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Large Offshore wind farms are planned in China and some are under constructions. DC grid or multi-terminal HVDC is the promising technology to delivery large offshore wind power over long distances. DC grid voltage levels need to be built to design optimal DC grid, without this voltage levels, DC grid may be sub-optimal, not cost-effective. This paper proposes the study framework of building voltage...
Multi-concurrent failures in electric grids are severe events for modern power systems, which might result in power failures, or even rolling blackout in a large area. Usually, the possibility of such a failure in a stable system is very low, but it increases dramatically when the system suffers extreme weather. Thus the system operator needs to evaluate the risk of power systems under extreme weather...
In this paper, observability reliability (OR) and loss of data expectation indices (LODE) are calculated considering data uncertainty. Single contingency of Phasor Measurement Unit (PMU) and branch outages are considered in the calculations and to achieve more realistic results, it is assumed that failure data (repair time and failure rate) of all branches and PMU components have uncertainty. Fuzzy...
In this paper, the problem of upgrading an electric urban distribution network is considered. Although network planning has attracted considerable attention in the field of power systems since the early 1970s, the urban distribution network of Milano (Italy) shows significant and challenging peculiarities. Due to historical reasons, there are two separate distribution networks, previously operated...
This paper describes an analysis on power system breakdown sequences caused by circuit breaker and protective relay failures, and applies this to plan a probabilistic test and maintenance schedule for these periodically tested components. The paper shows that a probabilistic and component importance based test and maintenance scheduling can minimize the system breakdown frequency caused by the component...
The main objective of this paper is a presentation of an improved probabilistic approach for estimating the additional operating reserve in modern power systems with a large share of renewable energy sources. A reliable operation of modern power systems can be ensured by application of the proposed method. Results show that the power-generation reliability in modern power systems and consequently...
In recent years the energy consumption, decentralised feed-in, storage of renewable energies [1] and the power system complexity have grown rapidly worldwide. Hence, some electrical networks are already working at their stability limits because they were not originally designed for today's load. Consequently, the risk of power system instability has greatly increased. Therefore, protecting electrical...
This paper demonstrates the influence of the fault arc on the magnitude of the fault current for single phase to ground faults in underground power cables. A method is suggested which allows incorporation of this impact in practical fault current calculations. Earth faults in underground cable networks depend on many parameters and are therefore complex to model and calculate exactly. Field measurements...
This paper aims at assessing the power system reliability by estimating loss of load (LOL) index using mutual information based Bayesian approach. Reliability analysis is a key component in the design, analysis and tuning of complex structure like electrical power system. Consideration is given to rare events while constructing the Bayesian network, which provides reliable estimates of probability...
In recent years, the penetration of renewable resources in electrical power systems has increased. These renewable resources add more complexities to power system operations, due to their intermittent nature. As a result, operators must acquire additional reserves in order to maintain reliability. However, one persistent challenge is to determine the optimal location and quantity of reserves; this...
The current development of distribution networks into active and smarter systems has been facilitated by the integration of novel technologies such as Microgrids (MGs) and Distributed Energy Resources. These new concepts are expected to bring about significant economic benefits at the distribution level in the form of network reinforcement deferral and increased reliability levels, among others. In...
The existing Ancillary Services (AS) in the Electric Reliability Council of Texas (ERCOT), Texas Independent System Operator (ISO), were developed in the late 1990s based on inherent characteristics of conventional synchronous generation in the grid. ERCOT system and its generation mix have undergone significant changes over the past two decades. Therefore ERCOT staff and stakeholders are currently...
The size and complexity of large power systems, such as the European one, often make them unmanageable for the purposes of Transmission Expansion Planning (TEP). Therefore, network reduction methods are necessary to condense their key features into a workable model, which should approximate the behavior of the nodal system as accurately as possible. We define critical branches as the transmission...
Aggregations of controllable loads can provide reserves to power systems; however, their reserve capacity is uncertain and affected by ambient conditions like weather. Past work proposed a stochastic optimal power flow formulation that used chance constraints to handle uncertain reserves and generation from wind. The problem was solved with a scenario-based optimization method. In this paper, we assume...
Consequence analysis, including the modelling of corrective actions, is an important component when performing power system reliability analyses. Using an integrated methodology for power system reliability analysis, we investigate the impact of different modelling choices for the consequence analysis on estimates for the energy not supplied. These investigations corroborate the large impact modelling...
Evaluating the performance of various power system reliability criteria and their management is important in order to obtain a cost effective reliability level of the power system. However, the performance of reliability criteria depends on several parameters, of which one is value of lost load (VoLL). Value of lost load is typically difficult and complex to model, which hampers making a general conclusion...
Due to renewable energy sources (RES) variable nature and their wide integration into power systems, setting an adequate operating power reserve is important to compensate unpredictable imbalance between generation and consumption. However, this power reserve should be ideally minimized to reduce system cost with a satisfying security level. Although many forecasting methodologies have been developed...
This paper discusses a decision-support model for asset managers to prioritise assets requiring additional maintenance or replacement, by estimating asset remaining-lifetime and failure impact. The asset health and risk model (AHRM) being the heart of this model is based on dedicated asset-condition assessment functions in combination with usage-based condition estimations and a statistical approach...
This paper proposes a multi-agent model and strategy for aggregator-based residential demand response, and details how elements in the system interact to solve an issue requiring load to be temporarily decreased. The system uses assets such as plug-in hybrid electric vehicles, air conditioning units, and electric water heaters to achieve this goal. Simulation results, based on probabilistic models...
The use of Information and Communication Technology (ICT)-based power system applications increases continually which poses new engineering challenges regarding the development, validation and management of both - the applications and the intertwined infrastructures. In this paper the need for a joint analysis of power and ICT systems for evaluating smart grid applications is discussed and a systematic...
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