• Virtual User Conference 2020

2020 EMTP® User Conference

About the conference

The 2020 EMTP User Conference is going VIRTUAL. The event will be accessible WORLDWIDE.

The conference takes place between September 21st and October 2nd, 2020 with three to four presentations a day.

Three themes are covered during the conference:

  • Inverter-based resources
  • Stability and Protection
  • Switching and insulation coordination
This event brings together power system experts, software users, EMTP developers, EMTP software support team and EMTP marketing personnel.

During the EMTP User Conference:
  • You can connect/interact with EMTP users working in the industry, research centers and universities
  • You can share, discuss your simulation problems, and learn about EMTP and power system transients in general
  • You can influence the development path of EMTP by making propositions and presentations
  • You can learn on the latest EMTP developments
  • You can make high-level technical presentations on power system transients






Day 1

Sep. 21, 2020

Day 2

Sep. 22, 2020

Day 3

Sep. 23, 2020

Day 4

Sep. 24, 2020

Day 5

Sep. 25, 2020

Day 6

Sep. 28, 2020

Day 7

Sep. 29, 2020

Day 8

Sep. 30, 2020

Day 9

Oct. 01, 2020

Day 10

Oct. 02, 2020


New York (EST)Paris (CEST)Chennai (IST)Beijing (CST)

Switching and insulation coordination

Inverter based resources

Stability and protection

10:00 am04:00 pm07:30 pm10:00 pm

EMT models to evaluate traveling wave based protection in distribution system (Language: English)

Kumaraguru Prabakar, NREL

The distribution system is going through significant changes. One of them is the high penetration of inverter-based distributed energy resources in the distribution system. Due to this high penetration, there is a need for a better protection system. Multiple organizations are working on creating novel protection techniques for distribution systems with high penetration of inverter-based DERs. One such innovative method is the use of traveling waves to detect and locate faults. Transmission system protection utilizes this approach, and commercial solutions exist for the transmission system. Using this approach in the distribution system is not straightforward and presents some challenges for implementation. This presentation will discuss the need for using wide-band models to model the traveling wave phenomenon in the distribution system.


11:00 am05:00 pm08:30 pm11:00 pm

Impact of Renewables on System Protection (Language: English)

Evangelos Farantatos, Electric Power Research Institute (EPRI)

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. 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 utilities.



12:00 pm06:00 pm09:30 pm12:00 am

Stability analysis of the CCS power plant during the tuning of the PSS and determination of the adjustment of the single-phase reclosing time of the San Rafael – El Inga 500 kV transmission line
Análisis de Estabilidad de la central CCS durante la sintonización de los PSS y determinación del ajuste del tiempo de recierre monofásico de la línea de transmisión San Rafael – El Inga de 500 kV (Language: English/Spanish)

L.M. Dután, J.C. Cepeda, CELEC EP Transelectric

This work shows the simulations performed using EMTP before and after tuning the PSS of the Coca Codo Sinclair hydro power plant (1500 MW) of the National Interconnected System of Ecuador. Each machine in the plant is modeled and its control systems (AVR and PSS) are represented by models created by the user and by library models. The results obtained are compared with real signals taken by the Wide Area Monitoring Systems. In addition, the analyzes performed are shown, from a point of view of the transient stability of the plant, to determine the adjustment of the single-phase reclosing dead time of the San Rafael – El Inga transmission line, at 500 kV, taking into account the secondary arc model of the EMTP library.

Este trabajo muestra las simulaciones realizadas usando EMTP antes y después de la sintonización de los PSS de la central hidroeléctrica Coca Codo Sinclair (1500 MW) del Sistema Nacional Interconectado del Ecuador. Cada máquina de la central es modelada y sus sistemas de control (AVR y PSS) son representados por modelos creados por el usuario y por modelos de librería. Los resultados obtenidos son comparados con señales reales tomadas del Sistema de Monitoreo de Área Extendida. Además, se muestran los análisis realizados, desde un punto de vista de la estabilidad transitoria de la central, para determinar el ajuste del tiempo muerto de recierre monofásico de la línea de transmisión San Rafael – El Inga, a 500 kV, tomando en cuenta el modelo de arco secundario de librería de EMTP.


10:00 am04:00 pm07:30 pm10:00 pm

Eigenvalue stability analysis of subsynchronous torsional interactions between a hybrid dual-infeed HVDC system and a nuclear generator (Language: English)

Stefan Kovacevic (presenting author), Dragan Jovcic, Pierre Rault, Olivier Despouys, University of Aberdeen

It is well-known that an LCC HVDC may deteriorate damping of torsional modes of nearby turbine-generators, and for weak AC grid connections the HVDC may even destabilize the system. There are fewer dynamic studies with MMC although recent literature indicates that an MMC HVDC connected in close proximity of an LCC HVDC may generally improve stability. However, these studies do not consider the generator-HVDC torsional interactions in the subsynchronous domain (SSTI).This article investigates the risk of the SSTI in a dual-infeed HVDC system (LCC and MMC) and in comparison to a single HVDC system. The test topology is inspired by the North French system in which a 2 GW LCC HVDC cross-channel link IFA2000 (1986) is connecting the French and the English AC grid. The HVDC is coupled on the French side with a 1.12 GW nuclear generator in the Gravelines plant and experimental studies showed that there may be a substantial risk of SSTI, particularly with respect to the dominant 6.3 Hz torsional mode. This system is now becoming a hybrid dual-infeed HVDC since a 1 GW MMC HVDC Eleclink is being installed in proximity of the existing LCC HVDC, on the French side. This raises concerns of new SSTI stability issues.


11:00 am05:00 pm08:30 pm11:00 pm

Performance of conventional sources vs Inverter based source during power system faults (Language: English)

Normann Fischer, SEL

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.



12:00 pm06:00 pm09:30 pm12:00 am

Use of EMTP in Transmission Planning Research (Language: English)

Bob Arritt, EPRI

The initiation of inverter-based generation (IBG), has been changing the characteristics of the grid. The addition of non-traditional generation sources gives rise to several grid concerns, such as reduced short-circuit fault current capacity and system inertia as well as ineffective voltage regulation. Because of this – the use of EMT studies has been becoming more common to accommodate “special” studies. This presentation will just highlight a few examples of the use of EMTP in transmission level planning.



09:00 am03:00 pm06:30 pm09:00 pm

On Site Measurement and Simulation of Transferred Lightning Overvoltages Through Power Transformers (Language: English)

Bruno Jurišić, KONCAR – Electrical Engineering Institute, Inc.

