When parts of a machinery control system are required for risk reduction of a hazard, they are considered a safety function. A typical safety function is comprised of safety input and output devices which are monitored and controlled by a safety logic device. Emergency stop buttons and guard door interlocks are typical safety input devices which are often remote, and field wired. Safety relays are typical safety logic devices and safety contactors, and variable frequency drives (VFDs) are typical output devices which are commonly located inside of a Low Voltage Motor Control Center (LVMCC). Safety functions must be engineered and implemented according to relevant machinery safety standards. Despite having common design requirements, safety functions often require customized engineering when applied to a LVMCC. This paper serves as an overview of how to promote standardization in the implementation of safety functions when using LVMCC's. Standardization reduces delivery times of safety rated LVMCC units, decreases overall cost of acquisition of a safety rated LVMCC, and enables users to maximize operational productivity while assuring a proper design of the safety function. The selection of standard safety rated motor controller units as safety function subsystems enables users to minimize personal and enterprise risk when engineering new safety functions.
Using a connector not rated for the application and improper installation is a cause of power interruption in industrial and commercial facilities. This paper provides a primer for proper selection and installation practices to improve electrical distribution system reliability and performance. The goal of any electrical system is to perform functionally for the life of the system. This paper reviews the types and technical characteristics of electrical connectors that are used for distinct functions within the overall electrical system, such as grounding, bonding, and power connections. Environmental considerations such as direct burial, wet locations, and sunlight resistance are addressed. New connector applications such as line side of the service ratings are introduced. The paper also addresses the characteristics of connectors and installation practices for applications over 1000 Volts. Connector installation information, such as torque requirements, finely stranded conductor impacts, hole spacing guides per the National Electrical Manufacturers Association (NEMA) standard, voltage limitations and temperature rating ampacity impacts are outlined.
Field site instances are described where a ship or coastal water radar operation, near an on-ship or land-based crane ASD, caused random software Code Redundancy Check [CRC] faults. Section II characterizes a wide range of radar source emission possibilities in terms of allocated radar frequency ranges IEEE S-band [3 GHz] or IEEE X-band [8 - 12 GHz], peak pulsed power variability [6 to 60 kW pk] and V/m (volts per meter) magnitude at the antenna surface. Section III describes antenna coupling mechanisms from antenna surface to V/m magnitude seen at separated ASD distance. At these frequencies, even small holes in standard ASD grounded metal cabinets allow unattenuated emission internally. Indeed, every opening in the control room door resulted in an immediate CRC trip. Separate research testing, simulating radar high E-fields at unshielded control boards, verified radar operation as the root cause of CRC faults. Existing IEC Radiated Electric Field Susceptibility requirements for land-based ASD only extend to 2.7 GHz and have V/m specifications much lower than those for powerful radar fields in proximity. When standards do not cover unique applications, they are classified as E3 events. Section IV reviews shielding effectiveness formulas and techniques to use to calculate dBV/m (voltage level in decibels reference to 1v per meter) attenuation levels required at the board level that eliminates radar source issues. Section V ends with a lesson learned summary on how to modify existing standard drive cabinets using an EMC hardened solution checklist on shielding materials and techniques.
Thermal overload protection is a critical part of any motor protection scheme. Older electromechanical relays provide thermal protection with an inverse-time overcurrent element. Replacing electromechanical relays with modern microprocessor-based relays requires the development of settings for a more sophisticated thermal protection element, such as the first-order thermal model. Additionally, this requires a planned outage to install the new relay and commission the settings. To correctly set the thermal element in a microprocessor-based relay, motor manufacturer data (such as a nameplate, data sheet, and system data) are needed. However, these data are not always available for older motors. This paper describes the settings required for the first-order thermal model and provides case studies from various end users illustrating how settings from existing electromechanical relays were used to develop settings for a microprocessor-based thermal element.
