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): Frédéric Colas
Type:Technical Presentation
Date: 2021-09-05

From FEMM to EMTP Cable Data – How to Use FEMM to Compute the Power Cable Parameters839

Abstract
In the context of the simulation of an electrical network, different models of lines / cables are available. Among these, we can cite the PI models, the frequency dependent models (FD-Line) or the mod... see moreels called Wideband. This last type of modeling is considered in the power system community as a sufficiently precise model to simulate the behavior of the cable under non-symmetrical faults and more particularly in the case of underground or submarine cables. However, the parameters of this type of model are generally still calculated from a standard geometry.

In this presentation, a methodology to obtain, from the software FEMM, the cable data parameters needed for EMTP will be presented. This methodology allows to easily obtain the correct parameters from specific cable geometry.

Tag(s): fem, cable, parameters

Author(s): Theofilos Papadopoulos
Type:Technical Presentation
Date: 2021-09-03

Simulation of Inductive EM Interference Caused by an HVDC Underground Cable Link on a Railway System853

Abstract
Scope of the presentation is to present results regarding inductive electromagnetic interference (EMI) between a real HVDC link and the nearby communication cables of a railway system under pole-to-gr... see moreound fault conditions.
?he HVDC and the railway system route in parallel at a part of the onshore section of the HVDC link. The inductive EMI on the communication cable arises from magnetic field variation of the high-frequency components contained in the transient response of the fault current, excited by the HVDC link.

Consequently, it is expected that no inductive EMI will occur by the DC current in the case of the HVDC system normal operation (steady-state) either in bipolar or monopolar (current return though the electrode) mode. The induced transient voltages and currents are calculated using the Electromagnetic Transients Program (EMTP-RV).

Tag(s): emi, wb cable, hvdc, interference

Author(s): Andreia Leiria
Type:Technical Presentation
Date: 2021-09-02

Real Case of a Resonance in a Power Plant851

Abstract
Overvoltages were identified on the MV and LV networks of a Hydro Power Plant as the cause of the trip of the LV maximum voltage protection, compromising the normal operation of the system. Following ... see morethis event, measurements were conducted and the presence of a very high 23rd harmonic, potentially responsible for the various overvoltages, was identified associated to the operation of the Plant’s Synchronous Machine Frequency Control System (FCS). It was concluded then that this harmonic would have its origin in the FCS and would be amplified due to a possible resonance in the Power Plant internal network. A digital simulation study, using EMTP-RV, was conducted to identify and characterize the resonance in the system and to propose mitigation solutions. The simulation models were developed using the equipment data and the system characteristics. The models were duly validated with measurements made both in time and frequency domains and it was possible to identify the origin of the overvoltages and their propagation in the system. It was concluded that the resonance occurred between a 30/11 kV Power Transformer and a 30 kV cable with 850 m.

This conclusion was supported by the results obtained in the measurements. Several alternatives were analyzed as mitigation solutions: - Installation of capacitors; - Different bonding techniques of the 30 kV cable sheaths; - Changing the 30 kV cable length; - Installation of a harmonic filter; The advantages and disadvantages of each solution were weighed also considering the ease of implementation, namely the available room. It was concluded that the installation of capacitors would be the best option. Measurements were conducted after the capacitor’s installation confirming the success of this solution.

Tag(s): harmonics, power uality, resonance