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This work proposes a novel frequency regulation paradigm for multi-area interconnected power systems. The developed approach capitalizes on phasor measurement units (PMUs) advanced monitoring to overcome design limitations imposed by legacy supervisory control and data acquisition (SCADA) systems. For this, a novel measurement-based controller integrating primary and secondary regulation is proposed. First, taking advantage of PMUs synchronized measurements, novel centralized corrective actions are developed using dynamic data aggregation. These actions provide a foreknowledge of generators expected steady-state during the system dynamics, significantly improving the system frequency rebound and steady-state realization while ensuring null area control errors (ACE). Next, a new local power system stabilizing perspective is developed. This controller provides local counterweighting actions allowing for faster corrective actions without compromising the system dynamic response, i.e., mitigating oscillations and overshoots. The proposed approach design considers monitoring and communication system non-idealities, such as: latency, processing and waiting time, measurements synchronization and sampling resolution. In addition, stability and steady-state objectives are mathematically demonstrated, and comparative simulation case-studies developed. Obtained results indicate a meaningful improvement of power systems frequency regulation and reliability, including faster steady-state realization and rebound, mitigation of oscillations and overshoot, improved service capacity and higher reliability to cascade events.

This paper proposes a novel frequency regulation outlook focused on the improvement of islanded microgrids resilience. The proposed method takes advantage of power systems enhanced situation awareness enabled by distribution-level phasor measurement units (D-PMUs) monitoring to overcome current design boundaries that limit an effective harnessing of flexible resources potential to support microgrids resilience. For this, capitalizing on D-PMUs high resolution, low latency and time synchronized measurements, a beforehand assessment of the power mismatch leading the microgrid to frequency nadir condition is achievable during the early stages of the system dynamics. Based on this information, new measurement-based control modules are designed to address individual stages of the frequency regulation process in a dedicated manner, respectively arrest, rebound and recovery stages. These controllers provide a significant improvement of microgrid's frequency arrest and rebound ability, while ensuring a smooth recovery process toward the system steady-state realization. The proposed approach stability is mathematically demonstrated and comparative case-studies developed considering monitoring and communication systems non-idealities. Obtained results indicate the proposed controller superior ability to address single and cascade large-scale disturbances, while simultaneously providing an improved frequency regulation performance and greater economic benefit for flexible resource support.

Seeking the improvement of frequency and voltage regulation of distributed energy resources (DERs) in islanded microgrids, this paper presents a novel distributed control paradigm based on distribution-level phasor measurement units (D-PMUs) monitoring. First, a novel strategy denoted synchrophasor aggregation is proposed. This strategy takes advantage of the high resolution, low latency and time-stamped synchronized measurements provided by D-PMUs to obtain a local foreknowledge of DERs steady-state operating condition during the system dynamics. Based on this information, novel measurement-based control parcels are developed to provide stabilizing and corrective adjustments of generators contribution. These controllers are able to effectively improve DERs dynamic performance, i.e. damping oscillations, overshoot and frequency nadir, while significantly speeding-up the realization of steady-state goals. Stability proof and steady-state analysis are developed. Comparative case-studies with state-of-art controllers, as well as with traditional SCADA systems, are conducted to evaluate the performance and robustness of the proposed controller under different scenarios, including: loading variation, communication failure, loss of generation, and plug-and-play capacity. Results showcase the proposed controller ability to significantly improve islanded microgrid regulation.

This paper proposes a secondary frequency control approach for distributed energy resources (DERs) in networks operating in stand-alone mode; i.e., islanded microgrids. The proposed approach takes advantage of the high resolution, low latency, and time-stamped synchronized measurements of the distribution-level phasor measurement units (D-PMUs) to iteratively adjust the generators contribution, considering the D-PMUs derived active power information, in a way that improves the dynamics of the islanded microgrid frequency regulation. These adjustments are performed using a novel adaptive time-variable droop characteristic capable of significantly speeding-up the secondary frequency regulation, mitigating oscillations, and reducing the frequency nadir. The proposed secondary frequency control can be held after the stabilization of the primary control, as well as simultaneously with the primary frequency regulation. Results show the effectiveness of the proposed approach in significantly improving the frequency regulation of islanded microgrids.

Smart initiative concepts as smart grids, cities, and microgrids are redefining the electrical power system. This new scenario enables a completely new perspective of applications that lead to a path of general improvement of grid performance, in which the participation of plug-in electric vehicles has great importance. In this view, this work proposes a comprehensive operation strategy of plug-in electric vehicles for unbalanced smart microgrid environments. The first contribution is the grid-to-vehicle strategy based on buses availability of power whose primary objective is the maintenance of satisfactory operating conditions for the grid while controlling the plug-in electric vehicles charging. The second contribution relates to a holistic vehicle-to-grid coordinated approach, which is triggered in the event of microgrid islanding. The goal, in this case, is to assist the network by using the plug-in electric vehicles available stored energy. At last, the main contribution is obtained by the combination of both methodologies providing a comprehensive operation of plug-in electric vehicles for smart microgrids environments. The proposed method is designed for general three-phase unbalanced distribution systems with a wide range of resources and present versatility in the communication requirements. For validation, simulations are performed in a comprehensive unbalanced three-phase distribution system considering different disruptive scenarios faced by microgrids. The results indicate that the proposed methodology is satisfactory and ensure the operation of the microgrid within acceptable limits in both connected and islanded situations.

