Centralized wide area damping controller for power system oscillation problems

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In this paper, three different centralized control designs that vary on complexity are presented to damp inter-area oscillations in large power systems. All the controls are based on phasor measurements. The first two proposed architectures use simple proportional gains that consider availability of measurements from different areas of the system and fulfill different optimization functions. The third controller is based on a more sophisticated Linear Quadratic Gaussian approach which requires access to the state space model of the system under investigation. The novelty of the proposed scheme resides in designing a single control to command the most influence group of machines in the system. To illustrate the effectiveness of the proposed algorithms, simulations results in the IEEE New England model are presented

Detection of frequency deviations for monitoring of power systems

​© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In this work an algorithm for identification of power system frequency deviation is presented. The proposed approach can be used to monitor frequency measurements from syncrophasor measurement units (PMU) and to store data only for important events and save storage in the local server. The detection algorithm use a sliding window that rise a flag if the measured frequency deviates from a predefined set point. If the alarm flag is constant over several sliding windows, an event is captured and locally stored for further analysis. To demonstrate the effectiveness of the proposed approach, real PMU measurements from the Swiss power system are used as input

Stability effects after massive integration of renewable energy sources on extra-large power systems

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In this work, a security metric to quantify the stability effects after integration of different levels of renewable energy sources (RES) in extra-large power systems is presented. The comparison is carried out through extensive number of Root Mean Square (RMS) simulations, using as a test system the initial dynamic model of continental Europe under different scenarios representing the implementation of combined energy strategies across Europe. The RMS simulations were performed using the commercial power system software DIgSILENT PowerFactory. The stability effects in the entire system are analysed, as result of massive integration of RES in 13 of the most significant countries e.g. those who have been modelled in more detail. The result of three study cases are presented, corresponding to the increase of different levels of renewable penetration: 10%, 20% and 30%, respectively. The results are compared in terms of the frequency response but also on the evolution of the proposed stability metric. The results suggest that countries located in the Eastern part of Europe are more sensitive to massive integration of RES than the rest of the network, from a gobal stability perspective

Analysis of grid events influenced by different levels of renewable integration on extra-large power systems

In this work, the impact of implementing a large amount of decentralized renewable energysources (RES) of different scales on an extra-large power grid is investigated. Three scenariosare created, substituting 10%, 20%, and 30% of the conventional energy production by RES.For this purpose, the initial dynamic model of Continental Europe in combination with theindustrial power system application DIgSILENT PowerFactory was used. In order to comparethe behavior of different applied scenarios, a performance index was developed to evaluate andrank the effects of network disturbances by means of time-domain simulations. The performanceindex was designed based on three different criteria that analyze the oscillatory content andthus, the severity of a given event. The initial power flow of the dynamic model was identifiedas a limiting factor for the integration of RES, therefore two additional power flows weredeveloped following an innovative procedure. Through the methodologies mentioned above, itwas found that Turkey is the most sensitive to such changes, which are amplified by increasingimplementation of RES and often lead to inter-area oscillation

Scaling version of Kundur’s two-areas system for electromechanical oscillations representation

​© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In this paper, the problem of real implementation of a transmission grid was addressed. In today's modern society, electricity is the most important form of energy for industry and society. A reliable and stable electrical power system is therefore essential. The growing amount of renewable energy sources leads to wheeling electrical power over long distances and to the growth in power electronics-based generation. Both affect the behavior of the electrical power system. The objective of this paper is the development of a scaled version of the Kundur's two areas system in order to implement it in a real laboratory. Additionally, this setup allows to change the rotational inertia and analyze all terminal quantities with phasor measurement units. The control structure of this island grid should reflect the reality as close as possible. All this together enables to study dynamic phenomena with a real small power system. With this laboratory implementation electromechanical swings such as inter-area oscillations after disconnecting a tie-line, changing loads and generation or tripping a synchronous machine can be shown

