Feeder Level Research Articles

Application benefits of Distribution Automation and AMI systems convergence methodology for distribution power restoration analysis

Abstract Self healing mechanisms to minimize the impact of faults and outages on distribution grid are being considered as one of the critical requirements for smart distribution grid. Many automation technologies were being developed and proposed in order to meet these requirements. Power restoration techniques based on Distribution Automation’s Fault Detection, Isolation and Restoration (FDIR) technology at feeder level and Advanced Metering Infrastructure’s Outage Management System (OMS) at the LV distribution level are two such complementary technologies evolved over the past few years in order to locate, isolate the faults and restore the power quickly to as many loads as possible, which are not affected by the faults or outages. With the evolution of new system level paradigm, Distribution Automation (DA) and Advanced Metering Infrastructure (AMI) System’s convergence, it is possible to improve the effectiveness and efficiency of power restoration schemes with AMI acting as a feedback system to the DA system supporting required communication latency, bandwidth and protocols. This paper illustrates the benefits of the distribution power restoration method based on DA–AMI convergence approach.

Using Smart Meter Data to Improve the Accuracy of Intraday Load Forecasting Considering Customer Behavior Similarities

With the deployment of advanced metering infrastructure (AMI), an avalanche of new energy-use information became available. Better understanding of the actual power consumption patterns of customers is critical for improving load forecasting and efficient deployment of smart grid technologies to enhance operation, energy management, and planning of electric power systems. Unlike traditional aggregated system-level load forecasting, the AMI data introduces a fresh perspective to the way load forecasting is performed, ranging from very short-term load forecasting to long-term load forecasting at the system level, regional level, feeder level, or even down to the consumer level. This paper addresses the efforts involved in improving the system level intraday load forecasting by applying clustering to identify groups of customers with similar load consumption patterns from smart meters prior to performing load forecasting.

Reliability analysis of smart grid communication network by simulation

In this paper, we study the reliability of a communication network at the feeder level of the distribution system of a smart grid. WiFi Mesh is indicated as the superior technology for smart grid applications at feeder level based upon availability and cost considerations. In this context, we provide a model for evaluating the transmission delay and energy consumption in the WiFi network, and relate these quantities to the reliability of message transmission of the network. The Energy Consumption Aware Shortest Path ECASP algorithm is developed to search the shortest delay routing for each message and keep updating the available energy capacity of each communication device. Simulation procedures are presented to get estimates of the delay of different types of messages and compute the communication network lifetime and message transmission reliability. The proposed approach is exemplified with reference to a realistic distribution system of a smart grid, with three types of messages exchanged at the feeder level.

Self-Healing Hybrid Protection Architecture for Passive Optical Networks

Expanding size of passive optical networks (PONs) along with high availability expectation makes the reliability performance a crucial need. Most protection architectures utilize redundant network components to enhance network survivability, which is not economical. This paper proposes new self-healing protection architecture for passive optical networks (PONs), with a single ring topology and star-ring topology at feeder and distribution level respectively. The proposed architecture provides desirable protection to the network by avoiding fiber duplication at both feeder and distribution level. Moreover, medium access control (MAC) controlled switching is utilized to provide efficient detection, and restoration of faults or cuts throughout the network. Analytical analysis reveals that the proposed self-healing hybrid protection architecture ensures survivability of the affected traffic along with desirable connection availability of 99.9994 % at minimum deployment cost, through simple architecture and simultaneous protection against failures.

Model of distribution system total supply capability considering feeder and substation transformer contingencies

Abstract This paper proposes a model for calculating the total supply capability (TSC) for distribution system considering both feeder and substation transformer contingencies. Existing models and methods for TSC only consider substation transformer contingencies and ignore feeder contingencies. However, the feeder contingencies occur much more frequently than substation transformer contingencies in practice. Moreover, some operation state fail the feeder contingencies N − 1 verification even they pass the transformer contingencies N − 1 verification. In this paper, a TSC model is firstly proposed in which feeder and transformer N − 1 contingencies are fully considered. This model is designed in feeder level, which means the topology of interconnection among feeders is accurately modeled. Secondly, a supplementary model for load balancing is set up for a better load distribution solution on feeders and transformers at TSC loading. Finally, the method is tested in a test distribution system and a real partial distribution network and the results are verified by the traditional N − 1 simulation.