High voltage electrical devices such as power transformers are often stressed by the overvoltages that occur during switching operation and atmospheric discharges. Consequently, it is of particular interest to monitor these events in the power network. Nowadays, power transformers can be equipped with transient recorders that measure the voltages at the bushing measurement taps. It is possible to simulate events captured by these recorders, in EMTP. In this process, the crucial element that has to be modelled properly is the power transformer.
In this paper, three wideband transformer models are presented: black-box, grey-box and white-box. These models are validated using the transmitted overvoltage measurements at high voltage laboratory. Then, the results of the simulation of the transient event recorded in 220/110 kV substation is presented and compared to the on site measurements results.


10:00 am04:00 pm07:30 pm10:00 pm

How to conduct an EMTP study when you don’t have input data: Synchronous condenser transformer energization with PAMSUITE (Language: English)

Manuel Martinez, Paul Poujade, EDF

In engineering studies, getting the necessary input data for performing EMTP simulations may be one of the most challenging tasks. Indeed, the characteristics of the system under study are usually badly known for a number of reasons: sometimes they are known with some inaccuracy, for example when parameters are associated with tolerances; sometimes, the characteristics are completely unknown, for example when the equipment is very old and the datasheets are not available, or when the study is about a future project for which many equipment characteristics are not known yet.
In addition, some parameters are inherently unknown because they take random values, for example the circuit-breaker closing angles, the transformer residual fluxes or the lightning current amplitude.
At the end of the day, the engineer in charge of a study knows how to model the system in EMTP but they lack the necessary input data to fill-in the forms with numerical values.
In this presentation, we show that, in spite of this, it is possible to perform EMTP studies even with very little input data. We illustrate this with a real study case consisting in the energization of the transformers of a synchronous condensers station. As this station is in a pre-project phase, almost no data is available on the characteristics of the synchronous condensers and the transformers. However, by using the right methods and tools, it is possible to study the energization consequences and provide meaningful insight to the customer.


11:00 am05:00 pm08:30 pm11:00 pm

Induced Currents and Voltages in Underground Metallic Pipelines due to nearby Power Lines (Language: English)

L. Czumbil, A. Mureșan, D.D. Micu, Technical University of Cluj-Napoca, Department of Electrotechnics and Measurements

During the last decades, environmental and economic reasons impose that gas or water pipelines share the same distribution paths with high voltage or medium voltage power lines, to restrain the financial and the ecological costs. Therefore, the cases where underground metallic pipelines and power lines share proximal rights-of way for considerable lengths are a common practice. The electromagnetic interference of power lines upon the metallic buried pipelines is an issue of priority, to avoid the development of induced voltages that could jeopardize the safety of the personnel and the integrity of the pipelines structure. Indeed, the developed voltages and currents can be dangerous for people who touch metallic structures connected with the pipelines or just stand nearby. Moreover, the induced voltages can result in the corrosion of a pipeline due to electrochemical effect, leading to repair or/and replacement costs and environmental repercussions. It is worth mentioning that the interference comprises an inductive, a conductive and a capacitive part. The capacitive part can be safely ignored in the case of buried pipelines, since the conductive component is considered only under fault conditions and affects the part of the pipeline near the faulted structure. The inductive component is present both during faults and normal operating conditions and is the dominant one. Due to the inductive interference, voltages and currents are induced in a buried metallic pipeline.
The current work focuses on the simulation and modeling in EMTP of the induced currents and voltages in underground metallic pipelines due to nearby underground medium voltage cables form Renewable Energy Sources (RES) as a source of electromagnetic interferences and/or overhead power lines connecting RES serving substations to the National Power Grid. The rapid development of the RES in the last years, due to the global concern for environmental issues and the need to mitigate the effects that lead to global warming, has resulted in the development of large (MWp) PV or wind farm power stations, where their medium voltage lines are neighboring with metallic pipelines. The impact of several factors (distance between power lines and pipelines, grounding of pipelines, soil resistivity, load of each phase etc.) on the magnitude of the developed induced voltages under steady state and fault conditions will be examined, in an effort to facilitate the appropriate and efficient design of such systems.


12:00 pm06:00 pm09:30 pm12:00 am

TOV for renewable, evaluating three different grounding technologies (Language: English/Spanish)

Diego F. Rodríguez, GERS

Temporary overvoltages (TOV) are oscillatory overvoltages mainly caused by switching or faults, which are of relatively long duration and undamped or slightly damped. Maximum overvoltages under faulted conditions can require considerable energy magnitudes absorbed by surge arresters. These energies may overpass maximum limits and lead to equipment damage. This project presented a study to identify the maximum TOV at the MV equipment of a PV power plant during fault-clearing events. Two methods of TOV suppression are evaluated, including grounding transformers and fast grounding switches under two different configuraions. An electrical model was elaborated in EMTP to perform the simulation of the transient overvoltage due to the un-balanced fault clearance, considering each inverter of the PV plant. The results show that considering no grounding technologies at the feeders, the energy absorption limit is overpassed in the islanded system. Therefore, a fast grounding switch or a system with grounding technology at each feeder is needed in order to protect the substation equipment.
Las sobretensiones temporales (TOV) son sobretensiones oscilatorias causadas principalmente por conmutación o fallas, que son de duración relativamente larga y no amortiguadas o ligeramente amortiguadas. Las sobretensiones máximas en condiciones de falla pueden requerir magnitudes de energía considerables absorbidas por los pararrayos. Estas energías pueden superar los límites máximos y provocar daños en el equipo. Este proyecto presentó un estudio para identificar el TOV máximo en el equipo de MT de una planta de energía fotovoltaica durante los eventos de eliminación de fallas. Se evalúan dos métodos de supresión de TOV, incluidos los transformadores de puesta a tierra y los interruptores de puesta a tierra rápida en dos configuraciones diferentes. Se elaboró ​​un modelo eléctrico en EMTP para realizar la simulación de la sobretensión transitoria debido a la eliminación de fallas no balanceada, considerando cada inversor de la planta fotovoltaica. Los resultados muestran que al no considerar tecnologías de puesta a tierra en los alimentadores, el límite de absorción de energía se sobrepasa en el sistema isleño. Por lo tanto, se necesita un interruptor de conexión a tierra rápido o un sistema con tecnología de conexión a tierra en cada alimentador para proteger el equipo de la subestación.


