Unexpected Power Research Articles

Practical partial discharge pulse generation and location within transformer windings using regression models adjusted with simulated signals

The early identification and location of high-frequency current pulses related to partial discharges (PDs) in the solid insulation of power transformers enable the optimization and planning of maintenance interventions, preventing unexpected power interruptions and reducing downtime. Even though several techniques for PD signal experimental generation and location have been proposed in the literature, limitations can still be noted, such as the difficulties in generating current signals similar to the PDs in incipient conditions and in the appropriate location. In view of these, in this work, new methods of experimental PD high-frequency current pulses generation and location are proposed, based on, respectively, the realization of small capacitive disturbances along the transformer windings and the use of multiple linear regression models. The proposed strategies allow the generation of current pulses similar to the PDs resulting from the initial degradation of the solid insulation and their effective location along the windings, even if only computational simulated data is employed in the adjustment of the locator linear regression models.

Silicon-on-insulator microring resonator sensor based on an amplitude comparison sensing function.

A novel, highly sensitive integrated sensor based on a silicon-on-insulator microring resonator is proposed and experimentally demonstrated. To achieve a fast-response and cost-effective sensing system, the new structure establishes a linear amplitude comparison sensing function (ACSF) by monitoring the optical powers from both the through port and drop port of an add-drop microring resonator simultaneously, where the contrast of the two ports eliminates the effect of unexpected power fluctuation of the input laser on sensor performance. A highly enhanced linear relationship between the resonant wavelength shift and the ACSF value is achieved with an R-squared value over 0.99. A proof-of-concept experiment for temperature sensing demonstrates an almost constant ACSF with only ±0.9% discrepancy, while the laser power is varied between 0dBm and -7 dBm.

Self-Sensing Electromagnetic Transducer for Vibration Control of Space Antenna Reflector

Space antenna reflectors are used by space vehicles to communicate with ground stations. These reflectors are generally subject to broadband random vibration and shock conditions during shipment and vehicle launch. While active vibration control methods can reduce any unexpected responses, sensors, controllers, power amplifiers, and actuators are all required to implement the control system. These additional external devices increase both the weight and the cost of the reflector, and reduce the reliability and safety of the space product. This study proposes a novel self-sensing vibration control method and applies a self-sensing electromagnetic transducer to suppress the vibration of a space antenna reflector. This transducer is used bifunctionally, acting as both an isolator and a velocity sensor. The vibration control principle of the proposed method is analyzed. A governing equation is established using the finite element method. A type of degree of freedom reduction method is used to obtain the response of the space antenna reflector. A ground experiment is then set up. The results demonstrate that the proposed self-sensing vibration control method can reduce the second-order and third-order vibrations of the space antenna reflector by 4 and 9 dB, respectively.

Design, construction and 13 K conduction-cooled operation of a 3 T 100 mm stainless steel cladding all-REBCO magnet

A conduction-cooled 3 T 100 mm winding bore multi-width and no-insulation (NI) all-REBCO magnet was designed, constructed and tested at 13 K. The magnet consists of a stack of double pancake (DP) coils wound with, for the first time, REBCO tapes having a 1 μm thick layer of stainless steel, named ‘metallic cladding’, that surrounds the tapes in a hermetic way to substantially reduce the NI charging delay. After construction, the magnet was cooled down to the target operating temperature of 13 K using a two-stage pulse-tube cryo-cooler. During charging–discharging tests up to 200 A, magnetic center field, voltage of each DP coil, power supply current, and magnet temperature were monitored. The charging time constant of the magnet was measured to be about 10.1 s, 13 times smaller than that of its NI counterpart. The magnet experienced, due to an unexpected power supply trip, a sudden discharge at a peak coil current density of 353 A mm2, yet it survived without any degradation. The results demonstrated strong potential of the metallic cladding NI-REBCO magnet for significant charging-delay reduction and self-protecting operation.

