Learn how TVA uses Python and ETAP for degraded voltage analysis and motor starting in nuclear plants

Any typical evaluation could generate well over 18000 pages per the criteria you're considering. Sorting through this data by hand is very time consuming. Thankfully, ETAP does have integrated Python support. Using less than a hundred lines of code, the evaluation was completely automated. It can be run whenever necessary to re-perform the calculation.
Preston Cooper, Technical Chair, ETAP Nuclear Utility User's Group

Recognizing that traditional approaches evaluate the electrical power systems in nuclear plants were lacking in efficiency, TVA used a new approach to simulation of degraded voltage relays (DVRS) in order to more efficiently evaluate protection compliance with federal design criteria capacity and capability requirements. By combining study cases, their revisions, and the configurations into repeatable studies, TVA was able to generate and evaluate their analysis results much more rapidly. The demonstration includes the use of an efficient solution using Python code with ETAP to run the studies and evaluate the resultant data.

The Tennessee Valley Authority (TVA) is a federally-owned electric utility corporation in the United States, providing low-cost electricity in seven Southeastern states as well as flood control, navigation, and land management for the Tennessee River system. With a generating capacity of approximately 35 gigawatts (GW), TVA has the sixth-highest generation capacity among utility companies in the United States and the third-largest nuclear power fleet, comprising seven units at three sites. In addition, they operate four coal-fired power plants, 29 hydroelectric dams, nine simple-cycle natural gas combustion turbine plants, nine combined-cycle gas plants, a pumped-storage hydroelectric plant, a wind energy site, and 14 solar energy sites.

Location: Knoxville, Tennessee, USA

Year: 2024

Faster motor starting voltage analysis with improved accuracy for large datasets

Areas for improvement

  • Reduce or eliminate manual or semi-manual methods for analyzing a degraded voltage relay (DVR) condition.
  • Identify robust tools and methods to produce electrical calculations quickly in full compliance with nuclear industry safety standards such as IEEE 741, within the full scope of voltage drops.
  • Develop specific analysis scenarios which reflect realistic motor-starting conditions.
  • Deliver understandable and condensed reporting to facilitate decision-making, suitable for electrical and non-electrical audiences.

Products used

This case study used the following ETAP solutions:

etapPy™ - ETAP's Python API and Integrated Development Environment (IDE) integrates Python scripts with ETAP power system analysis software to provide automation and extend reporting and plotting capabilities

ETAP Power Simulator Motor Starting Module - Comprehensive libraries and detailed modeling of induction and synchronous motors for dynamic motor starting simulation and motor acceleration

What we delivered

  • Significant time and cost savings to complete the DVR analysis report and make scenario adjustments according to the actual grid model
  • High-quality analysis reporting including the optimal amount of information to help avoid errors and oversights
  • Ease of use in integration of ETAP Python API and ETAP scenario wizards to build calculations
  • Automation efficiency to run the Python script with ETAP as needed on new datasets

Outcomes

  • Time savings from appx 50 hours to less than 1 hour when using Python for scenario calculations and review 
  • Output reporting from 18,000 or more pages to less than 12 pages when using Python for scenario calculations and review
  • Flexible customization allows switching from full automation to manual review of data for hands-on time in the model
  • Simplified approach to automation is easy to use with built-in samples, using less than 100 lines of code using the ETAP Python scripting API, integrated with ETAP power system analysis

ETAP provides an easy way to combine the study cases, revisions, and configurations into repeatable studies. These scenario wizards can be set up to combine all of the variables as necessary for each of these required computations.

Preston Cooper, Technical Chair, ETAP Nuclear Utility User's Group



Videos

Learn How TVA Uses Python & ETAP for Degraded Voltage Analysis and Motor Starting in Nuclear Plants

Learn how TVA uses Python and ETAP for degraded voltage analysis & motor starting in nuclear plants

Nuclear plants in the United States are governed by federal regulations requiring that the electrical power system provide sufficient capacity and capability to the nuclear plant. As part of this analysis, traditional approaches to manually perform single motor start calculations can be tedious and time-consuming. Also, the manual evaluation of the data can easily introduce errors. This presentation takes a closer look at degraded voltage relays (DVRS) and an approach to simulation used by the TVA that is holistic, using ETAP to easily combine the study cases, the revisions, and the configurations into repeatable studies. The demonstration includes the use of an efficient solution using Python code with ETAP to run the studies and evaluate the resultant data.


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