B. Don Russell

Intelligent Systems for Improved Reliability and Failure Diagnosis in Distribution Systems

Certain smart grid technologies can reduce the number of customers affected by prolonged outages, and thereby increase reliability through automated switching to restore service. Such technologies are useful, but reactive in nature, performing their function only after a fault occurs and an outage has been detected. They must presume that nonfaulted feeder sections and alternative feeders are healthy and capable of carrying increased power flow. Research at Texas A&M University has demonstrated that sophisticated, automated real-time analysis of feeder electrical waveforms can be used to predict failures and assess the health of distribution lines and line apparatus. Reliability can be substantially improved by detecting, locating, and repairing incipient failures before catastrophic failure, often before an outage occurs. Requirements for data and computation are substantially greater than for devices like digital relays and power-quality meters, but feasible with modern electronics. This paper provides selected examples of failures that have been predicted by intelligent distribution fault anticipation (DFA) algorithms. The data requirements and processing analysis to detect these failures are discussed. The problems related to full-scale deployment of the proposed system in a utility-wide application are presented. The authors use experience gained from their long-term research to propose concepts for overcoming these impediments.

Detection of Distribution High Impedance Faults Using Burst Noise Signals near 60 HZ

Previous papers have described a method for the detection of arcing fallen distribution primiary conductor faults using the electrical noise in feeder current above 2kHz. While this method provided improved detection of such faults, this high frequency signal often would not propagate past capacitor banks. In the present paper, we describe a technique for the identification of arcing high impedance faults using burst noise signals at frequencies near the power system fundamental and low order harmonics. Arcing generates non-synchronous burst noise signals which approximate white noise, providing a signal which can be differentiated from synchronous power system signals in the frequency bands of interest. The primary advantage of monitoring frequencies near the fundamental is that this arcing fault signal at low frequencies will exhibit little attenuation from capacitor banks or other sources. This paper provides preliminary results that arcing faults can be detected effectively using frequency components below 60 Hz or between low order harmonics of 60 Hz. The technique is demonstrated through analysis of analog signals recorded during numerouis staged utility downed conductor tests.

Improved algorithm for detecting arcing faults using random fault behavior

Abstract High impedance distribution feeder faults have been shown to generate considerable high frequency current when arcing is present. A new algorithm is presented which takes advantage of this phenomenon and its random behavior. Using recorded fault data, parametric analysis has been performed to pseudo-optimize the detection capability while maintaining a high degree of insensitivity to normal system events. A discussion of possible implementation constraints is included.

Communication Alternatives for Distribution Metering and Load Management

This paper contains the edited records of four presentations on Communication Alternatives For Distribution Automation presented at the 1979 Summer Power Meeting of the Power Engineering Society. The need for distribution system communications is established and the types of systems available are enumerated. Three systems utilizing the power lines for communications are described in detail. One approach using the existing telephone system is also described. The problems associated with each approach are listed and the advantages of each are discussed.

Harmonic behavior during arcing faults on power distribution feeders

Abstract The waveforms of normal and arcing fault currents on power distribution feeders are investigated and compared in terms of the percentage amplitude with respect to the amplitude of the normal fundamental. The purpose of the study is to find better parameters to indicate arcing faults. The effect of capacitor banks on distribution feeder harmonics is discussed briefly.

Feeder Protection and Monitoring System, Part II: Staged Fault Test Demonstration

This paper describes the demonstration of three Texas A&M University experimental Feeder Protection and Monitoring Systems during staged fault tests at Houston Lighting and Power and at Public Service Company of New Mexico. The purpose of the experimental devices is to demonstrate improvements in the protection and monitoring capabilities of distribution relays. The Feeder Protection and Monitoring System is a microcomputer-based device installed at a distribution substation which includes arcing fault detection and overcurrent relaying. The arcing fault detector identifies many ground faults which exhibit current too low to be picked up by overcurrent devices. The digital overcurrent relay provides several enhancements over electromechanical relays. The system also demonstrates some of the advantages of computer automation of distribution protective devices by providing remote monitoring, data retrieval and adjustment of settings. These features of the Feeder Protection and Monitoring System were demonstrated during the staged fault tests. The paper includes plotted data and logs of the system performance during the fault tests.

Feeder Protection and Monitoring System, Part I: Design, Implementation and Testing

This paper describes the development of a microcomputer-based Feeder Protection and Monitoring System at Texas A&M University. The Feeder Protection and Monitoring System includes an overcurrent relay to provide overcurrent protection for a distribution feeder and it includes an arcing fault detector which identifies some low current faults which are not cleared by overcurrent protection. The system also provides a monitoring capability which supports data storage and remote interaction with a user. The paper describes the design of the system, how the design was implemented, and the testing of three prototypes which were built for research purposes. These units properly demonstrated the overcurrent protection, arcing fault detection and monitoring functions of the system, as well as many of the features of power system automation.

Expert System Applications to Protection, Substation Control and Related Monitoring Functions

Abstract Application of expert systems to power system problems has become an area of strong research interest in the past few years. A number of papers have been published on the subject with an emphasis on applications that relate to the overall power system monitoring, operation and planning. However, less emphasis was placed on protective relaying, substation control and related monitoring functions. This paper is primarily concerned with the applications that are focused on power system protection, substation operation, and monitoring. It gives both a survey of the present research efforts and a discussion of future possibilities and trends in this area.

Microcomputer Based Feeder Protection and Monitoring System - Utility Experience

This paper describes the experience of Houston Lighting & Power Company with the field operation of the Feeder Protection and Monitoring System developed by Texas A&M University. The Feeder Protection and Monitoring System (FPMS) is fully described from a functional perspective. The paper describes the design objectives of the project. The field testing of the device and its subsequent use as a monitoring and diagnostic tool are reviewed in detail. The potential value of the system to utilities and the need for modifications and further research are included. The perspective of HL&P on integrated substation control and protection is given.

Reliability improvement of distribution feeders through real-time, intelligent monitoring

Feeder reliability has been receiving increased attention. Substantial industry efforts have defined standardized indices for quantifying reliability. Utility commissions and municipalities are requiring utilities to use these indices to identify and make improvements to poorly performing feeders. Reliability indices generally equate to the number and length of outages, and to the number of customers affected. While some outages are unavoidable, others are the result of incipient failures or apparatus malfunction. This paper illustrates how reliability can be improved through real-time situational awareness of faults and events. Emphasis is given to providing actionable information with little or no human intervention. The paper describes how Texas A&Ms Distribution Fault Anticipation (DFA) project documented naturally occurring faults and outages on 60 feeders, and examines how those events could be avoided with intelligent monitoring. Reliability improvements are projected through condition-based maintenance and quick response to outages using previously unavailable information on faults and events.