The problem of capacitor placement on a radial distribution system is formulated and a solution algorithm is proposed. The location, type, and size of capacitors, voltage constraints, and load variations are considered. The objective of capacitor placement is peak power and energy loss reduction, taking into account the cost of the capacitors. The problem is formulated as a mixed integer programming problem. The power flows in the system are explicitly represented, and the voltage constraints are incorporated. A solution method has been implemented that decomposes the problem into a master problem and a slave problem. The master problem is used to determine the location of the capacitors. The slave problem is used by the master problem to determine the type and size of the capacitors placed on the system. In solving the slave problem, and efficient phase I-phase II algorithm is used. >

Optimal capacitor placement on radial distribution systems

A novel method is presented for preparing load models for power flow and stability studies. The LOADSYN load model synthesis software package transforms data on load class mix, composition, and characteristics into the form required for commonly used flow and transient stability simulation programs. Typical default data have been developed for load composition and characteristics. The load-modeling techniques used in this software and results of initial testing are described. Significant improvements in simulation accuracy are demonstrated. >

Load modeling for power flow and transient stability computer studies

Load flow solution of distribution systems with voltage dependent load models

The nonlinear portion of electrical loads has increased significantly in recent years. Harmonic currents injected by these loads into the distribution system should be considered when solving the capacitor placement problem in order to assure that the optimal solution does not result in excessive harmonic distortion. A voltage-dependent current injection load model is presented to determine voltage waveform characteristics and additional losses at harmonic frequencies. Computer simulations show that the optimal capacitor sizes and locations depend heavily on the load model used at fundamental frequency and on harmonic signals, especially when limits are imposed on voltage waveforms. >

Effects of nonlinear loads on optimal capacitor placement in radial feeders

An investigation of several methods for aggregating induction motors is described. The accuracy of the methods is compared using frequency-domain techniques. A new method involving the use of one or two aggregate motors is described and shown to be superior to other methods.

Aggregation of Induction Motors for Transient Stability Load Modeling

Realistic load models are required to improve the quality of bulk power system studies For a better understanding of the basic nature of the load behavior under abnormal conditions, an extensive series of tests were conducted during different seasons at three test sites of two utility systems in New York State

Load Behavior Observed in LILCO and RG&E Systems

This paper is Part I of a two part series. The two papers will report part of the research project RP-1138 sponsored by EPRI and BPA on HVDC-AC System Interaction from AC Harmonics. The two papers deal with the harmonic impedance measurement of Bonneville Power Administration's (BPA) system as seen from the Celilo HVDC substation, the development of analytical techniques to calculate the harinonic impedance of the system, and comparison of the calculated and measured results.

HVDC-AC Harmonic Interaction Part I - Development of a Harmonic Measurement System Hardware and Software

This paper is Part II of a two part series. The two papers will report part of the research project RP-1138 sponsored by EPRI and BPA on HVDC-AC System Interaction from AC Harmonics. The two papers describe the harmonic impedance measurement of Bonneville Power Administration's (BPA) system as seen from the Celilo HVDC substation, the development of analytical techniques to calculate the harmonic impedance of the system, and comparison of the calculated and measured results.

HVDC-AC Harmonic Interaction Part II -AC System Harmonic Model with Comparison of Calculated and Measured Data

This study evaluated a prototype load modeling procedure developed by the University of Texas at Arlington (UTA) in EPRI project RP849-3. Tests were run on three different power systems to evaluate the procedure's accuracy in modeling the dynamic power response of loads (active and reactive) when subjected to limited excursions of voltage and frequency. In support activities, guidelines were developed for the load modeling procedure, and possible data sources for it were investigated. The period of performance was September 1976 to July 1980. The work accomplished is reported in a final report of four volumes. This volume, the executive summary, presents an overview and summary of results. Recommendations are made for the research necessary to develop a production grade load modeling procedure.

Determining load characteristics for transient performance. Volume 1. Executive summary. Final report. [Simulation using DSAP computer code]

This study evaluated a prototype load modeling procedure developed by the University of Texas at Arlington (UTA) in EPRI project RP849-3. Tests were run on three different power systems to evaluate the procedure's accuracy in modeling the dynamic power response of loads (active and reactive) when subjected to limited excursions of voltage and frequency. In support activities, guidelines were developed for the load modeling procedure, and possible data sources for it were investigated. The period of performance was September 1976 to July 1980. The work accomplished is reported in a final report of four volumes. In this volume guidelines are developed for a load modeling procedure, and induction motor characteristics and their effect on system stability are examined.

T. Gentile

Papers

Load Behavior Observed in LILCO and RG&E Systems

HVDC-AC Harmonic Interaction Part I - Development of a Harmonic Measurement System Hardware and Software

HVDC-AC Harmonic Interaction Part II -AC System Harmonic Model with Comparison of Calculated and Measured Data

Determining load characteristics for transient performance. Volume 1. Executive summary. Final report. [Simulation using DSAP computer code]

Determining load characteristics for transient performance. Volume 2. Load-model guidelines. Final report