Electric Power System Signals Research Articles

Energy Harvesting in the UNB-PLC Spectrum: Hidden Opportunities for IoT Devices

This article focuses on the hidden benefits of harvesting the wasted energy from undesirable components of electric signals in electric power systems for powering the transceivers of Internet of Things (IoT) devices. These components, mainly harmonics and interharmonics, occupy the ultranarrowband power line communication spectrum (i.e., frequencies below 3 kHz). In this context, we introduce a mathematical formulation that allows us to quantify the number of transceivers of IoT devices that this kind of wasted energy can power. Based on a measurement campaign in a building facility, we show that the wasted energy can be modeled as a cyclostationary random process on weekdays and a stationary one on weekends, mimicking the energy consumption profile in a building facility. Numerical results also highlight achievable data rates obtained in the building facility if the wasted energy is reused. This analysis shows that this kind of harvested energy from wasted energy is suitable for powering numerous transceivers of IoT devices in practical scenarios.

Benefits of energy recovery from the undesirable components of electric signals in electric power systems

This paper introduces an analytical framework for analyzing the benefits of using the waste-to-energy concept to improve power quality and energy efficiency in electric power systems. In this framework, closed-form expressions for evaluating the analytic cross-power spectral density between voltage and current signals are introduced to quantify the wasted energy associated with undesirable components of electric signals that result from the interaction between nonlinear loads and electric power systems. These expressions demonstrate the existing relationship between the analytic cross-power spectral density and the well-known complex power, which is widely used in electric power systems. In the sequel, it is shown that these expressions allow the introduction of the so-called Passive Filtering Energy Recovery, which aims to recover the wasted energy from the undesirable components of electric signals. Numerical results show that the Passive Filtering Energy Recovery, which relies on the waste-to-energy concept, can improve power quality and energy efficiency in the Brazilian and worldwide electric power systems.

An asymptotic and algebraic estimation method of harmonics

A new on-line and time-domain parameter estimation approach of harmonics in electric power system signals is introduced. The developed parametrical identification perspective is based on asymptotic and algebraic estimation techniques, and vibrating signal modeling. Specified harmonics and DC offset component of some measured distorted oscillating signal are reconstructed asymptotically. In this fashion, closed-form explicit formulae to compute into a small window of time, algebraically, on-line and in time-domain, the parameters of amplitude, frequency and phase of harmonics are then derived. Analytical, numerical and experimental results of six and twelve pulses converter reveal the effectiveness and efficiency of the proposed selective estimation approach for harmonics and corresponding parameters of measured oscillating electric signals into an operating frequency bandwidth. Among others, synchronization of power converters or switches to grid without the use of filtering can be achieved with this strategy.

Harmonic Load Diagnostic Techniques and Methodologies: A Review

<p>This paper will review on the existing techniques and methodologies of harmonic load diagnostic system. The increasingly amount of harmonic producing load used in power system are the main contribution in quantifying each harmonic disturbance effects of the multiple harmonic producing loads and it became very important. Literature proposes two different techniques and methods on the harmonic source identification under the soft computing technique classification. The advantages and disadvantages of harmonic load identification techniques and methods are discussed in this paper. In the proposed method, the issue on the harmonic contribution is determine and transformed to a data correlation analysis. Several techniques to identify the sources of harmonic signals in electric power systems are described and reviewed based on previous paper. Comparative studies of the methods are also done to evaluate the performance of each techniques. However, without sufficient information in this inconsistent environment on the property of the power system, accurate harmonic producing load diagnosis methods are important and further investigations in this regard assumes great implication.</p>

On-line parametric estimation of damped multiple frequency oscillations

Undesirable harmonic pollution is currently a reality in many electric power systems. Damped transients generated by the growing use of electronically controlled devices are an important source of harmonic distortion of voltage and current waveforms. Accurate real-time estimation of harmonics parameters during the on-line operation of some electric power system is thus an active and pertinent challenging research issue. In this paper a novel on-line algebraic parametric estimation method in time domain, for damped harmonic components on electric power system signals is introduced. Algebraic formulas to directly compute amplitude, damping, frequency and phase parameters and dc offset component into a small time window for variable multi-frequency oscillations are proposed. Parameter estimators enable the on-line and direct reconstruction in finite time of harmonic components and deviations of some measurable signal. Experimental results confirm the effectiveness of the algebraic parametric estimation on uncertain multi-frequency oscillating transient signals.

