Penetration Level Of Distributed Generation Research Articles

Multistage AC transmission expansion planning including fault current‐limiting high‐temperature superconducting cables and multiple distributed generations to improve short‐circuit level and grid‐scale flexibility

AbstractThis paper proposes a new multistage AC model for transmission expansion planning that finds an optimal combination of transmission lines, fault current‐limiting high‐temperature superconducting cables, and multiple distributed generations (DGs). On this basis, the proposed model, from a new perspective, allows for simultaneous improvement of the short‐circuit level and grid‐scale flexibility (GFLX) under both normal and fault conditions. The objective function to be minimized includes not only the net present worth of the total investment and operation costs but also the congestion‐induced GFLX degradation measure. This model also takes the AC power balance and flow relationships, equipment capacity limits, nodal voltage bounds, DG penetration level limit, as well as discrete logical and financial restrictions together into account with the short‐circuit level constraint. To overcome the complexity of solving the resultant non‐convex mixed‐integer non‐linear optimization problem, a multi‐objective integer‐coded melody search algorithm is employed, followed by a fuzzy satisfying decision‐making mechanism to obtain the final optimal solution. The exhaustive case studies conducted on the IEEE 24‐ and 118‐bus test systems verify the efficacy of the newly developed model in terms of cost‐effectiveness, flexibility, and short‐circuit level suppression when facing different normal and fault conditions.

AVALIAÇÃO DA INFLUÊNCIA DA INSERÇÃO DA GERAÇÃO DISTRIBUÍDA EM SISTEMAS DE DISTRIBUIÇÃO DE ENERGIA ELÉTRICA

This paper seeks to evaluate the impacts arising from the insertion of distributed generation (DG) in electrical power distribution systems. In this circumstance, using the OpenDSS computational tool, simulations of four different scenarios were carried out, varying the DG penetration levels as a function of the total feeder load, considering a specific point of operation. Finally, the same feeder was simulated with photovoltaic generating sources distributed in bars next to the loads, in order to analyze the temporal characteristic of solar generation as a function of demand. Through the simulations, it was possible to analyze, interpret and highlight the impacts that the insertion of DG produces in the electrical power distribution systems. It was evident that the increase in DG penetration led to an improvement in the feeder voltage profile, power flow inversion and reduction of electrical losses in the feeder. It should be noted that the insertion of DG from renewable sources is a Brazilian reality and a path to be followed, since the diversification of the energy matrix in line with the use of new technologies, such as smart grids, will provide electrical power systems with greater safety, operational efficiency and quality in the product delivered to consumers.

Distribution system reconfiguration based on MILP considering voltage stability

Reconfiguration of distribution network with consideration of voltage stability index (VSI) in the presence of distributed generation (DG) is a time consuming and complicated problem, which needs considering various technical constraints. Hence, in this paper a novel formulation based on the mixed integer linear programming (MILP) is proposed. Several linearization methods have been used to present a linear VSI. Network reconfiguration based on MILP not only increases accuracy and pace of solving, but also guaranties the optimal solution. Minimizing real power loss and improving VSI are the objectives of this problem. In addition, some constraints like branches currents, nodal voltage limits, radiality of distribution network, and penetration level of DGs are determined. In order to evaluate the performance of algorithm, the proposed method is tested on 33-bus and 69-bus radial network. All scenarios are simulated linearly and non-linearly in GAMS.

Microgrid Differential Protection Based on Superimposed Current Angle Employing Synchrophasors

The inclusion of multi-energy distributed generators (DGs), especially inverter-interfaced generators, presents challenges in the microgrid's protection strategy and operational constraints. The work for designing primary protection mechanism for microgrid is continuously progressing. In this regard, this article presents a positive sequence superimposed current differential angle (SCDA) based protection scheme employing only positive sequence current phasor from both ends of the line. The proposed scheme collects current phasor measurements from the low-cost micro-phasor measurement units ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula> PMUs). The performance of the proposed scheme is analyzed through simulations on a 7-node microgrid in grid-connected and isolated mode operation under various fault and no-fault situations, and also considering the effect of DG penetration level and DGs types. The simulations are also carried out in the IEEE-33 node network considering C37.118.1 standards-compliant PMUs. Furthermore, a real-time control hardware-in-loop (RTC-HIL) testing is performed to further validate the scheme for practical implementation.