Electrical equipment, fitted with arc quenching technologies, have been employed and have been providing personnel and equipment protection in many global installations for over two decades. This technology continues to evolve, advance, and provides significant reduction of arc incident energy. However, a limiting factor has become the actual standards which define some of the fundamental aspects of its design and applications. This work outlines how the present generation of arc quenching technologies continue to reduce arc incident energy and improve safety within switchgear, motor control centers or control panels. Very detailed testing results will provide conclusive evidence of a superior level of protection to not only the protected equipment and process, but also to personnel as well. The factory and site acceptance testing criteria for arc mitigation systems, to guarantee the correct operation of the system, will be discussed as well. Common myths and misconceptions surrounding arc quenching technologies, such as the system current impact expectations when using arc quenching technologies, are also covered.
High-efficiency LV motors are becoming more prevalent, even replacing old plant motors. The main drivers for this are legislative requirements to reduce electricity consumption, increased electricity costs, and pressure to reduce carbon footprints. But even when each motor has a lower power rating, there are often thousands of these LV motors installed in a typical petrochemical plant. This begs the question: Can high-efficiency LV motors be rewound while maintaining their original premium efficiency levels?This paper explains the high-efficiency motor design and components and evaluates the influence on performance of different repair levels; e.g., basic repairs, stator rewinds, core damage and rotor damage. Case studies are presented showing when repairs can maintain efficiency, when they can’t, and instances where the repair can increase efficiency. The paper concludes that it is definitely possible to repair a high-efficiency LV motor while maintaining or even improving efficiency.
There are many sources of energy used today to generate power in the form of electricity. The ideal vision for the future is to find a way to store energy in its purest form for extended periods of time. Today, industry has chemical and electrolytic means to store electricity, but only for a short duration, and its transportation is mostly grid-based. Hydrogen (H2), in the stable form of water (H2O), is present in large quantities and is well-suited for the energy supply chain as an energy storage mechanism and secondary energy source. 1 kg of H2 contains as much energy as 2.1 kg of natural gas or 2.8 kg of gasoline [1]. H2 is produced by electrolysis, which can be modeled by: Electricity + Water = Hydrogen + O2. The challenge is to make this process more efficient by using less expensive renewable electrical energy.
Electrical switching orders are step by step instructions that are critical to ensure personnel safety and equipment availability. The switching orders are used to either place equipment in an electrically safe working condition or to bring equipment back into service. The switching orders ensure that the work is done safely and establish a clear communication between the person calling out the instructions and the person receiving the instructions. The "science" aspect involves certain criteria that every switching order should contain, such as: only one instruction per line, every action line has a verification line, etc. The "art" aspect involves including lessons learned that may vary from each person who writes the switching order, such as: steps to notify Operations, steps to open all substation gates, etc. This paper will also emphasize: the need to call out each step, have each step repeated back, have proper reviews and sign offs of the procedure, and to have an accurate one-line diagram to accompany the procedure.
This paper presents a case study of the application of predictive analytics using a fiber-optic based temperature monitoring system on an electrically heat traced asphalt pipeline at a refinery in North America. A skin-effect trace heating system and a fiber optic Distributed Temperature Sensing (DTS) system was installed on an approximately 700m long section ("DTS zone") of an asphalt pipeline passing over various railroads and highways. The piping upstream and downstream of the DTS zone was only heat traced but not monitored by a DTS system (i.e., outside of the DTS zone). Based on the data collected by the DTS system, the system’s software analyzed the thermal behavior of the pipeline to identify weak spots in the thermal profile of the pipeline, predict potential product freeze at certain locations and the time to freeze in the absence of remedial actions. The system is also being utilized by the operators to analyze the product temperature entering and exiting the DTS zone to determine functionality and operating limits of the heat tracing systems outside the DTS zone.
Reducing the exposure and risk to arc flash in medium voltage switchgear is an important mission for industrial facilities. Several arc flash mitigation techniques are available using modern microprocessor-based protective relays. This paper will review and compare various protective relay based applications such as zone selective interlocking (ZSI) scheme, high impedance bus differential protection scheme, low impedance bus differential protection scheme, light and current sensing scheme, and maintenance / alternate setting scheme.
