Technical Presentations

Optimization of Control Parameters of Grid-Connected PV System in EMTP845

Abstract
It is observed that the controller gain parameters of the PV model have a significant impact on the PV plant’s response during the fault recovery and the PV plant’s interaction with the rest of th... see moree system in general. Manual tuning of the PV park parameter considering multiple fault and contingency scenarios is a time-consuming task and might even be impossible. Optimization techniques such as particle swarm optimization (PSO) can be used to optimize the gain parameters considering fault/ contingency scenarios. The presentation will talk about the implementation of PSO in EMTP using javascript to optimize PV park controller gain parameters.

Tag(s): pv plant, ibr, pso, optimization, scripting, pll, inverter control, inverter based resources, DER

Ground Fault Overvoltage with Inverter-Based Distributed Energy Resources841

Abstract
A Ground Fault Overvoltage (GFO) can occur in situations where an ungrounded transmission line and associated ungrounded transmission equipment is energized from distribution connected Distributed En... see moreergy Resource (DER) during a transmission single-phase-to-ground (SLG) fault. The condition could result in 1.73 pu overvoltage on phase to ground connected equipment which will be sustained until the DER ceases to energize the substation distribution transformer. Transmission equipment on the isolated circuit will be subjected to the above phase to ground overvoltage, also if there is frequency shift, the isolating transmission circuit breakers could potentially see up to 2.73 pu phase to ground overvoltage. Such an overvoltage can cause damage to customer or utility equipment and must be avoided. GFO concerns are already becoming a barrier to large-scale DER deployment either by posing low hosting capacity or by necessitating installation of costly mitigation equipment. Utilities need to study GFO risks and identify low-cost mitigation options to enable large-scale DER deployment. Given the fundamental differences in mechanisms and phenomena driving a GFO under DERs, classical GFO analysis methods do not apply to inverters, and advanced simulation methods and tools are required.


This presentation highlights EPRI’s work on GFO analysis, concerns, and evaluation of mitigation options using EMTP. The objective is to determine if or when high DER penetration presents a GFO problem and how to prioritize the mitigation and equipment evaluation. This includes evaluating the impact lightning arresters can have in reducing or clamping the overvoltage, the application and performance of high voltage substation overvoltage protection, and DER on-board voltage/frequency protection. The presentation further provides modeling recommendations for such a study using EMTP. As DER deployment increases, utilities will need to perform similar analysis to identify potential overvoltage risks and develop low-cost mitigation methods. This work provides a basis for such a study.

Tag(s): gfov, tov, ibr, DER, inverter, islanding, load rejection, inverter based resources

Performance of conventional sources vs Inverter based source during power system faults771

Abstract
This presentation will contract the performance of conventional power source to those of inverter based resources (IBR) and how this impacts the performance of traditional protection devices.

Impact of Renewables on System Protection768

Abstract
The presentation will describe how EMTP with its wind turbine model library, as well as its relay model library are being used at EPRI research projects to perform case studies for EPRI member utiliti... see morees.

The integration of inverter based resources (IBRs) into power systems introduces several technical challenges. One major challenge is the impact on system protection, resulting from the complex fault response characteristics of IBRs which are interfaced with the grid through power electronics and do not behave similar to conventional synchronous generators. EPRI is investigating the performance of legacy protection schemes in systems with high levels of IBRs, and potential misoperations which will compromise the grid reliability.