Alternative Transients Program Research Articles

Design, Implementation and Simulation of Non-Intrusive Sensor for On-Line Condition Monitoring of MV Electrical Components

Non-intrusive measurement technology is of great interest for the electrical utilities in order to avoid an interruption in the normal operation of the supply network during diagnostics measurements and inspections. Inductively coupled electromagnetic sensing provides a possibility of non-intrusive measurements for online condition monitoring of the electrical components in a Medium Voltage (MV) distribution network. This is accomplished by employing Partial Discharge (PD) activity monitoring, one of the successful methods to assess the working condition of MV components but often requires specialized equipment for carrying out the measurements. In this paper, Rogowski coil sensor is presented as a robust solution for non-intrusive measurements of PD signals. A high frequency prototype of Rogowski coil is designed in the laboratory. Step-by-step approach of constructing the sensor system is presented and performance of its components (coil head, damping component, integrator and data acquisition system) is evaluated using practical and simulated environments. Alternative Transient Program-Electromagnetic Transient Program (ATP-EMTP) is used to analyze the designed model of the Rogowski coil. Real and simulated models of the coil are used to investigate the behavior of Rogowski coil sensor at its different stages of development from a transducer coil to a complete measuring device. Both models are compared to evaluate their accuracy for PD applications. Due to simple design, flexible hardware, and low cost of Rogowski coil, it can be considered as an efficient current measuring device for integrated monitoring applications where a large number of sensors are required to develop an automated online condition monitoring system for a distribution network.

Simplified Modeling of Metal Oxide Surge Arresters

This paper describes simplified modeling of metal oxide surge arrester (MOSA) to operate analysis. This model is a new model proposed (P-K Model) to verify the accuracy in order to compare with IEEE and Pinceti Model. The simulations are performed with the Alternative Transients Program version of Electromagnetic Transient Program (ATP-EMTP). In the present paper, the MOSA models were verified for several medium voltages which consist of 18kV and 21kV, which 18kV arrester was used in 22kV system of Provincical Electricity Authority (PEA) and 21kV arrester was used in 24kV system of Metropolitan Electricity Authority (MEA) in Thailand. The P-K model was evaluate from different manufacturing, it is based on the General Electric (GE), Siemens and Ohio Brass as well as IEEE and Pinceti Model. The tests are performed by applying a fast front current surge with front time of up to 0.5μs and the standard impulse current surge (8/20μs). The results were compared between three models in order to calculate the error operation of the MOSA in the ATP-EMTP Program. The relative error of arrester models show that the P-K model can be used to simulate and calculate in ATP-EMTP program as well as IEEE and Pinceti model. In the case of fast front current surge, the P-K model has a maximum error of 5.39% (Ohio Brass, 10 kA, 21kV) and has a minimum error of 0.24% (GE, 10 kA, 18kV). Also, the standard impulse current surge, P-K model has a maximum error of 2% (Ohio Brass, 10 kA, 18kV) and has a minimum error of 0.32% (Siemens, 10 kA, 21kV) in the voltage response.

Design of Lightning Arresters for Electrical Power Systems Protection

This paper presents an overview of how the lightning strikes and their effects on power distribution systems can be modeled, where the results give a clear picture of how to eliminate the devastating impact, caused by lightning, by using lightning arresters. The program ATP-Draw (Alternative Transient Program) was used to simulate the problem and was applied on a part of a power network.The simulation was done once when the lightning strikes a transmission line and a substation with no lightning arresters in use and once more with their use. The source of the lightning was represented by the ATP models (Type-15 surge function and Type-13 ramp function) and the surge arrester was represented by the MOV-Type 92 component. The voltage was recorded at the substation 110/22 kV and at all loads in the electric network, and was drawn by the PlotXWin program. The results obtained indicate that the voltages induced by the lightning can reach values of the order of millions over insulation flashover levels for 22 kV equipment, where is clearly seen in Fig. 12 to 16 and Tab.10, which requires the installation of lightning arresters.

