Showing papers on "Spectrum analyzer published in 2021"

Distributed optomechanical fiber sensing based on serrodyne analysis

Abstract: Distributed measurement of forward stimulated Brillouin scattering (FSBS) attracted substantial attention for its ability to probe media surrounding optical fibers. Currently, all techniques extract the information from the FSBS-induced local energy transfer among distinct optical tones, this transfer being fundamentally sensitive to intensity perturbations imposed by nonlinear effects. Instead, here we propose to extract the local FSBS information by measuring the frequency shift of a short optical pulse subject to the phase chirp modulation caused by harmonic FSBS oscillation. In full contrast with existing techniques, the optical pulse is much shorter than the period of the acoustic oscillation, enabling ultrashort spatial resolutions, and its frequency shift is precisely probed by a standard Brillouin optical time-domain analyzer. The proposed technique is validated in both remote and integrally distributed sensing configurations, demonstrating spatial resolutions of 0.8 m and 2 m, respectively, substantially outperforming state-of-the-art techniques.

Waveguide-Coupled Rydberg Spectrum Analyzer from 0 to 20 GHz

Abstract: We demonstrate an atomic rf receiver and spectrum analyzer based on thermal Rydberg atoms coupled to a planar microwave waveguide. We use an off-resonant rf heterodyne technique to achieve continuous operation for carrier frequencies ranging from dc to 20 GHz. The system achieves an intrinsic sensitivity of up to $\ensuremath{-}120(2)$, dc coupling, 4-MHz instantaneous bandwidth, and over 80 dB of linear dynamic range. By connecting through a low-noise preamplifier, we demonstrate high-performance spectrum analysis with peak sensitivity of better than $\ensuremath{-}145\phantom{\rule{0.2em}{0ex}}\mathrm{dBm/Hz}$. Attaching a standard rabbit-ears antenna, the spectrum analyzer detects weak ambient signals including FM radio, AM radio, WiFi, and bluetooth. We also demonstrate waveguide-readout of the thermal Rydberg ensemble by nondestructively probing waveguide-atom interactions. The system opens the door for small, room-temperature, ensemble-based Rydberg sensors that surpass the sensitivity, bandwidth, and precision limitations of standard rf sensors, receivers, and analyzers.

A Methodology for Power Quantities Calculation Applied to an FPGA-Based Smart-Energy Meter

Abstract: A complete description of a field-programmable gate array (FPGA)-based smart energy meter is presented in this article. By implementing the power quantities definitions of the IEEE 1459–2010 Standard, a novel power quality analyzer capable of performing remote monitoring of electric power systems operating under sinusoidal, nonsinusoidal, balanced, and/or unbalanced conditions was developed. In order to ensure portability, the digital signal processing algorithms implemented on the FPGA device were entirely coded in hardware description languages, and all equations of them are fully described to be applied to any digital signal processing environment. These algorithms are completely defined as functions of the grid fundamental frequency, and by adjusting the sampling frequency, the adaptability of all modules developed is ensured. Experimental results were obtained using the developed platform in a three-phase four-wire system operating under several conditions, which were defined by the presence of harmonic components imposed by nonlinear loads and supply voltages, as well as by setting bidirectional power flow in distributed generation scenarios by employing a photovoltaic system. Real-time and parallel processes are validated as well.

Review on Speckle-Based Spectrum Analyzer

Abstract: Accurate spectral measurement and wavelength determination are fundamental and vital for many fields. A compact spectrum analyzer with high performance is expected to meet the growing requirements, and speckle-based spectrum analyzer is a potential solution. The basic principle is based on using the random medium to establish a speckle-to-wavelength mapping relationship for spectrum reconstruction. This article introduces current speckle-based spectrum analyzers with different schemes and reviews recent advances in this field. Besides, some applications by using speckle-based spectrum analyzers are also introduced. Finally, the existing challenges and the future prospects of using speckle for spectrum recovery are discussed.