The coordination of the available resources at the distribution system level can provide great opportunities to overcome many system challenges. Among the main features, distributed generators, renewables, and flexible loads, which may also become flexible resources such as electric vehicles and storage units, are a special branch with a great capacity to assist distribution system planning and expansion assessments. In this perspective, this chapter presents a smart coordination of these new features for improved distribution system planning. Because of this, controlled operation of flexible loads, local primary and secondary control strategies, and grid assistance application of flexible resources are developed. To validate the proposed methodology a holistic operative scenario with multiple events is presented. The results indicate that the coordinated operation of flexible resources can offer great solutions for many power system necessities as phase balancing, peak shaving, and mitigation of transmission congestion. Furthermore, the support provided by flexible units significantly improves system operative reality, allowing possible deferral of investments in new infrastructures and renewal of equipment.

The continuous developments toward active distribution systems have been providing the necessary conditions for islanded microgrids operation. In this mode, the islanded regions are expected to sustain the system operation within adequate limits, locally performing several control actions previously assumed by the main grid. Among these controls, the guarantee of generation/demand balance is one of the most critical aspects, which due to the limited amount of generation capacity can lead to massive load shedding. In this perspective, this paper seeks to evaluate the effects of plug-in electric vehicles (PEVs) in the improvement of islanded microgrids resilience. For this, a holistic methodology is proposed to determine whether the implementation of sophisticated controls for the use of PEVs as flexible resources render actual benefit for the islanded network. Simulations are held in the IEEE 34-bus test system considering modifications to represent a microgrid environment. The results indicate that the application of PEVs as flexible resources can significantly enhance microgrids resilience in the mitigation of load shedding.

Voltage stability margins of modernbulk power systems are significantly affected by renewable energy sources (RESs). The intermittency of these units can constantly move the critical location driving the system to voltage collapse along different coherence regions. Traditional approaches were not designed to deal with this scenario, typically providing a centralized actuation based on a system-wide perspective. In this sense, this paper proposes a novel area-based outlook to take advantage of the new possibilities enabled by power systems distributed controllable resources, e.g. flexible resources, to tackle this critical operational challenge. For this sake, a novel area-based sensitivity index, exploring both the network-wide sensitivity and the local characteristics of voltage collapse is proposed to determine the most effective buses for voltage support and their respective capability of increasing the system's load margin. Comparative case studies indicate the superior capability of the proposed direct method to deal with the new perspectives of modern power systems.

The increasing penetration of variable renewable energy sources (RESs) is introducing critical challenges to the power system operation. In this perspective, this paper proposes a novel method for the improvement of the static security region (SSR) based on a new network partitioning algorithm. The proposed algorithm focuses on modern power systems with high penetration of variable RESs generation. It divides the power system in coherence areas according to its criticality mapping. To this end, each bus is assigned a criticality index from the potential energy function, whereas this calculation is based on the data of the wide-area measurement system (WAMS) using phasor measurement unit (PMU). Afterwards, the obtained coherence areas are employed to adaptively determine the generators groups applied to the system SSR assessment in the short-term horizon. To validate the proposed approach, several cases studies are conducted on the IEEE 118-bus system. The results demonstrate the potential of the proposed methodology in the SSR improvement.

In stand-alone operation, microgrids are susceptible to potential shortages in generation capacity, requiring a consideration of all technically feasible opportunities to conserve energy in order to keep the islanded grid operational for as long as possible. In this sense, the network autonomy capacity must be considered in the islanded microgrid frequency control formulation, alongside the traditional concern related to the accomplishment of the dynamic frequency regulation requirements. This paper proposes a new outlook for secondary frequency regulation in islanded microgrids denoted as conservation frequency reduction (CFR). The proposed approach exploits the frequency dependency characteristics of microgrids by intentionally reducing the reference setpoint of the islanded network frequency in a controllable way in order to decrease the network’s demand and improve the autonomy duration of islanded microgrids, i.e., availability to supply demand in islanded mode; while ensuring the system operation within permissible limits. The results indicate that the proposed approach is able to significantly enhance islanded microgrids autonomy capacity while guaranteeing its frequency of operation within satisfactory dynamic and steady-state limits.

A comprehensive perspective of the adequate position of storage technologies regarding different applications and discharge times is given. In this chapter, storage applications are primarily focused on the transmission and distribution (T&D) systems by considering the significant increase in renewable sources insertion.