Modeling of Power Networks by ATP-Draw for Harmonics Propagation Study

This paper illustrates the possibilities of using the program ATP-Draw (Alternative Transient Program) for the modeling of power networks to study power quality problems with highly detailed analyses. The Program ATP-Draw is one of the most widespread and oldest programs. A unique characteristic of this program is its public domain and the existence of forums and study committees where new application cases and modification are presented and shared publicly. In this paper, to study the propagation of harmonics through a power network, a part of an industrial power network was modeled. The network contains different types of electric components, such as transformers, transmission lines, cables and loads, and there is a source of harmonics that injects <TEX>$3^{rd}$</TEX>, <TEX>$5^{th}$</TEX>, <TEX>$7^{th}$</TEX>, <TEX>$9^{th}$</TEX> and <TEX>$11^{th}$</TEX> harmonic currents into the network, causing a distortion of the wave form of the currents and voltages through the power network.

Harmonic Analysis and Filter Design for the Light Rail Transit Systems

This paper presents the light rail transit system (lrts) impact on the harmonic pollution of distribution feeder. To investigate the dynamic responses of the system voltage and current, the distribution system and lrts models are set up well by using the Alternative Transients Program (ATP). The harmonic analysis of the distribution system with the lrts is executed under various operation scenarios. The 6-pulses and 12-pulses rectifier are adopted for the lrts with a direct current (dc) power supply to the trams. Furthermore, the well-designed filters have also applied to improve the harmonic distortion resulted from the lrts.

Programmable logic design of a compact Genetic Algorithm for phasor estimation in real-time

The main objective of this work is to present an efficient method for phasor estimation based on a compact Genetic Algorithm (cGA) implemented in Field Programmable Gate Array (FPGA). To validate the proposed method, an Electrical Power System (EPS) simulated by the Alternative Transients Program (ATP) provides data to be used by the cGA. This data is as close as possible to the actual data provided by the EPS. Real life situations such as islanding, sudden load increase and permanent faults were considered. The implementation aims to take advantage of the inherent parallelism in Genetic Algorithms in a compact and optimized way, making them an attractive option for practical applications in real-time estimations concerning Phasor Measurement Units (PMUs).

A Fault Classification and Localization Method for Three-Terminal Circuits Using Machine Learning

This paper presents a traveling-wave-based method for fault classification and localization for three-terminal power transmission systems. In the proposed method, the discrete wavelet transform is utilized to extract transient information from the recorded voltages. Support-vector-machine classifiers are then used to classify the fault type and faulty line/half in the transmission networks. Bewley diagrams are observed for the traveling-wave patterns and the wavelet coefficients of the aerial mode voltage are used to locate the fault. Alternate Transients Program software is used for transients simulations. The performance of the method is tested for different fault inception angles, different fault resistances, nonlinear high impedance faults, and nontypical faults with satisfactory results.

The Voltage Distribution Characteristics of a Hybrid Circuit Breaker During High Current Interruption

Hybrid circuit breaker (HCB) technology based on a vacuum interrupter and a SF6 interrupter in series has become a new research direction because of the low-carbon requirements for high voltage switches. The vacuum interrupter has an excellent ability to deal with the steep rising part of the transient recovery voltage (TRV), while the SF6 interrupter can withstand the peak part of the voltage easily. An HCB can take advantage of the interrupters in the current interruption process. In this study, an HCB model based on the vacuum ion diffusion equations, ion density equation, and modified Cassie-Mayr arc equation is explored. A simulation platform is constructed by using a set of software called the alternative transient program (ATP). An HCB prototype is also designed, and the short circuit current is interrupted by the HCB under different action sequences of contacts. The voltage distribution of the HCB is analyzed through simulations and tests. The results demonstrate that if the vacuum interrupter withstands the initial TRV and interrupts the post-arc current first, then the recovery speed of the dielectric strength of the SF6 interrupter will be fast. The voltage distribution between two interrupters is determined by their post-arc resistance, which happens after current-zero, and subsequently, it is determined by the capacitive impedance after the post-arc current decays to zero.