High-resolution inelastic x-ray scattering at the high energy density scientific instrument at the European X-Ray Free-Electron Laser

Abstract: We introduce a setup to measure high-resolution inelastic x-ray scattering at the High Energy Density scientific instrument at the European X-Ray Free-Electron Laser (XFEL). The setup uses the Si (533) reflection in a channel-cut monochromator and three spherical diced analyzer crystals in near-backscattering geometry to reach a high spectral resolution. An energy resolution of 44 meV is demonstrated for the experimental setup, close to the theoretically achievable minimum resolution. The analyzer crystals and detector are mounted on a curved-rail system, allowing quick and reliable changes in scattering angle without breaking vacuum. The entire setup is designed for operation at 10 Hz, the same repetition rate as the high-power lasers available at the instrument and the fundamental repetition rate of the European XFEL. Among other measurements, it is envisioned that this setup will allow studies of the dynamics of highly transient laser generated states of matter.

The five-analyzer point-to-point scanning crystal spectrometer at ESRF ID26.

Abstract: X-ray emission spectroscopy in a point-to-point focusing geometry using instruments that employ more than one analyzer crystal poses challenges with respect to mechanical design and performance. This work discusses various options for positioning the components and provides the formulas for calculating their relative placement. Ray-tracing calculations were used to determine the geometrical contributions to the energy broadening including the source volume as given by the beam footprint on the sample. The alignment of the instrument is described and examples are given for the performance.

All-Ceramic LC Resonator for Chipless Temperature Sensing Within High Temperature Systems

Abstract: The primary focus of this work is to fabricate and evaluate electroceramic based LC resonators for wireless sensing at high temperatures. An all-ceramic planar LC resonator was fabricated on a polycrystalline Al2O3 substrate by using tin-doped indium oxide (ITO) as the electrode material. The LC resonators were deposited on the substrate by a novel two-step micro-casting technique. The resonator was designed using the ANSYS Maxwell package to operate within a wide frequency bandwidth from 10 to 80 MHz. A similar all-ceramic inductor was fabricated and used as the interrogator antenna to collect the wireless response at high operating temperature. The wireless characterization was performed by a radio frequency (RF) signal generator and an in-situ spectrum analyzer from 500 - 1200°C. The microstructural, chemical, and electrical stability of the LC resonator was investigated by SEM, 4-point conductivity, and XRD. Additionally, a robust adaptive signal processing algorithm was developed to analyze the wireless response of multiple LC resonator. The adaptive algorithm developed in this work is data driven and does not require a predefined model to analyze the wireless response from the LC resonator.

Measurement and Characteristic Analysis of Electromagnetic Disturbance of Coal Mine Fan Converter

Abstract: With the extensive use of converters in high-power ventilator, shearer, road header, conveyor, hoist, and other coal mine equipment, the electromagnetic disturbance problem of the converter is worthy of attention. In this paper, the field measurement and statistical method are used to analyze the radiation interference characteristics of frequency converter. Then, a typical fan converter is taken as an example, and the electromagnetic disturbance of the converter is tested in four key positions and two working frequencies, respectively. Multiple sets of data and spectrum are obtained by using a spectrum analyzer and other instruments, and the dominant frequency characteristic parameters of the converter are analyzed emphatically. The small sample data adopts the Shapiro–Wilk test, and the 80%/80% rule was used for statistical analysis. Finally, we got five common frequencies of electromagnetic interference generated by the converter (electric field dBμV/m). The CH4 sensor and other sensors work near these five dominant frequencies, which may affect the normal operation of the sensor and cause alarm. The test and analysis method proposed in this paper can be used to obtain the characteristic parameters of the converter electromagnetic disturbance, which can be used as a reference for the design of the immunity of sensors or control instruments.

Biased Balance Detection for Fiber Optical Frequency Comb Based Linear Optical Sampling

Abstract: Linear optical sampling (LOS) is a powerful technique to circumvent the electronic bottleneck arising in optical modulation analyzer (OMA). To extend the range of operation wavelength for the LOS-based OMA, the fiber optical frequency comb (FOFC) is proposed to replace the narrowband mode-locked fiber laser (NMFL) as an optical sampling source. However, this procedure reduces the signal-to-noise ratio (SNR), due to the constraints of the unideal response of balanced photodetector (BPD) and the limited power per FOFC tone. Here, we investigate the biased balance detection (BBD) scheme to overcome such issue. Our simulation results show that, the characterization performance of the FOFC-based LOS with the help of the BBD scheme is almost the same as that of the NMFL-based LOS, when the PDM-QPSK/16QAM/64QAM signals are set as the signal under test (SUT). Meanwhile, we find that the dynamic range of SUT input power is determined by the BPD imbalance and the FOFC power. By increasing either the average power of the FOFC from 4 to 10 mW or the imbalance of the BPD from 1.03 to 1.04, we can enhance the dynamic range of SUT input power by 8.8 mW and 6.6 mW, respectively. Finally, we develop the equipment and experimentally verify the BBD scheme by a precise characterization of 32 GBaud PDM-QPSK signal.

