Mario A Rios

• PhD Electrical Engineering
• Professor (Full) at Los Andes University (Colombia)

span lang="EN-US">Large-scale integration of inverter-based renewables is displacing synchronous machine generation, causing a reduction in the inertia of electrical power systems. This reduction is reflected in an increase in the rate of change of frequency (RoCoF). Additionally, the variation of the RoCoF will depend on the uncertainty associated...

This paper presents a research context on the virtualization of phasor measurement units (PMUs) and real-time power grids simulation with state estimation. In this research, real-time simulation is introduced to use powerful features for validating state estimation solutions with PMUs. Virtual and online measurement equipment are reviewed in this m...

The development of an online tool application that enables precise state estimate via synchrophasor processing tools to receive streams of sampled data from substation merging units via the IEC 61850-9-2 protocol is discussed in this study. This would make it possible for researchers to evaluate synchrophasor technology in a production setting in a...

p>Planning of high voltage direct current (HVDC) grids requires inclusion of reliability assessment of alternatives under study. This paper proposes a methodology to evaluate the adequacy of voltage source converter/VSC-HVDC networks. The methodology analyses the performance of the system using N-1 and N-2 contingencies in order to detect weaknesse...

The continuous development of DC technology and its increasing implementation in projects, mainly in Europe, North America, and Asia, have created the need for methodologies to plan the DC interconnections between countries. However, the planning process should not be developed in a local context but rather, in the long run, thus enabling the inclu...

Electrically isolated areas are separated by a great distance and, normally, have a considerably low demand; in consequence, these are non-interconnected from the main power grid or electrical national transmission systems. Great distance and low demand are the reasons why an interconnection project in high voltage AC is not feasible in most of the...

The use of renewable non-conventional energy sources, as wind electric power energy and photovoltaic solar energy, has introduced uncertainties in the performance of bulk power systems. The power system availability has been employed as a useful tool for planning power systems; however, traditional methodologies model generation units as a componen...

Transmission expansion planning in AC power systems is well known and employs a variety of optimization techniques and methodologies that have been used in recent years. By contrast, the planning of HVDC systems is a new matter for the interconnection of large power systems, and the interconnection of renewable sources in power systems. Although th...

Time-delay is inherent to communications schemes in power systems, and in a closed loop strategy the presence of latencies increases inter-area oscillations and security problems in tie-lines. Recently, Wide Area Measurement Systems (WAMS) have been introduced to improve observability and overcome slow-rate communications from traditional Superviso...

This study proposes a methodology for assessing the availability of voltage source converter high-voltage direct current (HVDC) grids based on the enumeration methodology of contingency analysis with N − 2 criteria and makes contributions in the computation of remedial actions and the definition and computation of reliability indices applied for HV...

This paper presents a methodology to determine the adequate percentage of reactive power compensation required to provide an appropriate voltage support and mitigate the impact caused by the massive installation of Wind Power Plants (WPP) in a power system. Mainly, the impact in the system’s loadability and the improvement achieved by installing se...

The integration of wind power plants at large scale has an impact on the reliability, the stability and the security of power systems. Recent events such as the blackout of Australia in 2016, a power system with large participation of wind generation, have demonstrated the need for appropriate tools to simulate and assess the impacts of wind energy...

The growth of utilisation of wind power plants (WPP) in power systems placed at long distance of the transmission power system has shown that the best connecting alternatives are by means of high‐voltage direct current lines (HVDC) using voltage source converter (VSC) stations. Generally, the bus closest to the WPP and with the highest level of sho...

Damping of weak electromechanical modes can be improved by means of supplementary controllers placed at embedded High Voltage Direct Current (HVDC) lines based on Voltage Source Converters (VSC) technology. For this purpose, some robust controllers H ∞ are proposed based on local single input single output (SISO) linear models of the power system p...

The interconnection of remote large power systems, and the connection of large non-synchronous renewable power sources to AC power systems have found solutions by means of transmission in high voltage direct current (HVDC) using technology based on voltage source converters (VSC). This technology has the advantage of fast response the possibility o...

This paper presents a three-phase loss allocation procedure for distribution networks. The key contribution of the paper is the computation of specific marginal loss coefficients (MLCs) per bus and per phase expressly considering non-linear load models for Electric Vehicles (EV). The method was applied in a unbalanced 12.47 kV feeder with 12,780 ho...

Automatic voltage regulators and power system stabilizers have been employed successfully to deal with fast dynamics associated to local oscillations phenomena. Whereas, inter-area oscillations damping in large power systems requires remote feedback controllers fed by Wide Area Monitoring Systems (WAMS). Although these improvements in the inter-are...