태양광 시스템의 침투 및 스위칭에 따른 임계 주파수 제한 시간 결정 및 과도상태 영향 분석

For carbon neutrality, many countries are increasing the rate of renewable energy-based distributed generators (DGs). The DG has advantages such as voltage drop compensation and power loss reduction. However, reverse current flows and overvoltage phenomenons occur due to the penetration of DGs. DGs have different output characteristics from synchronous generators, so when DGs penetrate the grid, DGs inevitably affect the power flow and power quality of the grid. Therefore, it is necessary to check transient stability when DGs penetrate the power system. In this study, the IEEE 9-bus system, a looped system, was set as a testbed. In addition, inverter-based photovoltaic (PV) systems were used as an example of DGs. And the critical frequency limitation time was determined according to the penetration level of DGs. This study also checked the effect of reducing frequency variations through specific methodology of the PV system. Events such as fault occurrence, switch opening, fault clearing, and switch closing were set. And all the simulations for the transient analysis were conducted through DIgSILENT Power Factory.

Impact of Distributed Generators Penetration Level on the Power Loss and Voltage Profile of Radial Distribution Networks

The Distributed Generator types have different combinations of real and reactive power characteristics, which can affect the total power loss and the voltage support/control of the radial distribution networks (RDNs) in different ways. This paper investigates the impact of DG’s penetration level (PL) on the power loss and voltage profile of RDNs based on different DG types. The DG types are modeled depending on the real and reactive power they inject. The voltage profiles obtained under various circumstances were fairly compared using the voltage profile index (VPI), which assigns a single value to describe how well the voltages match the ideal voltage. Two novel effective power voltage stability indices were developed to select the most sensitive candidate buses for DG penetration. To assess the influence of the DG PL on the power loss and voltage profile, the sizes of the DG types were gradually raised on these candidate buses by 1% of the total load demand of the RDN. The method was applied to the IEEE 33-bus and 69-bus RDNs. A PL of 45–76% is achieved on the IEEE 33-bus and 48–55% penetration on the IEEE 69-bus without an increase in power loss. The VPI was improved with increasing PL of DG compared to the base case scenario.

A data‐driven inertia adequacy‐based approach for sustainable expansion planning in distributed generations‐penetrated power grids

Reduced rotational inertia in power grids due to increasing penetration levels of distributed generations (DGs) may lead to degraded performance of the traditional frequency control scheme. In response to this challenge, inertia adequacy has recently emerged as a new research area in modern power systems. Accordingly, an attempt is made in this paper to tackle inertia adequacy in the generation expansion planning (GEP) problem. This in turn helps to realize sustainable economic development. For this purpose, the inertia adequacy constraint is tied to the frequency stability metrics. In other words, minimum permissible inertia that satisfies frequency dynamic standards is defined as an inertia adequacy constraint in the GEP formulation. Further, an experimentally validated model of a cluster of DGs is employed to realize a penetrated power grid to deal with sustainable planning development. Finally, an iterative-based algorithm is proposed to expand the system with minimum cost and with the highest permissible penetration level of DGs. The effectiveness of the proposed algorithm is examined in the Garver test system.

Optimal Location and Sizing of BESS for Performance Improvement of Distribution Systems with High DG Penetration

This work proposes an optimal location and sizing of battery energy storage system (BESS) installation for performance improvement of distribution systems with high distributed generation (DG) penetration level where the DGs comprise photovoltaics (PV) and wind turbines (WT). The installation of the BESS can reduce costs incurred in the systems, alleviate reverse power flow when the systems are in the high DG penetration level, and also achieve peak shaving during high demand. To find the optimal location and sizing of the BESS, three optimization algorithms, genetic algorithm (GA), particle swarm optimization (PSO), and salp swarm algorithm (SSA), are applied, and their performances are compared. The considered objective function is the system costs consisting of transmission loss cost, peak power cost, and voltage deviation cost. The system performance improvement is compared in terms of transmission loss, peak demand, and voltage regulation reductions. IEEE 33- and 69-bus distribution systems with high DG penetration are tested to investigate the performance improvement of the BESS installation. The results found that the installation of the BESS could successfully decrease system cost, improve voltage profile, reduce power losses, alleviate reverse power flow, and achieve peak shaving where PSO and SSA are found to be the best competitive algorithms. So, the proposed method can be further applied to find the optimal location and sizing of the BESS to improve the performance of practical systems in the future.

