Load modeling for power flow and transient stability computer studies
TL;DR: The LOADSYN load model synthesis software package as discussed by the authors transforms data on load class mix, composition, and characteristics into the form required for commonly used flow and transient stability simulation programs.
Abstract: 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. >
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Journal Article•
TL;DR: The goal of this paper is to promote better load modeling and advanced load modeling, and to facilitate data exchange among users of various production-grade simulation programs.
Abstract: The authors recommend standard load models for power flow and dynamic simulation programs. The goal of this paper is to promote better load modeling and advanced load modeling, and to facilitate data exchange among users of various production-grade simulation programs. Flexibility of modeling is an important consideration. For transient stability, longer-term dynamics, and small-disturbance stability programs, the authors recommend the structure of multiple load types connected to a load bus. Load types are static including discharge lighting, induction motors, synchronous motors, and transformer saturation. For each load type, multiple models may be connected to the bus. For longer-term dynamics programs, a model for LTC transformers is also recommended.
561 citations
TL;DR: In this article, the authors reviewed literature on using high speed thyristor based control of HVAC power system elements to enhance the power carrying capacity of existing transmission circuits without compromising reliability.
Abstract: The paper reviews literature which addresses the application of Flexible AC Transmission System (FACTS) concepts to the improvement of Power System utilisation and performance. It summarises literature on using high speed thyristor based control of HVAC power system elements to enhance the power carrying capacity of existing transmission circuits without compromising reliability. It describes a study system representative of existing power systems that has been developed to evaluate the economic and technical issues of loading transmission lines to their thermal limits. Considered are two scenarios, a multi-line corridor and a long radial interconnection, where the issues addressed are transient and dynamic stability, power flow control, reactive support and voltage stability. A benchmark system is developed to validate performance of die more simple devices. It is concluded that FACTS devices have the potential to significantly increase system stability margins thereby increasing loading capabil...
544 citations
TL;DR: In this paper, a measurement-based composite load model is developed to model load from field measurements, and two cases are studied to illustrate the accuracy of the developed load model on describing the load dynamic characteristics in the actual power system.
Abstract: The accuracy of the load model has great effects on power system stability analysis and control. Based on our practice in China on modeling load from field measurements, this paper systematically develops a measurement-based composite load model. Principles guiding the load modeling practice are discussed based on detailed analysis on stochastic characteristics of the modeling procedure. The structure of the measurement-based composite load model is presented. A multicurve identification technique is described to derive parameters. The generalization capability of this built load model is also investigated in this paper. Two cases are studied to illustrate the accuracy of the developed load model on describing the load dynamic characteristics in the actual power system.
315 citations
TL;DR: In this article, the experimental determination of the ZIP coefficients model to represent (static) modern loads under varying voltage conditions is presented, where a series of surveys was performed on typical residential, commercial, and industrial customers in New York City.
Abstract: This paper presents the experimental determination of the ZIP coefficients model to represent (static) modern loads under varying voltage conditions. ZIP are the coefficients of a load model comprised of constant impedance $Z$ , constant current $I$ , and constant power $P$ loads. A ZIP coefficient load model is used to represent power consumed by a load as a function of voltage. A series of surveys was performed on typical residential, commercial, and industrial customers in New York City. Household appliances and industrial equipment found in the different locations were tested in the laboratory by varying the voltage from 1.1-p.u. voltage to 0 and back to 1.1 pu in steps of 3 V to obtain the individual $P$ – $V$ , $Q$ – $V$ , and $I $ – $V$ characteristics. Customer load tables were built using seasonal factors and duty cycles to form weighted contributions for each device in every customer class. The loads found in several residential classes were assembled and tested in the lab. It was found that modern appliances behave quite differently than older appliances even from only 10 years back. Models of the different customer classes were validated against actual recordings of load variations under voltage reduction.
311 citations
TL;DR: A thorough survey on the academic research progress and industry practices is provided, and existing issues and new trends in load modeling are highlighted.
Abstract: Load modeling has significant impact on power system studies. This paper presents a review on load modeling and identification techniques. Load models can be classified into two broad categories: 1) static and 2) dynamic models, while there are two types of approaches to identify model parameters: 1) measurement-based and 2) component-based. Load modeling has received more attention in recent years because of the renewable integration, demand-side management, and smart metering devices. However, the commonly used load models are outdated, and cannot represent emerging loads. There is a need to systematically review existing load modeling techniques and suggest future research directions to meet the increasing interests from industry and academia. In this paper, we provide a thorough survey on the academic research progress and industry practices, and highlight existing issues and new trends in load modeling.
304 citations
References
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TL;DR: In this paper, the authors present a load model for power system stability studies, which is qualitatively different from generator load modeling in many aspects, such as reliability of load estimates, models of different components must be combined to obtain a reasonably manageable overall system model and field measurements are not at all easy.
Abstract: Proper representation of load is important in power system stability studies, but it is a difficult task. Load modeling is qualitatively different from generator modeling in many aspects. Composition of load needs to be reliably estimated, models of different components must be combined to obtain a reasonably manageable overall system model, and field measurements are not at all easy.
314 citations
TL;DR: In this paper, an investigation of several methods for aggregating induction motors is described and the accuracy of the methods is compared using frequency-domain techniques, and a new method involving the use of one or two aggregate motors was described and shown to be superior to other methods.
Abstract: 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.
98 citations
TL;DR: In this paper, a transfer function model was proposed for large rotating industrial loads and an induction motor model with shunt static load was used to model the real and reactive power responses of the paper mill loads.
Abstract: For several years power system load responses have been recorded during system transients by means of a remote data acquisition system developed by Ontario Hydro. Using these data, models for the loads are developed in the paper and parameters for the models are obtained. Conventional static load models are shown to represent adequately the characteristics of a residential/commercial feeder load. For large rotating industrial loads two models are developed. The first is a transfer function model which relates the small signal power and reactive power outputs to input changes in voltage and frequency. The second is an induction motor model with shunt static load. Recorded voltage is considered as an input to the model and the output real and reactive power are compared with the measured output. The weighted squared error between the measured output and the model output is minimized by obtaining optimum model parameters. Recorded and simulated responses of the paper mill loads are compared.
91 citations
TL;DR: In this paper, a series of load-voltage tests performed on the Southern California Edison Company system are described and the test results are summarized and used as the basis for individual bus load representation.
Abstract: This paper emphasizes the need for a correct representation of electrical loads in stability studies. Several series of load-voltage tests performed on the Southern California Edison Company system are described. The test results are summarized and used as the basis for individual bus load representation.
81 citations