10:00 am04:00 pm07:30 pm10:00 pm

AC fault studies of islanded grid including HVDC links in grid forming operation (Language: English)

Hani Saad, RTE

VSC-HVDC link can operate in VF-control (or grid-forming mode) when connected to a weak or islanded network to overcome the PQ-control (or grid-feeding) limitation. Up to now, the VF-control represents a challenge due to static and dynamic limits. This paper provides a dynamic performance, during AC faults, of HVDC link in VF-control connected to an islanded grid. The islanded grid is based on the Northern France network and includes synchronous generator and wind farm. The EMT-type simulations provides an insight on dynamic network behavior when HVDC is operating in VF-control.


11:00 am05:00 pm08:30 pm11:00 pm

Assessment of Interactions Involving Wind Farm Systems (Language: English)

Aramis Schwanka Trevisan, Enercon

Recently, field events involving adverse interaction between grid-connected inverters and the existing power infrastructure have been reported. Hence, the ever increasing integration of such devices is yielding the need for detailed EMT-Type models to better understand such phenomena, as well as reliable screening methodologies for the efficient identification of potentially critical scenarios during new interconnection processes. This work provides an overview of recently proposed generic EMTP wind turbine models, which have been validated against field measurements, and a benchmark study system for the assessment of low-frequency interactions involving wind farms in radial series-compensated grids. Based on these models, detailed EMTP results are presented and modal analysis is applied to help explaining some of the identified issues and provide mitigation. Finally, a recently proposed methodology aiming at the efficient identification of critical scenarios, namely, the DQ-Scanning technique, is outlined and its effectiveness demonstrated by its application to the aforementioned systems.


12:00 pm06:00 pm09:30 pm12:00 am

Methods of Generating COMTRADE Files Using EMTP for Testing SEL-T400L Traveling Wave Relays (Language: English)

Toby Russell, Dr. Prashanna Bhattarai, Dr. Milton Quinteros, Entergy

This presentation provides two different methods of generating COMTRADE files to playback through the SEL-T400L traveling wave relays using EMTP software. The first method of generating the COMTRADE files uses the standard export feature in ScopeView. The second method utilizes a beta version of the COMTRADE recorder meter block to generate the .CFG files, which are later converted to .PLY files to be played back on the T400L. The advantages and disadvantages for each method are discussed along with demonstration results.


10:00 am04:00 pm07:30 pm10:00 pm

Development of a benchmark on EMTP for the test of grid forming power electronic converters (Language: English)

Xavier Guillaud, L2EP

In the next years, the grid forming control will become a reality in the transmission grid. This a major milestone for the grid in order to be able to integrate even more power electronic converters and it represents also a major challenge. For doing so, the TSO will need to develop a bench mark to test the behavior of this new types of control. This presentation gives a first proposal of benchmark and give some example of the test on several types of grid forming controls. All the simulation model are developed on EMTP.



11:00 am05:00 pm08:30 pm11:00 pm

HVDC grid protection algorithm based on fault parameter estimation: requirements for voltage and current sensor accuracy (Language: English)

Alberto Bertinato, Paul VERRAX, SuperGrid Institute

Fully selective protection strategies for meshed HVDC grids need very fast DC fault identification and isolation which constitutes one of the main locks for large deployment of such grids. Transient based fault identification algorithms based on the modelling of the voltage and current traveling waves are seen as a promising solution to achieve fast fault identification. In addition, such algorithms are able to estimate the fault parameters such as the fault distance using local sensor data.
As a model based approach, the accuracy of the sensors may impact the fault identification results as well as the precision of the estimated fault parameters.
This presentation focuses on voltage and current sensors modelling and its application on a transient based protection algorithm within a 4-terminal HVDC grid simulated in EMTP.
In depth sensitivity analysis for different parameters of the sensor are carried out to outline the influence of the sensor characteristics on the fault identification results as well as the accuracy on the estimated fault parameters.


12:00 pm06:00 pm09:30 pm12:00 am

On a New Approach of Detailed Load Modeling in EMTP (Language: English)

Bahram Khodabakhchian, Hydro-Québec

A detailed load model based on component-based methodology is presented. Various Residential-commercial-industrial components such as VFD, LED, CFL, SMPS and other essential elements are developed. An event in Brossard substation is reproduced for validation purposes.



04:00 am10:00 am01:30 pm04:00 pm

Insulation Coordination Study of 765kV GIS SUBSTATION (Language: English)

N.K.Nathan , KNR Engineers Pvt. Ltd

Gas Insulated Substations provide cost effective solution due to reduced land requirements particularly in metropolitan area where power demand is registering steep growth. With the use of GIS technology, it is required to assess the risk of failure due to overvoltage. The Insulation Coordination study forms a very important aspect in design stage. This presentation deals with the IC study carried out for a large – 765/400/220kV GIS substation in a SUPER THERMAL POWER STATION in UTTAR PRADESH. Due to the decreasing ratio of lightning impulse withstand voltage to the system voltage, the difference between LIOV and VFTO decreases and this factor calls for VFTO performance analysis for 765kV GIS as well.
The discussion includes modeling of Extra High Voltage GIS, Temporary Overvoltage (TOV), Lightning Impulse Overvoltage (LIOV), Switching Overvoltage (SOV) and Very fast transient Overvoltage (VFTO) performance analysis on 765kV GIS substation. TOV typically caused by fault to ground, load rejections and energization of long lines are analyzed to decide the rating of the surge arrester. LIOV simulation studies are carried out for possible onerous paths including longer and short paths to decide the location of the arrester. SOV analysis deals with the overvoltage due to switching operations during line energization, re-energization and fault occurrence and clearance. The LIOV and SOV results have been validated with reference to protective levels prescribed. The VFTO analysis is performed with various GIS disconnector operations in accordance with the methodology and guidelines as per CIGRE WG D1.03-TB 519 and the results are validated with the limits specified.
Keywords: Insulation Coordination, VFTO, EHV, GIS, 765kV, Protective ratio.