PLC-based design of monitoring system for ICT-integrated vertical fish farm

The common cause of the mass mortality of fishes in a fish farm is a power failure. There can be many reasons for the power failures but most of them are the result of natural disasters, systematic faults, ill-willed sabotages, or mistakes of employees. Such incidents usually have a bad influence upon small or medium-scale farmers. To deal with unexpected power failures, this research proposes a status monitoring system utilizing both PLC and ICT. Consistent supply of electric power in Fish Farms is essential for the operation and management of farm facilities regardless of them being indoors or afloat. The statistics show that the power failure and the red tides are the major causes of ruining farmer’s earnings. The proposed system is autonomous and simple enough for the employees to operate such that prompt actions can be taken in times of crisis. There have been some concerns about applying the PLC technology as it often involves loss of transmission signals. To minimize signal losses, use of RUDP in the transmission layer was proposed as well. At the same time, a GUI-based operational mode has been embedded in the Android application to enhance user convenience for observing and managing farm’s activities such as controlling of seawater and farm accesses and checking locations, photoperiods, withdrawal periods, and system’s batteries. The proposed design can be quite suitable for the Vertical Fish Farm.

Unexpected power of low-depth arithmetic circuits

Complexity theory aims at understanding the "hardness" of certain tasks with respect to the number of "basic operations" required to perform it. In the case of arithmetic circuit complexity, the goal is to understand how hard it is to compute a formal polynomial in terms of the number of additions and multiplications required. Several earlier results have shown that it is possible to rearrange basic computational elements in surprising ways to give more efficient algorithms. The main result of this article is along a similar vein. We present a simulation of any formal polynomial computed by an arithmetic circuit by a shallow circuit of not-much larger size. Roughly, depth corresponds to the time required in a massively parallel computation. This result shows that efficient computations can be speedup to run in depth three, while requiring surprisingly low size. In addition to the possible usefulness of the shallow simulations, this theorem has implications in computational complexity lower bounds, since this implies that any small improvement in current lower bound approaches would lead to dramatic advances in lower bounds research.

Wavelet-Based Event Detection Method Using PMU Data

In order to deal with the nonstationary signatures of phasor measurement units (PMU) signals, this paper presents a wavelet-based detection algorithm. Moreover, for an application to PMU for event detection purpose, it is necessary for us to classify detected events into unexpected real power related accidents, such as generator trip or automated control, such as reactive power injection. The proposed normalized wavelet energy function calculates the root mean square (RMS) of detail coefficients from time-synchronized voltage and frequency that reflect nonstationary occurrence of significant changes in signals. For a robust detection, wavelet-based detection parameter is designed with consideration of nonstationary characteristics of events. Also, there are distinct transients in voltage and frequency caused by different event types, and distinct results are key-idea of event classification. Besides the determination of event occurrences, one can obtain the information of event characteristics that include event types and zonal information of event from the proposed method. Moreover, successful results of detection and classification in real-world cases are presented in this paper.

THE BELL OF FLIES

Fighting corruption is world wide a main issue. At stake is the human right on a decent state, rule of law and accountable government. In my paper I focus on our struggle to curb corruption in one of the major cities of Ukraine, Lviv. In that I highlight the unexpected power of moral learning as a critical leverage to curb corruption.In fighting corruption it makes sense to distinguish between high level and low level, survival corruption, in Russian called Blat. Survival corruption requires a »corrupted« mind: a strategy of moral learning of civil servants. This is not the mind of a malicious, greedy or corrupt civil servant, but a moral strategy to accommodate to (post) totalitarian and oligarchic political institutionalizing in Ukraine. The tragedy of the »corrupted« mind is that it not only helps to survive conditions of corrupt oligarchic political institutions, but also tend to reproduce them. Installing a process of moral learning to deconstruct the Ukrainian, Lvivian moral narrative, and design an alternative moral discourse with civil servants, seems therefore paramount.Based on seminars on moral learning with about 1500 civil servants in Lviv I first reconstruct this »corrupted« mind as a set of imperatives of organizational moral learning in Lviv City Council. Second I show that these imperatives are path dependent on three critical junctures of political institutionalizing in Lviv: totalitarian, oligarchic and national-democratic. In the 'oligarchic democracy', as Ukraine is called, the experience with totalitarianism still has its hold on the mind of the civil servant, although the totalitarian political institutions in itself no longer exist. This is reflected in the defensive moral reasoning shown in the »corrupted« mind, which I call the Bell of Flies. The thin and selfish morality of the oligarchic path leads only to further delegitimizing and erosion of trust in political institutions in contemporary Ukraine and Lviv, and a possible increase of low level and high level corruption. This makes plausible that breaking this spell of the Bell of Flies, and developing an alternative account of moral learning is crucial for lowering corruption and creating a decent local city administration, rule of law, and accountable City Council.The national-democratic path, going back to the Ukrainian independence in 1991, the Orange Revolution of 2004, and the Maidan uprising in 2013, is also reflected in the imperatives of the »corrupted« mind. It is the fertile ground for breaking up this self-defeating strategy of moral knowledge and learning and developing a new moral compass with civil servants of Lviv. By this moral learning in Lviv improves the national-democratic role of the civil servant, improves the legitimacy and trustworthiness of the civic administration, and leads to stronger and more just local political institutions.The main lesson learned from the Lviv experience is that fighting corruption has to be adjusted to the history and local experience of citizens and civil servants. On the one hand by creating communities of moral inquiry in communities of communal practice. On the other hand by historical institutional analysis, reconstructing the path dependence of experiences with corruption. Being a scholar and practitioner - a street scientist - is, so I argue, crucial in winning the fight against corruption.