Millimeter-Wave Integrated Side-Fire Leaky-Wave Antenna and Its Application as a Spectrum Analyzer

Abstract: An analog, low-profile and shielded spectrum analyzer is proposed for operation at mm-wave frequencies around the 60 GHz band based on a novel side-fire leaky-wave antenna (LWA) configuration. The proposed side-fire periodic LWA is systematically developed from a conventional three-port waveguide T-junction which is modified to a LWA unit cell with an internal matching mechanism to suppress the stopband and enable broadside radiation based on unit cell symmetry considerations. The resulting periodic side-fire antenna radiates in the plane of the antenna, whereby the leakage power can either be allowed to radiate in free-space or kept confined inside a parallel-plate waveguide (PPW) structure. The proposed side-fire structure can therefore be completely shielded, making it useful as a broadband spectrum analyzer that is compatible with substrate-integrated waveguide (SIW) technology. Furthermore, a convex side-fire antenna is demonstrated to focus the radiated beams in the near-field of the structure to make the entire system compact. The integrated spectrum analyzer is experimentally demonstrated between 59 and 66 GHz providing 1 GHz frequency resolution. Furthermore, a simple mathematical model consisting of an array of line sources is used to efficiently model the beam-scanning characteristics of the curved side-fire LWA in the near-field of the structure.

Near-Field Precision Measurement System of High-Density Integrated Module

Abstract: An automatic near-field precision measurement system was proposed in this article. The work was mainly focused on the hardware structure design of the near-field precision measurement system and the software development of the upper computer. At the same time, the electromagnetic field probes used in the system were selected and introduced. The near-field precision measurement system was composed of an upper computer control part, motion controller, power amplifier module, three-axes mechanical arms, spectrum analyzer, and near-field probes. Three-axes mechanical arm, multi-degree-of-freedom fixture, and electromagnetic field probe cooperate with each other for near-field measurement. The electromagnetic radiation emission of high-density integrated module and liquid crystal display (LCD)-printed circuit board (PCB) of laptop computer were measured. According to the measured data, the visual field distribution map was generated, and the measured results were analyzed. Compared with manual measurement method and commercial electromagnetic compatibility (EMC) scanners, the near-field precision measurement system has more accurate measurement results and can accurately locate the noise source.

Energy Conservation Approach for Continuous Power Quality Improvement: A Case Study

Abstract: This work focused on a harmonic mitigating filter and investigated the effect of the harmonic mitigating filter in the textile industry with innovative energy conservation strategies for energy bill reduction, which covers a pathway to climate change mitigation. Here, the effect of the harmonic filter is found out by the systematic energy audit methodology (Preliminary, Detailed and Post-Audit phase). From the energy auditing, it has been found that the textile industry needed a passive harmonic filter for harmonic mitigation. Since, third, fifth, and seventh order of harmonic predominantly exists in the system. The high stability at higher current, known tuning frequency, low cost and low power consumption makes the passive filter to be the best fit for the system. The voltage and current Total Harmonic Distortion Factor (THDF) have been measured using the class ‘A’ power quality and energy analyzer. The harmonic filter’s effect in harmonics mitigation is prominent; 66.45% of the reduction of current harmonics which is achieved after installing the passive filter at the Point of Common Coupling (PCC) of the system. Also, the reduction of harmonics ensures energy conservation through the reduction of additional losses (joule, copper and eddy current losses). The techno-economic analysis with payback period calculation is carried out and reported. Also, the effect of harmonics like mechanical anomalies (temperature rise) is carefully studied using an infrared thermo graphic technique in the textile industry’s motor loads. The energy conservation and their carbon emission reduction are calculated and reported.

Interband Cascade Laser Arrays for Simultaneous and Selective Analysis of C1-C5 Hydrocarbons in Petrochemical Industry.