Integration of wind power plant into power grids introduces power quality problems. The use of Doubly Fed Induction Generator into wind farm cause a distortion of the waveforms of voltage and current. The percentage of harmonic distortion is greater if the number of wind turbines is large. If the simulation model are not defined properly, the harmo...

This paper proposes a methodology to include HVDC-wind powerconnection schemes to the transmission expansion planning. The methodology includes the identification of specific problems, the definition of alternatives of interconnection, and the definition of selection criteria and, finally, the selection of the best alternative (using the Cost Minim...

The progressive development in power systems and their operational complexity has aroused interest in the power system dynamic security. Network operators cannot determine the exact state of the system in high-risk situations causing the spread of failures in the system and breakdowns in the worst cases. According to this, the current paper present...

The incorporation of renewable energy into large-scale systems exhibits technical problems due to power fluctuations. As an alternative solution to control these fluctuations, an implementation of energy storage systems can be considered. However, an oversizing of storage capacity may cause the project to be non-viable and inefficient. To determine...

This paper proposes a methodology for the computation of robust controls that guarantee robustness in a wide range of operating condition of a power system; such as contingencies, uncertainties and delays in the signals. This paper proposes a detailed modeling of uncertainties of the power system as additive uncertainties of the plant under the the...

Current and traditional methods of load shedding are based on threshold values of frequency and voltage; thus, when the power system falls below these values, some mechanical control actions are activated as countermeasure against stability problems. Nevertheless, in many cases the traditional mitigation methods based on load shedding cannot ensure...

Power systems control strategies that use global signals have shown better results than those based on local signals, but the remote signals are usually taken far away from the control center. Because of that, wide area power systems controlled using global signals are inherently delayed, and time delays jeopardize the stability of power systems. T...

A comprehensive methodology for transient studies of HVDC lines for interconnected AC power systems is proposed as a useful tool for its design and operation. This methodology is based on frequency dependent modelling of HVDC transmission lines and a full modelling of their associated equipment in order to do transient simulations. The model is use...

This paper proposes a methodology through an optimization model that allows decisions about expansion of a power system considering intermittent renewable energy sources, like wind energy, and other random variables in transmission and generation expansion planning. So, the uncertainty of the risk of failure in the system components, uncertainty in...

Power systems can experience poorly damped oscillations tendency which may cause loss of synchronism and security constraints infringement. This may be caused by disturbances in power consumption, failures, and recently by the presence of delays in monitoring process. In consequence, control systems, which must deal with delayed signals in monitori...

This paper proposes a methodology for simulating the power supply of a Bus Rapid Transit (BRT) system comprised of full-electric vehicles. These buses are based in the TOSA Project at Geneva, Switzerland; which are full electric articulated buses that run without overhead lines. As their charging method, flash charging, requires short-time and high...

This paper proposes a methodology for forecasting the electrical power demand associated to the penetration of electric vehicles on a distribution system. The simulation model is framed in a temporal and spatial base that considers a more detailed analysis of some demographical aspects and technical characteristics of the electric vehicles. This ap...

This paper proposes a methodology for computing the spinning reserve spinning reserve for a power system with a high penetration of wind power generation. The methodology uses a Point Estimate Method in order to calculate a Unit Commitment with several stochastic variables, including demand and wind forecast for a given day. Additionally, the model...

Aspects of terrestrial microgrids and ship power systems are examined. The work exposes a variety of technical synergies from these two power systems to effectively advance their technologies. Understanding their overlap allows congruent efforts to target both systems; understanding their differences hinders conflict and redundancy in early-stage d...

Since phasor measurement units (PMU) were invented, there has been growing interest in developing methodologies for improving monitoring, protection and control of power systems in real time. In this study, the authors propose a new methodology, based on graph modelling, to identify coherent groups of generators in a real-time fashion. The coherent...

This paper presents the application of fault tree analysis to calculate the probability of failure of a substation monitoring system based on branch phasor measurement units. Results of the fault tree analysis are used in a reliability-based model for the contingency-constrained phasor measurement units (PMUs) placement to find the minimum number o...

A strategy to estimatethe power demand incrementfor Plug-in Electric Vehicles (PEV) penetration in residential customers is proposed. This is based on a stochastic model of arrivals and leavings of vehicles and has as goal to generate diversified load curves for every hour of a day, and so on, to estimate the power demand by Electric Vehicles. So,...

