Arc Flash Studies for Wind Plants

Dec 4, 2012 | Blog

Arc Flash is the result of a rapid release of energy due to an arcing fault between multiple phases, a single phase and ground, and multiple phases and ground. An arc fault is often caused by 1) Human mistake (e.g., dropping a tool, accidental contact with live part), 2) Environment (e.g., water vapor), 3) Equipment failure (e.g., insufficient insulation, deteriorated insulation, corrosion), 4) Overvoltage conditions, and 5) A combination of the any of these. The energy released in the form of pressure is of concern for worker safety since the pressure wave can directly injure the worker or can destroy objects resulting in shrapnel that can injure the worker. In the context of an arc fault hazard analysis, the burn hazard during an arc fault is the main concern for worker safety.  The incident energy (specified in cal/cm2) is the energy that is impressed on a surface located at some distance from a source and is used as a measure to quantify the burn hazard from arc flash.

Modern wind turbines generate power at various output voltage levels (generally range from 480V to 1000V). This voltage is further stepped up to an industry standard collector system voltage of 34.5 kV (typical in North America). The collector system is a network of underground cables and comprises multiple stings of turbines called feeders. All these feeder strings terminate at main 34.5 kV bus at the substation yard where voltage is further stepped up to the local utility’s transmission voltage level. Wind plants are potentially exposed to variety of arc flashes and shock hazards and can cause serious injuries to workers. The main safety concern is inside wind turbines due to the limited area in the base of the tower and nacelle, as well as when operating pad mount transformers. The Occupational Safety & Health Administration (OSHA) requires all the wind plants to implement the safe working practices and training requirements.  Therefore wind plants are required to comply with National Fire Protection Association (NFPA) 70E standard.

EnerNex’s qualified power system consulting (PSC) group has performed many arc flash studies for wind plants that include analysis at main substation equipments, collection system equipments, and equipments inside the turbine tower.  For the arc flash hazard assessment, EnerNex uses the IEEE 1584 empirical model for voltages below 15 kV, which is widely accepted and for voltages above 15 kV, ArcPro model, which is a model that is compliant with NFPA 70E. The ArcPro model gives reasonable incident energy levels for high voltage levels.  EnerNex has developed its own arc flash program in Matlab for incident energy calculations. The program offers many special features such as calculations of arc flash parameters using conventional arc flash models, plotting of output results as well as export feature files as a figure or data files. This program has been successfully tested against some industry standard software’s such as Computer Aided Protection Engineer (CAPE) and EDSA.

In summary EnerNex’s arc flash hazard analysis services include:

  • Short circuit analysis
  • Arc flash hazard calculations using IEEE 1584 and ArcPro models
  • Recommendations on appropriate personal protective equipment (PPE)
  • Recommendation on safe flash protection boundary
  • Recommendation on safe working distances
  • Mitigation techniques for reducing arc flash hazards
  • Arc flash labels printing
Smart Metering (SM) and Advanced Metering Infrastructure (AMI)

Smart Metering and AMI is a transformational process addressing multiple business and technical needs of the utility enterprise. This is more than just smart meters and communications networks; it includes all of the back end applications that can leverage the meter assets, such as outage notification, demand response, call center optimization, disputed billing process handling, pre-payment opportunities, and service connection management methods and procedures, to name a few.

Implementing SM and AMI faces the same business, engineering, and operational challenges as any other across-the-utility information technology endeavors – most notably risk associated with embracing proprietary technology, missing functionality and early obsolescence. Effective SM and AMI development, implementation, and operation relies on a marriage of electric power engineering with information technology expertise: a key component of EnerNex’s expertise and experience.

EnerNex provides an array of engineering and consulting services geared towards intelligent and effective implementation of SM and AMI. This covers all phases of project development, starting with capturing system requirements where our experts leverage a “Use Case” centric view of activities needed to be accomplished and their interaction with systems and other users. Subsequent project steps typically examine other critical areas, such as: modeling of business cases, building inter-department consensus, assembling and assessing system functional requirements and non-functional requirements, developing a system design, hardware and software specifications and standards, complete procurement services including RFI and RFQ process support, supplier rating system, response evaluation methodology, deployment management, and training of office and field personnel.

Demand Response (DR)

Demand response can be as simple as load interruption directed by the energy supplier in response to severe demand requirements, to complex customer defined load management in response to price signals. DR is one of the components of a “Non-Wires Alternative” that many utilities are effectively using to avoid expensive distribution fortification or upgrade.