05:00 am11:00 am02:30 pm05:00 pm

Frequency and Voltage Data Processing Based Feeder Protection in Medium Voltage Microgrid Using EMTP (Language: English)

Dr. Sanjoy Kumar Parida, Indian Institute of Technology, Patna

The complexity of an active distribution system with distributed generation (DG) is increasing day-by-day. Therefore, a reliable protection system is very necessary to satisfy customer demand. Apart from main grid supply, active sources are also available near load centers due to which traditional protection schemes fails to function properly. The magnitude of fault current during grid connected mode of microgrid, is much higher than islanded operation. Therefore, in most of the previous works, overcurrent protection crashes if its pickup current value is not changed when microgrid is shifted to islanded mode. In this work, the current, voltage and frequency data sampled through PMU is processed to protect the system in both the operating modes. A centralized protection scheme is employed that takes
frequency data and voltage phasor to differentiate between islanding and fault condition. Further, it detects the faulted feeder and sends trip command to respective relays within a tolerant time. This method is devised to work as backup protection when main utility grid is available. However, it can work as a primary protection during islanded mode, when local overcurrent relay fails to operate due to settings based on grid connected mode. A standard IEEE 15 bus system modeled in EMTP is taken as test system for every analysis.


10:00 am04:00 pm07:30 pm10:00 pm

Analysis of voltage transformer failures at Jirau GIS with the EMTP
Análise de falhas de transformadores de potencial indutivos na GIS de 500 kV da Usina de Jirau com o EMTP (Language: English/Portuguese)

Angelica C O Rocha & Gustavo Oliveirra, ATG Engenharia & Federal University of Parana

The presentation will discuss the analysis of successive dielectric failures of inductive voltage transformers (VT) at a 500 kV GIS of Jirau hydroelectric plant in Brazil. All the failures involved the same region of the high voltage winding and the cause was undetermined. These incidents motivated a series of actions to identify the cause and improve the reliability of these equipment in the field.
One possibility the effect of very fast transients (VFTO) expected to occur during frequent switchings of disconnector and/or circuit-breaker at GIS. It well known that VFTO may stress inductive equipment insulation leading to a dielectric failure.
In this context, different switching conditions were simulated with the EMTP to determine the transient overvoltage at the potential transformer terminals. A special high frequency model of the VT was developed based on its frequency admittance matrix measured in the field. The result of the simulations was discussed together with the VT manufacturer and a final diagnosis of the failures was achieved.

A apresentação discutirá a análise de falhas dielétricas sucessivas de transformadores de potencial indutivos (TP) em um GIS de 500 kV da usina hidrelétrica de Jirau no Brasil. Todas as falhas envolveram a mesma região do enrolamento de alta tensão e a causa foi indeterminada. Esses incidentes motivaram uma série de ações para identificar a causa e melhorar a confiabilidade desses equipamentos em campo.
Uma possibilidade levantada foi o efeito de transitórios muito rápidos (VFTO) que ocorre durante manobras frequentes de seccionadores e / ou disjuntores em subestações blindadas. É sabido que os VFTOs podem estressar o isolamento de equipamentos indutivos, levando a uma falha dielétrica.
Nesse contexto, diferentes condições de chaveamentos foram simuladas com o EMTP para determinar as sobretensões transitórias nos terminais dos TPs. Um modelo especial de alta frequência do TP foi desenvolvido com base em sua matriz de admitancia no domínio da frequência medida em campo. O resultado das simulações foi discutido em conjunto com o fabricante da TP e um diagnóstico final das falhas pode ser alcançado.


11:00 am05:00 pm08:30 pm11:00 pm

Energización sistema de 66 kV (ST) a partir de una barra de 13.2 kV (MT) de baja potencia de cortocircuito
Energizing 66 kV (ST) system from a 13.2 kV (MT) bar with low short-circuit power (Language: Spanish)

Jesús Viciana Pérez, Servicios de Ingenieria Eléctrica y Electromecánica

En el presente trabajo se analizó la factibilidad de energización de las EETT de 66/13.2 kV Las Catitas, La Dormida y La Paz desde la barra de 13.2 kV de la ET Bajo Río Tunuyán (BRT); la particularidad de esta maniaobra es precisamente energizar desde una barra de nivel 13.2 kV, transformadores 66/13.2 kV y líneas de subtransmisión de 66 kV, a fin de resolver una contingencia que deja aislada parte del sistema de ST de la red eléctrica.
La necesidad de este estudio de factibilidad se funda en que la inserción de transformadores de potencia de un sistema de subtransmisión de AT a partir de una barra con baja potencia de cortocircuito del sistema de distribución de MT, como en este caso, pueden generar transitorios de gran amplitud y duración tanto de la tensión como de la corriente, debido a las condiciones de alinealidad por saturación del núcleo, como al efecto de histéresis y al magnetismo remanente; también es importante vigilar los niveles de tensión resultantes luego del transitorio inicial a fin de que no se superen los niveles de tensión aplicada de 1 seg; por esto la factibilidad de la maniobra se decidió evaluando: las corrientes máximas de inserción, las sobretensiones y el nivel de tensión resultante luego del transitorio.
Para este estudio se utilizó el programa EMTP versión 3.5 del Coordination Group (DCG) [1] y la metodología de trabajo propuesta en la publicación “Determinación de las Corrientes de Inserción de Transformadores en una Red Eléctrica, de Héctor R. Disenfeld y Jorge N. L. Sacchi del Comité 33 – Coordinación de Aislamiento de Sistemas de Potencia presentado en el IX ERLAC” [2], y en el trabajo “Conexión Segundo Transformador 500/345/34.5 kV 450 MVA de la ET Cobos. Estudios de Transitorios Electromagnéticos, de Manuel Viciana (SIEyE) y Jesús Viciana (SIEyE) realizado en diciembre de 2013 para TERMOANDES.

In this work, the feasibility of energizing the 66 / 13.2 kV EETT Las Catitas, La Dormida and La Paz from the 13.2 kV bar of the Bajo Río Tunuyán ET (BRT) was analyzed; the peculiarity of this maneuver is precisely to power from a 13.2 kV level bar, 66 / 13.2 kV transformers and 66 kV subtransmission lines, in order to resolve a contingency that leaves part of the ST system isolated from the electrical grid.
The need for this feasibility study is based on the fact that the insertion of power transformers of an AT subtransmission system from a bus with low short-circuit power of the MV distribution system, as in this case, can generate transients of great amplitude and duration of both voltage and current, due to the conditions of non-saturation linearity of the nucleus, as well as the hysteresis effect and the remaining magnetism; It is also important to monitor the resulting voltage levels after the initial transient so that the applied voltage levels of 1 sec are not exceeded; for this reason the feasibility of the maneuver was decided evaluating: the maximum insertion currents, the overvoltages and the resulting voltage level after the transient.
For this study, the EMTP version 3.5 program of the Coordination Group (DCG) [1] and the work methodology proposed in the publication “Determination of the Insertion Currents of Transformers in an Electric Network, by Héctor R. Disenfeld and Jorge NL Sacchi of Committee 33 – Coordination of Isolation of Power Systems presented at the IX ERLAC ”[2], and in the work“ Second Transformer Connection 500/345 / 34.5 kV 450 MVA of the ET Cobos. Electromagnetic Transient Studies, by Manuel Viciana (SIEyE) and Jesús Viciana (SIEyE) carried out in December 2013 for TERMOANDES.