This paper proposes a general procedure to compute the load profile of a bus rapid transit station where a fleet of full-electric buses is charged. Such procedure is divided in two stages. At first, in order to determine if the flash charging is feasible given a certain travel route, the state of charge of a bus during its operation is modeled, bas...

Generally, stochastic point processes are employed in reliability analysis of repairable systems. However, when failures and reparations of these systems occur in a non-stationary trend over time, for example due to aging, it is required to use non-homogeneous Poisson process. In this paper, it is presented a general methodology for reliability ass...

Power security planning becomes an important issue in the actual growth of power system due to the dependence of modern society to a reliable, secure and flexible network. Major blackouts are started by cascade failures which successively weaken the system and make further failures more likely. It is recognized that the utilization of distributed g...

This study proposes a general procedure to compute the load demand profile from a parking lot where a fleet of buses with electric propulsion mechanisms are charged. Such procedure is divided in three different stages, the first one models the daily energy utilisation of the batteries based on Monte Carlo simulations and route characteristics. The...

as part of the correct operation of any electrical system it is necessary to guarantee the safety of the persons and the equipment or elements that constitute the system; therefore, the electrical traction systems must be furnished with a grounding system that takes into account their particularities and differences with regard to other electrical...

Since phasor measurement unit (PMU) was invented, there has been growing interest in developing methodologies for finding the minimum number of PMUs for complete system observability. The methods for the PMU placement must consider the fact that the network topology may change when the power system is affected by a contingency event. Therefore the...

This paper addresses two aspects of the optimal Phasor Measurement Unit (PMU) placement problem. Firstly, an ILP (Integer Linear Programing) model for the optimal multistage placement of PMUs is proposed. The approach finds the number of PMUs and its placement in separate stages, while maximizing the system observability at each period of time. The...

Situational awareness has become an important subject for the operation of power systems because it will give information of the state of functioning of the system and important data for taking control actions in the power systems. Among the different aspects to be included in the situational awareness to be monitored in a wide-area monitoring syst...

SUMMARY Active power filters have demonstrated effective harmonic compensation of dynamic nonlinear loads in DC traction systems. In this paper, it is proposed a practical methodology for allocation of active power filters in DC traction systems using the least number of filters and minimizing the size of them. Active compensation is placed at the...

The massive utilization of Plug-In Hybrid Electric Vehicles supposes more electrical loads that represent an extra effort for current distribution systems. This paper is intended to assess the impact of incorporating this new burden not only from a steady state perspective but also from a spectral viewpoint (harmonics performance) under a non-contr...

A genetic algorithm to find the optimal location and sizing of shunt FACTS devices is used to optimize a multi-objective problem, which is formed by first swing stability margin and voltage stability margin. The first swing stability margin is determined by analyzing the output results of the conventional time domain simulation method, basically, m...

The technological development and enhancement of new strategies related with Wide Area Measurement and Control Systems (WAMCS) is playing a key role with large interconnected power systems in order to assure stability under Low Frequency Oscillations (LFO). In this document a hierarchical intelligent controller scheme for multi-machine systems is p...

This paper proposes a procedure of adjustment of settings of overcurrent protections for distribution networks when distributed generation is incorporated in. Then, the procedure establishes the required steps to detect faults, isolate faulty zones, detect and create possible island modes, and finally restore the total operation of the system in or...

This paper proposes the identification of electromechanical modes based on signals obtained from Phasor Measurement Unit using a moving time window and a growing window during the post-disturbance state, considering both Prony's method and the Hankel's total least square method. Results show that the two methods can be used for online identificatio...

This paper presents a novel method for finding coherent groups of generators in large power systems, based on graph partitioning and clustering methods commonly used in other areas like image processing and gene expression analysis. First, the power system is modeled as a graph in order to obtain a maximum spanning tree that represents the stronges...

Due to its intermittent behavior wind speed supposes a WTG generating model of more than two states. Uncertainty in wind power implies a non-constant power output; hence, there are a risk of loss of capacity and loads. This paper proposes a multistate model of wind generating unit, to include the effect of wind variability besides conventional gene...

Due to its intermittent behavior wind speed supposes a WTG generating model of more than two states. Uncertainty in wind power implies a non-constant power output; hence, there are a risk of loss of capacity and loads. This paper proposes a multistate model of wind generating unit, to include the effect of wind variability besides conventional gene...

A methodology of visualization of the power system oscillation among operational areas is proposed based on PMUs measurements. The method is based on the definition of the center of inertia by operational areas based on phasor measurements on generation nodes. This visualization takes measurements of the PMUs in every single operation area and make...