Abstract: The detection and measurement of hydrocarbons are of high interest for a variety of applications, for example within the oil and gas industry from extraction throughout the complete refining process, as well as for environmental monitoring and for portable safety devices. This paper presents a highly sensitive, selective, and robust tunable laser analyzer that has the capability to analyze several components in a gas sample stream. More specifically, a multi-gas system for simultaneous detection of C1 to iC5 hydrocarbons, using a room temperature distributed feedback interband cascade laser array, emitting in the 3.3 µm band has been realized. It combines all the advantages of the tunable laser spectroscopy method for a fast, sensitive, and selective in-line multicomponent tunable laser analyzer. Capable of continuous and milliseconds fast monitoring of C1-iC5 hydrocarbon compositions in a process stream, the analyzer requires no consumables (e.g., purging, carrier gas) and no in-field calibration, enabling a low cost of ownership for the analyzer. The system was built based on an industrial GasEye series platform and deployed for the first time in field at Preem refinery in Lysekil, Sweden, in autumn 2018. Results of the measurement campaign and comparison with gas chromatography instrumentation are presented.

Health Analysis of Transformer Winding Insulation Through Thermal Monitoring and Fast Fourier Transform (FFT) Power Spectrum

Abstract: This paper presents a health analysis technique for transformer winding insulation through thermal monitoring and Fast Fourier Transform (FFT) power spectrum. A novel thermal model for the Kraft paper insulation of transformer is proposed by using the transformer’s top-oil and winding hot-spot temperature models. The relationship between the temperature rise of oil inside the transformer tank and the winding insulation degradation are considered by utilizing the data-sets and daily load cycles of a 10/13 MVA, 132/11 kV, 50 Hz, ONAF grid power transformer. The model based on IEEE Guide for loading mineral-oil-immersed transformers is developed in Simulink. The hotspot temperature rise from the thermal model is used as a reference to analyze the winding insulation degradation in the form of high frequency partial discharges (PDs) upon the output parameters of the transformer. Using data analysis techniques, a correlation is presented between the load cycles and the hot-spot temperature through which the health status of the transformer winding insulation is estimated. Moreover, the high frequency transients were detected using the Fast Fourier Transform (FFT) spectrum analyzer tool in MATLAB. The preliminary study shows that high frequency PDs are detected for the overheated and deteriorated state of the winding insulation. The results show that the proposed technique is feasible for the health analysis of power transformers and successfully predicted the deterioration of the transformer winding insulation.

Time-of-flight photoelectron momentum microscopy with 80–500 MHz photon sources: electron-optical pulse picker or bandpass pre-filter

Abstract: The small time gaps of synchrotron radiation in conventional multi-bunch mode (100–500 MHz) or laser-based sources with high pulse rate (∼80 MHz) are prohibitive for time-of-flight (ToF) based photoelectron spectroscopy. Detectors with time resolution in the 100 ps range yield only 20–100 resolved time slices within the small time gap. Here we present two techniques of implementing efficient ToF recording at sources with high repetition rate. A fast electron-optical beam blanking unit with GHz bandwidth, integrated in a photoelectron momentum microscope, allows electron-optical `pulse-picking' with any desired repetition period. Aberration-free momentum distributions have been recorded at reduced pulse periods of 5 MHz (at MAX II) and 1.25 MHz (at BESSY II). The approach is compared with two alternative solutions: a bandpass pre-filter (here a hemispherical analyzer) or a parasitic four-bunch island-orbit pulse train, coexisting with the multi-bunch pattern on the main orbit. Chopping in the time domain or bandpass pre-selection in the energy domain can both enable efficient ToF spectroscopy and photoelectron momentum microscopy at 100–500 MHz synchrotrons, highly repetitive lasers or cavity-enhanced high-harmonic sources. The high photon flux of a UV-laser (80 MHz, <1 meV bandwidth) facilitates momentum microscopy with an energy resolution of 4.2 meV and an analyzed region-of-interest (ROI) down to <800 nm. In this novel approach to `sub-µm-ARPES' the ROI is defined by a small field aperture in an intermediate Gaussian image, regardless of the size of the photon spot.

Quantum Harmonic Oscillator Spectrum Analyzers.

Abstract: Characterization and suppression of noise are essential for the control of harmonic oscillators in the quantum regime. We measure the noise spectrum of a quantum harmonic oscillator from low frequency to near the oscillator resonance by sensing its response to amplitude modulated periodic drives with a qubit. Using the motion of a trapped ion, we experimentally demonstrate two different implementations with combined sensitivity to noise from 500 Hz to 600 kHz. We apply our method to measure the intrinsic noise spectrum of an ion trap potential in a previously unaccessed frequency range.