An Investigative Analysis of the Protection Performance of Unbalanced Distribution Networks With Higher Concentration of Distributed Energy Resources

Despite the substantial reliability and power quality improvements, the proliferation of distributed energy resources can introduce many protection complexities in distribution networks (DNs). This research article presents a comprehensive investigative analysis of the distributed generation (DG) impacts on the protection performance of the DN. Various protection coordination case studies have been analyzed under different operating conditions by varying the DG penetration level or the fault conditions to highlight the potential risks of the protection networks. The severity of the risks is evaluated by considering the DG locations, protection settings, and fault types/impedance parameters on a standardized IEEE 13 node test feeder in DIgSILENT Power Factory/MATLAB softwares. The subsequent protection hazards are examined for the mutual coordination of the overcurrent relays, auto-reclosers, and series fuses in DNs along with the differential protection issues for dc bus system. Furthermore, the impacts of DGs/PDs types are assessed on the nuisance tripping of the protection networks and results are reported.

A Robust Fault Detection and Location Prediction Module Using Support Vector Machine and Gaussian Process Regression for AC Microgrid

Better reliability of power supply is assured with the inculcation of distributed generators (DGs) in a distribution network. Smart sensors and latest grid communication protocols have played a crucial role in the development of intelligent microgrids (MGs). Conventional protection schemes do not provide reliable performance when implemented in MGs. This article proposes an approach which requires root mean square value of one cycle three -phase voltage and current measurements during fault. These data are treated as inputs for developing a fault isolation and locator module. This module is supposed to be available at central protection system, and is designed using machine learning (ML) based techniques viz. Gaussian process regression for fault location prediction and support vector machine for fault identification. Effectiveness of the proposed methodology is evaluated by considering practical grid scenarios with load variation and different DG penetration level. Furthermore, the robustness of the proposed model is assessed by performing sensitivity analysis with consideration of variation in line parameters and load as well as effect of DG correlation. A 7-bus meshed ac MG test system consisting of three DGs and two grid sources is modeled in SIMULINK platform, and is used to demonstrate the proposed module. Data analytics tools of MATLAB 2020a has been explored to develop an ML-based fault isolation and location module for MGs. The proposed scheme has also been validated with real-time MG data obtained from OPAL Real time (OPAL-RT) real-time simulator OP-4510. The accuracy in predicted results proves that the proposed scheme is pertinent for real-time practical applications.

Enhancement of Large Renewable Distributed Generation Penetration Levels at the Point of Common Coupling

The occurrence of distortion and over voltage at the Point of Common Coupling (PCC) of Renewable Distributed Generation (RDG) limits its penetration levels to the power system and the RDG integration is expected to play a crucial role in power system transformation. For its penetrations to be sustained without disconnection from the system, there must be a solution to the voltage rise, distortion, unbalanced current and grid reactive power control strategy at PCC. It is an IEEE-1547 requirement that RDG integration to the power system should be regulated at PCC to avoid disconnection from the network due to power quality criteria. RDG integration must meet up with this specification to uphold power quality and avoid damage to the sensitive equipment connected at PCC. In this paper, voltage rise, unbalanced current, reactive power and distortion are being managed at PCC while Distribution Network (DN) accepts more RDG penetration levels without violation of the IEEE and South Africa grid code act. Active Power Filter and Full Bridge Multi-Level Converter (FBMC) are considered to safeguard power quality to the grid, they are modelled in MATLAB/SIMULINK and the results obtained shown that the proposed strategy can successfully regulate voltage rise, distortion, unbalanced current and continuously improve power quality with RDG integration at PCC. The proposed method's key innovation is the strategic generation and absorption of reactive power to curtain an overvoltage, reverse power flow, and distortion at the PCC, allowing more RDG penetration levels to the grid without disconnection while maintaining the standard requirement for power quality at the PCC. The simulation outcomes validate the superiority of the FBMC over the active power filter with respect of reactive power generation/absorption, dynamic response, and damping capability.

