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This paper describes methods and issues related to interfacing electromagnetic transient simulation programs with general mathematical algorithms, which are either custom-developed by the user or are available through other mathematical analysis platforms. Various interfacing types and techniques are described along with potential areas of application. Implementation methods are detailed for each type of interface as well. This paper presents several interfacing examples from a wide variety of applications, including advanced switching schemes for power converters and controller implementation. [ABSTRACT FROM AUTHOR]

This paper presents an integrated model for recognizing power-quality disturbances (PQD) using a novel wavelet multiclass support vector machine (WMSVM). The so-called support vector machine (SVM) is an effective classification tool. It is deemed to process binary classification problems. This paper combined linear SVM and the disturbances-versus-normal approach to form the multiclass SVM which is capable of processing multiple classification problems. Various disturbance events were tested for WMSVM and the wavelet-based multilayer-perceptron neural network was used for comparison. A simplified network architecture and shortened processing time can be seen for WMSVM. [ABSTRACT FROM AUTHOR]

In this paper a detailed description, an analysis, and an assessment of a frequency-domain technique highly applicable to power systems transient analysis (i.e., the numerical Laplace transform) are presented. The errors due to truncation and sampling when converting a frequency-domain signal to the time domain are analyzed. Additionally, the use of odd and regular sampling is discussed. Two major goals of the paper are the revival of the mentioned technique and its friendly description for power systems engineers. As an application, a transmission-line transient is presented. [ABSTRACT FROM AUTHOR]

Due to their ability to provide reactive power support and control active power flow, voltage-sourced-converter (VSC)-based flexible ac transmission system controllers can be used to improve the power transfer capability of congested transmission lines. A converter-based controller structure has the inherent feature to be used to provide shunt or series compensations. This inherent feature is utilized in the convertible static compensator installed at the New York Power Authority's Marcy substation, which can operate in 11 configurations of shunt and series compensations. Moreover, each configuration can be operated in different control modes. The paper presents a novel approach to model converter-based transmission controllers for load-flow calculations. The paper focuses on modeling converter-based controllers when two or more VSCs are coupled to a dc link (e.g., unified power-flow controller (UPFC), interline power-flow controller, and a generalized unified power-flow controller). This approach also allows efficient implementation of various VSC operating limits, where one or more VSCs are loaded to their rated capacity. A computer program incorporating this approach is developed to illustrate the maximum dispatchability of UPFC and IPFC in a large power system. [ABSTRACT FROM AUTHOR]

This paper presents the method for taking into consideration the influence of metallic installations surrounding the feeding line on the ground fault current distribution in supplied substations. When a ground fault occurs in a substation supplied by a cable line, these installations can significantly participate in reducing the part of the ground fault current emanating through the grounding system of this substation into the surrounding earth. Since only this part of the ground fault current creates potentials on the grounding system, this also means the reduction of all potential differences (touch and step voltages) appearing during the ground fault inside and in the vicinity of the supplied substation. However, current analytical expressions for the determination of the cable line reduction factor do not take into consideration this favorable effect. It is also not possible to determine it by direct measurements. This paper presents a method which enables us to achieve this by using the results of reduction factor measurements and by modeling surrounding metallic installations as a single equivalent conductor, cylindrical in form and parallel with the cable line. [ABSTRACT FROM AUTHOR]

Voltage fluctuations and interharmonics have an inherent relationship. The magnitude of voltage waveform can fluctuate if it contains interharmonics. Although the impact of voltage fluctuation caused by a single interharmonic has been understood due to recent research activities, little knowledge is available on the impact of a pair of interharmonics. In reality interharmonics often appear in pairs. The objective of this paper is to investigate voltage fluctuations caused by a pair of interharmonics. Using rms and peak values as indices, the amount of voltage fluctuations caused by a pair of interharmonics is determined. Analytical formulas to estimate the impact are developed. One of the interesting findings of this work is that the voltage fluctuation impact of a pair of interharmonics can be equivalenced into that produced by one interharmonic component. This paper also presents potential applications of the findings. [ABSTRACT FROM AUTHOR]

The paper presents the small-signal stability analysis of ac/dc system with a novel discrete-time HVDC converter model based on multirate sampling. The complete ac/dc system model has been developed in state space framework in modular fashion along with suitable interface of various subsystems involved. The model development is proposed in generalized framework and any degree of detail can be easily included. The sample case study has been carried out for the ac network in which an HVDC link is embedded. The studies reported in this paper are very much confirmatory as the model-based control design is concerned and the same has been validated through detailed nonlinear digital simulation. The model can be effectively utilized for stability study of two terminal systems. [ABSTRACT FROM AUTHOR]