This paper proposes an adaptive secondary control to islanded microgrids focused on autonomy enhancement and power quality, thus establishing an increase in its survival upon being islanded and guaranteeing its operation within established limits. The proposed control defines the contribution parcel of each storage unit for the frequency regulation based on how much energy is available in each unit and the actual microgrids’ frequency level. The influence among dispatchable units is also analyzed. To validate the results of the proposed control model, the comparison between a traditional and the proposed secondary control strategy is made. The modified IEEE 34 bus system considering the insertion of energy storages devices is employed as the case studies. The analyses were held for three scenarios of communication infrastructure: without communication, with implicit communication, and with full communication. The results show great improvement in autonomy when the proposed control method is implemented.

This work presents an unbalanced three-phase frequency dependent load flow for microgrids at distribution level considering the insertion of renewable energy sources, distributed generation and frequency dependent loads. To assess the frequency influence on microgrids, the IEEE 34 Bus test feeder was employed. Further, simulations were held for both traditional and frequency dependent load flow approaches. The results indicated that the frequency dependency interaction accounted by the proposed methodology provides a more realistic scenario leading to a better-conditioned microgrid operation, which is fundamental for islanded system studies when compared to the traditional approach, which provides a more pessimistic perspective.

This chapter presents a comprehensive perspective of the application of Smart Grid technologies in Brazil. The main motivations, projects, thematics covered, amount of investment, regional distribution, and research and development activities are some of the addressed aspects. Furthermore, an overview of the Brazilian road map for Smart Grid deployment is followed by lessons learned while diagnostic and barriers obtained from previous and ongoing projects are stressed. Finally, the actual level of maturity of the Smart Grid concepts in Brazil and a discussion about the necessities of an integrated effort of government, industry, utilities, and research/academic institutions in establishing dynamic standards of good and acceptable enactments within all dimensions for a complete engagement is presented.

This paper addresses the influence that different type of loads and renewable distributed generation have in microgrids load margin. Considering different load types, in order to bring the system closer to a practical case, and renewable generation is fundamental given its ascension in the latest years. To validate this analyses, the IEEE 57 bus transmission system was employed. Simulations were performed for different amount of renewable generation penetration, being each scenario performed for all the different load types considered. The results indicate significant variations in microgrids load margin are greatly influenced by the load type and the share of renewable sources present in the system.

The demand profile knowledge is vital for a wide variety of power systems studies. Furthermore, meaningful information may be obtained regarding optimization and maximization decision-making strategies that may help a wide variety of consumers optimize their facilities usage, redefine low priorities equipment operating hours, as well as promote actions seeking production increase. With the spread of Smart Grids, this data is becoming easily available through the complete system range. Therefore, this study proposes a processing methodology that aims to make the information hidden at the load profile readily accessible at any level. For this sake, two processing stages are employed, first the profile is filtered by a Windowed Sinc filter and then a linearization process is performed. To validate the methodology high, average and low demand profiles from the Centre of Excellence in Smart Grids (CERIn) were considered. The results exhibit an efficient methodology capable of clearly provide meaningful information regarding the demand profiles.

As modern society electrical energy consumption requirements increase, a growing need for more efficient and lower costs power electronics processing devices is featured. Even though this kind of devices have high efficiency, it creates a problem by injecting harmonic currents. This paper aims to address the harmonic distortion impact caused by non-linear loads and renewable generation on a typical university research building connected at the distribution system level. For this sake, actual data from the Centre of Excellence in Smart Grids (CERIn) featuring Uninterruptible power supply (UPS), Relays, Real Time Digital Power System Simulator (RTDS) and distributed generation (DG) were considered and three occupancy rates were held, low, average and high scenario. The results indicate desktop computers as major contributors to the harmonic losses. For special loads, the UPS 5th harmonic presents itself as the second greatest influence, while Relays and RTDS have an average participation. These results allow a better understanding and definition of measures to reduce the harmonic impact, cancellation techniques and filtering.

Power systems are under a huge transformation because of the growing penetration of renewable sources. In this sense, microgrids may become a reality, since local sources and manageable loads and batteries may help the system to be self-sustainable under emergency conditions. This paper proposes a three phase power flow for microgrids which considers the droop method. Hence, frequency and voltage level at the sources may vary. The proposed approach is tested with the help of a modified IEEE 34 test system.

Harmonic contents are a growing and challenging problem. The increasing number of electronic appliances and the use of adjustable speed drivers (ASD) in fridges, dryers and washers as well as the insertion of distributed generation (DG) in smart grids using power electronics converters are some of many generators of harmonic contents presented in distribution systems. This study proposes an approach to identify the harmonic losses generated by appliances in distribution power systems likely to microgrid environments considering DG and susceptible of islanding. To develop this methodology models of appliances using real data measurements associated in different scenarios are created. A typical distribution system multi grounded neutral (MGN) is employed to determine the impact that each appliance harmonic contents have in the distribution power system technical losses.