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This paper proposes a method for a coordinated control of LRT and power factor by means of a multi-agent approach. The proposed multi-agent system consists of two types of agent: substation agent (S_AG), and bus agent (B_AG). In the proposed system, the S_AG decides the LRT tap position according to the information from B_AGs, while the B_AG decides the power factors of the distributed generator (DG)...
This paper demonstrates the already established fact that by using Distributed Generation (DG), voltage profile of a distribution system can be improved. N-R method is used for load flow analysis. A standard IEEE 14-bus power system is used. To reduce losses three optimization techniques i.e. PSO(Particle Swarm Optimization), GSA(Gravitational Search Algorithm) and hybrid PSOGSA is applied to the...
In this paper, we present a day-ahead optimal scheduling for reactive power of PV inverters and tap position of on-load tap changer (OLTC) in distribution network. We used a pattern search optimization algorithm based on the forecasted load demand and PVs active power generation. While the objective is to minimize the node voltage deviation and network losses, the maximum number of tap operation is...
This paper presents a model for a MV/LV bidirectional solid state transformer (SST) for distribution system studies. A multilevel converter configuration is used in the MV side for voltage and current harmonic reduction. The model has been implemented in the ATP version of the EMTP. Several case studies have been carried out in order to evaluate the behavior of the SST model under different operating...
In order to meet requirements of distributed generator (DG) integration with distribution system and real-time simulation, a novel voltage optimization algorithm which is used to solve the active power output of DG units in distributed environment is presented in this paper. Firstly, an automatic partitioning method based on hierarchical agglomerative clustering (HAC) is proposed to decompose the...
In this paper, a distributed control method for distribution system with integration of distributed generations is proposed based on multi-agent system technology. Considering the requirement of voltage control and power factor correction, the distribution system voltage/var control model is built under the multi-agent system framework. To realize distributed control, the voltage adjustment message...
This paper investigates the impact of unbalanced loads and SWT penetrations over three phases on voltage violation of residential distribution networks (RDNs). In this research, the point estimate method (PEM) is applied to identify the voltage violation of the network with various SWT penetration and distribution scenarios, taking into account the time varying characteristics of loads and wind speeds...
The capacity of installed photovoltaic (PV) generation in Japan is the world's 3rd largest and has been increasing rapidly due to the governmental subsidy and feed-in tariff programs. The rapid increase in PV installations drives electric utilities to various problems on how to operate the electric power systems stably. Then the utilities have to invest heavily in the systems. Under the circumstances,...
This paper proposes a hybrid three-phase load flow method for ungrounded distribution systems. Based on topology connectivity analysis, the system is partitioned into a mainline system and multiple tap systems. A Newton method with constant admittance matrix is used to solve the mainline system, such that zero impedance branches are merged into adjacent impedance branches to be considered, and constant...
Distributed resources (DR) provide several challenges to distribution system analysis due to the models and solution techniques that are required for adequate representation and solution. Load flow analysis is used to determine voltage magnitude and phase angle at each system bus, power flow in each system branch, power injected by each generation source, and system losses. The power flow formulation...
Small- and large-scale wind and solar photovoltaic (PV) generation systems are interconnecting to the distribution system at a rapid pace. Penetration limits are often imposed due to the impact these additional distributed resource can have on voltage. In order to accommodate high penetration scenarios without impacting power quality or reliability, additional control functions must be utilized. A...
One of the most important operational requirements for any electrical power network for both distribution and transmission level is voltage control. Many studies have been carried out to improve or develop new voltage control techniques to facilitate safe connection of distributed generation. In Saudi Arabia, due to environmental, economical and development perspectives a wide integration of photovoltaic...
This paper deals with the optimal evaluation algorithms for voltage regulation in the case where new dispersed sources are operated in distribution systems. It is very difficult and complicated to handle the interconnection issues for proper voltage managements, because professional skills and enormous amounts of data for the evaluations are required. The typical evaluation algorithms mainly depending...
This paper presents the optimal dispatch for the under load tap changer (ULTC) of a substation transformer, substation capacitors, and feeder capacitors for volt/VAr control in a distribution system. Three objectives of interest in the problem consist of energy loss, total capacitor kVAr to be switched on, and total number of daily switching operations of the ULTC and all capacitors. The optimization...
This paper describes an optimal dispatch for the under load tap changer (ULTC) of a substation transformer, substation capacitors, and feeder capacitors for volt/VAr control. The objective function of the problem is to minimize the system energy loss for a given daily load pattern. The problem is subjected to power flow equations, bus voltage limits, voltage distortion constraint and the maximum number...
When the volume of the distributed generation (DG) is increased, the voltage variation may occur in the distribution line. To keep the distribution line voltage for smooth power supply, a research project ldquoDemonstrative Project on Power Network Technologyrdquo was carried out from 2004 to 2008 under the research contract with the New Energy and Industrial Technology Development Organization (NEDO)...
Distribution system has witnessed numerous problems due to concentrated power loading in cities. Stability, reliability, peak demand, poor power quality, unbalanced loading are some of the major issues besides handling of large AC networks. This paper proposes an insertion of DC power dam connected between transmission and distribution system, through bidirectional voltage source converter (VSC) both...
The matrix converter features natural bidirectional power flow, sinusoidal current/voltage waveforms, and a reduced size and weighty compared to standard direct static power converters. However, it is sensitive to polluted AC supplies because no storing elements are present and thus any disturbance would reach the load terminals. Typical disturbances in the AC distribution systems are voltage unbalances,...
Voltage and Var control (VVC) schemes (i.e., centralized and decentralized controls) are discussed. Probabilistic load flow (PLF) method is applied on a real distribution system; the results from Monte Carlo simulations of both control schemes are compared. Models of WC element (on load tap changer, shunt capacitor and automatic voltage regulator of generator) are discussed. Voltage and reactive power...
This paper concentrates on the contribution of distributed generation (DG) to distribution system voltages. DG is utilized to help to regulate the system voltage profile to lie close to the desired value, i.e. to reduce the voltage variation. With the varieties of dispersed locations, operating modes, and allowable sizes, DG can be properly designed and controlled to be a powerful means of voltage...
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