How to Perform a Unified Protection and Transient Stability Study to Capture Interactions between System Dynamics and Protection System Accurately

When we look at the features and capabilities of ETAP, we have a Sequence of Operation Viewer. We have a Transient Stability Action Viewer. So, we unified these two. So, when you run transient stability with the protection, you're going to get a unified sequence of operations and TS actions.
Mr. Mohammad Zadeh, ETAP Chief Product Officer

This case study shows a solution for Unified Protection and Transient Stability Study available in the ETAP. Many protection functions, such as over/under frequency, out-of-step, and generator loss of excitation, are set based on power system dynamic characteristics. These protection functions were conventionally set with the assumption that system dynamics are predictable using simplistic and aggregated models. Higher penetration of distributed energy resources (DERs) has made power system dynamics considerably more complex to predict through conventional approaches. ETAP offers a new solution to perform unified protection and transient stability studies to capture interactions between system dynamics and the protection system accurately.

ETAP is a California-based company that provides power system analysis software. It is a software-agnostic vendor offering electrical design and engineering cloud platform solutions for infrastructure, buildings, and industry. ETAP was founded in 1986 and is headquartered in Irvine, California. Companies, government agencies, and educational institutions use ETAP software. The Electrical Transient Analyzer Program is an electrical network modeling and simulation software tool that accelerates digital transformation.

Location: Irvine, California, USA

Year: 2021

Unifying dynamic and protection studies for electrical systems

Challenges

  • Improving electrical analysis efficiency by allowing the analysis of electrical system protection and transient stability together in one sequenced process.
  • Researching dependencies between events in the grid network modeled in ETAP and making them understandable.
  • Finding a dependency between different types of electrical faults and a method for showing them. Electrical systems are now dynamic because of new energy sources, like renewable generators. Many protection functions, like Out-of-step protection or power swing blocking, loss-of-excitation, and frequency protection, depend on the system's dynamic characteristics.
  • Capturing inter-area oscillations between generators and measuring their impact on the system behavior and stability of the grid.
  • Ensuring that the protection system works correctly, despite the impact of dynamics. As we add more renewables to the system, there is a massive need for integrated stability and protection studies to ensure that the protection system works correctly during the system dynamics heavily influenced by the inverter-based resources.
  • Simulation and clear visualization of transient stability alongside protection relays' actions is crucial when analyzing grid faults with Distributed Energy Resources.

Co-Simulation of protection and transient stability together

Used applications

ETAP Digital Twin is the leading solution. T&D Protection & Coordination Analysis Software StarZ™ and Transient Stability Software offer a hybrid simulation of protection and transient stability to ensure the protection system works correctly during the system dynamics.

The Sequence of Operation Viewer and Transient Stability Action Viewer enable clear visualization of the processes. ETAP PlotView, Advanced Framework for Plotting & Live Charts, plots live study results directly on the one-line diagram for multiple devices.

Why do they use ETAP?

Main Customer Benefits

  • By unifying protection with transient stability actions, engineers evaluate all sorts of protection functions, including overcurrent, differential, distance, directional, reverse power, out-of-step, and loss-of-excitation. By running transient stability alongside the protection analysis, users get a unified sequence of all grid operations.
  • Solving the problem with the network blackouts faster and precisely. Proces can be checked event by event, second by second. Thanks to scenarios and process viewing over time, users can observe where and when the trip can be, and why a specific event took place. For example, researchers can see when the relay detects the loss-of-excitation, and why it trips. They can evaluate, set loss-of-excitation, and check how it performs.
  • Integrating data from transient stability, protection, and vendor-specific models makes the system more reliable and controlled. The number of faults has decreased.
  • When the user combines the two analyses alone, it doesn't help much with their studies. But if he sees this information together, and understands dependencies, he can find the solution faster. 
  • An easy-to-use plot manager shows the results of the StarZ analysis and the transient stability together. At the same plot manager, the user can plot the speed of the generator and also the performance of the protection relays, to see how they work together. The graphics, colors, names, and notifications are clear and easy to interpret.
  • Possibility to create and save lot of scenarios, to solve specific topics, according to the dynamic situation on the grid, like vendor equipment specific characteristic change.

What do they think about ETAP?

Opinions

It's much easier for ETAP to marry these two modules (TS and Protection). We have done it in ETAP by running transient stability at each step, as the main engine, the main solver, drives all the sequenced network values, voltages, and currents. And those voltages and currents are fed to the protection relay models. And then, if the protection relay determines that the circuit breaker needs to be tripped or something else, the switch needs to be changed, or the status changed, they're all transferred to a network, and the configuration gets dynamically updated.

Mr. Mohammad Zadeh, ETAP Chief Product Officer 

So, ETAP StarZ not only has a result annotation for protection, but also all the result annotations of the transient stability. It has all the powers and speeds that were only available in transient stability. We also had relay models like loss-of-excitation, and out-of-step.
Mr. Mohammad Zadeh, ETAP Chief Product Officer 



Videos

Integrated Stability & Protection Sequence of Operation

Many protection functions such as over/under frequency, out-of-step, generator loss of excitation are set based on power system dynamic characteristics. These protection functions were conventionally set with the assumption that, system dynamics are predictable using simplistic and aggregated models. Higher penetration of distributed energy resources (DERs) has made power system dynamics considerably more complex to predict through conventional approaches. ETAP offers a new solution to perform unified protection and transient stability study to accurately capture interactions between system dynamics and protection system. This solution allows protection engineers and network planners to 1- tune protection settings to act properly during system dynamics, 2- design and test remedial protection schemes, 3- evaluate all protection functions such as out-of-step, overcurrent and generator loss of excitation protection function and 4- perform grid code studies that require evaluating DER performance along with its protection system.


Solutions


Packages/Products