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): Neeraj Patel
Type:Technical Presentation
Date: 2021-09-07

Reactive Power Energy Management, Analysis of Reactive Power Consumption in Solar Power Plant847

Abstract
For any Power Plant, it is aimed to have maximum Energy Generation and yielding for the Power Output. Solar power plant comprises PV cells, framing array by connecting with each solar panel and then c... see moreonnected with step-up transformer (Inductive element) by cable network (capacitance formed). The energy generated by PV cells are being converted by Solar inverters (Power electronics) and operated at almost Unity Power Factor.
It has been observed that with export of Active energy and increasing output, there is also import of Reactive energy varying with solar generation. The Tariff charges are involved and applicable for Reactive Power Consumption in said solar power plant. Active energy also imported during evening and night hours in absence of solar generation to run critical equipments and trend between active and reactive energy has been observed vice versa.
As per the State Tariff regulations, beneficiary must pay/gets paid for reactive power drawl/supply which is decided and bounded by the system voltage limit (e.g. 97% to 103% of Rated system voltage).

Considering varying MVAR absorption phenomena associated with active power generation and effect of supply voltage, it has been decided to study and model solar generation in EMTP. Different cases have been simulated in EMTP software. Major sources consume Reactive Power identified from modelling and matched observation with actual recorded data. Mitigation technique for reactive power compensation has been studied and modelled. Rating for reactive power compensation source has been validated. Switching phenomena associated with reactive power compensation technique along with voltage profile at different points has also been studied and appropriate rating for switching devices/switchgear has been suggested.
Detail study and simulation results will be shared during presentation.

Tag(s): reactive power, compensation, pv park, inverter

Author(s): Philipp Hackl
Type:Technical Presentation
Date: 2021-09-07

Switching of Inductive Currents and Dimensioning of RC-Snubbers with PAMSUITE846

Abstract
In order to control the voltage in distribution and transmission networks shunt reactors can be used for compensation of reactive power. Due to the switching of their inductive currents, unacceptable ... see moreswitching transient voltages might occur which can lead to damage of equipment. Furthermore, the breaker must be able to withstand the transient recovery voltage (TRV), amplitude and rate of rise (RRRV) respectively. One possibility to mitigate these switching transients are so-called RC Snubbers. They have to be dimensioned according to the topology and the values of R and C can be optimized with the PAMSUITE tool. In this presentation the modelling and the results of the TRV due to shunt reactor switching is discussed and the mitigation with RC Snubbers with the help of PAMSUITE is shown.

Tag(s): TRV, PAMSUITE, snubber, switching

Author(s): Carlo Alberto Nucci & Fabio Tossani
Type:Technical Presentation
Date: 2021-09-07

Response of Overhead Lines to Direct Lightning Strikes: Assessment of the LEMP Effects852

Abstract
In the usual practice, the evaluation of the overvoltages due to direct lightning strikes to overhead power line conductors is focused on the representation of the effects of the lightning current inj... see moreection, whilst the effects of the coupling between the conductors and the lightning electromagnetic pulse (LEMP) is disregarded. Motivated by recent results obtained for the case of a medium voltage line configuration with a shield wire, this extends the analysis to assess the contribution of the LEMP on the lightning performance of an overhead distribution with and without periodically grounded wires and surge arresters. Moreover, the presentation deals with the LEMP effect on the occurrence probability of flashovers on different phases, which is an important information on the service continuity of networks with isolated or compensated neutral earthing. A validation of the results is obtained by comparing the overvoltages calculated by using EMTP, together with the LIOV library for the LEMP calculation, and those obtained by a three-dimensional finite difference time-domain approach.

Tag(s): lightning, pulse, LIOV, surge, arrester

Author(s): Rohit Kunte
Type:Technical Presentation
Date: 2021-09-06

Induced Voltage Study843

Abstract
MidAmerican Energy has conducted studies at some locations on our system to identify voltages that are induced due to lines on the same structures. For example, MidAmerican added a new 161 kV line fro... see morem substation D to substation E (not shown) through substation C. The line is mostly single circuit except between substations B and C where a second 161 kV line was added on the structures. There is also an existing 13.2 kV underbuilt distribution circuit on the structures between substations A to C.

The induced voltage study was performed to get an understanding on the level of voltages that may be expected when the 161 kV line from substation A to substation C is out of service, but the 161 kV line from substation D to substation C is in service and vice versa. The analysis provided very useful information on the level of induced voltages that may be expected on the 13 kV distribution feeder and helped MidAmerican to develop mitigation measures.

Tag(s): line, induced voltage, EMI