Different Types Of Distributed Energy Resources Research Articles

Energy management schemes for distributed energy resources connected to power grid

In a technically advanced world where demand is increasing very fast especially large number of non-linear loads and electric vehicles has led to energy crisis and pollution of grid power. Depleting conventional energy sources and environmental concerns has led to integration of large number of distributed energy resources (DERs) at distributional level to resolve problem of energy crisis and reduce emissions. With grid connected to different types of DERs, it is very challenging to manage the power flow, resolve energy crisis and maintain good power quality. Improper energy management may lead to inefficient operation of DERs and may build up stress on energy storage systems (ESS) impacting their life cycle. Thus, it is necessary to use energy management schemes (EMS) for efficient and reliable operation. EMS helps to enhance overall system efficiency and reduce the stress on ESS. This paper presents the analysis of different EMS applied on distribution system for efficient and economic operation of DERs and carryout stress analysis on ESS. Overall system efficiency, Hydrogen utilization in fuel cell, state of charge (SoC) of batteries and supercapacitor are the main parameters considered for performance comparison. To analyze the proposed work a simulation model is designed in MATLAB.

A Supervised Learning Approach for Centralized Fault Localization in Smart Microgrids

This article proposes a supervised learning approach for centralized localization of faults in microgrids with radial configuration that can operate in grid-connected or islanded mode. The key concept is to identify faults by learning and analyzing the features of voltage and current disturbances detected by a microgrid central protection unit. Two algorithms are developed that determine fault indices and transient features for simulation-based training, classification, and backup protection purposes. The proposed data-driven approach is effective under high penetration of distributed energy resources (DERs), and is robust under microgrid topology variations. Moreover, it requires few sensors (two for radial structure) and is easy to implement, yet provides high degree of reliability. The performance and accuracy of the developed approach are verified through extensive simulations of low-voltage microgrids that incorporate different types of DERs, including wind and solar photovoltaic systems.

Hosting a community‐based local electricity market in a residential network

This paper presents the potential of building a local electricity market (LEM) to boost the deployment of the local energy communities, centred around active customers with distributed energy resources (DERs). To conduct a comprehensive and detailed study on different cases with reduced computational burdens, this paper adopts a simplified modelling approach where the market and network model simulations are performed in a cascaded, decoupled fashion. This allows achieving the optimal LEM output for the energy community with different DER assets that are not bounded by the network constraints. The investigation involves quantifying the benefits brought by LEM to energy communities by tapping the flexibility associated with trading inside the energy community. Moreover, it presents the influence of different types of DERs (mainly photovoltaics (PV) and energy storage (ES)) in customers' premises on the outcome of the LEM. The LEM demonstrates successfully the reduction of cost associated with the energy purchased from the energy retailer and maximises the consumption of locally generated clean electricity. Among the studied DER portfolios, the combination of PV and ES solution shows the highest economic potential but deteriorates the voltage profiles and shows high active power loss in the winter month among all the cases examined.

Aggregate Temporally Coupled Power Flexibility of DERs Considering Distribution System Security Constraints

The proliferation of distributed energy resources (DERs) makes it possible for the transmission system operator to exploit the DERs' power flexibility. Modeling the aggregate power flexibility of different types of DERs in the distribution system continues to be a vexing scientific problem. This paper rigorously derives the exact mathematical expression of aggregate temporally coupled power flexibility of DERs considering linear distribution system security constraints. A flexibility optimization method and a backtracking elimination method are proposed to calculate the parameters in the aggregate flexibility model. Based on the exact model, an approximate model is proposed to reduce the complexity, which can be used for practical applications. We further developed a transmission system economic dispatch model considering the power flexibility of distribution systems. Finally, numerical tests are carried out on IEEE test systems to verify the correctness of the derived model and the effectiveness of the proposed methods.