Load Segmentation for Convergence of Distribution Automation and Advanced Metering Infrastructure Systems

Abstract Distribution automation (DA) applications are limited to feeder level today and have zero visibility outside of the substation feeder and reaching down to the low-voltage distribution network level. This has become a major obstacle in realizing many automated functions and enhancing existing DA capabilities. Advanced metering infrastructure (AMI) systems are being widely deployed by utilities across the world creating system-wide communications access to every monitoring and service point, which collects data from smart meters and sensors in short time intervals, in response to utility needs. DA and AMI systems convergence provides unique opportunities and capabilities for distribution grid modernization with the DA system acting as a controller and AMI system acting as feedback to DA system, for which DA applications have to understand and use the AMI data selectively and effectively. In this paper, we propose a load segmentation method that helps the DA system to accurately understand and use the AMI data for various automation applications with a suitable case study on power restoration.

Model-Based Estimation of Energy Savings in Load Control Events for Thermostatically Controlled Loads

Load control (LC) of populations of air conditioners (ACs) is considered suitable to shift energy from on- to off-peak times, and track the intermittent power output of renewable generation. From a technical and economical point of view, it is paramount to quantify the amount of energy that can be saved by implementing these LC events. This paper proposes a new causal methodology to estimate such energy savings using a Kalman filter that includes a parametric second-order model of the aggregate demand of a population of ACs. The proposed methodology relies only on readings of aggregate electrical power at the feeder level and does not require historical load data, or a control group, and hence, it can be used where other methods reported in the literature are inapplicable. The proposed estimator is evaluated on a numerical case study that embeds simulated ACs in real power and temperature data from a 70-house residential precinct.

Demand Forecasting in Smart Grids

Data analytics in smart grids can be leveraged to channel the data downpour from individual meters into knowledge valuable to electric power utilities and end-consumers. Short-term load forecasting (STLF) can address issues vital to a utility but it has traditionally been done mostly at system (city or country) level. In this case study, we exploit rich, multi-year, and high-frequency annotated data collected via a metering infrastructure to perform STLF on aggregates of power meters in a mid-sized city. For smart meter aggregates complemented with geo-specific weather data, we benchmark several state-of-the-art forecasting algorithms, including kernel methods for nonlinear regression, seasonal and temperature-adjusted auto-regressive models, exponential smoothing and state-space models. We show how STLF accuracy improves at larger meter aggregation (at feeder, substation, and system-wide level). We provide an overview of our algorithms for load prediction and discuss system performance issues that impact real time STLF. ® 2014 Alcatel-Lucent.

Optimal Penetration of Photovoltaic Systems in Distribution Networks

The penetration level of a PV system is often limited due to the violation of voltage variation introduced by the large intermittent power generation. This paper discusses the use of an active power curtailment strategy to reduce PV power injection during peak solar irradiation to prevent voltage violation so that the PV penetration level of a distribution feeder can be increased to fully utilize solar energy. When using the proposed voltage control scheme for limiting PV power injection into the study distribution feeder during high solar irradiation periods, the total power generation and total energy delivered by the PV system over a 1-year period are determined according to the annual duration of solar irradiation. With the proposed voltage control to perform the partial generation rejection of PV systems, the optimal installation capacity of PV systems can be determined by maximizing the net present value of the system so that better cost effectiveness of the PV project and better utilization of solar energy can be obtained.

Demand response: a strategy to address residential air-conditioning peak load in Australia

Rapid growth in electricity network peak demand is increasing pressure for new investment which may be used for only a few hours a year. Residential air-conditioning is widely believed to be the prime cause of the rise in peak demand but, in the absence of detailed residential demand research, there is no bottom-up empirical evidence to support this supposition or to estimate its impact. This paper first examines the developments in network peak demand, at a national, network distribution, and local distribution feeder level to show recent trends in peak demand. Secondly, this paper applies analytics to the half-hourly consumption data of a sample of Ausgrid’s interval metered customers, combined with local weather data, to develop an algorithm which can recognize air-conditioner use and can identify consumption patterns and peak load. This estimate is then compared to system peaks to determine residential air-conditioning’s impact on overall demand. Finally, this paper considers the future impacts of air-conditioning load on peak demand as penetration rates reaches saturation levels and new minimum energy performance standards take effect reducing new units peak impacts.