Bias and tracking accuracy in voting projections using the New Zealand attitudes and values study

ABSTRACTWe introduce a method for assessing the overall level of bias and relative tracking accuracy in time series analysis of polling data on voter intentions by comparing two data sets: the New Zealand Attitudes and Values Study (NZAVS; N = 13,936) and the One News Colmar Brunton election polls (N = 10,210). The NZAVS is a national probability longitudinal postal panel survey started in 2009. It was set up to track stability and change in values, without any intention to predict election results. The One News Colmar Brunton Poll is a nationally representative random-digit dial telephone survey conducted by Colmar Brunton specifically to measure voter sentiment. Our comparison focused on responses to both surveys from February 2014 to September 2014, in the run up to the New Zealand general election. The NZAVS and One News Colmar Brunton Poll detected nearly identical changes in party vote over time, and both effectively predicted the outcome of the 2014 General Election. This shows the unexpected power of national-scale probability postal studies to track change in democratic decisions that affect all members of a society. These results further support the validity of the NZAVS as an independent and impartial source that might be ‘repurposed’ to create a continuous monitor tracking political attitudes and detecting citizens’ reaction to, and relative change in, opinions toward different social policies, values, and attitudes, over time.

Frequency control by wide-area dispatching of short-term supply-demand imbalance in multi-area power system with a large penetration of renewable energy

AbstractRecently, a lot of distributed generations such as WT (Wind Power Generation) have been installed into power systems. However, the output of these generations is so unstable that the frequency fluctuation will increase. This paper aims at solving the short-term supply-demand imbalance in an area where a large amount of renewable energy has been introduced and proposes a new method of dispatching the fluctuations of renewable energy based power to another area through a tie line. For the frequency analysis, we use the two-area interconnected power system model with a large amount of WT. It was made clear that without the proposed control, the unexpected power flow deviation through the tie line is very large, however, the proposed control method can suppress such deviation effectively. It was also shown in this paper that the proposed method is effective in the frequency control with a large integration of renewable energy into grid.

Revisitation: a trans phenomenology of the media image

How might certain moving images move us into transgender becoming? 
 
 The recent proliferation of transgender images in the media of the Global North has been widely regarded as supporting transgender political and social equality. But do these images do justice to the complexity of transgender lives? Who are images of transgender identity made for, and whose interests do they serve? Instead of discussing media that produce a transgender object for public consumption, this essay’s author is interested in theorizing a trans point of media reception for the popular image. This essay illustrates how transgender subjects might fashion their own archives of becoming through encounters with media that unintentionally support transgender embodiment as a possibility in the world. Revisiting his phenomenological encounters with the film Under the Skin and the “Milk: It Does a Body Good” ad campaign, the author analyzes how certain media objects have the unexpected power to “move” the transgender subject into becoming.

Shocking Tales: A Look at the Strange and Unexpected [Guest Editorial

The theme of shocking tales describes some unexpected power system events. It is the intention to offer ways in which power engineers can learn from these unintended events and apply lessons learned by thinking beyond the usual routinized system contingencies. Attention to standards, procedures, and training are vital to the operation of the system. System planners and engineering departments should carefully consider the addition of needed facilities that can improve the robust design and operation of the system.

