Author(s): Husam Samkari & Rafael Castillo Sierra
Type:On-demand webinars
Date: 2022-02-17

Slideshow of the projects from our grand prize winners857

Abstract
During this webinar, our two winners of the EMTP® Research Contribution Prize Program 2021 will present their work. The aim of the award is to recognize student contributions to the technology associ... see moreated with power system transients. The two competition categories are:
- Best accepted IEEE, IET, PSCC, EPSR or IPST journal or conference paper on EMT simulations;
- Best EMTP® model developed.

Discover our winner and the topics of their presentation:

o Husam Samkari, Ph.D. and P.E. in Electrical Engineering
Impact of Distributed Inverter-Based Resources on Incremental Quantities-Based Protection

Abstract:
This paper studies the impact of distributed inverter-based resources (IBR) on time-domain incremental quantities-based relays. One implementation of the incremental quantities for protection is a high-speed sub-cycle directional element. The incremental, also known as superimposed, quantities are fault-generated instantaneous components of voltages and currents. The directional element indicates fault direction based on the transient voltages and currents’ relative polarities. It is essential to ensure that the element does not fail to indicate the correct direction if IBRs fault current responses impact the quantities. IBRs’ fast control response impacts the current quantities by changing both magnitude and angle.

This paper characterizes the incremental quantities-based relay response to IBRs’ nonlinear fault currents. A modified IEEE 34-bus distribution with an IBR system is modeled and simulated using the electromagnetic transients program (EMTP-RV) for demonstration.

o Rafael Castillo Sierra, Electrical Engineer, Ph.D. Student
Model category for his model on Power System with a Transmission Line operating at low frequency

Abstract:
The transmission of electric power with alternating current (AC) faces constraints that are inherent both to the stable operation of the power system and to the physical properties of the transmission lines or cables. Many factors stand to motivate the alleviation of these constraints without a need to construct new transmission lines or cables. One demonstrated method to accomplish this is to lower the electrical frequency of a transmission branch or section of the network, an approach known as low frequency AC (LFAC) transmission. The resulting lower reactance of the lines improves the transmission under the stability concerns which arise with long, inductive overhead lines, as well as under thermal concerns that can be substantial due to charging currents in underground cables. In this order of ideas, the Modular Multilevel Matrix Converter (MMMC) offers the necessary frequency conversion for low-frequency transmission, while allowing controllability of power through the transmission line.

For this reason, this presentation focuses on the EMTP modeling and simulation of this converter starting from a design that meets the typical voltage and power requirements for a transmission line. The averaged model of the converter has been implemented to evaluate its performance as a frequency converter and how it interacts with the power system. Simulations have been carried out under nominal operating conditions in a study case power system.

Tag(s): EMTP, Prize winners, IBR, Protection, Power system, Transmission Line, Low frequency,

Author(s): Stefano Vitali
Type:Technical Presentation
Date: 2021-09-06

Analysis and Calculations in Medium Voltage Electrical Systems833

Abstract
The electrical installation of an industrial site is a complex structure. Analyzing behavior in a transient condition allows optimum selection of the operation and protection devices in the installati... see moreon design phase; in addition, possible weaknesses and critical points can be highlighted in advance, allowing prevention of potential problems, damage to machinery, and costly periods of down time.

In order to completely satisfy the needs and expectations of the customer, in ABB Electrification Business an important role is played by analyses and consulting services offered by Field Application Support (FAS) specialist.

In this session of the "EMTP User conference", representatives from the Italian ABB Distribution Solution division, based in Dalmine (BG), will show how EMTP tool supports the analyses performed within the "Medium Voltage Circuit Breaker Suitability" reports that are provided to customers looking for switching devices for special applications. In particular, the today presentation will focus on "CB suitability" study approach for the Generator Circuit Breaker and the Filter Harmonics switching applications

Tag(s): TRV, generator breaker, filter, switching

Author(s): Pr. Bozidar Filipovic
Type:Technical Presentation
Date: 2021-09-03

Impact of Power Transformer Energization on Relay Protection Operation844

Abstract
One of the main causes of the incorrect operation of transformer relay protection are inrush currents. The transient inrush current occurs when energizing the unloaded transformer, and it is a consequ... see moreence of the transformer core saturation. This paper presents analysis of transients caused by energization of 300 MVA three-phase autotransformer with stabilizing winding and voltage ratios 400/115/10,47 kV.

Using the PAMSUITE Toolbox in EMTP, many simulations were performed to show the impact of model’s parameters on the amplitude and duration of inrush currents as well as the probability of 2nd harmonic differential current amplitude occurrence. Simulation results show that controlled switching reduces inrush currents amplitudes and increases 2nd harmonic content in differential currents. A Protection Toolbox in EMTP was used for modelling CT saturation and operation of transformer’s differential protection relay.

Based on the simulation results the optimal differential protection settings were determined, and the probability of false relay protection operation was calculated.

Tag(s): transformer, energization, inrush, differential, protection, harmonics, bctran, pamsuite

Author(s): Mr. Suyash Kulkarni - Mr. Suved - M. Pakade
Type:Technical Presentation
Date: 2021-09-03

Ground Fault Detection and Feeder Protection of 2x25kV Railway Traction System840

Abstract
In a new 2X25 kV System, Scott transformer is used as a traction transformer and to supply the power to the railway traction system. It is protected using the percentage differential relay.

... see more
However, region from the low voltage side of the Scott transformer to the first autotransformer is unprotected at the field and to protect the system during fault on this region is very important. Thus, development of protection scheme is required. Herein, we modeled 2X25kV traction system in EMTP, simulate faults and developed a specific relationship to provide the protection for this scheme. We have taken the current input from feeder current transformers and observed its current during the faults.


This performance of this scheme is verified using EMTP. Further, impedance to distance ratio is non-linear due to the autotransformer between catenary, rail and feeders in 2x25kV railway traction system. To observe this behavior as per field details and provide the accurate relay setting, we simulate the faults over the length of protected line in EMTP and field test are carried out. In the event of a fault on unprotected region and on the protected line, trip occurs and relay recorded fault details at the field.

Tag(s): Fault Detection, protection, railway, traction

Author(s): Aboutaleb Haddadi
Type:Technical Presentation
Date: 2021-09-02

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