This paper deals with scale models of power distribution systems for the study of lightning induced voltages on over- head lines. The scale model technique is useful for the investigation of situations which are prohibitively complex to be treated theoretically. For instance, urban distribution networks are usually characterized not only by complex topologies but also by the presence of nearby buildings, whose influence on the lightning induced effects can be successfully evaluated by means of reduced models. The paper first describes the scale model implemented for such a purpose at the University of São Paulo, São Paulo, Brazil. It then presents a comparison between the experimental data obtained with the scale model and the computer simulations obtained by using the LIOV-EMTP code, a software tool able of calculating lightning-induced electromagnetic transients in distribution systems having complex configurations. Finally, the paper shows an application of the scale model in the evaluation of lightning induced voltages on distribution networks considering the presence of nearby buildings. [ABSTRACT FROM AUTHOR]

The paper discusses the concept of a mini custom power park in which the voltage inside the park is tightly regulated by a distribution static compensator (DSTATCOM). It will be shown on the basis of simulations with ideal components that solid state protection devices, along with the DSTATCOM will eliminate many transients in all the loads of the park during disturbances. Moreover, the DSTATCOM, backed by a diesel generator, will supply the most sensitive loads during the total line outages, thereby nearly making them both transient and interruption free. In this paper, a configuration of the park is proposed and then various issues involved with the operation of the park are discussed. The proposed operation of the custom power park is verified through extensive digital computer simulation studies. [ABSTRACT FROM AUTHOR]

The aim of this paper is to present the operating principle of a new resonant device, called the fault decoupling device (FDD), able to improve power quality in electrical distribution systems. In low-voltage networks, this device can be employed in order to mitigate voltage dips due to faults or large induction motor startup. Moreover, in the presence of distributed-generation (DG) units, the FDD allows one to obtain various benefits such as a reduction of the fault current in each node of the network and an increase in the voltage at the DG unit node. In order to show the performances of the FDD, analytical studies and computer simulations were carried out which took into account various working operation conditions. Finally, the prototype of the FDD as well as the preliminary experimental results are presented. [ABSTRACT FROM AUTHOR]

The application of all-dielectric self-supporting fiber-optic cables (ADSS) in overhead transmission lines leads to an improvement in a communication network's transmitting capabilities. The problem with ADSS cables results from reported damage to the outer coating of cables exposed to electrical, mechanical, and chemical stresses during operating conditions. This paper presents the results of investigations of discharge mechanism on the coating of ADSS cables, causing erosion processes on a cable surface. A novel method for detecting dryband arcing processes on an ADSS cable coating based on phase-resolved discharge acquisition is presented. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to investigate the effect of air-gap position, length, and number on the phenomena preceding flashover along a typical 735-kY porcelain station post insulator unit under heavy ice accretion. Under these conditions, this type of insulator seems to be the most likely subject to flashover. The numerical simulations were performed using Coulomb 3D, a commercial software based on the boundary element method (BEM). Computer simulations were performed during a melting period. Special attention was paid to the presence of a conductive water film at the ice surface and to a partial arc along an air gap. The results obtained showed that the number of air gaps, with or without the presence of a partial arc along them, has a direct effect on the distribution of potential along the iced insulator. Moreover, for the same total arcing distance, the number of air gaps and their position did not affect the average electric field per arcing distance that was used to determine the partial arc presence. Based on these results, suggestions for improving station insulator geometry for icing conditions were proposed. [ABSTRACT FROM AUTHOR]

An important macroscopic are parameter, describing its complex nature is the are resistance. It can be easily calculated by using the well-known Warrington formula. Authors investigated the results of Warrington's tests. By taking into account the conditions under which they are obtained (e.g., inaccurate measurement devices), it is unquestionable that these results are today highly empirical and not accurate and general enough. Laboratory testing provided in the high-power test laboratory FGH-Mannheim (Germany), in which long high current arcs are initiated, was the basis for the research results presented in the paper. Based on the analysis of laboratory-recorded arc voltage and current waveforms, the new arc model is derived. An example of arc computer simulation using the new model is given. Based on the new arc model, a new approach to arc resistance calculation is presented. The new formula for arc resistance is compared with the old Warrington formula. [ABSTRACT FROM AUTHOR]

This paper presents an enhancement to motor starting simulation programs which allows them to analyze the motor starting effects on system protective devices. According to a given relay's operating principle, a method is presented to deter- mine if it will trip by comparing the accumulated energy during the motor starting to the energy needed to trip the relay based on its time current characteristics curve. Under special circumstances, motor starting can cause nuisance tripping of protective devices. Hence, the protective device coordination enhancement presented here can be a useful addition to motor-starting simulation programs. [ABSTRACT FROM AUTHOR]