A Control Strategy to Mitigate the Sensitivity Deterioration of Overcurrent Protection in Distribution Networks With the Higher Concentration of the Synchronous and Inverter-Based DG Units

This article focuses on the indeterminate protection challenge of the sensitivity deterioration (SD) (also known as protection blindness) of the overcurrent protection (OCP) devices due to the large-scale integration of distributed energy resources (DERs) in the unbalanced distribution networks (DNs). The protection blindness of the OCP has been demonstrated through novel mathematical formulations to quantify the percentage of the SD for different types of distributed generation (DG) units and for the varying DG penetration levels. Furthermore, this issue has been realistically analyzed for the different fault impedances and DG locations to examine its impact on the existing OCP system. A mitigation strategy has been proposed to overcome the SD issue of the OCP protective devices (PDs) for a steadfast operation of the OCP devices without requiring costly upgrades of the protection system. This protection blindness issue has been explored and the mitigation strategies have been tested for both synchronous and inverter-based DGs using the IEEE standardized test feeders. The proposed mitigation strategy has been validated in the IEEE 34-bus test system. The simulation results prove the effectiveness of the proposed mitigation strategy to restore the protection coordination and suitability to improve grid resilience.

Protection philosophy for distribution grids with high penetration of distributed generation✰

Distributed Generation (DG) can cause several problems in electrical systems that are not prepared to deal with these new sources: situations such as bidirectional power flow and large variations in short-circuit current values. This article presents changes in the actual distribution systems protection philosophy that intend to make the protection system always work properly and reliably eliminate any short-circuit. Furthermore, it shows that the actual philosophy is inefficient in systems with high DG penetration level and, through modifications in the actual philosophy, using available functions in the protection devices, it is possible to increase the reliability and assertiveness of the protection system for any fault.

A novel method for determination of maximum penetration of distributed generation in radial distribution network

ABSTRACT The several benefits of distributed generation (DG) have encouraged the utility companies for the integration of different DG technologies in the radial distribution network. The large penetration of DG units has significantly influenced the voltage stability of the radial distribution network. In this paper, in order to determine the penetration level of DGs in the radial distribution network, a static voltage stability index (VSI)-based method has been explored for the identification of optimal locations at various penetration levels. The proposed method is compared with modal analysis-based optimal placement method at the various penetration levels of DGs. For the identification of the maximum penetration level (PL) of DGs in the radial distribution network, the IEEE 33 and 69 node radial distribution network with various DG penetration levels, i.e. 20%, 40% and 60% have been utilised in this study. The results show that the placement of DGs at nodes sensitive to voltage collapse has increased the voltage stability margins (VSM). It is also observed that the DGs penetration level beyond a certain limit have an adverse effect on static voltage stability margin and power losses of the network.

Switching Analysis of Power Distribution Network Including Distributed Generations Using ATP.(Dept.E)

The distributed generation (DG) emerged as an ideal option deals with the growth in electricity demand. With such a new system there is always a chance of some transient disturbances. A transient can be caused by a number of power system switching events or faults such as lightning strikes, short circuits, or equipment failure. The purpose of this work is to identify the best location of DG connection and if the DG should be concentrated in one location or distributed among different location in distribution network as well as identifying the suitable DG penetration level that can be inserted without affecting the distribution system voltage stability or its power quality based on the European technical standard and the Standard for Interconnecting Distributed Resources with Electric Power Systems IEEE-1547 standard. To achieve these goals, a transient simulation is developed for DG energization with different penetration levels and different locations on power distribution network to investigate voltage stability and power quality of the distribution system. The DG can greatly affect the voltage profile, reverse power flow, power quality, and so on. General purpose Alternative Transients Program (ATP) version of Electromagnetic Transient Program (EMTP) is used to accomplish the above goals. IEEE 13 node test feeder distribution system is used in this work.