12:00 pm06:00 pm09:30 pm12:00 am

Switching overvoltages studies for Live Working on the Uruguayan 500 and 150 kV transmission network (Language: Spanish)

Sofía Aparicio, Andrea Pizzini, Nicolás Morales, The National Administration of Power Plants and Electrical Transmissions (Spanish: Administración Nacional de Usinas y Trasmisiones Eléctricas) UTE

In order to obtain the distances required to perform live working maintenance on the Uruguayan transmission network under secure conditions, electromagnetic transient (EMT) studies are conducted to obtain the maximum switching overvoltage that can be found in 500-150 kV transmission network. Two different approaches were considered for these studies. On one hand, a simple approach is used, analyzing line switching transients on simplified two line network models. On the other hand, a detailed approach is considered, analyzing line switching overvoltage transients on a complete network model. This complete model considers 500 kV and 150 kV overhead lines, 500/150 kV transformers, cables, reactive power shunt compensation, hydraulic and thermal generators. Electromagnetic transient studies and the complete network model are performed in EMTP software. Finally, a comparison between the results obtained considering each approach is performed.


01:00 pm07:00 pm10:30 pm01:00 am

Modeling And Evaluation Of Overvoltage In Systems Involving Medium Voltage Vacuum Breakers, Cables And Transformers (Language: English)

Jin Yang, Ener-Phase Solutions

A case study will be presented demonstrating modeling of overvoltage in a moderately sized system involving medium voltage vacuum breakers, cables and transformers. The focus is on simulating high frequency overvoltage generated by circuit breaker prestrikes and re-ignitions and evaluating the impacts on transformer insulation.
-Results obtained from a customized breaker TRV model which is capable of controlling the capability of switching high frequency current will be presented.
-The methodology of analyzing severity of overvoltage in the frequency domain was applied in this project. Results and discussions regarding frequency domain analysis will be shared.
-Simulation results regarding typical system configurations with variation of key parameters such as cable lengths, load power factors will be briefly presented.
-Application of EMTP study results in assisting equipment specification, as well as overvoltage mitigation methods including optimizing switching sequences, necessity of snubber circuits will be discussed.
-Case specific strategies to improve simulation speed and work flow with EMTP will be introduced and discussed.
-Some numerical issues encountered in the case study will be shared.


04:00 am10:00 am01:30 pm04:00 pm

POWERGRID Experience with EMTP (Language: English)

Umesh Sen, Power Grid

To meet the increasing power demand, a number of extra high voltage (EHV) transmission lines is being added to the power system network, which enhances the complexity of power system network. It is essential duty of power engineer to fulfill the growing demand ensuring the reliability, stability & security of GRID. Transient simulation tools like EMTP play a vital role to provide the flexibility to power engineer for simulating/studying the various case scenarios which couldn’t be simulate in physical power system. Such tools eventually help power engineer to build a sustainable and secure GRID. In POWERGRID, being a central transmission utility, various studies are being carried out to arrive the technical particular of new transmission system and optimize or fine tuning of existing system. Some of them i.e. Transient Recovery Voltage (TRV) study of 1200kV Transmission network, Smart Power from insulated earth wire of EHV transmission line and 1200kV Transformer Inrush current study are discussed in presentation. 1200kV National Test Station was established & successfully charged along with the transmission line in state of BINA in India. TRV study was carried out for assessment of various test duties of 1200kV Circuit Breaker. Presentation cover the detailed discussion of 1200kV TRV study and a brief about the facilities like HIL, HVDC control Replica setup, STATCOM replica setup available at Powergrid Advanced Research and Technology Centre (PARTeC).


05:00 am11:00 am02:30 pm05:00 pm

Single Pole Auto Reclosure and NGR Analysis (Language: English)

Neeraj Patel, Adani Power

Unsuccessful auto reclosure has been observed in 765 kV HVAC transmission lines connected with Generation Bus. Back up Impedance Protection of Line reactor triggered during AR dead time due to power frequency oscillations in faulty phase (disconnected phase). It triggered tripping of Non Switchable Line Reactor at one end, which resulted tripping of 765 kV HVAC Line and avoidable Generation loss.
These Unsuccessful AR operations triggered us to study and model entire phenomena in Power System Analysis software (EMTP).
Initially, two circuits of 765 kV Transmission Line commissioned between Generation Station and Transmission Station with Line Reactor and NGR in both line at either end. Successful auto reclosure observed during single-phase faults on these lines. Intermediate Switching station constructed and both lines were divided in 4 section as per new requirement. Same configuration (rating) of Line Reactor and NGR adopted at newly constructed station on each line. Unsuccessful AR observed during AR running cycle on these lines after new configuration. Backup Impedance protection of Line Reactor found operated during AR Dead time.
Different sets of simulations has been carried out to understand the phenomena

  • Single Phase fault and Auto reclosure in 765 kV Transmission line in different section of entire corridor with Varying Shunt compensation (Value of Line Reactor)
  • Different NGR values and observations for above simulations
  • Trip the Line Reactor Breaker during Auto Reclosure Phenomena to avoid operation of Backup Impedance protection and its consequences

After EMTP Simulations and study, it was concluded that

  • Line Reactor (Degree of compensation) should be adjusted with adequate value while line length altered from its original design.
  • NGR re-sizing can address the issues at some extent. Suitable value of NGR (based on Line Length and amount of shunt compensation) should be employed

Appropriate Solution and mitigation suggested after detail simulation & study.


