scholarly journals Improved Performance of M-Class PMUs Based on a Magnitude Compensation Model for Wide Frequency Deviations

Mathematics ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 1361
Author(s):  
Jose Roberto Razo-Hernandez ◽  
Ismael Urbina-Salas ◽  
Guillermo Tapia-Tinoco ◽  
Juan Pablo Amezquita-Sanchez ◽  
Martin Valtierra-Rodriguez ◽  
...  
Keyword(s):  
Power Systems ◽  
Frequency Range ◽  
Magnitude Response ◽  
Modulation And Demodulation ◽  
Variable Function ◽  
Low Pass ◽  
Measurement Units ◽  
Phasor Estimation ◽  
Improved Performance ◽  
Reporting Rates

Phasor measurement units (PMUs) are important elements in power systems to monitor and know the real network condition. In order to regulate the performance of PMUs, the IEEE Std. C37.118.1 stablishes two classes—P and M, where the phasor estimation is carried out using a quadrature oscillator and a low-pass (LP) filter for modulation and demodulation, respectively. The LP filter plays the most important role since it determines the accuracy, response time and rejection capability of both harmonics and aliased signals. In this regard and by considering that the M-class filters are used for more accurate measurements, the IEEE Std. presents different M-class filters for different reporting rates (when a result is given). However, they can degrade their performance under frequency deviations if the LP frequency response is not properly considered. In this work, a unified model for magnitude compensation under frequency deviations for all the M-class filters is proposed, providing the necessary values of compensation to improve their performance. The model considers the magnitude response of the M-class filters for different reporting rates, a normalized frequency range based on frequency dilation and a fitted two-variable function. The effectiveness of the proposal is verified using both static and dynamic conditions for frequency deviations. Besides that, a real-time simulator to generate test signals is also used to validate the proposed methodology.

Optimal design of fractional order low pass Butterworth filter with accurate magnitude response

2018 ◽  
Vol 72 ◽  
pp. 96-114 ◽  
Author(s):  
Shibendu Mahata ◽  
Suman Kumar Saha ◽  
Rajib Kar ◽  
Durbadal Mandal
Keyword(s):  
Optimal Design ◽  
Fractional Order ◽  
Magnitude Response ◽  
Butterworth Filter ◽  
Low Pass

scholarly journals An Accurate Method for Delay Margin Computation for Power System Stability

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3466 ◽  
Author(s):  
Ashraf Khalil ◽  
Ang Swee Peng
Keyword(s):  
Time Delay ◽  
Power Systems ◽  
Power System ◽  
System Stability ◽  
Area Measurement ◽  
Power System Stabilizer ◽  
Iteration Algorithm ◽  
Measurement Units ◽  
System Stabilizer ◽  
Delay Margin

The application of the phasor measurement units and the wide expansion of the wide area measurement units make the time delay inevitable in power systems. The time delay could result in poor system performance or at worst lead to system instability. Therefore, it is important to determine the maximum time delay margin required for the system stability. In this paper, we present a new method for determining the delay margin in the power system. The method is based on the analysis in the s-domain. The transcendental time delay characteristics equation is transformed to a frequency dependent equation. The spectral radius is used to find the frequencies at which the roots cross the imaginary axis. The crossing frequencies are determined through the sweeping test and the binary iteration algorithm. A single machine infinite bus system equipped with automatic voltage regulator and power system stabilizer is chosen as a case study. The delay margin is calculated for different values of the power system stabilizer (PSS) gain, and it is found that increasing the PSS gain decreases the delay margin. The effectiveness of the proposed method has been proved through comparing it with the most recent published methods. The method shows its merit with less conservativeness and fewer computations.

scholarly journals State Estimation in Electric Power Systems Leveraging Graph Neural Networks

2022 ◽  
Author(s):  
Ognjen Kundacina ◽  
Mirsad Cosovic ◽  
Dejan Vukobratovic
Keyword(s):  
Power Systems ◽  
Power System ◽  
State Estimation ◽  
Electric Power Systems ◽  
State Variables ◽  
Evaluation Phase ◽  
Measurement Units ◽  
Synthetic Datasets ◽  
Graph Neural Networks ◽  
Test Scenarios

The goal of the state estimation (SE) algorithm is to estimate complex bus voltages as state variables based on the available set of measurements in the power system. Because phasor measurement units (PMUs) are increasingly being used in transmission power systems, there is a need for a fast SE solver that can take advantage of PMU high sampling rates. This paper proposes training a graph neural network (GNN) to learn the estimates given the PMU voltage and current measurements as inputs, with the intent of obtaining fast and accurate predictions during the evaluation phase. GNN is trained using synthetic datasets, created by randomly sampling sets of measurements in the power system and labelling them with a solution obtained using a linear SE with PMUs solver. The presented results display the accuracy of GNN predictions in various test scenarios and tackle the sensitivity of the predictions to the missing input data.

