David B. Durocher

Energy evaluation goes wireless

In this article, a closed-loop industrial plant energy evaluation and planning system with a WSN architecture has been proposed. This system eliminates the costs associated with the installation and maintenance of communication cables. The scheme outlined has been implemented in a simplified prototype WSN system, and its industrial feasibility has been verified by the experimental results. The main contributions of this system lie in its nonintrusive, intelligent, and low-cost nature. The efficiency and operating cost of the plant are estimated nonintrusively. The use of speed and torque transducers is eliminated. The motors normal operation is not impeded. The deployment of a WSN makes high-level intelligent power management feasible

Predictive maintenance techniques

This article discusses the importance of PdM for industrial process applications and investigates a number of emerging technologies that enable this approach, including online energy-efficiency evaluation and continuous condition monitoring. The article gives an overview of existing and future technologies that can be used in these areas. Two methods for bearing fault detection and energy-efficiency estimation are discussed. The article concludes with focus on one pilot installation at Weyerhaeusers Containerboard Packaging Plant in Manitowoc, Wisconsin, USA, monitoring three critical induction motors: a 75-hrho blower motor, a 50-hrho hydraulic pump motor, and a 200-hp compressor motor. Finally, the field experience gained in this plant is presented as two case studies.

Future control technologies in motor diagnostics and system wellness

Over the past few years, industrial manufacturing disciplines have evolved from a strategy of routine scheduled maintenance of electrical equipment to condition based maintenance (CBM). In the CBM approach, equipment maintenance based on a routine schedule can be replaced with an approach based on system wellness diagnostics. This approach might rely on noninvasive monitoring of three-phase induction motors to report equipment condition and enable maintenance intervention before a failure occurs. Research conducted at the University of Sussex in the United Kingdom and at Georgia Institute of Technology has been conducted developing algorithms of motor current signature analysis (CSA) and power signature analysis (PSA) resulting in a reliable model to predict motor and driven load failure. Pump cavitation, rotational unbalance and mechanical alignment are some of the areas where a mathematical model has been developed using fast Fourier transform (FFT) analysis enabling online diagnostics during operation. An extensive testing program to validate and refine the mathematical model was conducted both in the test lab and in field process applications. A motor wellness relay is under development in a mechanical package designed to replace a conventional thermal-overload relay of a NEMA or IEC rated motor starter. With this approach, the on-line motor wellness relay enables CBM via a control device that is already required for the control circuit. This paper discusses the mathematical model and field tests to validate the model and introduce a motor wellness relay that could be used to perform on-line diagnostics. Alternative system communication architectures to support a wellness platform are also reviewed and discussed.

Proper application & maintenance of molded case breakers to assure safe and reliable operation

This paper will discuss the importance of reliable and repeatable performance of molded case circuit breakers in todays power distribution systems. The paper will review existing standards for maintenance of molded case breakers including procedures outlined in NEMA AB4 and IEEE1458. Common misconceptions and system application issues regarding these devices will be discussed. Several examples of on-line infrared scans of circuit breakers over the course of a five year period will be presented and reviewed. Experiences at an integrated paper mill located in Longview, Washington USA explains documented cases where infrared thermography has been used as a predictive maintenance tool in determining potential problems with breakers while in service. Follow-up analysis by the circuit breaker manufacturer has generally validated mill maintenance decisions to remove a breaker from service and replace it, based on infrared scan results. Periodic infrared scanning used as a tool in identifying potential problems with sealed molded case circuit breakers will be discussed. This and other breaker off-line testing methods used at this site will be reviewed. Finally, overall reliability improvement and impact on the results of the existing mill-wide safety compliance programs will be summarized.

Mining industry process upgrades to reduce energy intensity while improving end product quality

In an environment of constantly cyclical mineral market prices, operators of sites in the global mining industry are challenged to continuously improve processes in order to remain competitive with their peers. Although not necessarily a priority in the past, the issue of energy efficiency project upgrades has moved to the forefront of mine operations. The dual benefits of both serving as a means of offsetting rising energy costs and reducing emissions to reduce environmental footprint are compelling. This paper is a case study of one such energy efficiency project recently implemented at a coal prep plant in Western Canada. The project began with a coal dryer energy efficiency feasibility study performed by a global energy services engineering company. Solicitation for the feasibility study was supported by the local utility company serving the mine site, who actually funded the cost of the study. The paper will review the analysis methods used and recommendations included in the study, followed by site implementation of one of the key study deliverables, a proposed plan to install a 6000Hp medium-voltage adjustable frequency drive to improve control of the main coal dryer exhaust fan. The paper will also describe the unique adjustable frequency drive selected for installation for this load, including an overview of the power electronics topology and resulting performance both in delivering improved energy efficiency and also process improvements. This upgrade ultimately assured both that energy and operational costs were reduced while the coal prep plant delivered a superior end-product to its customers.