 

Often the success and/or failure of demand response programs can be linked to program implementation challenges such as rate/tariff design rate structures communication (e.g. price signals) or ineffective incentives used by utilities to encourage customers to accept operational change. The issues of program design, rate structure and customer impact have a tremendous influence on the success or failure of load management initiatives. Demand response has traditionally been used as a tool of the energy industry to ensure system stability. However, the introduction of microelectronics, communications, home automation and the Internet of Things (IoT) has led to the development of cost effective solutions that have the capability to allow the consumer to take control of managing their energy load and ultimately, the price they pay for energy.

EnerNex has the experience and skills to turn your DR program into a successful operational asset and customer engagement process that can deliver value to all parties.

Energy Assurance Planning

Natural and man-made disasters cause an estimated $57B in average annual costs for all parties; large single events have resulted in losses of $100B or more. Events, such as the World Trade Center disaster, Hurricane Katrina, and most recently Hurricane Helene, have demonstrated an acute need to revisit, revise and implement an effective energy assurance plan. Energy assurance plans assess the functionality and interdependencies of buildings and infrastructure systems and the role they play in sustaining service and rapidly restoring critical services to a community following a hazard event.

 

EnerNex assists our clients in developing comprehensive energy assurance plans that mitigate and minimize the impact of energy disruptions. Our experts assess critical infrastructure risks and evaluate appropriate mitigation strategies and can help in developing an effective business continuity/disaster recovery (BC/DR) plan for utilities and your customers.

Microgrid Development

As the electric grid becomes more distributed and interactive, microgrids are playing an increasingly important role in our energy future. Decision makers at military bases, corporate and institutional campuses, residential communities and critical facilities across the world are exploring and implementing microgrids to meet economic, resiliency and environmental goals. Utility-grade microgrids are being deployed to meet transmission constraints, reliability requirements and safe-havens in the event of a significant storm event.

Microgrid_development Graphic steps to support grid modernization

Bringing together a portfolio of distributed energy resources into a controllable, islandable microgrid comes with its own set of challenges. The key to solving these challenges is in architecting a system to support information exchanges between components across well-defined points of interoperability (interfaces) in a technology independent manner. This interoperability ensures that the system is resilient to technology change. Modern systems engineering techniques must be employed to ensure that individual sub‐systems are clearly identified, their functions enumerated, their data requirements known, and the points of interoperability clearly specified, along with the commensurate monitoring, command and control that is needed to ensure grid stability. With such architecture, we can apply best of breed technology available today to support those information exchanges at interface boundaries but be free to upgrade / change the implementation technology later without causing a ripple effect throughout the system.

Enterprise Architecture

Enterprise Architecture focuses on aligning an organization’s business strategies with its anticipated, desired and planned technology enhancements. Enterprise Architecture provides a framework to cost-effectively transition from a current “as-is” technology to future enterprise-wide technological solutions. An effective Enterprise Architecture program aligns business investments with long-term business strategies while minimizing risk and providing superior technological solutions. EnerNex’s key asset is its highly skilled and experienced staff who are closely connected to both the smart grid and EA standards and practices. We provide clients with the insight necessary to operate a fully functioning smart grid, which is flexible, scalable, and vendor independent.

Grid Modernization Roadmap

Utility companies across the globe are continually modernizing their grid. Each company often has different rationales, objectives and priorities. Frequently, smart grid plans are developed for individual, incremental initiatives, rather than as a part of a whole, intelligent and interoperable infrastructure. Planning may be developed around technology choices rather than business and technical requirements. The result of incremental and flawed planning leads to increased cost and risk, lost opportunities, disconnected expectations and dead ends.

 

EnerNex’s approach to grid modernization roadmap development follows a proven, industry-standard approach to grid modernization planning by collaboratively working with the utility to develop a set of prioritized and time-phased grid modernization initiatives unique to its business strategy and objectives. The roadmap developed is holistic, requirements-based, business value driven and actionable. It often builds on and leverages existing applications and infrastructure, and incorporates industry standards to ensure interoperability, flexibility and reduced cost and risk.

Utility Communications

Utility communication and control systems are increasingly interconnected to each other and to public networks and as a result, they are becoming increasingly more susceptible to disruptions and cyber attacks. EnerNex has experience with the various issues relating to development, implementation and optimization including feasibility analysis, design, software development and customization, project management and acceptance. Our expertise extends from being involved in the development of the fundamental standards that support utility communication and automation, through deployment and securing of those resources. EnerNex personnel were heavily involved in development of such standards and protocols as IEC 61850, IEC 60870-5 and DNp3. Our staff played a key role in the EPRI Utility Communication Architecture (UCA) project and the IntelliGrid Architecture effort.

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