A Quick Response Power Factor Detector for Nonlinear Loads

2013 ◽  
Vol 284-287 ◽  
pp. 2433-2438
Author(s):  
Maoh Chin Jiang ◽  
Bing Jyun Shih
Keyword(s):  
Power Systems ◽  
Transient Response ◽  
Power Factor ◽  
Nonlinear Loads ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Active Power Filters ◽  
Power Filters ◽  
Low Pass ◽  
Fast Power

A fast power factor detector for nonlinear loads is proposed to overcome the drawback of conventional detectors, which can measure only the power factor of linear loads. The design of the proposed detector is based on the concept of additional characteristic of trigonometric function. It does not require any low-pass filter or integrator. Therefore, the transient response of the proposed detector is much faster than that of the conventional detectors. The theoretical response time of the proposed detector is less than one-fourth of a cycle. Because of its promising accuracy and rapid transient response, it can be used in many systems such as the control of power systems, and active power filters, to improve their transient performance. Theoretical analysis and experimental results are also detailed in this paper.

Electrical conductivity and capacitance spectra of Bi1.37Sm0.13Zn0.92Nb1.50O6.92 pyrochlore ceramic in the range of 0–3 GHz

2014 ◽  
Vol 07 (02) ◽  
pp. 1450018 ◽  
Author(s):  
A. F. Qasrawi ◽  
Faten M. Bzour ◽  
Eman O. Nazzal ◽  
A. Mergen
Keyword(s):  
Electrical Conductivity ◽  
Electric Field ◽  
Dielectric Breakdown ◽  
Microwave Cavity ◽  
Frequency Range ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Microwave Cavities ◽  
Rejection Filter ◽  
Low Pass

In this work, the electrical properties of samarium-doped bismuth niobium zinc oxide ( Sm -doped BZN ) pyrochlore ceramics are investigated by means of temperature dependent electrical conductivity and capacitance spectroscopy in the frequency range of 0–3 GHz. It was observed that the novel dielectric Sm - BZN ceramic exhibits a temperature and electric field dependent dielectric breakdown. When measured at 300 K, the breakdown electric field is 1.12 kV/cm and when heated the breakdown temperature is ~ 420 K. The pyrochlore is thermally active above 440 K with conductivity activation energy of 1.37 eV. In addition, the room temperature capacitance spectra reflected a resonance–antiresonance switching property at 53 MHz when subjected to an AC signal of low power of 5 dBm. Furthermore, when the Sm - BZN ceramics are used as microwave cavity and tested in the frequency range of 1.0–3.0 GHz, the cavity behaves as low pass filter with wide tunability up to a frequency of 1.91 GHz. At this frequency it behaves as a band rejection filter that blocks waves of 1.91 GHz and 2.57 GHz frequencies. These properties of the Sm -doped BZN are promising as they indicate the usability of the ceramics in digital electronic circuits as resonant microwave cavities suitable for the production of low pass/rejection band filters.

Intelligibility of Filtered Synthetic Sentences

1967 ◽  
Vol 10 (2) ◽  
pp. 289-298 ◽  
Author(s):  
Charles Speaks
Keyword(s):  
Low Frequency ◽  
Normal Hearing ◽  
Frequency Filtering ◽  
Frequency Range ◽  
Frequency Bands ◽  
Low Pass ◽  
High Pass

The effects of frequency filtering on intelligibility of synthetic sentences were studied on three normal-hearing listeners. Performance-intensity (P-I) functions were defined for several low-pass and high-pass frequency bands. The data were analyzed to determine the interactions of signal level and frequency range on performance. Intelligibility of synthetic sentences was found to be quite dependent upon low-frequency energy. The important frequency for identification of the materials was approximately 725 Hz. These results are compared with previous findings concerning the intelligibility of single words in quiet and in noise.

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