scholarly journals AACO technique for solving multiobjectives in electrical distribution system

Author(s):  
P. Ravi Babu ◽  
Srivani Molughu

The multi objectives in electrical distribution system are service restoration and minimization of Ohmic losses. These objectives can be achieved by artificial ant colony optimization through reconfiguration. Service restoration is also a major aspect for reliable service. If any fault occurs in the system, faulted zone is isolated from healthy system. This originates discontinuity in power supply. To maintain the continuity in power supply there is a necessity to provide service to these loads from adjacent healthy feeders through reconfiguration without infringement of radiality, load balance and critical parameters. In distribution system Ohmic losses are 30 to 40 percent. In order to minimize these losses, there is a need for reconfiguration of the system and perform the power flow analysis to get bus voltages, branch currents and power losses (i.e. real or Ohmic or copper loss and reactive power loss). A direct load flow analysis is adopted in the proposed work. In this paper four feeder test system used for service restoration and IEEE 33 bus, IEEE 69 bus test systems for minimization of Ohmic losses have been obtained.

Author(s):  
Rudy Gianto ◽  
Purwoharjono Purwoharjono

This paper proposes a new and simple method to incorporate three-phase power transformer model into distribution system load flow (DSLF) analysis. The objective of the present work is to find a robust and efficient technique for modeling and integrating power transformer in the DSLF analysis. The proposed transformer model is derived based on nodal admittance matrix and formulated by using the symmetrical component theory. Load flow formulation in terms of branch currents and nodal voltages is also proposed in this paper to enable integrating the model into the DSLF analysis. Singularity that makes the calculations in forward/backward sweep (FBS) algorithm is difficult to be carried out. It can be avoided in the method. The proposed model is verified by using the standard IEEE test system.


Author(s):  
Fredrick Nkado ◽  
Franklin Nkado

Recently, the demand for electrical energy has increased more than energy production due to the growing population and industrialization. Therefore, the distributed generators integration (DGs) into the distribution system has been widely adopted. This work examines the effect of photovoltaic-based distributed generator (PV-DG) integration on power quality effect of a radial distribution system. Firstly, the capacity and optimum placement of the PV-DG units in the distribution network are determined by employing the particle swarm optimization (PSO) algorithm. Then, the impact of PV-DG integration on voltage harmonic distortion is analyzed by performing harmonic load flow analysis. Also, the P-V curve method is used to evaluate the effects of higher PV-DG penetration levels on loading margin and voltage magnitude. The simulation results show that as the PV-DG units’ penetration level increases, a greater level of harmonic distortion is injected, implying that the PV-DG units should only be integrated up to the network’s maximum capacity. Therefore, high harmonic distortion is produced when the PV-DG units are penetrated beyond this maximum penetration level, which has a negative impact on the system’s performance. The total voltage harmonic distortion is 4.17 % and 4.24 % at PCC1 and PCC2 at the highest penetration level, allowing the acceptable harmonic distortion limit. Also, grid-connected PV-DG units improve loading margin and voltage magnitude, according to the P-V curve results. The standard IEEE-33 bus distribution system is modelled in ETAP software and is used as a test system for this study.


2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
M. Venkata Kirthiga ◽  
S. Arul Daniel

This paper attempts at developing simple, efficient, and fast converging load flow analysis techniques tailored to autonomous microgrids. Two modified backward forward sweep techniques have been developed in this work where the largest generator is chosen as slack generator, in the first method and all generator buses are modeled as slack buses in the second method. The second method incorporates the concept of distributed slack bus to update the real and reactive power generations in the microgrid. This paper has details on the development of these two methodologies and the efficacy of these methods is compared with the conventional Newton Raphson load flow method. The standard 33-bus distribution system has been transformed into an autonomous microgrid and used for evaluation of the proposed load flow methodologies. Matlab coding has been developed for validating the results.


Author(s):  
Tebbakh Noureddine ◽  
Labed Djamel

<p>Distributed generations (DG), specially including renewable sources such as wind and sun are offering several opportunities for the currently in existence distribution networks and becoming one of the keys of treatment of its problems. Knowing the effects of each kind of DG on distribution networks is a primordial task because DG impacts differ from one kind to another. In this paper, we have analyzed and compared the effects of two kinds of DG, DG which provides real power only and DG which provides real power and reactive power at the same time connected at the critical bus in DN on the voltage profile, real and reactive power losses. We have proposed Newton Raphson method using Matlab to investigate the impacts of these two kinds of DG on 57-bus IEEE distribution test system. The obtained results have been exposed in detail at the end of this paper.</p>


Author(s):  
Shenghu Li

The induction generators (IGs) are basic to wind energy conversion. They produce the active power and consume the reactive power, with the voltage characteristics fragile compared with that of the synchronous generators and doubly-fed IGs. In the stressed system states, they may intensify var imbalance, yielding undesirable operation of zone 3 impedance relays.In this paper, the operation characteristics of the zone 3 relays in the wind power systems is studied. With the theoretical and load flow analysis, it is proved that the equivalent impedance of the IGs lies in the 2nd quadrature, possibly seen as the backward faults by the mho relays, i.e. the apparent impedance enters into the protection region from the left side. The undesirable operation may be caused by more wind power, larger load, less var compensation, and larger torque angle.


2019 ◽  
Vol 3 (1) ◽  
pp. 26 ◽  
Author(s):  
Vishnu Sidaarth Suresh

Load flow studies are carried out in order to find a steady state solution of a power system network. It is done to continuously monitor the system and decide upon future expansion of the system. The parameters of the system monitored are voltage magnitude, voltage angle, active and reactive power. This paper presents techniques used in order to obtain such parameters for a standard IEEE – 30 bus and IEEE-57 bus network and makes a comparison into the differences with regard to computational time and effectiveness of each solver


Author(s):  
Gaikwad Vikas Subhash ◽  
Swati S. More

Reactive power compensation is an important issue in electric power systems, involving operational, economical and quality of service aspects. Consumer loads (residential, industrial, service sector, etc.) impose active and reactive power demand, depending on their characteristics. This paper presents an efficient method for solving the load flow problem in distribution systems and which is implemented for Pune city (India) to check the validity of proposed method. A simple algebraic matrix equation to solve the load flow problem is derived by using the complex power balance equations. By adopting the rectangular coordinate, which requires the neglect of only second order terms in the linearization procedure, the proposed method gives better convergence characteristics. Newton-Raphsonmethod is the famous load flow calculation technique, and normally used dueto its rapidness of numerical convergence. The proposed method estimates the incremental changesof active power on each generation bus with respect to the total system power loss, efficiency and the estimated value are used to update the slack bus power.


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