Distribution System Supplies Research Articles

Polar Coordinates based N-R Method for Load Modelling in Electrical Power Distribution Systems

In this paper, load modelling has been done in electrical distribution system using local real time test data. This distribution system supplies base loads, residential, industrial, commercial and composite loads. Using power and current-mismatch functions in polar form, a comprehensive framework for applying the Newton–Raphson method to solve power flow problems is presented. The Newton–Raphson approach for solving power flow problems can be applied in six different ways using these two mismatch functions. For load (PQ)buses and generator (PV) buses, we propose a theoretical framework for analyzing these versions. In addition, we compare newly created versions of the Newton power flow method to current variants in this study. Numerical studies on distribution networks are used to study the convergence behavior of all approaches. The measurements are formed for short term load forecasting with different types of realistic loads such as base loads, residential, industrial, commercial and composite loads. The long-term load forecasting and their losses also has been performed along with short term load forecasting. The results are obtained and validated through MATLAB.

Effect of Voltage Dependent Load Model on Placement and Sizing of Distributed Generator in Large Scale Distribution System

Distribution system supplies power to variety of load depending upon the consumer’s demand, which is increasing day by day and lead to high power losses and poor voltage regulation. The increase in demand can be met by integrating Distributed Generators (DG) into the distribution system. Optimal location and capacity of DG plays an important role in distribution network to minimize the power losses. Some researchers have studied this important optimization problem with constant power load which is independent of voltage. However, majority of consumers at load center uses voltage dependent load models, which are primarily dependent on magnitude of supply voltage. In practical distribution network, the assumption of constant power load can significantly affect the location and size of DG, which in turn can lead to higher power losses and poor voltage regulation. In this study, an investigation has been performed to find the increase in power loss due to the use of inappropriate load models, while solving the optimization problem. Furthermore, an attempt has been made in this study to reduce power losses occurring in large test bus systems with loads being dependent on voltage rather than the constant power load. Different test cases are created to analyse the power losses with appropriate load model and in-appropriate load model (constant power load model). The load at distribution network is not mainly dependent on any single type of load model, it is a combination of all load models. In this study, a class of mix load viz., combination of residential, industrial, constant power, and commercial load, is also considered. In order to solve this critical combinatorial optimization problem with voltage dependent load model, which requires an extensive search, Adaptive Quantum inspired Evolutionary Algorithm (AQiEA) is used. The proposed algorithm uses entanglement and superposition principles, which does not require an operator to avoid premature convergence and tuning parameters for improving the convergence rate. A Quantum Rotation inspired Adaptive Crossover operator has been used as a variation operator for a better convergence. The effectiveness of AQiEA is demonstrated and computer simulations are carried out on two standard benchmark large test bus systems viz., 85 bus system and 118 bus system. In addition to AQiEA, four other algorithms (Genetic Algorithm (GA), Particle Swarm Optimization (PSO), Gravitational Search Algorithm (GSA), Grey Wolf Optimization (GWO), and Ecogeography-based Optimization (EBO) with Classification based on Multiple Association Rules (CMAR)) have also been employed for comparison. Tabulated results show that the location and size of DGs determined using in-appropriate load model (constant power load model) has significantly high power losses when applied in distribution system with different load model (other voltage dependent load models) as compared with the location and size of DGs determined using the appropriate load model. Experimental results indicate that AQiEA has a better performance compared to other algorithms which are available in the literature.

Improved complementary reservoir solution to evaluate nodal outflow under pressure-deficient conditions

Water distribution system supplies water to the consumers as per the designed condition if requirement of water matches with designed level. It seldom matches the designed condition during operation scenario. Uncertainty of the demand, failure of components, diversion of water, aging of pipeline, permanent increase in the demand at certain supply node, fire demand etc. creates deficit in supply. In such situations, it is important to assess actual flow that can be delivered from nodes so that the authority concerned can take up alternate steps to tackle the situation immediately. Though there are several methods available to analyze pipe networks under pressure-deficient conditions, researchers evolve new approaches or improve existing approaches that can be implemented easily with existing software. This paper proposes an improved method for pressure-driven analysis to minimize the number of addition or deletion of complementing reservoirs in complementary reservoir solution approach. Main logic of the improved method is that no supply from a node is possible if the pressure drop at a node exceeds the difference in hydraulic gradient of source and maximum pressure drop node. The proposed method is applied to three benchmark networks and results of the study show that the improved method simplifies the analysis process by reducing number of addition of complementing reservoirs.

Design of the control system for the cryogenic distribution system of the European XFEL project

In order to produce pulsed electron beam with the energy of 17.5 GeV, the European X-ray Free Electron Laser (XFEL) linear accelerator is under construction. The XFEL accelerator will contain the linear accelerator (linac) and the injector. The XFEL cryogenic distribution system supplies the linac and the injector with cooling helium. The cryogenic supply of the linac is separated in parallel cryogenic sections called ‘strings’.Operation of the XFEL cryogenic distribution system is under the process control system for Experimental Physics and Industrial Control System (EPICS). A complementary component of EPICS is the Open Source software suit CSS (Control System Studio) providing an integrated engineering, maintenance and operating tools for EPICS as well as human machine interface. Cryogenic instrumentation used for operation and diagnostic is connected to PROFIBUS. More than 300 PROFIBUS nodes control the XFEL cryogenic system. DESY introduced the monitoring system based on Field Device Tool (FDT). FDT framework contains Data Tool Management (DTM) applications to examine the correct installation and configuration of all PROFIBUS nodes in real time.This paper describes the control system for the XFEL cryogenic distribution system including all steps from engineering to the pre-service tests.

Reliability benefit analysis of adding WTG to a distribution system

Wind turbine generators (WTG) used as alternative supply in a distribution system have different impacts on the system reliability performance than conventional alternative supplies due to the variable wind speed. This paper investigates the system reliability benefits of adding WTG as alternative supply in a rural distribution system. The wind generation interrupted energy benefit (WGIEB), the wind generation interruption cost benefit (WGICB), the equivalent number of conventional generators (ENCG) and the equivalent conventional generator capacity (ECGC) of one MW WTG are introduced. These indices provide direct reliability benefit indicators on the addition of WTG, and are important information for system planners to make planning decisions such as the selection of a wind site and the number of WTG. A test rural distribution system is utilized to illustrate the proposed technique. The effects on the system reliability benefits of the wind site selection and the number of wind units are investigated.

Power-supply and public-address systems at the New York fair

An 80,000-kva electric distribution system supplies the Fair's light and power loads; an extensive public-address system broadcasts programs and announcements throughout the Fair grounds.

Discussion on “motor-generators vs. synchronous converters, with special reference to operation on long-distance transmission lines.” at New York, March 22, 1907

In regard to the use of motor-generators or synchronous converters, the question seems to me to be one of voltage regulation. The requirements of a railway system fed from a general transmission system are best met as to first cost and efficiency of operation by the adoption of the synchronous converter, and its almost universal use in railway installations would seem to leave no room for argument. The requirements of a direct-current lighting load can also be best met by the adoption of the synchronous converter, provided the distribution system is used for lighting only. Where, however, the distribution system supplies a mixed lighting and railway load (or any other load occasioning extreme fluctuations) the lighting system should be fed through motor-generator sets in order to smooth out the effect of unavoidable voltage fluctuations. Taking this broad view of the situation, there is a well-defined field for both synchronous converters and motor-generator sets, the question of voltage regulation determining the choice of either type of apparatus.