Traditionally, repairs has been modeled in power system reliability as part of the component reliability models; an alternative way is to represent them by means of queuing theory concepts. One of the advantages of this approach is that it allows assessing the performance of crews, a feature not offered by any other method. However, the application...

The special integrated protection systems (SIPS) are alternative tools in order to improve the security of power systems that have been developed or formulated to mitigate the impact of particular problems when a disturbance occurs in the power system. This paper proposes a methodology of planning focused in the selection of sets of SIPS in a joint...

In this paper it is proposed a real-time stability index based on the wide-area measurement made by PMUs. The proposed index can identify inter-area stability problems based on two parameters mainly: the voltage magnitude change (reduction), and the phase angle movement (separation). The most considerable feature of this index is its fast and easy...

Sequential islanding is a strategy that consists of tripping off properly selected lines to separate the network into one or more islands as a way to improve the security of the power system. This paper proposes an application of some concepts of the spectral graph theory to identify the minimum cutset of transmission lines that allows the partitio...

In this paper graph theory is used to identify coherent groups of generators and to locate PMUs for Inter-Area monitoring. Initially, the problem of identifying coherent groups is presented as a graphical problem. Then, three graph clustering methods are implemented to group coherent generators. Finally, when the electric network is separated in co...

The post-mortem analysis of several blackouts has shown that cascade phenomena are involved in many of them. So, it is important to evaluate the power system vulnerability in the scope of this kind of events. This paper proposes a methodology to classify cascade events based on both interrupted load under a blackout and the time required by the sys...

It is expected that electric vehicles market growth is coming ahead due to ecological concern and energy efficiency maximization. As Plug-In Hybrid Electric Vehicles are by now the up to date development in the electric vehicles area and being aware of its plug to grid skills, it can be inferred that the new loads these represent could affect curre...

For studying the occurrence of high order failure scenarios (HOFS) in bulk power transmission systems, these authors presented in a previous issue of this journal a method based on stochastic point processes (SPP) modeling and Monte Carlo simulation (MCS) that in contrast to other ones can manage time varying failure rates and avoids the cumbersome...

Rectifier substations in DC electric transportation systems are an important source of harmonic distortion. One of the best compensation actions is to use active power filter due to its adaptation capacity to different load conditions. This paper presents a computational model of DC traction supply systems that allows the presentation of the curren...

High Voltage Direct Current (HVDC) technology has important characteristics which makes it attractive to connect two or more weak power systems, increasing the power transmission; or when the power systems are separated by long distances, in order to reduce electromechanical oscillations. However, CSC-HVDC technology has disadvantages related to th...

The n-1 reliability criterion has been applied extensively for power systems because the loss of two or more components over a short period due to independent failures has traditionally been considered not credible. However, the post-mortem analysis of some blackouts has shown that these kinds of events do occur; hence, the question about what cont...

El presente documento determina las demandas de las subestaciones rectificadoras y las metodologías para los esquemas de conexión entre ellas y las subestaciones reductoras de AT/MT requeridas para la integración de un operador férreo al operador de red.

This paper presents the typical characteristics in a massive electric traction transportation system using trams, such as size, weight and passenger capacity. It also describes the characteristics of the electric supply, like AC or DC, and the connection means to the medium voltage electric power distribution system like, for example, rectifier sub...

This paper presents a decentralized robust control scheme for two types of FACTS devices: SVC and TCSC, to enhance the voltage and angular stability in a power system. The robust control scheme is based on reduced order models, which are computed using the Hankel reduction theory. After that, computation of decentralized robust controls is proposed...

In power systems are normally localized linear controllers placed at several subsystems located in different geographical zones. In addition, there have been introduced new technologies of non-linear control, with applied methodologies of feedback linearization, where all the system is transformed to a linear system. Nevertheless, the decentralized...

The present paper develops a methodology to choose the best connection scheme for traction substations of a Massive Electrical Railway System (MERS) and distribution substations in urban areas using graph theory and economical optimization.

Los sistemas eléctricos de transporte masivo (SETM) se han convertido en una de las alternativas para solucionar los problemas de movilidad en zonas urbanas o interurbanas. En este artículo, se presenta la teoría que permite modelar y determinar la demanda de potencia eléctrica de los SETM, la cual sirvió de base para el desarrollo de un modelo com...

The electrified Mass Rapid Transit Systems (EMRTS) are one of the possible alternatives in solving mobility problems in urban and interurban areas. In this paper, we present the theory which allows modeling and determination of the EMRTS electric load, which serves as a base for the development of a computing model. The paper presents two examples...