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The paper presents a new wind power generation planning framework by considering the reactive power capabilities of generators. The motivation is to maximize the utilization of renewable power hosting capacity without violating the security constraints of distribution networks. The objective is to maximize the net present value of the investment considering the cost of grid energy transaction, initial...
The problems associated with the harmonics needs more attention as more number of distributed generators like PV and wind are integrated into a distribution system. Although the integration presents a lot of benefits, satisfying the needs of local load requirements by reducing the line losses and facilitating congestion management, the problems of power quality that impact the distribution system...
this study evaluates the impact of wind power generation connected to distribution systems. Three load profiles (residential, commercial and industrial) connected to the distribution network were analyzed considering the impact on voltage levels for different wind speeds and wind generator control strategies. The wind generator model is based on doubly fed induction generator (DFIG) and were developed...
This paper analyses the existing protection scheme of a real distribution system with distributed generators, in Greece. Network protection utilizes three successive reclosers at the main trunk and fuses at the laterals. The generating units are protected by overcurrent and voltage/frequency relays. The analysis focuses on the fault-ride-through capability of the generating units and proposes the...
This paper proposes a simple voltage stability index (VSI) to assess static voltage stability of a radial distribution system integrated with fixed speed wind generators. The proposed VSI guarantees existence of positive real solutions of bus voltage magnitude. All generators parameters are carefully incorporated into its equivalent circuit by retaining two internal buses in addition to terminal bus...
Conservation Voltage Reduction (CVR) has been an efficient way to achieve power demand reduction and, consequently, a relief in distribution networks. In this work is presented an assessment of the distributed generation (DG) impacts on the efficiency achieved with the CVR. The DG is considered as a controllable source of active and reactive power through an approach based on an integrated Volt-Var...
In the recent years there is a great interest in integration of distributed generation (DG) units at distribution level; this integration leads to planning as well as operational challenges. Some possibilities to handle grid planning issues are addressed in this paper. Effects on grid protection, fault current level, and voltage profile are investigated and described for different types of DG units;...
Wind generators are increasingly being integrated into high voltage transmission systems as well as low or medium voltage distribution systems. The increased penetration of wind generators into power grid may significantly change the system voltage profile, losses and other operating characteristics. This paper investigates the effects of wind generators on voltage profile and losses of a distribution...
An optimal distributed generation (DG) placement and sizing problem is formulated in this paper, for existing three-phase feeders and future microgrids. Similar to various optimal DG placement and sizing formulations, nonlinear AC power flow relations and binary selection variables representing presence (or absence) of DG units render the proposed optimization problem NP-hard. Nevertheless, a relaxed...
In the recent years the electrical power networks are undergoing rapid restructuring and developing process worldwide. Advancement in technologies and concern about the environmental impacts have led to increase interconnection of renewable energy based distributed generations (DGs) in distribution networks. The DGs have significant impacts on the distribution systems; these impacts may be either...
Distributed generation (DG) is more and more installed and integrated in the electric power systems, mainly in distribution networks. The conventional method of voltage control with on-load tap changer transformers is not efficient enough to deal with the growth of integration of distributed generators. The DG power regulation will contribute to optimize the steady voltage profile in network and thus...
The microgrid concept has the potential to solve major problems arising from large penetration of distributed generation in distribution systems. A microgrid is not a robust system when compared to a power system. Therefore, proper control strategies should be implemented for a successful operation of a microgrid. This paper proposes the use of a coordinated control of reactive sources for the improvement...
The selection of generation projects is based on the amount of energy consumption in the expected growth of demand in the amount of operating reserves and needs to regulate the system. A viable solution to meet energy needs and expansion of systems is the Distributed Generation - DG. Single source of DG does not guarantee economic generation, reliability, flexibility and controllability in energy...
Distributed Generators (DG) are generally modeled as PQ or PV buses in power flow studies. But in order to integrate DG units into the distribution systems and control the reactive power injection it is necessary to know the operation mode and the type of connection to the system. This paper presents a single-phase and a three-phase mathematical model to integrate DG in power flow calculations in...
The objective of this paper is to present the current status and state-of-the-art of microgrid systems as well as the barriers that are being encountered for their integration to the network. The expectation about the microgrid performance is high, thus, issues related to the microgrid standards, autonomous operation, control strategies, regulatory barriers as well as its protection and islanding...
The impact of distributed generation (DG) in a distribution network depends on the design of the protection system and the coordination between the different protective devices. This paper presents the main features of a library of protective devices implemented in an EMTP-type tool for power quality studies in distribution networks with distributed generation. The document discusses the present protection...
It is known that the increasing penetration of Distributed Generation (DG) implies different technical problems in the operation of distribution systems. This paper focuses the electrical Power Quality (PQ) aspects. DG can be responsible for different PQ problems, like poor voltage quality, unwanted protection trips on healthy feeders, and “islanding”. Voltage quality, in particular, can become a...
The impact of distributed generation (DG) on voltage sags in a distribution network depends on the design of the protection system and the coordination between the different protective devices. DG changes the radial nature of distribution systems and affects the performance of the protection system. This paper summarizes the impact of conventional synchronous machine-based DG on the present protection...
The thrust on renewable power generation is enthusing a large number of distributed generators to join the distribution system at varied locations. With multiple players in the emerging restructured market, regulators require a robust model for the complex problem of network cost allocation. In such an environment, Cooperative Game Theory provides a stable cost allocation model for network usage to...
This paper gives an overview of the design and operation issues in distribution and transmission systems due to the integration of distributed generation. The hosting-capacity approach has been developed to obtain a quantitative measure on the amount of generation that can be connected without impairing the performance of the system. The hosting-capacity approach requires a set of well-defined performance...
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