Search

ZIP load modeling has been used in various power system applications. The aggregate load modeling is common practice in utility companies. However, little research has been done on the theoretical formulation of the aggregate load and on various factors that affect accurate estimation of the parameters. This paper proposes new methods to systematically formulate the aggregate ZIP load model using the single ZIP load model and comprehensively examines the factors that may affect aggregate ZIP load estimation. Moreover, novel analysis of reactive power ZIP parameter calculation considering different compensating device modeling is presented. ZIP parameter estimation methods including least squares method, optimization method, and neural network method have been used in this paper to estimate ZIP parameters. The proposed new method was illustrated using the IEEE 13-bus and 34-bus systems built in OpenDSS. In addition, the ZIP parameter estimation is also performed using field data, and the conservation through voltage reduction (CVR) factor is further computed based on the estimated ZIP load model. The results provide guidance on calculation and interpretation of CVR estimates. Note that this paper was first presented at PAC world conference 2021 which provides no published conference proceedings. [ABSTRACT FROM AUTHOR]

Transmission lines are essential components of electric power grids. Diverse power system applications and simulation based studies require transmission line parameters including series resistance, reactance, and shunt susceptance, and accurate parameters are pivotal in ensuring the accuracy of analyses and reliable system operation. Commercial software packages for performing power system studies usually have their own databases that store the power system model including line parameters. When there is a physical system model change, the corresponding component in the database of the software packages will need to be modified. Manually updating line parameters are tedious and error-prone. This paper proposes a solution for streamlining the calculation of line parameters and updating of their values in respective software databases. The algorithms used for calculating the values of line parameters are described. The software developed for implementing the solution is described, and typical results are presented. The proposed solution is developed for a utility and has a potential to be put into use by other utilities. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a framework for estimating transmission line positive sequence parameters, temperature, and sag utilizing on-line voltage and current phasors measured by Phasor Measurement Units. Transmission line parameters, temperature, and sag are vital inputs to various power system analyses and applications, such as the power flow analysis, the protective relaying application, and the dynamic thermal rating application. In this study, different types of transmission line topology are classified and modeled to facilitate the development of corresponding algorithms. All models are based on distributed parameters, so it automatically considers the shunt capacitance effect of long lines. It is assumed that the line is transposed. The proposed least squares based algorithms harness the non-linear optimal estimation theory and are capable of detecting and identifying bad data, minimizing the impact of measurement errors and thus significantly improving the estimation accuracy. The line temperature and sag are calculated according to the obtained parameter estimates. Numerical case studies based on simulated data are presented. [Copyright &y& Elsevier]

This article describes a novel and accurate algorithm to determine the fault location on power transmission lines without requiring line parameters. Voltage and current measurements at the two ends of the transmission line during the fault are utilized for fault location, and no pre-fault data are needed. In the past, a two-terminal method has been proposed based on a simplified transmission line model with no shunt capacitances. This article presents a new and accurate method considering line shunt capacitances for unbalanced faults. In deriving the unknown fault location, the line parameters, including series impedance and shunt capacitance, are treated as unknown variables as well. Approaches based on both synchronized and unsynchronized measurements are described. Since there is not enough information in three-phase balanced fault cases, shunt capacitances are not considered for balanced faults; however, the method for balanced faults still proves to be quite accurate. The chief merit of the algorithm is that only voltage and current measurements during the fault are required, and there is no need to worry about line parameters in order to pinpoint the fault location. Evaluation studies based on simulated data have indicated that the new approaches yield quite accurate results. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new fault location method for parallel transmission line is developed. [•] Accurate zero-sequence distributed parameter line model is employed. [•] The new method is independent of source impedance. [•] The method uses only local measurements. [ABSTRACT FROM AUTHOR]