other voltage-controlled devices.

Transformer Fuses—Mind the Gap

Fuses are commonly used to provide medium voltage (MV) protection to distribution transformers. Unfortunately, there are certain deficiencies introduced when primary-side fuses are used. In paper mill power systems, given the unique organization of the paper mill loads around individual feeders to facilitate load shedding, it may be advantageous to provide transformer differential relay protection from the primary of the transformer to the load side of the main secondary breaker instead of primary fuse protection. This protection can then trip either a primary-side grounding switch (with fuses) or a primary-side feeder circuit breaker using a fiber or a WiMAX (Worldwide Interoperability for Microwave Access) connection. Protection against overload is provided by a secondary main circuit breaker and by design.

FeederGAN: Synthetic Feeder Generation via Deep Graph Adversarial Nets

This paper presents a novel, automated, generative adversarial networks (GAN) based synthetic feeder generation mechanism, abbreviated as FeederGAN. FeederGAN digests real feeder models represented by directed graphs via a deep learning framework powered by GAN and graph convolutional networks (GCN). Information of a distribution feeder circuit is extracted from its model input files so that the device connectivity is mapped onto the adjacency matrix and the device characteristics, such as circuit types (i.e., 3-phase, 2-phase, and 1-phase) and component attributes (e.g., length and current ratings), are mapped onto the attribute matrix. Then, Wasserstein distance is used to optimize the GAN and GCN is used to discriminate the generated graphs from the actual ones. A greedy method based on graph theory is developed to reconstruct the feeder using the generated adjacency and attribute matrices. Our results show that the GAN generated feeders resemble the actual feeder in both topology and attributes verified by visual inspection and by empirical statistics obtained from actual distribution feeders.

Centralized radial feeder protection in electric power distribution using artificial neural networks

Abstract The paper deals with a new way of determining a fault location in an electric power distribution radial feeder using an artificial neural network (ANN) and presents a new centralized protection method based on ANN. The aim of the devised algorithm is to detect the presence of a fault in a radial feeder and to disconnect faulted laterals from the distribution network. The protection schemes that are currently in use cannot leave the whole feeder energized by disconnecting faulted laterals only without even short de-energization of the healthy part of the feeder. A simulation model is also made for training the ANN and for testing the results. Current values for faulty and healthy states are generated by the simulation model and are used as training and testing data for the algorithm. The purpose of the algorithm is to make a decision which feeder circuit breakers should trip. The simulation model and the ANN are modeled by using MATLAB tools. The results show that the tripping of circuit breakers initiated by the algorithm is correct for all states.

Analysis of on-board wireless sensor network as an alternative to traditional wired network

Wireless networks based on the principle and technology of Wireless Avionics Intra-Communications (WAIC), that is, wireless avionics or wireless onboard intercom are becoming increasingly widespread on modern aircraft. The development and deployment of WAIC on board is a complex task, as its solution is directly related to ensuring safety of flights. It requires preliminary careful scientific analysis. The article analyzes the on-board wireless sensor network as an alternative to a traditional wired network using the example of a short-haul aircraft. A rough estimate of the length of the electrical harness connecting the sensors of the aircraft systems with the electronic units is carried out in order to determine the possible gain in the length of the wires when switching to a wireless sensor network (WSN). To solve this problem, the aircraft sensors of each aircraft system are placed on a large-scale grid; for each sensor, analyze the feeder circuits by the composition of the plug connectors, the number of occupied contacts and the length of wires for each contact to the corresponding electronic unit. It is shown that the heterogeneous sensor system of the aircraft with wireless sensors can reduce the number of wires by about 1200, the length of the wires of the feeder network by about 15 km. The most promising aircraft systems in terms of switching to wireless sensors are: fuel system (about 3400m), fire equipment system (about 1300m) and hydraulic system (about 1300m). Further scientific research is required to make an informed decision about the technical feasibility and advisability of using a wireless sensor network for each specific aircraft system.