A Decentralized Approach for Voltage Control by Multiple Distributed Energy Resources

The design of a decentralized control scheme is presented which is capable of counteracting voltage variations and offering the ancillary service of voltage regulation to the Distribution Network (DN) by acting on reactive and active power injections of Distributed Energy Resources (DERs). The design is based on a complete dynamic Multi-Input Multi-Output (MIMO) model of the distribution system with different types of DERs interfaced to the DN by inverters. Each DER is equipped with a state–feedback controller and two standard regulators of type PI and I, which realize the dynamic voltage adjustment, ensure null regulation error of voltage and active power at the Point of Common Coupling (PCC) and guarantee robust stability. This control objective is achieved without communication links among the local controllers and in presence of parameters uncertainty affecting the MIMO model. Finally, the proposed approach is validated by dynamic simulations on the IEEE 123 node test feeder with 15 additional DERs of three different types in presence of different scenarios of the distribution system, inaccuracy of the DN line parameters and voltage sags.

Characterization of non-intentional emissions from distributed energy resources up to 500 kHz: A case study in Spain

Narrow Band Power Line Communications (NB-PLC) systems are currently used for smart metering and power quality monitoring as a part of the Smart Grid (SG) concept. However, non-intentional emissions generated by the devices connected to the grid may sometimes disturb the communications and isolate metering equipment. Though some research works have been recently developed to characterize these emissions, most of them have been limited to frequencies below 150 kHz and they are mainly focused on in-house electronic appliances and lightning devices. As NB-PLC can also be allocated in higher frequencies up to 500 kHz, there is still a lack of analysis in this frequency range, especially for emissions from Distributed Energy Resources (DERs). The identification and characterization of the emissions is essential to develop solutions that avoid a negative impact on the proper performance of NB-PLC.In this work, the non-intentional emissions of different types of DERs composing a representative microgrid have been measured in the 35–500 kHz frequency range and analyzed both in time and frequency domains. Different working conditions and coupling and commutation procedures to mains are considered in the analysis. Results are then compared to the limits recommended by regulatory bodies for spurious emissions from communication systems in this frequency band, as no specific limits for DERs have been established. Field measurements show clear differences in the characteristics of non-intentional emissions for different devices, working conditions and coupling procedures and for frequencies below and above 150 kHz. Results of this study demonstrate that a further characterization of the potential emissions from the different types of DERs connected to the grid is required in order to guarantee current and future applications based on NB-PLC.

Determining optimal virtual inertia and frequency control parameters to preserve the frequency stability in islanded microgrids with high penetration of renewables

Preserving the frequency stability of low inertia microgrids (MGs) with high penetration of renewables is a serious challenge. To rise to this challenge, the inertia constant of MGs would be virtually increased using energy storages. However, it is important to determine the suitable value of inertia constant for these systems such that the frequency stability is preserved with a lower cost. Frequency droop coefficient of distributed energy resources (DERs) and load frequency controllers’ parameters would also affect the frequency response of MGs. Hence, in this paper, inertia constant is tuned together with frequency droop coefficient of DERs and load frequency controllers’ parameters. Determining these parameters is modeled as a multi-objective optimization problem and, because the number of objectives is higher than three, the problem is solved by a many-objective optimization algorithm. Comparative simulation studies have been done on an MG with different types of DERs to prove that using the proposed strategy for tuning the MG parameters not only the frequency deviation is highly decreased but also the amount of load shedding is considerably diminished. This would increase the customers’ satisfaction. Moreover, considering the inertia constant as a minimization objective, frequency stability would be preserved with a lower cost.

Optimal distributed energy resources planning in a competitive electricity market: Multiobjective optimization and probabilistic design

This paper presents a probabilistic multiobjective framework for optimal distributed energy resources (DERs) planning in the distribution electricity networks. The proposed model is from the distribution company (DISCO) viewpoint. The projected formulation is based on nonlinear programming (NLP) computation. The proposed design attempts to achieve a trade-off between minimizing the monetary cost and minimizing the emission of pollutants in presence of the electrical load as well as electricity market prices uncertainties. The monetary cost objective function consists of distributed generation (DG) investment and operation cost, payment toward loss compensation as well as payment for purchased power from the network. A hybrid fuzzy C-mean/Monte-Carlo simulation (FCM/MCS) model is used for scenario based modeling of the electricity prices and a combined roulette-wheel/Monte-Carlo simulation (RW/MCS) model is used for generation of the load scenarios. The proposed planning model considers six different types of DERs including wind turbine, photovoltaic, fuel cell, micro turbine, gas turbine and diesel engine. In order to demonstrate the performance of the proposed methodology, it is applied to a primary distribution network and using a fuzzified decision making approach, the best compromised solution among the Pareto optimal solutions is found.