A fast parametric estimation approach of signals with multiple frequency harmonics

A new fast algebraic estimation scheme in time domain is proposed for amplitude, frequency and phase parameters in electric power system signals with multiple frequency harmonics. Time domain integral operators are properly used in the synthesis of the proposed parametric estimation approach. In this fashion, time derivatives of signals and initial conditions of the system are unnecessary. Analytical and numerical results confirm the effectiveness of the proposed algebraic approach for fast and simultaneous estimation of amplitude, frequency and phase parameters of harmonics, inter-harmonics and sub-harmonics on electric power system signals.

An implementation of a Power System Smart Waveform Recorder using FPGA and ARM cores

In this paper, the design and the prototype implementation of a Power Quality (PQ) disturbance detector and compressor are described. This instrument, named Power System Smart Waveform Recorder (PSSWR), is able to acquire the samples of the Electric Power System (EPS) signals and process them in order to detect, compress and store the disturbances waveforms into an SD card, from which it can be reconstructed and analyzed offline with a suitable computer application. The prototype uses, among other devices, Field Programmable Gate Array (FPGA) and ARM platforms to work with the EPS signals in a smart way. The PSSWR is able to detect and record either the waveform of the well-known PQ disturbance as well the new PQ disturbances not yet observed in EPS, thanks to the Novelty Detection concept. This characteristic is important in the new context of smart grids where hidden disturbances can be detected by the methodology.

Adaptive structural analysis of input signals of digital and relay protection and automation

The foundations of the theory of adaptive structural analysis of electric power system signals are developed. The relationship between the current mode signal order of the electrical system and the structural model effective order is shown. Optimal structural models for signals of periodic and transient modes of the electrical system and hybrid models convenient for the implementation in digital relay protection systems are proposed. Methods for the recognition and decomposition of transient signals at a high sampling rate are developed. It is shown that the best method for increasing the resolution of adaptive structural models in the case of signal processing with a high sampling rate is sampling decimation in the model. Examples of the structural analysis of actual fault signals in the electrical network are given.

Identification of harmonic sources by a state estimation technique

A reverse power flow procedure is described to identify the sources of harmonic signals in electric power systems. Methods have been reported elsewhere to analyze the propagation of these harmonics signals throughout the network. Here the reverse problem of how to identify the source (and potentially the type) of harmonic signals is considered. Line and bus data at several points in the network are used with a least-squares estimator to calculate the injection spectrum at buses suspected of being harmonic sources. When energy at harmonic frequencies is found to be injected into the network at a bus, that bus is identified as a harmonic source. >

Decision functions for electric power system signals

Abstract An investigation of electric power system component deterioration has led to the development of a mathematical procedure which can be used to predict incipient failure or assess the integrity of individual components while they are operating in the power system.

Power system excitation and governor design using optimal control theory

Abstract Integrated excitation and/or governor control systems are the result of using novel approaches for the selection of stabilizing signals in electric power systems. Such controllers have usually been derived on the basis of a linearized system model, an attractive practical feature of these being that a linear, time-invariant optimal controller may be derived. The power system is non-linear, however, and it is for this non-linear system that an optimal controller is ideally required. Previous work in the area is shown to be deficient in the light of this requirement and subsequently time-invariant integrated controllers suitable for use with the non-linear system are developed. These controllers incorporate model following with integral action and are shown to effect improved control of the nonlinear system over a wide range of operating conditions. The manner in which the proposed control system design procedure may permit the integrated control of large power systems is also of considerable pract...