Examination of wide area control methods to face inter-area oscillations

​© 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Transmission systems are prone to experience interarea oscillations, triggered by groups of generators situated on different geographical locations oscillating against each other. In this paper, this particular problem is addressed and different control methodologies using wide-area monitoring that vary on complexity are proposed. The first approach is a proportional (P) gain that consider availability of measurements from different areas of the system and solve an optimization function to command the most influence group of machines in the system. The second approach is a Linear Quadratic Gaussian methodology that uses wide area measurements as control inputs. Finally, a proportional-integral (PI) controller that considers the availability of measurements from different areas is discussed. The first two approaches were tested through different simulations on IEEE benchmark models and the latest approach was tested using a control-in-the-loop and hardware-in-the-loop setup. To conclude, a perspective of wide-area damping controller implementation in a real laboratory demonstrator is presented

Export of a Toxoplasma gondii Rhoptry Neck Protein Complex at the Host Cell Membrane to Form the Moving Junction during Invasion

One of the most conserved features of the invasion process in Apicomplexa parasites is the formation of a moving junction (MJ) between the apex of the parasite and the host cell membrane that moves along the parasite and serves as support to propel it inside the host cell. The MJ was, up to a recent period, completely unknown at the molecular level. Recently, proteins originated from two distinct post-Golgi specialised secretory organelles, the micronemes (for AMA1) and the neck of the rhoptries (for RON2/RON4/RON5 proteins), have been shown to form a complex. AMA1 and RON4 in particular, have been localised to the MJ during invasion. Using biochemical approaches, we have identified RON8 as an additional member of the complex. We also demonstrated that all RON proteins are present at the MJ during invasion. Using metabolic labelling and immunoprecipitation, we showed that RON2 and AMA1 were able to interact in the absence of the other members. We also discovered that all MJ proteins are subjected to proteolytic maturation during trafficking to their respective organelles and that they could associate as non-mature forms in vitro. Finally, whereas AMA1 has previously been shown to be inserted into the parasite membrane upon secretion, we demonstrated, using differential permeabilization and loading of RON-specific antibodies into the host cell, that the RON complex is targeted to the host cell membrane, where RON4/5/8 remain associated with the cytoplasmic face. Globally, these results point toward a model of MJ organization where the parasite would be secreting and inserting interacting components on either side of the MJ, both at the host and at its own plasma membranes

A National Spinal Muscular Atrophy Registry for Real-World Evidence.

BACKGROUND: Spinal muscular atrophy (SMA) is a devastating rare disease that affects individuals regardless of ethnicity, gender, and age. The first-approved disease-modifying therapy for SMA, nusinursen, was approved by Health Canada, as well as by American and European regulatory agencies following positive clinical trial outcomes. The trials were conducted in a narrow pediatric population defined by age, severity, and genotype. Broad approval of therapy necessitates close follow-up of potential rare adverse events and effectiveness in the larger real-world population. METHODS: The Canadian Neuromuscular Disease Registry (CNDR) undertook an iterative multi-stakeholder process to expand the existing SMA dataset to capture items relevant to patient outcomes in a post-marketing environment. The CNDR SMA expanded registry is a longitudinal, prospective, observational study of patients with SMA in Canada designed to evaluate the safety and effectiveness of novel therapies and provide practical information unattainable in trials. RESULTS: The consensus expanded dataset includes items that address therapy effectiveness and safety and is collected in a multicenter, prospective, observational study, including SMA patients regardless of therapeutic status. The expanded dataset is aligned with global datasets to facilitate collaboration. Additionally, consensus dataset development aimed to standardize appropriate outcome measures across the network and broader Canadian community. Prospective outcome studies, data use, and analyses are independent of the funding partner. CONCLUSION: Prospective outcome data collected will provide results on safety and effectiveness in a post-therapy approval era. These data are essential to inform improvements in care and access to therapy for all SMA patients