Radial Primary Distribution Research Articles

Improvement of Power Quality in Primary Distribution Systems Based on Static-Var Compensators

A flexible AC Transmission Systems (FACTS) is a new technology offers a fast and reliable control over the transmission and distribution parameters like voltage and phase angle between the sending end voltage and receiving end voltage. Distribution static synchronous compensator (DSTATCOM) is a second generation member of the (FACTS) controllers. Reactive power compensation is an important aspect in the control of distribution systems. Reactive current in addition to increasing the distribution system losses, introduces voltage drop at lead point and finally it causes poor power quality in power systems. Primary radial distribution feeders have high resistance to reactance ratio, which causes voltage drop and high power loss in radial distribution systems. providing high demanding power to entire load while maintaining voltage magnitude at acceptable range is one of the major system constraints, using of capacitor banks to improve the reactive power have not quite enough at high reactive power feeder, because it have more slow in step by step response and have not capable to generate continuously variable reactive power. In some primary distribution feeders at the state of Khartoum, it is observed that there are some appropriate drops in voltage and quality service at high reactive power loads although some individual capacitor banks have been connected at these feeders, from here we researched for a new technology to overcome this problem. A steady-state model of (DSTATCOM) is proposed and developed to compensate the reactive power by using a Voltage Source Converter (VSC) with Pulse Width Modulation (PWM) and cascade control of four direct proportional integral controllers (PI) in synchronous reference frame. The detailed modeling and control design of (DSTATCOM) with specific typical radial primary distribution feeders (industrial, commercial, residential) are presented and implemented along necessary mathematical model equations in the Matlab software. Simulation schemes of (DSTATCOM) are done with help of control block diagrams and stability analysis. Load flow is an important method for analysis, operation and planning studies of any power system in a steady-state condition. In this research backward forward sweeps load flow method (Kirchhoff’s Laws) has been proposed rather than Newton-Raphson and Fast decoupled methods because the distribution feeders have a high R/X ratio which make the systems are ill-conditioned iterations analysis. (DSTATCOM) was installed on specific typical radial feeders at the (DSTATCOM) which using for distribution lines and load compensation has been the subject of considerable interest beside it is a new technology for a good power quality solution. Keywords: Power System, Flexible AC Transmission Systems (FACTS) Devices, STATCOM, PI Controller DOI: 10.7176/ISDE/13-1-05 Publication date: May 31 st 2023

Impact of Reactive Power Compensators on Primary Distribution Network Performance

Abstract—Active and reactive power losses have become one of the most challenging in power system. Loss reduction through various methods have evolved and hence improving voltage profile. One effective loss minimization method is reactive power management by placing shunt compensators at appropriate places with proper size. This paper presents a complete methodology for optimal allocation of two VAR compensator which are Static Var Compensator (SVC) and shunt capacitors to improve the overall performance of a radial primary distribution network. The impact of optimal allocation of shunt compensators on primary distribution networks performance with different load levels (20% increased or 20% decreased) is also studied. Modified IEEE 33-bus primary distribution network is used to verify the effectiveness of the proposed methodology with different load levels. Implementation of the suggested methodology is carried out by Power World Simulator (PWS). The outcome of this work helps in design and operational reactive power planning for the voltage and reactive power management

00/00244 Long-term optimization of radial primary distribution networks by conductor replacements

Benzyl chloride reduction was studied in a powder macroelectrode (PME) made of silver, graphite or silver/graphite mixtures (1:3, 1:1 and 3:1) in absence of solvent, or using a very low amount of DMF as solvent (PhCH2Cl/DMF 3:1). A 0.1 mol L−1 KCl aqueous solution was used as anolyte. A competitive hydrogenation and dimerization process was observed, affording the respective toluene and bibenzyl products. The well-known electrocatalytic effect of silver on reduction of the CCl bond was confirmed by a significant positive shift of the benzyl chloride reduction potential in comparison with pure graphite powder. The products distribution was analysed after linear sweep voltammetries at low scan rate (0.1 mV s−1), indicating high yields of bibenzyl produced on Ag/graphite-PME. Pure graphite-PME was not selective towards dimer formation. The best results for bibenzyl production occurred at more positive potentials, in the presence of silver. A small amount of solvent (DMF) play an important role on the electrode surface desorption and diffusion of intermediary species.

