Carl Turner, PE

Modern synchronous machines are applied with the widest array of protective functions of any type of equipment on the power system. This course will provide a tour of the unique characteristics of synchronous machines that drive the commonly applied protection schemes. Philosophies will be presented and tied back to base machine design characteristics.  Common pitfalls and application issues will be covered for several of the key protective functions, including example calculations based on actual operating machines where possible. Examples will include calculations for compliance with NERC reliability standards applicable to Bulk Electric System generators.

Biography:

Carl attended the University of Toledo in Ohio, where he obtained his Bachelor of Science in Electrical Engineering with a focus on power systems and power electronics courses of study in 2003. He started his career at Davis-Besse Nuclear Power Station in the Design-Basis Engineering Unit, where he spent 3 years, following through from a co-op to full engineering position. He moved on to working for R.W. Beck and Associates in Boston, MA, and spent 10 years working for R.W. Beck / SAIC, Inc / Leidos working on a variety of power system engineering topics and project management roles. Engineering fields included transmission planning, power system stability, generator, transmission, substation, and distribution protection, and substation design and construction.  Carl provided generator protection analysis to a wide variety of clients and types of plants, including island power systems and large data centers, as well as traditional combined cycle power plants. While at R.W. Beck, Carl got involved with IEEE PSRC, largely reviewing papers. After moving to Florida, Carl moved to the Utility side of the power business as Engineering Services Director at Florida Municipal Power Agency, where he spent 9 years building an engineering and transmission planning team. At FMPA Mr. Turner spent 6 years on the NERC Planning Committee / Reliability and Security Technical Committee and 9 years on the FRCC Planning Committee, and developed FMPA’s engineering processes and procedures.  He also developed training materials for his staff on a variety of topics, and functioned as FMPA’s protection system lead on generator protection matters, including troubleshooting any generator relay operations or power system events at FMPA’s power plants.  Carl completed his MBA with a finance focus from Ohio University in 2021. 

Sebastien Billaut, PE

Part I – What’s the Rush?

The increasing penetration of Inverter Based Resources (IBRs) in the grid requires us to reconsider many previous firmly held assumptions that, if left unchallenged could result in problems such as misoperation, equipment damage, and unnecessary re-work, etc. One assumption is the response of transformers to energization events. It is generally understood that transformers energized with a rotating machine-dominated grid will experience between 8 and 12 times their steady state current values in magnetizing current and, for a short period, will have a high percentage of second and fourth harmonics.

Here, we will analyze inrush for transformers in grids dominated by IBRs and in microgrids to determine their response to the energization and to evaluate current industry best practice protection schemes. Modeling is accomplished with actual inverter models from different inverter manufacturers that are currently in service on the grid and with electromagnetic transient simulation software for utmost accuracy. We will also vary the transformer magnetic design characteristics to estimate the impact of transformer design on the results.

The configuration of system source strength about the transformer size will be varied to determine if the strength-to-transformer size ratio impacts the results. This consideration could help system planner improve their interconnection requirement consideration.

In the United States, the electric grid has been built with the goal of maintaining effective grounding. With the rise of microgrids, it is possible that effective grounding could be lost when the microgrid is disconnected from the larger utility grid. This is especially true when considering the case of microgrids that depend on inverter-based resources (IBRs) as their main source of power generation when operating in local microgrid mode. In some instances, the zero-sequence sources, also called the ground sources, are found exclusively in the transmission system or at the distribution substation and not on the microgrid’s distribution line, causing a loss of this “source” when the microgrid is separated from the larger utility grid.

Part II – Let’s keep our feet on the ground!

This presentation addresses how system grounding is achieved and how to measure the effectiveness of the grounding. High penetration of inverters or islanded microgrids may lose effective grounding due to the nature of the converters.

The presentation provides a sequence of components and asymmetrical fault current introduction (or refresher). We will look at the different transformer configuration that promotes grounding.

The effectiveness of the microgrid system grounding depends on the criteria, measured as the coefficient of grounding. This coefficient has consequences on insulation coordination, fault protection, and isolation detection.

Biography:

Sebastien Billaut, PE is Associate Director at Commonwealth Associates. Mr. Billaut holds an MS in Mechanical and Electrical Engineering from ESTP in France. He has 30 years of utility-related engineering experience, setting protection relays, and power system modeling. He is the patent author for a microgrid fault management technology and coauthor of a patent on battery life extension. He actively participates in industry-wide standards about microgrid, distribution and transmission protection systems. He serves as Chair of the IEEE PSRC Working Group K29 and D44 and is a member of IEEE PSRC Main and Subcommittees D and C. He is currently contributing to IEEE 1547.x and IEEE 2800.x.