Distribution Automation Schemes Research Articles

A Data Analytic Approach to Automatic Fault Diagnosis and Prognosis for Distribution Automation

Distribution automation (DA) is deployed to reduce outages and to rapidly reconnect customers following network faults. Recent developments in DA equipment have enabled the logging of load and fault event data, referred to as “pick-up activity.” This pick-up activity provides a picture of the underlying circuit activity occurring between successive DA operations over a period of time and has the potential to be accessed remotely for off-line or on-line analysis. The application of data analytics and automated analysis of this data supports reactive fault management and post fault investigation into anomalous network behavior. It also supports predictive capabilities that identify when potential network faults are evolving and offers the opportunity to take action in advance in order to mitigate any outages. This paper details the design of a novel decision support system to achieve fault diagnosis and prognosis for DA schemes. It combines detailed data from a specific DA device with rule-based, data mining, and clustering techniques to deliver the diagnostic and prognostic functions. These are applied to 11-kV distribution network data captured from Pole Mounted Auto-Reclosers as provided by a leading U.K. network operator. This novel automated analysis system diagnoses the nature of a circuit’s previous fault activity, identifies underlying anomalous circuit activity, and highlights indications of problematic events gradually evolving into a full scale circuit fault. The novel contributions include the tackling of “semi-permanent faults” and the re-usable methodology and approach for applying data analytics to any DA device data sets in order to provide diagnostic decisions and mitigate potential fault scenarios.

Methods for Harmonic Analysis and Reporting in Future Grid Applications

The rollout of advanced metering infrastructure, advanced distribution automation schemes, and integration of generation into distribution networks, along with a raising of awareness of power quality (PQ), means that there is an increase in the availability of power system monitoring data. In particular, the data for harmonics, whether it is voltage or current harmonics, is now available from a large number of sites and from a diverse range of PQ instruments. The traditional analysis and reporting of power quality examines harmonic orders to the 50th. This means that the harmonic data available for analysis are significantly larger than, for example, steady-state voltage variations where only a few parameters are examined (e.g., the voltage on each phase). Higher frequency components, sometimes called high-frequency harmonics, in the 10–250 kHz range arising primarily due to power-electronic interfaced generation are also becoming significant. Given the vast amount of harmonic data that will be captured through grid instrumentation, a significant challenge lies in developing methods of analysis and reporting that reduces the data to a form that is easily understood and clearly identifies issues but does not omit important details. This paper introduces a number of novel methods of analysis and reporting which can be used to reduce vast amounts of harmonic data for individual harmonic orders down to a small number of indices or graphical representations which can be used to describe harmonic behavior at an individual site as well as at many sites across an electricity network. The methods presented can be used to rank site performance in order for mitigation strategies. The application of each method described is investigated using real-world data.

Composite automated distribution system reliability model considering various automated substations

Due to the fact that automation can significantly improve reliability of substation as well as distribution system, this paper presents a composite reliability assessment model of distribution system which illustrates the impacts of substations automated by various automation configurations on the reliability of primary distribution systems equipped with a specific distribution automation (DA) scheme. First, three architectures of substation automation systems (SASs), known as ring, cascading, and star, are reviewed and their reliability block diagrams (RBDs) are developed. Reliability assessments for five types of automated substations are then done using the event tree and the concept of expectation methods. Afterwards, a particular automated distribution scheme designated as the low interruption system (LIS) is reviewed and the interaction between the SAS and the DA is then modeled using the event tree methodology. Finally, by presenting explicit formulas for reliability evaluations of the automated distribution system, the composite reliability assessment models are completed. The proposed approach is applied to the five distribution system configurations.

The Design and Implementation of an Integrated Distribution Automation Scheme

According to the statistic of the distribution network operation, distribution network fault is generally located on line branch, rather than the main line. In view of the structure and characteristics of the current distribution automation system, combining the distribution network reformation and construction practice, this paper puts a comprehensive distribution automation solution that the branch line is equipped with distribution automation terminal which integrates protection and reactive power compensation function. It can achieve the rapid isolation of the distribution network failures and the power supply reliability, and dynamically improve the quality of power supply.

Communication Systems for Load Management

Load management and distribution automation schemes of electric utilities require an extensive, reliable and economical communication system. Several communication technologies have been investigated, tested and employed to optimize these schemes. This paper examines these communication techniques, discusses advantages and disadvantages of each with a special emphasis on power line carrier system (PLC), and finally presents recommendations and suggests areas for future research.

Discrete-Tap Control Scheme for Capacitive Compensation of Distribution Feeders

Substation-based computers for control of reactive power on distribution primary feeders are being included within the distribution automation schemes now undergoing installation. This paper develops the algorithmic basis for the optimal control strategies necessary to capacititively compensate distribution feeders having capacitors with multipletap settings. The theory underlying these discrete-control strategies is presented along with simple numerical examples which show how to minimize the kilowatt power losses as reactive load varies on the feeders.

Discrete-Tap Control Scheme for Capacitive Compensation of Distribution Feeders

Substation-based computers for control of reactive power on distribution primary feeders are being included within the distribution automation schemes now undergoing installation. This paper develops the algorithmic basis for the optimal control strategies necessary to capacitively compensate distribution feeders having capacitors with multiple-tap settings. The theory underlying these discrete-control strategies is presented along with simple numerical examples which show how to minimize the kilowatt power losses as reactive load varies on the feeders.

Optimal Design and Control Scheme for Continuous Capacitive Compensation of Distribution Feeders

Distribution automation schemes being considered for implementation by electric utilities will rely heavily on substation-based computers for control of reactive power on primary feeders. To assist such implementation a new, continuously controllable, capacitive compensation scheme for primary distribution feeders is presented. This compensation scheme allows optimal placement and sizing of time-variable capacitors based on an optimal operating strategy which provides for power loss minimization as a function of time. A numerical example involving a realistic physically existing feeder is provided to explify the design and control schemes.

Optimal Design and Control Scheme for Continuous Capacitive Compensation of Distribution Feeders

Distribution automation schemes being considered for implementation by electric utilities will rely heavily on substation-based computers for control of reactive power on primary feeders. To assist such implementation a new, continuously controllable, capacitive compensation scheme for primary distribution feeders is presented. This compensation scheme allows optimal placement and sizing of time- variable capacitors based on an optimal operating strategy which provides for power loss minimization as a function of time. A numerical example involving a realistic physically-existing feeder is provided to exemplify the design and control schemes.