High performance computing for detection of electricity theft

Transmission and distribution of electricity involve technical as well as Non-Technical Losses (NTLs). Illegal consumption of electricity constitutes a major portion of the NTL at distribution feeder level. Considering the severity and devastating effects of the problem, illegal consumption of electricity has to be detected instantly in real-time. To this end, this paper investigates the possibility and role of High Performance Computing (HPC) algorithms in detection of illegal consumers. This paper designs and implements an encoding procedure to simplify and modify customer energy consumption data for quicker analysis without compromising the quality or uniqueness of the data. This paper parallelizes overall customer classification process. The parallelized algorithms have resulted in appreciable results as displayed in the results section of the paper.

Optimization of Photovoltaic Penetration in Distribution Systems Considering Annual Duration Curve of Solar Irradiation

The penetration level of a photovoltaic (PV) system is often limited due to the violation of voltage variation introduced by the large intermittent power generation. This paper discusses the use of an active power curtailment strategy to reduce PV power injection during peak solar irradiation to prevent voltage violation so that the PV penetration level of a distribution feeder can be increased to fully utilize solar energy. The PV power generation is simulated according to the hourly solar irradiation and temperature data provided by the weather bureau. The voltage variation at the point of common coupling (PCC) is also derived by executing the 3-φ load flow analysis to investigate the maximum PV power injection without causing a voltage violation problem. When using the proposed voltage control scheme for limiting PV power injection into the study distribution feeder during high solar irradiation periods, the total power generation and total energy delivered by the PV system over a one-year period are determined according to the annual duration of solar irradiation. The annual cash flow from sales of PV power, the O&M cost over the system life cycle, and the capital investment in the PV system are then used to calculate the payback years and the net present value (NPV) of the PV project. With the proposed voltage control to perform the partial generation rejection of PV systems, the optimal installation capacity of PV systems can be determined by maximizing the net present value of the system so that better cost effectiveness of the PV project and better utilization of solar energy can be obtained.

Assessing electrical bottlenecks at feeder level for residential net zero-energy buildings by integrated system simulation

Recent European communications focus on the enforcement that by 2020 all new buildings are nearly Zero-Energy Buildings (ZEBs) and on the deployment of a European Smart Grid. The presented work focuses on assessing the electrical challenges at neighborhood level of an building stock evolving towards ZEBs, and identifying the resulting challenge in multidisciplinary dynamic simulation models required to perform this assessment.A tool for Integrated District Energy Assessment by Simulation (IDEAS) is developed. This IDEAS tool allows simultaneous transient simulation of thermal and electrical systems at both building and feeder level.Residential ZEBs show a self-consumption of locally generated photovoltaic (PV) electricity of 26±4% at building level. Resulting feeder voltage fluctuations and possible transformer overload are quantified as bottlenecks. When all dwellings are intended to achieve a ZEB status, (i) a fraction of 14–47% of local PV supply is wasted by inverter curtailing depending on the feeder strength, while (ii) the peak transformer load is found to be 3.3kVA per dwelling which may affect power security in existing feeder designs.

Analysis of Influencing Factors for Costs on Substation Siting Based on DEMATEL Method

Choosing an optimum location of a distribution sub-station has always been a concern to the distribution planners. A lot of work has been carried out in this regard but all have made either the use of man machine interface or have made some approximations. In addition, it performs operational and contingency switching and protection duties at both the transmission and feeder levels, and provides a convenient local site for additional equipment such as communications, storage of tools, etc. The location of a substation depends upon many factors. This paper uses DEMATEL method to rank the major cost sensitivities involved in substation sitting in order of typical economic importance to overall decision making. The seven major factors considered are: feeder impact, sub transmission impact, feeder getaway, geographic factors, site preparation, land cost and weather exposure.

