Delivering COBie data - Focus on curtain walls and building envelopes

COBie is a standard data framework whose main purpose is to transmit useful, reliable and us-able information collected throughout the whole building process and to be consumed in order to properly maintain the facility. Focusing on Facility Management information exchanges and considering the UK BIM policies and requirements, this paper shows the results obtained applying COBie to complex products such as curtain walls. Two Information Delivery Manuals (IDMs) were also developed, in order to provide a com-monly known and standardized framework, which can regulate the COBie-based information exchanges. Fu-ture developments of this study could concern the application of the developed IDMs to different case studies in order to overtake that specificity characterizing each single project and verify the validity of the proposal

Geometric Deep Learning: a Temperature Based Analysis of Graph Neural Networks

We examine a Geometric Deep Learning model as a thermodynamic system treating the weights as non-quantum and non-relativistic particles. We employ the notion of temperature previously defined in [7] and study it in the various layers for GCN and GAT models. Potential future applications of our findings are discussed.Comment: Published on Proceedings of GSI 202

Real time parameter estimation for power quality control and intelligent protection of grid-connected power electronic converters

This paper presents a method to identify power system impedance in real-time using signals obtained from grid- connected power electronic converters. The proposed impedance estimation has potential applications in renewable/distributed energy systems, STATCOM, and solid state substations. The method uses wavelets to analyze transients associated with small disturbances imposed by power converters and determine the net impedance back to the source. A data capture period of 5ms is applied to an accurate impedance estimation which provides the possibility of ultra fast fault detection (i.e. within a half cycle). The paper describes how the proposed method would enhance the distributed generation operation during faults

Stability assessment of power-converter-based AC systems by LTP theory: eigenvalue analysis and Harmonic Impedance estimation

Stability analysis of power-converter-based AC systems poses serious challenges not only because of the non-linear nature of power converters, but also because linearisation is not generally applied around a steady-state operating point, as in the DC case, but around a time-periodic operating trajectory. Typical examples are single-phase and unbalanced three-phase systems. In this paper, two general methods to assess stability of the aforementioned systems are presented. Both are based on the Linear Time Periodic (LTP) systems theory. The first is model-based and relies on the evaluation of the eigenvalues of the linearised model, assuming a complete knowledge of the parameters. By contrast, the second proposes a set of small-signal current injections to measure the Harmonic Impedances and applies the LTP Nyquist Criterion, so that stability of the system can be assessed with a black-box approach, without relying on knowledge of the system parameters. The basic LTP systems theory is reviewed in order to provide a mathematical justification for the second method. As case study, a simple network, consisting of a source full-bridge converter in AC voltage-control mode and a load full-bridge converter in AC current-control mode including PLL, is considered. Analytical results based on average modelling and simulations based on both average and switching models are presented, showing good accuracy in the identification of the stability thresholds for both the proposed methods

Sizing of power electronics EMC filters using design by optimization methodology

This paper proposes a synthesis of EMC filter design method for power electronics converters. It starts with the description of the legacy approach, using the usual Common Mode / Differential Mode decomposition, and underlines the need of symmetry and the associated limits. Then an illustration of a design by optimization process is provided in the case of a simple switching cell. Finally, a full system composed of a PFC rectifier is provided, using EMC filters on both AC and DC sides. This example requires a design by optimization, since the two filters exhibit strong interactions

Stability assessment of high-bandwidth DC voltage controllers in single-phase active-front-ends: LTI vs LTP models

In recent years, a considerable effort has been made to minimise the size of DC-link capacitors in single-phase activefront-ends (SP-AFE), to reduce cost and to increase power density. As a result of the lower energy storage, a high-bandwidth outer DC voltage control loop is required to respond to fast load changes. Linearised modelling is usually performed according to the power-balance method and the control is designed using LTI techniques. This is done assuming negligible voltage ripple at twice the grid frequency, and the model is considered valid up to the grid frequency. However, its precise validity limits are usually unknown and the control design becomes empirical when approaching these boundaries. To overcome this drawback, Linear Time Periodic (LTP) theory can be exploited, defining the range of validity of the LTI model and providing precise stability boundaries for the DC-link voltage loop. The main result is that LTP models more accurately describe the system behaviour and provide superior results compared to the LTI ones. Theoretical analysis, simulations and extensive experimental tests on a 10 kW converter are presented to validate the claims

Volcaniclastic debris flow occurrences in the Campania region (southern Italy) and their relation to Holocene - late Pleistocene pyroclastic fall deposits: implications for large scale hazard mapping

The Campania Region (Southern Italy) is characterized by the frequent occurrence of volcaniclastic debris flows that produce damage to property and loss of life (more than 170 deaths between 1996 and 1999). Historical investigation allowed the identification of more than 500 events during the last four centuries; in particular, more than half of these occurred in the last 100 years, causing hundreds of deaths. The aim of this paper is to identify debris flow proneness and to quantify hazard. To this end, we compared several elements such as the thickness distribution of pyroclastic fall deposits from the last 18 ka of the Vesuvius and Phlegrean Fields volcanoes, the slopes of relieves, and the historical record of volcaniclastic debris flows from AD 1500 to the present. Results show that flow occurrence is not only a function of the cumulative thickness of past pyroclastic fall deposits but also depends on the age of emplacement. Deposits younger than 10 ka (Holocene eruptions) apparently increase the risk of debris flows, while those older than 10 ka (Late Pleistocene eruptions) seem to play a less prominent role. This is probably in relation to different climatic conditions, and therefore different rates of erosion of pyroclastic falls between the Holocene and the Late Pleistocene. Based on the above considerations, we compiled a large-scale debris flow hazard map of the study area in which five main hazard zones are identified: very low, low, moderate, high and very high