Long-term optimization of radial primary distribution networks by conductor replacements

A method dealing with the technoeconomical long-term optimization of currently operating radial primary power distribution networks is developed in this paper. This method, taking into account the realistic locations and growth of the load served by the examined network and specific technoeconomical constraints, results in the proposal of conductor replacements which must be realized in the network segments at specified years of the plan period. This is in order to optimize the network technically as much as possible, defraying the minimum cost.

Optimum long-term planning of a radial primary distribution network: Part I: Data description and first proposed network form

An algorithm for the technoeconomically optimum longterm planning of a radial primary power distribution network, dealing with the proper conductor selection for the network segments, is, proposed in this article which is completed in two parts. Load data (annual growth, load distribution), necessary economic functions and technical constraints (thermal conductor capacity, permissible voltage drop, thermal short-circuit conductor strength), which are taken into account during the planning procedure, are given in this Part L New quantities, such as the long-term economic conductor capacity and sets of allowable conductor selections for every network segment, accompanied by their possible replacement years, are also determined in this part. A network form is finally proposed as the first step of the long-term planning; procedure, which is completed in the following Part II.

Optimum long-term planning of a radial primary distribution network: Part II: Development of the optimum long-term planning method

With this second part the paper dealing with the optimum long-term planning of a radial primary power distribution network is completed. In this part an algorithm for this planning is developed, taking into account the locations and the time variation of the load served by the examined network, technoeconomical constraints and functions given in Part I of this paper and previous papers of the authors. This algorithm finally proposes a network form selecting the proper conductors for the network segments and concrete years with the kinds of specific improvements to which this form must be subject inside the specific plan period in order to satisfy the continuous growing load in the technoeconomically best way.

98/00410 Optimum long-term planning of a radial primary distribution network—part II: development of the optimum long-term planning method

An empirical examination of factors that influence a public utility's choice regarding the degree of nonuniformity in its price schedules is reported in this paper. In particular, the results support the Sherman-Visscher theory that tighter rate-of-return regulation encourages a monopolist to adopt more rapidly declining rate structures. Some types of regulatory authority have flatter rate structures than others, suggesting that the rate-of-return induced distortion may be countered by direct regulatory oversight. Somewhat surprisingly, scale economics influence rate structures only weakly, casting doubt on the traditional claim that average price declines because of decreasing average cost.

98/00409 Optimum long-term planning of a radial primary distribution network—part I: data description and first proposed network form

98/00409 Optimum long-term planning of a radial primary distribution network—part I: data description and first proposed network form

Economical optimization of a radial power network based on voltage drop criterion

This paper presents a Turbo Pascal program, which optimizes an operating radial primary distribution power network. The program suggests changes of conductor sizes so as to have an acceptable voltage profile across the entire network with the minimum cost. By using pointers and tree data structures the computation procedure is dynamic and the problem solution fast and complete.

NEAR-OPTIMUM CAPACITOR ALLOCATION ON DISTRIBUTION FEEDERS FOR VOLTAGE CONTROL

ABSTRACT This paper presents a method for determining the near-optimum location and amount of reactive power necessary to bring the voltage profile within tolerance on a radial primary distribution feeder, for a user-defined number of compensating reactors (i.e. capacitors). The method is simple, accurate, and requires no assumptions with regard to the system radial topology, impedances, or loads. Implementation of the method requires the capability of solving the power flow problem on a radial unbalanced system. A numerical example demonstrating the application of the method is provided.

Digital Calculation of Sequence Impedances and Fault Currents for Radial Primary Distribution Circuits

Digital Calculation of Sequence Impedances and Fault Currents for Radial Primary Distribution Circuits