06:00 am12:00 pm03:30 pm06:00 pm

TRV Calculations in Vietnam 500 kV Transmission Network with EMTP (Language: English/Vietnamese)

Le Quoc Anh, Power Engineering and Consulting Company 1, EVN-PECC1

In the Vietnam power system, the very great length of the 500 kV transmission lines with series capacitors (SC), plus the relatively high source impedances that supply it, result in the transient recovery voltage on line breakers being very high. This presentation investigates the calculation of circuit breaker transient recovery voltages (TRV) for the Vietnam 500 kV transmission network. Several events that can produce high transient recovery voltage levels on the 500 kV line circuit breakers (existing or new installations for more than forty 500 kV line sections) have been studied, such as three-phase-to-ground, phase-to-phase grounded, phase-to-phase ungrounded and phase-to-ground fault clearing. The series capacitors protected by varistors, used on the Vietnam 500 kV network, play an important role to increase the TRVs across line circuit breakers when clearing fault currents. The influence of fault location on TRV has been investigated. Several measures in order to reduce the TRVs have been proposed. A toolbox has been developed to support automatic TRV calculation. Solutions to reduce TRVs have also proposed, in accordance with IEC 62271.100-2005.
With the help of these TRV calculations, a decision was made to install circuit breakers with two breaking chambers instead of four breaking chambers for all new installations. This significantly reduces costs and improves reliability


10:00 am04:00 pm07:30 pm10:00 pm

Implementation of a hydrogen fuel cell stack model in the EMTP (Language: English)

Franjo Vukovic, Ivo Uglesic, Alain Xemard, EDF and FER

This presentation describes the implementation of a fuel cell stack model in the EMTP. An EMTP model of a fuel cell stack was developed based on an approach similar to the one presented in [1] and available in the Matlab package. The developped model is an electro-chemical model and therefore is suitable for simulations of both electrical and chemical aspects of fuel cells. In other words, the fuel cell stack model can be used not only in simulations of electrical systems but also to simulate the effects of flow rates and pressures of hydrogen and air on the electrical behaviour of a fuel cell. The EMTP model of the fuel cell stack represents the behaviour of fuel cell stacks that use hydrogen as fuel and air as oxidant. It can simulate the behaviour of fuel cells when temperature, flow rates, supply pressures and compositions of air and fuel are either constant or variable. The model requires input data which can be obtained from the datasheet of a real fuel cell stack or by performing experiments on an actual fuel cell stack. The EMTP model was validated by comparison against the results obtained from the literature. Furthermore, it was used to study the interaction of a hydrogen fuel cell stack with a low voltage system. This system consisted of a fuel cell stack, DC-DC converter and variable load. The output voltage of the fuel cell is not constant since it depends on the current drawn from the fuel cell. Furthermore, the output voltage of a fuel cell may be too low or too high for certain loads. Thus, fuel cells must be interfaced to loads through power electronics. In the simulation, a converter was used to adjust and regulate the fuel cell voltage to the desired value. The voltage regulation of the converter was realized by a simple PI controller.


11:00 am05:00 pm08:30 pm11:00 pm

Locating faults in electrical power networks using EMTP: a practical case (Language: English)

Asia Codino, Streamer

In the context of modern and active power distribution grids, reliable and efficient fault location functionalities are increasingly required to match strict power quality constraints. Indeed, when a fault occurs, power supply restoration can be faster if the location of the fault is either known or can be estimated with satisfactory accuracy. The presentation will show how EMTP can be used to locate faults in electrical power grids, describe a practical implementation in a power distribution grid, and report some experimental results of a test campaign.



12:00 pm06:00 pm09:30 pm12:00 am

161kV Capacitor Bank Relay Tripping Investigation Using EMTP (Language: English)

Jeff Hart, MidAmerican Energy Company

A MidAmerican Energy Company (MEC) 161kV capacitor bank has been tripping via the bank protective relay’s voltage differential element upon bank energization. The bank relay trips have been random and the bank will often go through many iterations of bank energization before tripping again. The 37.8 MVAR 161kV capacitor bank has an externally fused capacitor can design, and is protected by an SEL-487V capacitor bank relay. Capacitor bank voltage differential is the primary form of bank protection utilizing measured voltages from 161kV bus connected capacitive voltage transformers and 69kV potential transformers connected near the bank “midpoint” to form the bank voltage differential zone. Relay event reports have shown significant signal distortion from the 69kV potential transformer secondary voltage relay inputs when the voltage differential element trips. In an attempt to explain the voltage waveform distortion, the capacitor bank was modeled and a switching study performed utilizing EMTP. The study shows that significant core saturation is occurring in the 69kV potential transformers upon bank energization, often resulting in severely distorted voltage waveforms mimicking those of the relay event reports. In addition, the EMTP COMTRADE recorder tool was utilized to play back the simulated switching study voltages into an SEL-487V relay using a relay test set – proving that the distorted waveform from potential transformer core saturation is causing the voltage differential element to trip.


01:00 pm07:00 pm10:30 pm01:00 am

Exponential Load in EMTP – Design and Validation (Language: English)

Omar Saad & Luc Gérin-Lajoie, Hydro Québec

The Exponential Load model proposed by [1] intended to perform classical dynamic studies in stability software’s. EMTP well known for electro-magnetic studies is now addressing new studies fields that include FACTS technologies, Distributed Generator, HVDC, PV, Windfarm and other power electronics based equipment’s; The new version of EMTP offer a precise models of those type of equipment’s .
This paper present an implementation of the Exponential Load model which combined with the models of AVR and Governor in the « Exciters and governors » library of EMTP, allow to perform classical and sophisticated dynamic-stability studies in EMTP without any limitations.
The paper presents first the challenge to model adequately the exponential equations based on direct sequence and frequency measurements. The validation of the model is performed using a network where the exponential load is fed by a source U1(t) and varying the amplitude up to ±0.15pu and the frequency up to 10Hz/s.
The IEEE39 is used as a typical network example.

Load, Dynamic, EMTP, Exponential.

[1] IEEE Task Force on Load Representation for Dynamic Performance. Load Representation for Dynamic Performance Analysis. IEEE Transactions on Power Systems, Vol. 8, No. 2, May 1993.

Luc Gérin-Lajoie, Alain Nantel, Omar Saad.


04:30 am10:30 am02:00 pm04:30 pm

A Simple Approach to Fit a frequency Dependent Equivalent Circuit for Transmission Line Models (Language: English)

Dr. Gurunath Gurrala, Indian Institute of Science and Technology, Bangalore

Accurately fitting rational functions to the frequency response of characteristic impedance and characteristic admittance is very crucial for frequency dependent modeling of transmission lines. Vector fitting is a most popular method for fitting rational functions to the frequency dependent characteristic impedance of transmission line. An R-C equivalent circuit will then be obtained from rational functions to simulate transmission line using Marti’s model. A single step method is described in this talk to accurately fit an equivalent circuit to the characteristic impedance. A close enough fitting is achieved with lesser number of poles & zeros using the proposed method. This is found to reduce the simulation time drastically by 89.84%.