Analysis of Sound Frequency on Guzheng Using Advanced Spectrum Analyzer Pro

Abstract: Physics learning about sound frequency will be more effective if equipped with practicum activities. This practicum activity can be done by linking it with a cultural because cultural values have the potential to be implemented in physics learning, such as musical instruments for sound frequency. As for the culture used in this research is the Guzheng. This research aims to analyzed of the Guzheng sound frequency, the comparison of the sound frequency to the prime tones, and the comparison of the sound frequency to the octave tones. The research type that was used is based on laboratory experiment with the aids of Advanced Spectrum Analyzer Pro application which is already installed in the smartphone to measure the sound frequency of 21 strings of Guzheng. The result of the analyzed showed that the longer of string so the sound frequency produced is the lower. As for of simple linear regression test showed that the sound frequency is linearly distributed to the prime tones and to the octave tones. The result of research can be applied in physics learning by conducting practicum activities and utilizing technology by the Advanced Spectrum Analyzer Pro application to measure the sound frequency both on musical instruments and on other objects that can make a sound.

Performance Evaluation of Radio Frequency Interference Measurements from Microwave Links in Dense Urban Cities

Abstract: Radio frequency interference (RFI) constitutes a significant problem in achieving a good quality of service in radio links. Several techniques have been proposed to identify and mitigate RFI in wireless networks. However, most of these techniques are not generalized for all propagation environments due to varying geographical features from one environment to another. The need for extensive frequency scan measurements on the links to identify the available channels, evaluate the performances of the links, and detect RFI in the channels becomes imperative. This study presents a performance evaluation of frequency scan measurements from active microwave links comprising eighteen base stations. The measurements equipment included a spectrum analyzer and a 0.6 m antenna dish. The frequency scans were taken at 6 GHz, 7 GHz, and 8 GHz with full azimuth coverage of the horizontal and vertical polarization. Measured data were processed to determine the available frequencies and RFI in the channels. The histogram and probability density function of the frequency scans were computed. The cumulative distribution functions were determined, and the statistical error characteristics of the frequency scans for the estimated normal distribution and the estimated fitness curve were derived. The short-time Fourier transform of the noisy signal was obtained, and the signal without noise was recovered using the inverse short-time Fourier transform. Analysis of the scanned signals before and after the noise removal is demonstrated. The denoised signals compare favorably with related results in the preliminary literature. Overall, these frequency scans would be beneficial in evaluating RFI measurements and spectrum planning and hold great promise for designing robust RFI detection algorithms for future wireless systems.

Error Estimation of BFS Extraction With Optimized Neural Network & Frequency Scanning Range

Abstract: We present and investigate a scheme for the error estimation formula derivation of Brillouin frequency shift (BFS) extraction based on an optimized neural network and frequency scanning range for a Brillouin optical time-domain analyzer (BOTDA) system. The system uses a general single mode optical fiber as the sensing medium, and the pump pulse duration is much longer than the phonon lifetime to ensure that the measured gain spectra are close to a Lorentzian shape. The performance of the network for extracting the BFS from f s to f e with different frequency scanning ranges is studied in detail, where f s∼ f e is the measurement range needing high precision. The results show that the optimal frequency scanning range is f s-20∼ f e + 20 (MHz). Based on the optimized network, the influences of the signal-to-noise ratio (SNR), linewidth of the gain spectrum (Δ v B) and frequency step ( δ ) on the error of BFS extraction are each discussed in detail. The error declines exponentially as the SNR improves and rises linearly as Δ v B increases. The linear interpolation method is used to obtain the desired input data for the network under different frequency steps, and the error shows a linear relationship with δ . Finally, a comprehensive error estimation formula for the BFS extraction of a BOTDA is constructed according to the above three relationships and completed by fitting the errors under various SNRs, Δ v B and δ .

