Denis V. Coury

EPOCHS: a platform for agent-based electric power and communication simulation built from commercial off-the-shelf components

This paper reports on the development and subsequent use of the electric power and communication synchronizing simulator (EPOCHS), a distributed simulation environment. Existing electric power simulation tools accurately model power systems of the past, which were controlled as large regional power pools without significant communication elements. However, as power systems increasingly turn to protection and control systems that make use of computer networks, these simulators are less and less capable of predicting the likely behavior of the resulting power grids. Similarly, the tools used to evaluate new communication protocols and systems have been developed without attention to the roles they might play in power scenarios. EPOCHS integrates multiple research and commercial off-the-shelf systems to bridge the gap.

Artificial neural network approach to distance protection of transmission lines

A distance relay for the protection of transmission lines is usually designed on the basis of fixed settings. The reach of such relays is therefore affected by the changing network conditions. The implementation of a pattern recognizer for power system diagnosis can provide great advances in the protection field. This paper demonstrates the use of an artificial neural network as a pattern classifier for a distance relay operation. The scheme utilizes the magnitudes of three phase voltage and current phasors as inputs. An improved performance with the use of an artificial neural network approach is experienced once the relay can operate correctly, keeping the reach when faced with different fault conditions as well as network configuration changes.

Power Transformer Differential Protection Based on Clarke's Transform and Fuzzy Systems

The power transformer is a piece of electrical equipment that needs continuous monitoring and fast protection since it is very expensive and an essential element for a power system to perform effectively. The most common protection technique used is the percentage differential logic, which provides discrimination between an internal fault and different operating conditions. Unfortunately, there are some operating conditions of power transformers that can affect the protection behavior and the power system stability. This paper proposes the development of a new algorithm to improve the differential protection performance by using fuzzy logic and Clarkes transform. An electrical power system was modeled using Alternative Transients Program (ATP) software to obtain the operational conditions and fault situations needed to test the algorithm developed. The results were compared to a commercial relay for validation, showing the advantages of the new method.

Agent technology applied to adaptive relay setting for multi-terminal lines

This paper discusses the adaptation of the settings of distance relays for multi-terminal lines employing agents. Agents are software processes capable of searching for information in networks, interacting with pieces of equipment and performing tasks on behalf of their owners (relays). Results illustrating the performance of the adaptive method proposed compared to conventional fixed settings are presented. It is shown that the digital relays and agents acting within a communication structure (also called middleware) can alter adaptive settings to ensure correct performance over a wide variety of operation conditions, without the need of an additional communication link. The proposed relaying scheme can also be utilized for first zone clearing over the entire line.

An Agent-Based Current Differential Relay for Use with a Utility Intranet

This paper proposes an agent-based current differential relay for use with a communication network. Agents are software processes capable of searching for information in networks, interacting with pieces of equipment, and performing tasks on behalf of their owners (relays). Results illustrating the performance of the agent-based differential method proposed acting within a communication structure are presented for different traffic conditions. These results also show that a dedicated utility Intranet is a viable and recommended option as a communication media for the proposed scheme.

A differential relay for power transformers using intelligent tools

This paper presents alternative approaches using artificial neural networks (ANNs) for the protection of power transformers. A complete protection scheme was implemented. An ANN subroutine was used to discriminate internal faults from other situations, replacing the traditional Fourier method for harmonic restraint. In addition, a routine for reconstruction of saturated current signals based on recurrent ANNs is also proposed. The proposed methods were extensively tested and then compared to the traditional differential protection algorithm, showing promising results. The application of the ANN tools is a new and important stage in the differential relay analysis methodology for power transformer protection

An ANN Routine for Fault Detection, Classification, and Location in Transmission Lines

This article presents an Artificial Neural Network (ANN) approach to simulate a complete scheme for distance protection of transmission lines. The protection technique is based on a modular approach whereby different neural network modules have been adopted for fault detection, fault classification and fault location. Three-phase voltage and current samples were utilized as inputs for the proposed scheme. The Alternative Transients Program (ATP) software was used to generate data for the transmission line (400 kV). The results obtained show that the global performance of the ANN architectures is highly satisfactory under a wide variety of different fault conditions.

Transient analysis resulting from shunt capacitor switching in an actual electrical distribution system

The quality of electric power has been a constant topic of study, mainly because inherent problems to it can bring great economic losses, mainly in industrial processes. Among the various factors that affect power quality, those related to the transients originated from capacitor bank switching in the primary distribution systems must be highlighted. In this work, the characteristics of the transients resulting from the switching of the utility capacitor banks are analyzed, as well as factors that influence their intensities. The conditions under which these effects am mitigated can then be investigated. In addition, a spectral analysis of the current and voltage waves is made. This procedure can reveal the harmonic component, which can affect the operation of control and protection equipment, as well as sensitive loads of the industry. A circuit that represents a real distribution system, 13.8 kV, from CPFL (Cia Paulista de Forca e Luz-a Brazilian utility) was simulated through the software ATP (Alternative Transients Program) for purposes of this study.

Transient analysis concerning capacitor bank switching in a distribution system

Abstract The quality of electric power has been a constant topic of study, mainly because inherent problems to it can lead to great economic losses, especially in industrial processes. Among the various factors that affect power quality, those related to transients originating from capacitor bank (CB) switching in the primary distribution systems must be highlighted. In this work, the characteristics of transients resulting from the switching of utility CBs are analyzed, as well as factors that influence their intensities. The conditions under which these effects are mitigated can then be investigated. A circuit that represents a real distribution system, 13.8 kV, from Cia Paulista de Forca e Luz (CPFL—a Brazilian utility) was simulated through the software Alternative Transients Program ( atp ) for purposes of this study. Finally, a comparison with real-life data recorded at the distribution system was performed in order to validate the present simulation.

FPGA implementation of Genetic Algorithms for frequency estimation in power systems

The main objective of this research is to present a fast and efficient method based on genetic algorithms (GAs) to measure the frequency deviation, as well as the voltage magnitude and phase angle of a noisy sinusoid wave. The frequency estimation is formulated as an optimization problem, where the aim is to minimize the estimation error. The use of GAs has an advantage of better immunity against noise disturbance present in the input data. In addition, this work investigates the implementation of a GA scheme in FPGA (field-programmable gate array) in order to obtain a device that can work properly in real time. The new approach is able to accurately estimate the frequency, voltage magnitude and phase angle, simulating an on-line frequency relay. The proposed methodology provides an efficient alternative to frequency relays having advantages compared to traditional approaches.