06:30 am12:30 pm04:00 pm06:30 pm

Study of Offshore Wind Farm Connection to Vietnam Power System with EMTP (Language: English/Vietnamese)

Dr. Le Cao Quyen, Power Engineering and Consulting Company 4, EVN-PECC4

Vietnam’s sea area has the average wind speed in many years at the height of 100m: from 7 11 m/s. There is huge potential for developing offshore wind power. Especially the southern sea. The potential of developing offshore power at Binh Thuan with in 70km and depth of 50m is about 12,000 MW. This presentation presents a study of Thang Long offshore wind farm connection to 500 kV Vietnam transmission network via HVDC link using EMTP. The project will be constructed between 20km and 50 km from the Ke Ga cape located in Binh Thuan with 3,400 MW in total and 600MW for the first phase. Simulations are performed for both the offshore wind farms, as well as the HVDC link and their controls. Different scenarios of operation of this system in normal and disturbance state are investigated. Ancillary services contributed by this system to Vietnam power system are also identified and examined. Simulations are performed in order to choose the optimal architecture to satisfy technical and economic constraints.
This study is a collaboration between PECC3 and PECC4.


07:30 am13:30 pm05:00 pm07:30 pm

On state-space formulation of large-scale power systems for EMT simulation (Language: Chinese)

Xiaopeng Fu, School of Electrical and Information Engineering, Tianjin University

State-space model-based analysis is gaining popularity in the fields of converter-interfaced renewable generations, direct current (DC) transmissions, and active distribution networks, thanks to its well-established set of theoretical tools. The generation of these models for large-scale power networks is still a challenging topic, which limits our analytic power for many practical studies. Added complexity comes with power converters. The time-varying nature of these devices requires recurrent model updates in the course of a time-domain simulation. This talk presents recent research for the automatic generation of state-space models that accommodates very large power networks. A novel partial reformulation functionality is proposed for model updates induced by power electronic switches, which consumes only a fraction of the computation time for full formulations. Besides, a compensation technique is introduced for the previous modeling constraints and enables the algorithm to handle arbitrary topology and nonlinear device connections. A series of case studies, including power converter cases and large-scale distribution network benchmarks, with the state dimension up to 20,000, are presented, where superior computation performance is clearly demonstrated.




10:00 am04:00 pm07:30 pm10:00 pm

Grid Import Tool For EMTP Using CIM CGMES Format (Language: English)

César Martin, RTE

The need of automation for the exchange of power system information between simulation tools is an increasing one. There are several methods for creating modeling portability between applications. Using a standard facilitates interoperable exchanges of power system network data between and within organizations and is substantial to become a durable portable method. This presentation targets CIM CGMES standard solution to data portability in relation to an EMT-type application. CIM is a format that attempts to be accessible and understandable to all. The grid import tool allows to import static data from planning tools into EMTP that is the first step for frequency scan studies and time-domain simulations. Exchanging CIM dynamic data is in progress, some standard control systems have already been successfully imported.



11:00 am05:00 pm08:30 pm11:00 pm

Harmonic induced voltages on distribution cable sheaths and nearby pipelines using EMTP (Language: English)

Theofilos PAPADOPOULOS, Electrical and Computer Engineering Department Democritus University of Thrace

The increased installation of switching power electronic converters in power systems has raised the scientific interest in harmonic pollution problems during the recent years. Harmonics cause a series of issues, e.g. additional conductor and equipment losses, errors in electric power and energy measurements, and induced voltages to nearby metallic parts. This presentation is about the impact of harmonic voltage induction in underground cable systems of distribution networks. The analysis focuses on the induced voltages and currents on cable sheaths and nearby coated pipelines, the latter being located in the vicinity of the excited cable system. To systematically evaluate EMI due to the presence of harmonics, a benchmarking analysis is carried out in EMTP RV. The feasibility of the research is also examined in a cable system excited by current harmonics using data from measurements published in the recent literature.


12:00 pm06:00 pm09:30 pm12:00 am

Voltage Source Converter (VSC) and DC Grid Models (Language: English)

Prof Jardini, Escola Politécnica da Universidade de São Paulo

During the CIGRE B4-72 work seven benchmark models were proposed and simulated with all EMT software;This presentation include model developed for BM1 and BM4. BM1 is a 500 kV DC Grid with renewable; BM4 was a on shore and off shore system created in B4-57 include three subsystem: point-to-point; bipolar grid 400 kV; and symmetrical monopole 200 kV. Part of the system is with submarine cable and part with overhead transmission line. The 400-200 kV are interconnected with DC-DC converter. AC-DC and DC-DC converter were modeled in detail using VSC converter of the EMTP RV library. AC and DC faults were simulated modeling AC and DC breakers.



09:00 am03:00 pm06:30 pm09:00 pm

Lightning protection of a multi-circuit HV-MV overhead line (Language: English)

Professor Alberto Borghetti , Department of Electrical, Electronic and Information Engineering – School of Engineering – University of Bologna

This presentation focuses on the statistical appraisal of the so-called lightning performance of power distribution networks, i.e., the estimation of the mean annual number of line flashovers that overhead distribution lines can experience. Initially, it describes the application of the stratified sampling technique able to reduce the computation effort typical to this type of calculation. The calculation of the overvoltages caused by direct and indirect lightning strikes is obtained using the LIOV-EMTP software. After that, the Monte Carlo procedure is applied to the case of hybrid configurations, in which medium voltage (MV) and high voltage (HV) lines share the same structures. We focus on the case of a 15-kV line with compact configuration that is supported by the concrete poles of a 69-kV or a 138-kV transmission line. Due to the taller HV pylons and conductors, the number of direct events to the multi-circuit line is higher than for a MV line alone. The presence of the HV conductors and of the overhead ground wire reduces the amplitudes of the induced overvoltages in the MV conductors due to indirect lightning events. For the considered configurations, with a compact MV line, the number of flashovers per year expected in the double-circuit line due to both direct and indirect flashes is lower than in a MV line alone. The analysis of the overvoltages transferred on the LV side of the distribution transformers is also performed. The content of the lecture is mainly based on [1][2][3].