Design and Testing of a Power Analyzer Monitor and Programming Device in Industries with a LoRA LPWAN Network

Abstract: Electrical installations represent an important part of the industry. In this sense, knowing the state of the electrical installation in real time through the readings of the installed power analyzers is of vital importance. For this purpose, the RS485 bus can be used, which most electrical installations already have. An alternative to the bus wiring and its distance limitation is the use of low-power wide area networks (LPWAN). The long range (LoRa) protocol is ideal for industries due to its low-power consumption and coverage of up to 10 km. In this research, a device is developed to control all the reading and programming functions of a power analyzer and to integrate the device into the LoRa LPWAN network. The power analyzer monitor and programming device (PAMPD) is inexpensive and small enough to be installed in electrical panels, together with the power analyzer, without additional wiring. The information collected is available in the cloud in real time, allowing a multitude of analysis be run and optimization in real time. The results support high efficiency in information transmission with average information loss rate of 3% and a low average transmission time of 30 ms.

Fast processing of underwater polarization imaging based on optical correlation.

Abstract: Underwater polarization differential imaging requires the estimation of different parameters, and the parameters can be accurately obtained by using optical correlation. However, optical correlation as a criterion function to estimate parameters takes a lot of time. To expedite the parameters’ estimation process, we propose two operations to process underwater polarization images. One operation is to update the analyzer angle range to reduce the number of processed images. The other is image downsampling, which reduces the amount of calculation for the corresponding images. In experiments, we confirmed the feasibility of our method. We have obtained an average of 42 times the calculation speed increase under the conditions of updating the analyzer angle range 3 times and reducing the image scale by 16 times. The results of our method are consistent with those of traditional methods. This established method is conducive to the practical application of underwater polarization differential imaging.

Precise dynamic characterization of microcombs assisted by an RF spectrum analyzer with THz bandwidth and MHz resolution.

Abstract: The radio frequency (RF) spectrum of microcombs can be used to evaluate its phase noise features and coherence between microcomb teeth. Since microcombs possess characteristics such as high repetition rate, narrow linewidth and ultrafast dynamical evolution, there exists strict requirement on the bandwidth, resolution and frame rate of RF measurement system. In this work, a scheme with 1.8-THz bandwidth, 7.5-MHz spectral resolution, and 100-Hz frame rate is presented for RF spectrum measurement of microcombs by using an all-optical RF spectrum analyzer based on cross-phase modulation and Fabry Perot (FP) spectrometer, namely FP-assisted light intensity spectrum analyzer (FP-assisted LISA). However, extra dispersion introduced by amplifying the microcombs will deteriorate the bandwidth performance of measured RF spectrum. After compensating the extra dispersion through monitoring the dispersion curves measured by FP-assisted LISA, the more precise RF spectra of microcombs are measured. Then, the system is used to measure the noise sidebands and line shape evolution of microcombs within 2s temporal window, in which dynamic RF combs variation at different harmonic frequencies up to 1.96 THz in modulation instability (MI) state and soliton state are recorded firstly. Therefore, the improved bandwidth and resolution of FP-assisted LISA enable more precise measurement of RF spectrum, paving a reliable way for researches on physical mechanism of microcombs.

Dual-Band Dual-Mode Filter-Enhanced Linearity Measurement

Abstract: This letter presents, for the first time, a new filter-enhanced linearity measurement technique using a dual-band and dual-mode filter. While traditional two-tone linearity tests are simple and effective, their ultimate performance is determined by the quality (dynamic range and noise floor) and cost of the employed equipment. On the other hand, the proposed method consists of a simple conventional single-tone test facilitated by a low-cost appropriately designed bandstop filter (BSF). In particular, the employed dual-band/dual-mode absorptive BSF suppresses the fundamental frequency by over 35 dB (absorptive notch) and the second harmonic by over 25 dB (reflective notch), allowing for accurate measurement of the third harmonic, and hence, IP3. The proof-of-concept system is demonstrated at 2 GHz. The filter absorbs with better than 20 dB of reflection the excitation signal at $f_{0}=2$ GHz and reflects the signal at $2f_{0}=4$ GHz. With just the insertion of the presented filter and without improving the measurement equipment, we demonstrate an improvement of over 12.7 dB in the IP3 characterization to a maximum of 81 dBm. We also demonstrate the ability to conduct this test with just a low-cost power detector in lieu of a spectrum analyzer leading to a simple scalable measurement technique.

Power quality and its characteristics

Abstract: This chapter discusses the various power quality problems and characteristics such as transients, short-duration root mean square (RMS) variation, long-duration RMS variation, unbalance, voltage fluctuations, waveform distortions, and power frequency variations. The causes, impacts, and examples are given for these power quality problems. The practical recorded power quality problems through the power quality analyzer and simulation of power quality problems through PSCAD simulation software are presented in this chapter.