In a global effort to reduce carbon intensity, heavy industries are actively exploring methods to cut greenhouse gas emissions, with carbon capture emerging as a viable solution. The enactment of the Inflation Reduction Act (IRA) of 2022 has made carbon capture economically feasible, thanks to enticing tax incentives aimed at curbing scope 1 emissions. Nonetheless, integrating new carbon capture units into existing industrial complexes presents mechanical, civil, electrical, and environmental challenges. This paper describes the electrical considerations of such projects, addressing hurdles and strategies. Emphasizing early engagement with utilities, it examines their role in managing project costs, schedules, and scopes. Key factors like power requirements, CO2 compressor sizing, and utility transformer procurement are crucial for seamless implementation. Furthermore, it shows the decision-making process concerning the main CO2 compressor, including various starting methods and voltage level selections that significantly impact project costs. Ultimately, this paper aims to provide an electrical perspective to aid in navigating the integration of carbon capture within existing industrial settings.
This work, based on [1], presents and discusses the solutions to overvoltages experienced by the medium voltage system (13.8 kV) in an existing refinery resulting from the switching of power transformers supplied by a high voltage system (230 kV) through insulated cables. The analysis demonstrates the influence of the other feeder cables and the transient interaction between them and the switched feeder, due to their high capacitances, leading to the increase of overvoltages to values over the insulation withstand. These overvoltages exhibit high frequency and high amplitude and are primarily transferred from the high voltage side to the medium voltage side mainly through transformer capacitive couplings. This process may lead to insulation breakdown in medium voltage equipment, as confirmed by simulations and practical observations. Solutions for overvoltage mitigation, such as surge arresters and pre-insertion resistors applied to switching circuit breakers, are presented.
Large industrial motors are commonly designed to provide over 20 years of reliable service. Oftentimes, the actual service life is significantly shorter than the design life. When this occurs, end users often associate the decreased life (i.e. the actual service life) as being caused by inferior manufacturing quality a deliberately shortened design life (i.e. motor cost reduced at the expense of designing for long life) without understanding all the aspects that impact the actual service life.This paper will explore the multiple facets that need to be addressed to optimize the actual service life. Environmental conditions, input power (e.g., power quality, operation on a drive, synchronous bus transfer, etc.) and maintenance practices will be discussed within the context of how they impact motor reliability and longevity. In addition, periodic offline testing as well as continuous trending of key performance indicators will be explained to understand how these things can be useful to determine proper maintenance and operating practices which result in maximized service life.
The rapid advancement and adoption of lithium-ion batteries in battery electric vehicles and battery energy storage systems has people considering replacing their existing lead-acid and nickel-cadmium stationary batteries with lithium-ion. The potential space and weight savings can be substantial however safety, reliability, and cost are major considerations. Lithium-ion batteries pose fire risks and increased building fire loads that lead-acid and nickel-cadmium batteries do not present. Additionally, lithium-ion batteries have reliability issues, not present in lead-acid and nickel-cadmium batteries, which must be addressed. Inserting lithium-ion batteries into traditional lead-acid and nickel-cadmium roles is not a simple battery swap. The additional costs and risks must be carefully evaluated when considering a swap from traditional technologies to lithium-ion batteries.
This paper provides insight into the impact on the facility electrical circuit distribution voltages resulting from the significant increase in power demand of large industrial facilities. Historically the high voltage circuits for industrial facilities were limited to the point of connection with the local utility; however, with the shift in power demand, it is now commonplace for these facilities to utilize high voltage power distribution within the plant boundary. This shift in power demand is primarily related to the need to accommodate an entirely electric driven production model. EPC firms are traditionally accustomed to distribution systems using cable with voltages up to 35kV in which the underground and above ground cable design allows additional flexibility for cable routing. This paper will highlight how underground and above ground designs using large high voltage cable require additional considerations for the planned cable routing, offsets, transition points, pull points, and installation methods. Furthermore, the paper will highlight the advantages of having a joint team of the engineer, the installer, and the cable manufacturer working together early in the project design stage is critical and how this early collaboration and planning can minimize changes in the design as the project moves into the execution phase. The paper will provide recommendations on the discussion points that need to be investigated at the onset of high voltage underground design for an in-plant power distribution system. Lastly, this paper will present a case study of a 138kV underground distribution within a large LNG facility and highlight the key considerations implemented during the design phase which resulted in improved constructability and ease of cable pulling/installation.