[1] A. Borghetti, F. Napolitano, C. A. Nucci, and F. Tossani, “Application of the Monte Carlo method to lightning protection and insulation coordination practices,” in Lightning Interaction with Power Systems – Volume 2: Applications, A. Piantini, Ed. Institution of Engineering and Technology, 2020, pp. 1–25.
[2] A. Borghetti, G. M. F. Ferraz, F. Napolitano, C. A. Nucci, A. Piantini, and F. Tossani, “Lightning protection of a multi-circuit HV-MV overhead line,” Electr. Power Syst. Res., vol. 180, no. November 2019, p. 106119, 2020, doi: 10.1016/j.epsr.2019.106119.
[3] F. Napolitano, F. Tossani, A. Borghetti, and C. A. Nucci, “Lightning Performance Assessment of Power Distribution Lines by Means of Stratified Sampling Monte Carlo Method,” IEEE Trans. Power Deliv., vol. 33, pp. 2571–2577, 2018, doi: 10.1109/TPWRD.2018.2795743.


10:00 am04:00 pm07:30 pm10:00 pm

Shunt Reactor Design Considerations and Analysis (Language: English)

Tommy Quinn, Booth & Associates, LLC

During lightly loaded periods, a power system can experience a number of issues due to the inherent capacitance of a long transmission line, especially considering high voltage underground cables. With significantly reduced system loads the power factor can become severely leading capacitive and cause elevated voltages which could cause long term degradation to equipment. A switchable shunt reactor enables system operators to compensate for the poor power factor by switching in an inductive load. The design of the shunt reactor and where it is placed on the power system can be based on many parameters including reactive power requirements, system capacity, availability of physical space, NERC compliance requirements as defined for a Bulk Electric System, and of course power system transient analysis. Using EMTP a case study was analyzed for the design of a shunt reactor system. This presentation examines the sizing, placement, and switching analysis of a shunt reactor designed with regards to the design parameters above.


11:00 am05:00 pm08:30 pm11:00 pm

Case study of a new type of ferroresonance in solar power plants (Language: English)

Chandra Pallem, EnerNex

We present the results from an investigation of a new type of ferroresonance issue that caused the failure of substation surge arresters at a PV solar power plant in North America. Ferroresonance in power systems has been extensively studied in the past and it is known from literature, that ferroresonance occurs when the magnetizing inductance of a transformer or of a coil with ferromagnetic core interacts with the system capacitance, forming a series resonant circuit during abnormal operation of the system. At this solar plant, the transient overvoltages that occurred were similar in phenomena to classic ferroresonance cases, except that they occurred without any single-phasing conditions by fuse operation or any other switching means. In order to investigate the issue, a detailed transient model of the solar plant was developed using EMTP software program and the phenomenon was studied. From the simulations, it was determined that the combination of transformer grounding schemes used at the solar plant resulted in these high overvoltage conditions and surge arrester failures. The EMTP simulations were useful in understanding the ferroresonance phenomena at the solar plant and in providing a mitigation solution to control these high overvoltage conditions.


12:00 pm06:00 pm09:30 pm12:00 am

Zero-missing phenomenon due to sectionalizing of compensated transmission lines (Language: English)

Davi Sixel, Felipe Camara, Marco Albuquerque, FURNAS

To overcome environmental or physical constraints, the network expansion planning is sometimes followed by the sectionalizing of compensated transmission lines to integrate new substations. As a consequence, the resulting lines might present a high compensation factor if the shunt reactor is still connected to the line end. In this work, we address some real cases in the Brazilian Interconnected Power System when the decision of sectionalizing a given line provoked an issue associated with the so-called zero-missing phenomenon. Time-domain simulations will demonstrate this phenomenon and also the transient current behavior through the circuit breaker. The available countermeasures and the proposed solution will be discussed.



10:00 am04:00 pm07:30 pm10:00 pm

An Efficient FDNE Custom Model on the EMTP Tool for Supporting of Very Large Power System Representation (Language: English)

Felipe Dicler & Henildo M. de Barros, Operador Nacional do Sistema Elétrico – ONS

Network reduction through the method known as Frequency Dependent Network Equivalent (FDNE) is well established and has been used successfully for several applications such as simulation of large power systems, models of transmission lines, cables and transformers, aggregation of generators, etc. However, its computational performance still poses a challenge, as the order of the equivalent system is often high so as to provide an accurate output. The present work will discuss techniques for improving the computational performance of FDNE equivalents that are based on the Vector Fitting method. A significant increase in performance was achieved using a vectorial representation of the state matrices that result from the Vector Fitting, in comparison with the complete, highly sparse system solution. In addition, it has been shown that for balanced systems, the use of symmetrical components can also increase the performance without compromising accuracy.


11:00 am05:00 pm08:30 pm11:00 pm

Motor Start Flicker Mitigation Through Fast Reactive Power Compensation Using Current Change as a Parameter (Language: English)

Senay Berhane & Saeed Kamalinia, S&C Electric Company

The presentation discusses the use of EMTP for fast reactive power compensation analysis during a motor start. An industrial facility with large 7000 hp motor loads was creating significant voltage sags several times a day during motor starting operations. The voltage sag caused perceptible flicker in the surrounding areas that were considered unacceptable by the local utility and was irritating to the local customers. To mitigate flicker, a reactive power compensation system with a fast response time was proposed to be interconnected at key locations on the industrial facility’s point of interconnections.

Traditional reactive power compensation involves directly measuring the power system voltage variations and providing reactive power to counteract voltage sags or swells. This voltage measurement or voltage droop approach used in motor starting applications can be slightly delayed due to the relatively slow power system and transducer delayed voltage responses. Motor starting operations generally create the largest voltage sag due to the motor locked rotor current within the first few cycles. By the time the voltage change is measured, processed and reactive power is injected or supplied to the power system, the voltage sag has been noticed and blinked adjoining customers. A much faster response and solution appropriate for motor starting applications was required. To decrease the response time, the controls of a reactive compensation device (i.e. STATCOM) were modified to monitor the change in current and provide reactive compensation accordingly. By directly monitoring the instantaneous current change of the power system due to a motor starting operation, this technique eliminated many delays in the controls and power system responses to provide the desired faster response. The controls detected the current change immediately and the control system commanded and supplied the desired amount of reactive power (reactive current) to support the required motor starting reactive current reducing the voltage sags that would permeate the transmission and distribution systems. The EMTP analysis performed in this case includes determining the appropriate size of reactive power compensation devices that could be deployed to mitigate the observed voltage sag issues. Furthermore, the analysis determined appropriate filter time constants and other parameters of the reactive power compensation devices to ensure that the injection of reactive current (power) will effectively (efficiently) neutralize the observed voltage sags without introducing other unnecessary transients.


This event is organized by EMTP Alliance. For any questions, please contact us.