발전기 공급능력 산정 및 예측 기술개발

Supply Capability of the generator, if the maximum demand occurs, refers to the maximum power that can be stably supplied and it is possible to maintain stable power supply to be greater than actual load. However, unexpected power demand and reduction in supply Capability due to stop of unexpected generator in operation can temporarily make a big chaos in power system. In fact, due to a lack of power supply Capability in the country, enforced emergency load adjustment to the September 15, 2011, the circulation power outage has occurred in several cities. As the result, interrupted operation of the elevator and stopped hospital medical equipment led to a great deal of trouble to people's lives, causing a social problem. At that time, it was found that a failed frequency control because of smaller actual supply Capability than that of predicted. The difference was about 1,170 MW with Gas turbine power plant. By accurately calculating the generator supply capability, we can not only grasp the power reserve rate, but also correspond to the time of power supply instability.

Wireless monitoring algorithm for wind turbine blades using Piezo‐electric energy harvesters

AbstractWind turbine blade failure can be catastrophic and lead to unexpected power interruptions. In this paper, a Structural Health Monitoring (SHM) algorithm is presented for wireless monitoring of wind turbine blades. The SHM algorithm utilizes accumulated strain energy data, such as would be acquired by piezoelectric materials. The SHM algorithm compares the accumulated strain energy at the same position on the three blades. This exploits the inherent triple redundancy of the blades and avoids the need for a structural model of the blade. The performance of the algorithm is evaluated using probabilistic metrics such as detection probability (True Positive) and false alarm rate (False Positive). The decision time is chosen to be sufficiently long that a particular damage level can be detected even in the presence of system sensor noise and wind variations. Finally, the proposed algorithm is evaluated with a case study of a utility‐scale turbine. The noise level is based on measurements acquired from strain sensors mounted on the blades of a Clipper Liberty C96 turbine. Strain energy changes associated with damage from matrix cracking and delamination are simulated with a finite element model. The case study demonstrates that the proposed algorithm can detect damage with a high probability based on a decision time period of approximately 50–200 days. Copyright © 2016 John Wiley & Sons, Ltd.

Turning music into colors a wi-fi chip has unexpected power [Resources_Hands On

Several years ago, I wrote an algorithm I called ColorChord, which assigned colors to notes. The neat thing about it was that every time I played a note, the same color was assigned-regardless of the octave. By using these color values to control LEDs, I had a whole new way to visualize chords and melodies. Sadly, the algorithm was a bit clunky. The Pentium-based processors available at the time had difficulty running the algorithm in real time, forcing me to use specialized graphics processors.

Dynamo

Data center power is a scarce resource that often goes underutilized due to conservative planning. This is because the penalty for overloading the data center power delivery hierarchy and tripping a circuit breaker is very high, potentially causing long service outages. Recently, dynamic server power capping, which limits the amount of power consumed by a server, has been proposed and studied as a way to reduce this penalty, enabling more aggressive utilization of provisioned data center power. However, no real at-scale solution for data center-wide power monitoring and control has been presented in the literature. In this paper, we describe Dynamo -- a data center-wide power management system that monitors the entire power hierarchy and makes coordinated control decisions to safely and efficiently use provisioned data center power. Dynamo has been developed and deployed across all of Facebook's data centers for the past three years. Our key insight is that in real-world data centers, different power and performance constraints at different levels in the power hierarchy necessitate coordinated data center-wide power management. We make three main contributions. First, to understand the design space of Dynamo, we provide a characterization of power variation in data centers running a diverse set of modern workloads. This characterization uses fine-grained power samples from tens of thousands of servers and spanning a period of over six months. Second, we present the detailed design of Dynamo. Our design addresses several key issues not addressed by previous simulation-based studies. Third, the proposed techniques and design have been deployed and evaluated in large scale data centers serving billions of users. We present production results showing that Dynamo has prevented 18 potential power outages in the past 6 months due to unexpected power surges; that Dynamo enables optimizations leading to a 13% performance boost for a production Hadoop cluster and a nearly 40% performance increase for a search cluster; and that Dynamo has already enabled an 8% increase in the power capacity utilization of one of our data centers with more aggressive power subscription measures underway.