Slope-Permissive Under-Voltage Load Shed Relay for Delayed Voltage Recovery Mitigation

In this paper, a new relay algorithm is proposed for under-voltage load shedding (UVLS) based on rate of voltage recovery and predicted time to recover above a preset voltage threshold. Simulation experience in the Southern Electric System has shown that conventional UVLS relay logic is ill-suited to the task of mitigating delayed voltage recovery and fast voltage collapse situations while maintaining compliance with existing NERC Reliability Standards. The proposed scheme continuously monitors both voltage magnitude and rate-of-change of voltage magnitude and uses these values to determine a projected voltage recovery time following a contingency event. If the projected recovery time is such that resultant system conditions are unacceptable (e.g., major load loss, loss of generation, or voltage collapse), the relay will operate to shed load at the distribution feeder level. This unique scheme has been implemented in a commercially-available programmable relay and is presently installed and active in a number of substations in Georgia Power Company.

Protection, Control and Monitoring System with Web Interface for Small Distribution Substations

The paper describes in detail the functional and communications architecture of an integrated system for small distribution substations. It analyses the requirements for protection, control and power quality monitoring and disturbance recording at the substation and distribution feeder level. It describes the distribution of different functions between the IEDs used by the system.

Optimal volt/var control in distribution systems

A new approach to optimal reactive power and voltage control in radial distribution systems is proposed in this paper. The optimal control is to find a proper dispatch schedule for shunt capacitor banks and on-load tap changer at substation and shunt capacitor banks on feeders so that the power loss is minimized and the voltage profile is improved. To reduce computation burden, the whole control is decomposed into two sub-problems, namely sub-problem on substation level and sub-problem on feeder level. A simplified dynamic programming and a fuzzy logic control algorithm are used to deal with the two sub-problems, respectively. Coordination of the two algorithms provides an appropriate solution to the whole control problem. The numerical results demonstrate that the proposed approach is effective and feasible.

Monitoring load control at the feeder level using high speed monitoring equipment

The use of a high-speed data acquisition system (50 samples a second) to monitor load control is described. The system has proved extremely effective in evaluating the impact of load control. A methodology for detecting appliance starts within the high-speed data is described and given a preliminary test. This high-speed monitoring technology promise to be relatively inexpensive and highly reliable and to provide real-time information which can be used by power system operators to make decisions about load control actions. >

Effects of Cage Design and Bird Density on Layers: 2. Bird Movement and Feeding Behavior

Two experiments, one with a commercial strain and one with an experimental strain of Single Comb White Leghorns, compared the effects of cage shape, feeder space, cage barrier, bird density, level of feeding, and period observed on feeding behavior and bird movement. In Experiment 1, only period observed significantly affected time spent feeding; the commercial strain of hens generally ate more in the p.m. (1700 to 1900 hr) than in the a.m. (0700 to 0900 hr). A significant (P<.05) feeder-space × period observed interaction indicated that increased feeder space is important in reducing feeder competition during peak feeding times.Only feed consumption of the experimental strain was significantly (P<.05) affected by bird density; hens housed 2 birds per cage ate 10.5 g per hen per day more than those housed 3 per cage (Experiment 2). Birds spent 38. 4 sec more eating during 0600 to 0700 hr than 1700 to 1800 hr (P<.05). Maximum number of birds feeding simultaneously was significantly (P<.05) affected by feeder space, bird density, and level of feeding. Hens with 45.7 cm of feeder space per cage, housed 3 per cage and receiving 90% of full feed had more simultaneous feeding than hens with 25.4 cm of feeder space, housed 2 per cage and on full feed. Hens in deep cages had significantly (P<.05) more quadrant-to-quadrant moves than hens in shallow cages.

Distribution System Integrated Voltage and Reactive Power Control

Automated distribution systems offer new opportunities for improved control of voltage and reactive power at the distribution substation and feeder level. Digital processor algorithms which can have the objective functions of controlling voltage and reactive power and minimizing feeder losses in an integrated fashion according to specified priorities are described. Simulation results using a representative simplified distribution feeder configuration are presented based on the algorithms developed in connection with the PROBE [1] substation and feeder automation research project. This work is being advanced as a part of the development of the Integrated Distribution Control and Protection System engineering prototype for EPRI in Project RP 1472-1.