Technical Presentations

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

EMTP® studies for IBR integration at Hydro-Quebec777

Abstract
Abstract:

Hydro-Quebec has been involved in EMTP® development since the 80s and has collaborated with several organizations worldwide through the Development Coordination Group of EMTP (DC... see moreG-EMTP). Hydro-Quebec was the key player in the EMTP recoding project that allowed the delivery of the latest generation of the software in 2003. The new EMTP was developed at IREQ (Hydro-Quebec’s research center) from 1998 to 2003.

Hydro-Quebec was the first organization to simulate its complete transmission grid in EMTP. Hydro-Quebec was also the first system operator to require that manufacturers of wind turbines provide detailed EMT-type (EMTP®) models for wind park integration studies. This webinar will present:
• How EMTP simulations are integrated into Hydro-Quebec’s work process?
• How EMTP simulations can complete RMS simulations?
• Future simulation challenges

Speakers:
• Karine Gauthier, ing.
• Pascal Prud’homme, ing.
• Saad Omar, ing.

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.