Development and Performance of a Battery-Free Disaster Prevention Radio “HOOPRA” Using the Energy Harvested from Radio Waves

A battery-free radio receiver, HOOPRA (<span class=”underline”>hoop</span> type <span class=”underline”>ra</span>dio), is proposed for acquiring information using middle wave AM radio broadcasting during unexpected power failures or disasters, with emphasis on wide coverage, immediate information acquisition, and energy saving. The HOOPRA utilizes middle waves for energy harvesting. As this radio is intended for use during disasters, the protection methods, receiving performance, and the applications of energy harvesting are reported in this paper. The HOOPRA is ring-shaped with a diameter of 20 cm when retracted, for portability and 60 cm when expanded, for usage and is lightweight (180 g). The HOOPRA works on the principle of a crystal radio but has an adequate receiving performance without an external antenna that is generally necessary for crystal radios and is portable. It could receive a radio broadcast within an area of radius 15 km from a transmitting station of the NHK Fukui Daiichi Broadcasting (JOFG, 5 kW). Further, the energy harvested from the middle waves utilizing the high sensitivity of the HOOPRA was found to light-up a white LED. In a field test with the HOOPRA, it was found that the receiving sensitivity was particularly enhanced near a tall building, probably owing to the diffraction effect of the radio waves. Use of this effect for enhancing the sensitivity of the battery-free radio is also explained.

How to explain microemulsions formed by solvent mixtures without conventional surfactants

Ternary solutions containing one hydrotrope (such as ethanol) and two immiscible fluids, both being soluble in the hydrotrope at any proportion, show unexpected solubilization power and allow strange but yet unexplained membrane enzyme activity. We study the system ethanol-water-octanol as a simple model of such kinds of ternary solutions. The stability of "detergentless" micelles or microemulsions in such mixtures was proposed in the pioneering works of Barden and coworkers [Smith GD, Donelan CE, Barden RE (1977)J Colloid Interface Sci60(3):488-496 and Keiser BA, Varie D, Barden RE, Holt SL (1979)J Phys Chem83(10):1276-1281] in the 1970s and then, neglected, because no general explanation for the observations was available. Recent direct microstructural evidence by light, X-ray, and neutron scattering using contrast variation reopened the debate. We propose here a general principle for solubilization without conventional surfactants: the balance between hydration force and entropy. This balance explains the stability of microemulsions in homogeneous ternary mixtures based on cosolvents.

Oxide‐Modified Nickel Photocatalysts for the Production of Hydrocarbons in Visible Light

AbstractMetallic nickel nanostructures that were partially decorated by discrete nickel oxide layers were fabricated by in situ reduction of calcinated Ni‐containing layered double hydroxide nanosheets, the structure of which was confirmed by extended X‐ray absorption fine structure spectroscopy, X‐ray photoelectron spectroscopy, and transmission electron microscopy. The existence of the abundant interfaces between the surface Ni oxide overlayer and metallic Ni altered the geometric/electronic structure of the Ni nanoparticles, making them apt for CO activation under light irradiation. Most importantly, the unique structure favors the C−C coupling reaction on its surface, which confers the catalyst unexpected reaction power towards higher hydrocarbons at moderate reaction conditions. This study leads to a green and sustainable approach for the photocatalytic production of highly valuable chemical fuels.

Oxide-Modified Nickel Photocatalysts for the Production of Hydrocarbons in Visible Light.

Metallic nickel nanostructures that were partially decorated by discrete nickel oxide layers were fabricated by in situ reduction of calcinated Ni-containing layered double hydroxide nanosheets, the structure of which was confirmed by extended X-ray absorption fine structure spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The existence of the abundant interfaces between the surface Ni oxide overlayer and metallic Ni altered the geometric/electronic structure of the Ni nanoparticles, making them apt for CO activation under light irradiation. Most importantly, the unique structure favors the C-C coupling reaction on its surface, which confers the catalyst unexpected reaction power towards higher hydrocarbons at moderate reaction conditions. This study leads to a green and sustainable approach for the photocatalytic production of highly valuable chemical fuels.