Exploration of DG Placement Strategy of Microgrids via FMFO Algorithm: Considering Increasing Power Demand and Diverse DG Combinations

Distributed energy resource (DER) has been widely deployed, and distributed generation (DG) can complement the distribution system. Favorable DG deployment provides the grid-connected microgrid (MG) with stable voltage and reduces emission and power generation costs. DGs are considered distributed feeders, and MG is required to be operated under the optimal state. Reconfiguration is a practical approach to optimizing resource allocation. The optimal global solution is obtained via optimization algorithms. In this paper, three objectives are defined, namely, minimization of economic cost (ECC), emission cost (EMC), and voltage deviation (VD). Consequently, a fuzzy moth-flame optimization (FMFO) algorithm is proposed to coordinate the interests of multiple objectives. Moreover, the simulation is conducted based on the standard IEEE 33-bus radial distribution system (RDS), under which the impact of deployment of various DG type and quantity on the MG is explored. In particular, diverse DG combinations are tried under the increasing power demand, and a high-stable voltage strategy is proposed to meet the specific demands. The simulation results reveal that: (1) the DG type has a significant impact on ECC and EMC; (2) penetration level of DG shows a positive-like relationship with the MG stability; and (3) the proposed FMFO algorithm exhibits an efficient performance in convergence.

Acceptable DG Capacity for Radial Distribution System Based on Traditional Protection Scheme (Dept.E)

Traditional electric distribution systems are radial in nature. These networks are protected by very simple protection devices such as over-current relays, fuses, and reclosers. Recent trends in distributed generation (DG) and its useful advantages perfectly can be achieved while the relevant concerns are deliberately taken into account. For example, penetration of DG disturbs the radial nature of traditional distribution networks. Therefore, protection coordination will be changed in some cases, and in some other cases it will be lost which is very costly in that two cases. In developed countries it could be cost effective if adding DGs network keeping the traditional protection system unchanged. To tackle that point of research, authors proposed technique to maintain the old protective devices coordination unchanged up to a specific DG penetration level. In this paper, a framework is presented for determining the maximum capacity of DG penetration level to keep traditional protection scheme for distribution network unchanged. Applying that framework in the developing countries could save money and time during the integration of DGs to the network on a large scale based on country regulation. The proposed framework is implemented on a simple distribution network using MATLAB SIMULINK and finally the numerical results are presented in order to validate the suggested framework.

A Hybrid Optimization Approach for Power Loss Reduction and DG Penetration Level Increment in Electrical Distribution Network

The electrical distribution system has experienced a number of important changes due to the integration of distributed and renewable energy resources. Optimal integration of distributed generators (DGs) and distribution network reconfiguration (DNR) of the radial network have significant impacts on the power system. The main aim of this study is to optimize the power loss reduction and DG penetration level increment while keeping the voltage profile improvements with in the permissible limit. To do so, a hybrid of analytical approach and particle swarm optimization (PSO) are proposed. The proposed approach was tested on 33-bus and 69-bus distribution networks, and significant improvements in power loss reduction, DG penetration increment, and voltage profile were achieved. Compared with the base case scenario, power loss was reduced by 89.76% and the DG penetration level was increased by 81.59% in the 69-bus test system. Similarly, a power loss reduction of 82.13% and DG penetration level increment of 80.55% was attained for the 33-bus test system. The simulation results obtained are compared with other methods published in the literature.

Multi-Criteria Optimal Sizing and Allocation of Renewable and Non-Renewable Distributed Generation Resources at 63 kV/20 kV Substations

The optimal allocation and sizing of distributed generation (DG) resources are important in installing these resources, to improve the technical parameters of the network, including the power losses, voltage profile, and short-circuit level, as well as to increase economic factors. In this paper, a new multi-criteria algorithm and objective function are proposed for the optimal sizing and allocation of renewable and non-renewable DG resources simultaneously. The proposed algorithm is implemented on 63/20 kV substations at 20 kV levels. In the proposed objective function, all important technical and economic factors as well as important constraints, such as penetration level of DGs and budget constraint, are considered in a way that all factors are assigned to monetary values. Moreover, a new mathematical formulation is introduced for the allocation of renewable DG resources to reduce run-time optimization. The genetic algorithm (GA) is employed in the proposed algorithm to minimize the objective function. For renewable DG resources, photovoltaic panels and wind turbines, and for non-renewable DG resources, gas turbines are considered. The 115 buses network of Bakhtar Regional Electric Company (BREC) in Iran is used to evaluate the performance of the proposed algorithm. The results demonstrate that the proposed algorithm improves technical factors efficiently and maximizes the profitability of the investment.

Optimal Directional Overcurrent Relay Coordination Using Artificial Immune Algorithm. (Dept. E. )

window.dataLayer = window.dataLayer || []; function gtag(){dataLayer.push(arguments);} gtag("js", new Date()); gtag("config", "UA-72322659-1");