The 2021 Published Versions of IEEE Recommended Practice (RP) 1017.1, RP1017.2 and RP1017.3 (formerly RP1017, RP1018 and RP1019) contain the most significant modifications to the documents since their initial publication in 1984. Version 5 (the 2021 version) includes greatly expanded content and a complete revamp of the group of Recommended Practices. All three RPs were expanded to include 8 kV rated cable in addition to the 3 kV and 5 kV historic rated voltages. Additionally, cable sizes were expanded to include #3/0 AWG and #4/0 AWG. RP 1017.1 was expanded to include all testing: factory, acceptance, and field testing. Additionally, advanced test methods including very low frequency tan-delta (VLF tan-delta) and partial discharge (PD) were included, along with interpretation guidance. Testing for surface feedthroughs and downhole connectors was added. New tests for qualification of encapsulating materials for non-lead metallic barrier cables with encapsulating jacket were also added. RP 1017.2 and RP 1017.3 were modified to include non-lead metallic barrier cables (sometimes called "tubing encapsulated power cable" or "TEPC"). The insulating and jacket material specifications were expanded to include reinforced high modulus materials. Finally, the Neher-McGrath curves were updated to correct an error and to make them more readable and usable.
Using matrix converters for AC-to-AC power conversion provides economy on weight and size, high reliability and efficiency. For these reasons, the matrix converter technology is currently being adopted in underground mining applications (such as variable speed AC drives for underground vehicles). This paper treats harmonic issues around the matrix converter operation, such as transfer of the supply side distortions to the load and the injection of excessive current harmonics into the supply. The paper explores fundamental limitations to the harmonic performance and proposes a flexible control scheme that provides harmonic compensation at both the supply and the load sides of the matrix converter. Several strategies are formulated and tested. An optimized combination of the harmonic suppression at both sides is achieved. This makes matrix converter-based drives suitable for power systems with weak supply and voltage distortions. The presented ideas are validated by simulations.
Measurement and monitoring power quality is becoming increasingly important across industrial plants. There are various parameters that are used to quantify power quality and different methods for monitoring these parameters to ensure efficient and proper operation of equipment connected to the industrial distribution system. As industrial distribution networks are becoming increasingly complex, with loads from variable speed drives fed by pulse width modulation (PWM) inverters along with local generation from inverter based distributed energy resources (DERs), the need for power quality monitoring is essential to maintaining operational resilience. This paper analyzes some types of power quality disturbances, such as harmonics, flicker, etc. and how they affect industrial distribution systems. This paper also analyzes different techniques and methods used to measure power quality, such as CBEMA curves, EN 50160 reporting, waveform capture, and other web-based methods, and explains how each method focuses on specific areas of power quality. Power quality monitoring can be taken a step further with analytics and identification of specific circuits or devices which are the source of these disturbances to the distribution system. This allows for corrective actions to be taken effectively without hampering overall efficiency and functionality of the system. It is important to understand how the different monitoring methods provide varying levels of visibility into the system’s operation and efficiency, which will then allow preemptive action to be taken.
IEEE 1584 provides models and an analytical process to enable the calculation of the predicted incident thermal energy and the arc-flash boundary. The Guide provides typical dimensions and working distances for different types of electrical distribution equipment where arc-flash hazards exist. However, this typical data is generally focused on equipment manufactured to ANSI/NEMA standards. This paper will highlight the differences when applying the IEEE 1584 models and analytical processes to equipment manufactured to IEC standards.
Large power transformers are critical components of the electrical distribution network in complex energy projects, facilitating the seamless transmission of power across multiple voltage levels. The On-Load Tap Changer (OLTC) is an essential component within these transformers, responsible for regulating the voltage ratios and adapting to variations in load and supply conditions. Three-winding transformers with two secondary windings require regulation taking into consideration the loading on both windings which may be different. Other important parameters that users must consider include selection of impedance to achieve desired short circuit levels downstream, large motor starting, location of tap changer that may impact the size and arrangement of the transformer. This technical paper provides an in-depth review of the function and application of OLTCs, implementation on high voltage (HV) versus low voltage (LV) winding(s), space considerations and optimization strategies for large power transformers. Proper specification and application of the OLTC by users in large power transformers is key to reduce cost, minimize complexity of the design, and bring the best value for the project.