Autonomous Neural Models for the Classification of Events in Power Distribution Networks

This paper presents a method for automatic classification of faults and transients in power distribution networks, based on voltage oscillographies of the distribution networks feeders. For signal preprocessing, the discrete wavelet transform was used with the performances of several families of wavelet functions being compared. In the classification stage, three neural models were assessed: multi-layer perceptrons, radial basis function networks, and support vector machines. The models were trained autonomously, i.e., using automatic model selection and complexity control. Promising results were obtained using a set of simulations generated using the Alternative Transients Program (ATP). Initial results obtained for real data acquired from a set of oscillograph loggers installed in a distribution network are also presented.

Application of Wavelet Transform to Obtain the Frequency Response of a Transformer From Transient Signals—Part 1: Theoretical Analysis

This paper introduces a new theoretical method to obtain the frequency-response curve with the transformer in service (online) from the transient signals analysis by applying the continuous wavelet transform. To validate the method, the transient signals were simulated in the Alternative Transient Program for two cases: 1) under injection of pulses over the 60-Hz wave and 2) under switching operations, respectively. To simulate the transformer, a suitable wide-bandwidth model was employed. This study proposes a new setup of the Morlet wavelet, denominated Morlet-Modified, which showed the best results obtained for our application purpose (FRA On-line). This paper is a contribution for signal processing for the online frequency-response analysis technique on transformers.

Transmission lines fault location using transient signal spectrum

This paper proposes a method for fault location on transmission lines, which is based on time to frequency domain transformation of transient signals of the fault instant measured at one end. Fast Fourier Transform (FFT) is used for time to frequency domain transformation and frequency of the first fault generated harmonic is utilised for determination of the fault location using the travelling wave theory of the transmission line. The accuracy of the method has been tested using the simulations carried out in Alternative Transients Program (ATP/EMTP) with frequency-dependent distributed parameter transmission line model by considering several cases and various types of faults, different values of fault resistance and phase angle at fault instant. The method has good accuracy and the simulation results show that the accuracy of the method is insensitive to the fault resistance and phase angle of the fault instant. Reactive elements may affect the resolution but, it can be removed by applying the correction procedure proposed.

The Algorithm Implementation and the Principle of Microcomputer Relay Protection in Power Transformer

Abstract The power transformer is very expensive and essential equipment in power system. Therefore, it requires continuous monitoring and rapid protection. The most common measures usually use ratio differential logic protection, which provides the detailed information of transformer internal fault in the different working conditions. However, it may lead to the conventional protection action in the power transformer of some working condition, and affect the stability of the power system. Through the fuzzy logic, artificial neural network and genetic algorithm.A new algorithm is put forward to improve the protective performance. The power system and the differential relay model use the alternative transients program to obtain test normal and fault conditions, and then to test for presented algorithm. The simulation results show that, compared with conventional methods, the proposed method has fast response and good reliability.

TRANSIENT VOLTAGE DISTRIBUTION IN TRANSFORMER WINDING (EXPERIMENTAL INVESTIGATION)

In this work, the non-liner voltage distribution in transformer winding is investigated that occurs due switching and lightning. Transformer winding is modeled in the alternative transients program (ATP) version of Electromagnetic transients program (EMTPRV). EMTP software is used to simulate the very fast transient overvoltage. An experimental setup that consist of , Recurrent surge generator, CRO and transformer winding model has been developed and voltages measured at different point along the transformer winding. Simulation results show good agreement with the experimental result.

Classification of Events in Power Transformers Using Wavelet Packet Transform and Fuzzy Logic

A monitoring algorithm based on wavelet transform and fuzzy logic was developed in this paper to perform event classification in power transformers. These events were observed in an electrical power system simulated using the alternative transients program software. It should be emphasized that the modeled system presented transformers connected in parallel, which allowed the study of specific operational events, including sympathetic inrush. The proposed algorithm presented a satisfactory performance to many situations, identifying the causes of the differential currents, either caused by faults or other operation conditions.

Obtaining the Electrical Impedance Using Wavelet Transform From the Time Response

This letter presents a new mathematical concept for electrical impedance based on the transient response, by means of the coefficient's energy of the continuous wavelet transform. To validate the new proposed method, signals were simulated in the Alternative Transients Program, and the experimental results were compared with the short time Fourier transform. This contribution has been particularly applied to power transformers in order to identify possible damages from just analyzing the transient responses in the wavelet domain.