Evaluation of an Optimal Radial-Loop Configuration for a Distribution Network With PV Systems to Minimize Power Loss

This paper proposes a method to determine an optimal radial-loop configuration to minimize power loss in a distribution network with photovoltaic (PV) systems and evaluates the effectiveness of this configuration. Due to the disaggregation of transmission and distribution in a deregulated power system, stable and efficient operations in terms of voltage regulation and power loss reduction utilizing existing equipment is becoming more important for distribution system operators (DSOs). Japanese DSOs operate distribution networks in a radial configuration while supplying power to customers with high reliability. One method to reduce further power loss is to upgrade the network topology to a radial-loop configuration, which achieves partial loop structures by closing the tie-switches of the radial configuration. To implement a radial-loop configuration, DSOs must first evaluate the reliability, as a loop configuration can cause a feeder circuit breaker (FCB) malfunction and an expansion of the nonsupplied area during fault conditions. However, the impact of a radial-loop configuration on reliability and effectiveness has not been verified. Therefore, this paper proposes a method to determine an optimal radial-loop configuration that minimizes active power loss and maintains high reliability. In a numerical simulation, the reliability of radial-loop configurations is verified, and the effectiveness of the configuration is analyzed in terms of active power loss and voltage regulation under several PV system penetration conditions. A 6.6 kV distribution network consisting of 6 feeders and 11 tie-switches is modeled based on an existing Japanese distribution network and used for numerical simulation.

Maximizing PV hosting capacity of distribution feeder microgrid

To meet energy and environmental goals and challenging reliability and resiliency targets, the electric grid is transitioning from solely central generation to the inclusion of distributed energy resources (DERs). With a high penetration of DERs on primary circuits (feeders), utility substation communication, automation, and control must adopt to this new paradigm. In principle, utility substations can transition to and operate the feeder circuits in an islanded mode, effectively as Distribution Feeder Microgrids. This creates the need for research to address the challenges associated with integrating and managing significant deployment of DERs on circuits served by distribution substations. In response, this study addresses substation control to manage circuits emanating from utility substations as a microgrid. To this end, a model for substation automatic control using a Generic Microgrid Controller compliant with the IEEE 2030.7 standard was developed, and the role and impact of substation control to improve energy management, increase renewable penetration, and reduce greenhouse gas emissions were evaluated.The detailed digital simulation model developed encompassed two 12 kV distribution circuits emanating from a utility distribution substation. Individual homes were modeled and results verified using field data collected from a previous study. Various scenarios were simulated in order to determine PV hosting capability of the circuits equipped with a controller at the substation and with three energy storage configurations: (1) A residential energy storage unit (RESU) where all customers own a battery energy storage behind the meter, (2) a community energy storage (CES) unit where a utility-owned battery energy storage is deployed near each transformer, and (3) a circuit battery where a relatively large battery is deployed at the substation serving the entire feeder microgrid.Results show that substation automation and control can increase renewable penetration and reduce emissions without any necessary upgrades to the grid infrastructure. Moreover, the CES configuration was found to be a more economic approach for achieving high PV penetration and GHG reduction than residential storage, achieving a 660 mTCO2eq reduction per MWh of installed energy storage and overall 32% reduction in greenhouse gas emissions.

Theoretical and Experimental Study to Determine Voltage Violation, Reverse Electric Current and Losses in Prosumers Connected to Low-Voltage Power Grid

The impact of PV generation distributed in a low voltage transmission line depends on many factors: The distribution lines and PV generators characteristics, its location, operational control, local meteorological conditions, electricity consumption profile, and the electricity cost variation. An atypical and challenging behavior of photovoltaic distributed generation (DG) insertion in consumer units (CUs), implies in some circumstances, as the reverse directionality of the power flow between the load equipped with a photovoltaic system generator and the electrical grid, when a CU contains a distributed generation and low power consumption, the power flow will be directed to the power electric grid. In this work, the modeling of a low-voltage real feeder was performed, setting the variables of the system under real operating conditions. As result, voltage levels variability throughout the feeder, the electrical losses, and the asymmetry between the phases were observed. Through simulation scenarios, the occurrence of voltage increase under different penetration scenarios of distributed generation was verified and there was a 10% increase in reference voltage as well as the occurrence of higher electrical losses by reverse current, reaching 1200% more with a DG penetration, in the massive presence of the photovoltaic generator. The mitigatory action used in this work was able to attenuate the negative impacts to the feeder circuit, ensuring the integrity grid and the consumer unit.