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New sources of ancillary services are expected in the power system. For large and conventional generation units the dynamic response is well understood and detailed individual measurement is feasible, which factors in to the straightforward performance requirements applied today. For secure power system operation, a reliable service delivery is required, yet it may not be appropriate to apply conventional...
This paper optimizes the thermodynamic behavior of buildings through demand response (DR) by operating their mechanical heating/cooling systems at 50% or 100% output capacity on a 15-minute basis. The optimization's objective is either minimizing cost or net electricity consumption, considering hourly prices and renewable energy resource availability in the local microgrid. The proposed DR framework...
The strong growth that is felt at the level of photovoltaic (PV) power generation craves for more sophisticated and accurate forecasting methods that could be able to support its proper integration into the energy distribution network. Through the combination of the vector autoregression model (VAR) with the least absolute shrinkage and selection operator (LASSO) framework, a set of sparse VAR structures...
It is expected that bad data and missing topology information will become an issue of growing concern when power system state estimators are to exploit the high measurement reporting rates from phasor measurement units. This paper suggests to design state estimators with enhanced resilience against those issues. The work presented here include a review of a pre-estimation filter for bad data. A method...
Electromagnetic time reversal (EMTR) has been shown to be an efficient method for locating faults in AC and DC power grids. In the available literature, the back-propagation medium has been considered to have identical losses as the direct-time medium. However, the telegrapher's equations describing the travelling wave propagation are time-reversal invariant if and only if inverted losses are considered...
The paper presents a tunable flickermeter based on a generalized lamp model able to account for lamp technologies different from incandescent. The generalized lamp model is based on the use of only three input parameters derived from the type of the lamp and its electrical circuit. The flickermeter concept and scheme are described. Compliance with the Standard IEEE 1453 (IEC 61000-4-15:2010) is demonstrated...
This paper discusses the analysis of dynamic interactions above the fundamental frequency in networks with high penetration of converters. For this purpose, interaction studies require a good representation of network resonances and converter dynamics. However, current methodologies present some limitations in this respect. On one hand, the harmonic impedance obtained from the frequency scan in software...
The paper presents the design principles of a Phasor Data Concentrator (PDC) that implements both the absolute and relative time data pushing logics together with a third one that aims at minimizing the latency introduced by the PDC without increasing the data incompleteness, as suggested in the IEEE Guide C37.244-2013. The performance of the aforementioned logics are assessed and compared in terms...
This article elaborates on a new issue that should progressively receive attention by Photovoltaic (PV) installation industry and utility management entities. It specifically introduces stray current corrosion blind spots that are inherent to PV systems' grounding and associated DC ground fault detection mechanisms. These blind spots arise as the existing thresholds for DC leakage currents have been...
This paper presents a novel approach, which identifies a buffer zone around a given study system and replaces the external system with an equivalent. The aim is to obtain a reduced system, which is suitable for assessment of long-term voltage and frequency dynamics in the study system. First, the proposed methodology ensures that all components, which are impacting the voltage profile of the study...
This paper investigates the impact of the Fault Ride-Through (FRT) capability and the dynamic reactive power support of large-scale PhotoVoltaic (PV) systems according to the newly proposed German Grid Code (GGC) on short-term voltage stability. The PV system is based on a generic model and realistic parameters are used that are determined in consultation with a manufacturer. In this context, improvements...
To achieve expected active power balancing in the transmission network and regulate frequency in a practical way, aggregate controllable loads would be useful. Such a scheme would need to be granulated down to sub-transmission networks in which active power flows affect both frequency and bus voltage, and hence a new control method should be adopted. A control scheme is proposed for sub-transmission...
Today the wide and increasing implementation of smart meters on the household level is making it possible to better know the use of electricity by residential consumers. This contributes to improving the quality of the services provided to the consumers and also developing new strategies for planning and operation by the power grid managers. This paper analyses the discovering of patterns in the use...
Although being the most used method for detection and identification of gross errors in measurements in the state estimation process, the largest normalized residual test fails in determined situations. Aware of this fact, the authors of this paper aim to clarify the reasons for these failures and to present an alternative method for processing gross errors, based on the geometrical interpretation...
The main objective of this paper is to comparatively assess alternative control schemes for high voltage dc (HVDC) links based on voltage source converters (VSCs), adapted for island systems with mixed ac and dc interconnectors operating in parallel. A suitable study-case system is selected, which corresponds to the planning for the future interconnection of Crete island to the Greek mainland system,...
The methods currently used for transformer tap estimation are not robust against measurement errors, while the well-documented Least Absolute Value (LAV) State Estimator (SE) is not robust against transformer tap errors. This paper addresses these shortcomings by introducing the so-called Sparse Extended Least Absolute Value (SELAV) SE. By strategically modifying the formulation of LAV SE, the “sparse”...
This paper illustrates the potential of commercial buildings to act as frequency reserves providers through an experimental demonstration conducted in a multi-zone university building. The proposed control methodology is presented in detail, including the control architecture, the controller design, model identification, and hardware description. Finally, the effectiveness of the presented approach...
The work in this paper is motivated by the computational challenges in monitoring very large scale interconnected power transmission systems. The main idea is to exploit the robustness property of the recently developed PMU-based linear estimator while eliminating hierarchical computational complexity. It is recognized that state estimation can be implemented for observable islands in an efficient...
Area coverage is a critical issue which will have a major impact on the sensing quality over targeted regions in wireless sensor networks (WSNs). This paper studies the area coverage problem (ACP) with non-penetrable obstacles in microgrids, where a sensor cannot be deployed or sensing signals cannot pass through. The target coverage region is discretized in a deployment map representation of non-penetrable...
Higher shares of electricity generation from renewable energy sources and market liberalization is increasing uncertainty in power systems operation. At the same time, operation is becoming more flexible with improved control systems and new technology such as phase shifting transformers (PSTs) and high voltage direct current connections (HVDC). Previous studies have shown that the use of corrective...
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