Parameters Identification and Modeling of High-Frequency Current Transducer for Partial Discharge Measurements

Rogowski coil (RC) is a low-cost, air-cored, and flexible induction sensor for nonintrusive condition monitoring and thus can be used in a variety of applications. In this paper, a lumped parameter model of RC is presented and an experiment-based methodology is developed to determine its parameters. The performance of the RC is analyzed for detection and measurement of high-frequency (pulsed) signals such as partial discharge (PD) current pulses. A simple and efficient technique of numerical integration is adopted to avoid the conventional type of expensive and complex design analogue integrators. RC is modeled and simulated in the alternative transient program-electromagnetic transient program environment. The designed coil is tested to measure PDs in the laboratory. Simulated and experimental performance of RC is compared with a high-frequency current transformer. This comparison shows a good match and, hence, validates the design of RC for PD applications.

Simulation of a Wind-Power Plant Linked to a Transmission GridPart I: Modeling the Basic Wind Farm

This paper is divided into two parts, the first presents the modeling and simulation of a wind generator connected to the power grid, is covered in detail each component of the wind farm. For the simulation package is used Alternative Transients Program (ATP) showing the versatility of this model to incorporate non-existent models. All parameters respond to simulated models of commercial properties and specifications provided by power system operators. Shows in detail the implementation of the wind turbine by using the simulation language MODELS ATP itself. The paper concludes with a simulated wind contingency showing the response of the entire chain. The ATP package is shown capable of simulating the studies requested by the Compania Administradora del Mercado Mayorista Electrico (CAMMESA). The second part deals with two basic studies related to wind power, capacitive compensation and blade control.

Simulation of a Wind-Power Plant Linked to a Transmission Grid:Part II: Capacitive Compensation and Pitch Control

In the first part of this paper discussed the modeling and simulation of the components that make up a wind farm, the following is a basic study on two aspects that arise in a wind farm, the capacitive compensation and blade control. The review of the compensation done at static and dynamic problems is presented with some possible solutions. The concepts of blade control are presented and the simulation of two types of control, fixed gain and variable gain are given. The exchange of active power and reactive power between the grid and the wind farm is analyzed and the effects and solutions to various contingencies wind are shown. It shows the ability of the package ATP (Alternative Transients Program) to conduct studies of Stage I, Stage II and Stage III requested by the Compañía Administradora del Mercado Mayorista Eléctrico (CAMMESA), especially those that refer to electromagnetic transients and power quality.

High-Impedance Bus Differential Protection Modeling in ATP/MODELS

This paper presents a modeling of a high-impedance bus differential protection logic using the ATP (Alternative Transients Program) MODELS language. The model is validated using ATP simulations on an electrical system consisting of a sectionalized bus arrangement with four transmission lines (TLs) and two autotransformers. The obtained results validate the model and present some of the advantages of using this type of bus protection, such as fast and safe operation, even when under adverse conditions such as current transformers (CTs) magnetic core saturation upon the occurrence of external faults.

Simulation of transient processes on overvoltage in electric transmission lines using ATP-EMTP

In this paper, the mathematical modeling and simulation of electromagnetic transient processes is considered, which is of vital importance for examining the overvoltage phenomenon of power transmission systems. In the mathematical models of the AC power transmission systems that contain a power source, the power transformer, transmission line, and power autotransformer block are presented. The mathematical model of each system component is obtained based on the branch voltages, flux linkages, and branch voltages of the magnetic circuits individually. As for the simulation, an alternative transient program (ATP) environment is used to model the electric power system's elements. One of the power system's overvoltages occurs because of the fault and switching events. The usage of reactors at the sending and receiving ends of the line limits the overvoltages. The ATP has a powerful tool to simulate the transient events: specifically, the fault transients in the time domain. In order to test the simulation model's performance, the overvoltage measurements from a field test of a 500 kV electric transmission system is used. The simulation shows that the obtained results give satisfactory solutions to investigate the power system's overvoltage events. Selected results of the evaluation are presented.