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The extensive installation of gas-fired power plants in many parts of the world has led electric systems to depend heavily on reliable gas supplies. The use of gas-fired generators for peak load and reserve provision causes high intra-day variability in withdrawals from high pressure gas transmission systems. Such variability can lead to gas price fluctuations and supply disruptions that affect electric...
The paper proposes an approximated yet reliable formula to estimate the frequency at the buses of a transmission system. Such a formula is based on the solution of a steady-state boundary value problem where boundary conditions are given by synchronous machine rotor speeds and is intended for applications in transient stability analysis. The hypotheses and assumptions to define bus frequencies are...
This paper presents the development of a new methodology for the simulation of Power Line Communication (PLC) within the popular Electromagnetic Transients Programme-Alternative Transients Programme (EMTP-ATP). As a first application, the comparative performance of the emerging Orthogonal Frequency Division Multiplexing (OFDM) based Prime and G3-PLC narrowband standards is investigated. Models of...
In this paper we investigate the impact of zonal network management in the operation of power systems with significant levels of renewable energy integration. Our study is inspired by the current state of the European energy market, and we focus on a case study of the Central Western European (CWE) system. First, we present a hierarchy of models that account for unit commitment, the separation of...
With high penetration of distributed generation (DG), the conventional underfrequency load shedding (UFLS) faces many challenges and may not perform as expected. This paper proposes new UFLS schemes, which are designed to overcome the shortcomings of the traditional load-shedding scheme. These schemes utilize directional relays, power flow through feeders, wind, and photovoltaic (PV) measurements...
Evolutions in the power system challenge the manner in which power system reliability is managed. In particular, currently used reliability criteria, typically the deterministic N-1 criterion, are increasingly inadequate. Moving to an alternative approach is difficult as quantifying benefits is hard in a multifaceted environment and system operators are reluctant to move away from the easy and transparent...
This paper introduces the methods development of the modern phase earthing system. The target is to reduce the harmful short interruptions experienced by the customers and electricity producers with temporary phase-to-earth faults of a medium-voltage (MV) system. Especially in neutral isolated MV networks, the earth fault arc does not usually become extinct without an automatic reclosing function...
This paper provides a focus upon forecasting electricity prices in the medium term (from a few weeks to several months ahead) in which accurate estimates of tail risks, e.g. at the 1%, 5%, 95% and 99%, are important. Medium term forecasting and risk analysis are important for operational scheduling, fuel purchasing, trading and profit management. We extend the research on hybrid forecasting methods,...
Transmission system operators (TSO) should be able to assess power quality levels in a network in order to properly address the mitigation of power quality problems. High flicker levels might be a serious power-quality problem in transmission networks and are usually caused by arc-furnace operation. TSO can assess flicker levels in real time only at nodes where power-quality measurements are available...
In this paper, typical strengths, fault levels and source impedances are thoroughly analysed and calculated for the study of quality of supply in 230/400V 50Hz distribution systems. Considering all the disparity in distribution network design, this study is based on a comprehensive database containing typical arrangements and equipment in UK/European systems, as well as on fully documented generic...
Transition to smart distribution grids is highly dependent upon their reliable real-time monitoring. Optimally allocated measurement devices are the backbone of advanced metering systems for concrete observability and accurate state estimation (SE). This paper proposes a new approach for optimized meter placement in distribution grids by minimizing errors in estimated state vector. The placement problem...
Dependable power quality (PQ) monitoring is crucial for evaluating the impact of smart grid developments. Monitoring schemes may need to cover a relatively large network area, yet must be conducted in a cost-effective manner. Real-time communications may not be available to observe the status of a monitoring scheme or to provide time synchronization and, therefore, undetected errors may be present...
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...
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 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...
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...
Low Voltage Direct Current (LVDC) distribution systems potentially enable more efficient power distribution and wider uptake of distributed renewables and energy storage. They do however present significant fault protection and safety challenges. To address these, the use of advanced protection techniques or significant system redesign is required. This paper reviews these protection key challenges,...
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