Understanding circuit breaker design and operation to improve safety and reliability in underground mining

Traditional “above-ground” applications of circuit breakers for overcurrent protection in industry are generally well understood. Defined design and test standards, which vary somewhat across the globe, provide a framework for users of these devices to assure that they are not misapplied. Attention to detail in circuit breaker maintenance generally assures that these devices will operate reliability and safety across the industry. However, when circuit breakers are applied in underground mining applications, traditional design and test standards give way to in-country mining safety authorities who typically dictate requirements in these special applications. Because of this, ratings and test requirements for low-voltage molded-case circuit breakers, low-voltage power circuit breakers, medium-voltage vacuum and medium-voltage sulphur hexafluoride (SF6) circuit breakers in underground mining are typically different. In this environment, the user must be aware of issues specific to the application to assure that these devices operate such that they assure miner safety and operation reliability. This paper will discuss specific circuit breaker applications in underground mining and recommend methods to maximize the effectiveness of these protective devices in this environment.

Unit Substation Design

As new challenges emerge in power distribution systems reliability and electrical workplace safety, it is the responsibility of the systems designer to seek out new approaches and solutions to address them. Stepping back and looking at the big picture, the systems designer has an onerous responsibility in specifying or selecting the best designs. Design decisions made today will impact cost, safety, and serviceability of the installed systems for 40 or 50 years during the useful life for the owner. Studies have shown that this cost is an order of magnitude of seven to ten times the installed cost of the power distribution equipment. The work by the project design team in this effort is considered a significant step forward in innovation in unit substation design. In the current environment of emerging codes and standards such as NFPA 70E focused on improved electrical workplace safety, the obvious first choice for any power systems designer is to design the hazard out. Industry must continue to focus on safety by design as the most effective approach in minimizing electrical hazards while improving system reliability. Developments such as those described in this article and efforts by a recently formed working group within the IEEE and discussed are considered driving forces in accomplishing this important objective.

Online and nonintrusive continuous motor energy and condition monitoring in process industries

Maintaining electrical and mechanical systems within the industrial process environment continues to present a daunting challenge. With electrical motors at the center of most processes, prognostics are best accomplished during motor operation. However, since disruption of the process is rarely possible, often systems must be de-energized during scheduled outages before they can be maintained. Predictive maintenance techniques offer a viable solution to this dilemma. As a result, predictive maintenance has been the subject of many recent technical papers. Nonintrusive continuous monitoring of critical systems is emerging as the best method to maximize reliability and uptime with minimal impact on the plant process operation. This paper discusses the importance of predictive maintenance for industrial process applications and investigates a number of emerging technologies that enable this approach, including online energy efficiency evaluation and continuous condition monitoring. The paper gives an overview of existing and future technologies that can be used in these areas. Two methods for bearing fault detection and energy efficiency estimation are discussed. The paper concludes with focus on one pilot installation at Weyerhaeuserpsilas Containerboard Packaging Plant in Manitowoc, Wisconsin USA, where the site is realizing benefits from a new and novel approach.

Infrared windows applied in switchgear assemblies: taking another look

Maintenance of electrical power distribution assemblies applied in industry has been critical in assuring facility uptime and reliability. One important metric in assuring reliability is electrical terminations of energized conductors. During normal energized service, terminations both at conductor bus joints and at cable terminations are subject over time to thermal expansion and contraction, ultimately resulting in loosened connections and excessive heat. Deteriorating terminations left unchecked will ultimately fail, resulting in electrical hazards for personnel and also costly loss of production. Infrared (IR) inspection has proved to be an excellent maintenance method used to identifying problems with loose electrical terminations. However, the design of Internal Arc Classified (lAC) switchgear assemblies to address arc-flash concerns has changed assembly designs that now limiting line of sight access necessary for IR inspection via windows. This paper will discuss global Standards, how they affect switchgear designs and application ofIR windows, then present some alternative technologies that in some applications may be more suitable.

The journey of an enterprise in a process industry toward improved electrical workplace safety

This paper is a case study outlining the experience of a multisite cement producer and their experience in implementing an enterprisewide electrical workplace safety program, including compliance with the National Fire Protection Association 70E-2012 standard. Following a brief primer regarding arc-flash hazards, this paper outlines how the company first established a case for change and buy-in across the enterprise that includes 13 cement plants that are located across the USA and Canada, and then proceeds in describing the processes used to identify the defined work scope, select a supplier partner, and complete arc-flash studies at each site. The advantages of scale in areas, including common methods of data collection, selected software, standardized labels, site training, and energized work permits, are addressed. Finally, the lessons learned during this project and a phased remediation plan at each site, which was developed to reduce or eliminate potentially hazardous conditions, will be discussed. Finally, a few concepts based on “safety by design” will be explored, where there might be an opportunity to design the hazard out or down for new plant projects or expansion.