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A Smart Transformers (ST) is an automated transformer based on the latest power electronics and communication technologies. It aims not only at replacing the traditional transformer, but at providing also ancillary services to the grid, thanks to the greater flexibility offered by power electronics. However, in the case of grid overload caused by high load demand or high production from renewable...
Due to high power in-feed from photovoltaics, it is expected that more battery systems will be installed in the distribution grid in near future. In this paper, we present a method to optimally control multiple battery sets in real-time to collectively provide services to power systems. The method is based on a Model Predictive Control (MPC) framework that tries to track an aggregated signal, while...
Extreme weather may have a significant influence on the resilience of transmission systems. However, modelling the impact of weather is very challenging due to its stochastic and unpredicted nature and behaviour. To cope with these challenges, this paper presents a Sequential Monte Carlo based time-series model for evaluating the effect of weather on power system components, with focus on the wind...
The classical equal area criterion in the power-angle domain, which is typically used for power systems planning/stability studies, is modified to the time domain for out-of-step protection. Wide-area measurements are necessary to obtain the power-angle information if the traditional equal area criterion is applied for out-of-step detection. However, its time-domain modification requires only the...
A demand response program designed to mitigate peak load during hot summer days has been designed. Pacific Northwest National Laboratory (PNNL) developed taxonomy distribution feeder has been used to evaluate the effectiveness of the demand response program. The simulation includes direct load control, dynamic price control, residential PV penetration and their comparisons. The results will help guide...
The large-scale integration of stochastic generation requires additional operating reserves to cope with the uncertainty in power system operation, due to the large forecast error with existing methodologies. Previous research shows that allocating power reserves dynamically according to conditional distribution of power forecast error would benefit the generation scheduling in day-ahead electricity...
The problem of voltage regulation, at transmission level, remains pivotal for the economic and secure dispatch of power in large power systems. In this paper, we present a multivariable, Model Predictive Control based scheme for the coordination of reactive power reserves, for secondary voltage regulation. The proposed scheme is validated using a 23-generator equivalent model of the Nordic power system...
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...
The unstable output of renewable energy sources, such as wind turbines or photovoltaics, causes various issues in power system operation. With a large number of renewable energy sources, it is well known that the supply and demand balance control becomes a difficult issue. In addition, together with the progress of the electric power deregulation, the power flow problem will be more complex and important...
This paper presents a nonlinear controller for a permanent-magnet synchronous generator (PMSG) wind turbine system in the framework of port-controlled Hamiltonian system. For the simplification, this work focuses on the nonlinear control law of the grid side converter (GSC) that is directly connected to the grid and affected during network disturbances. The proposed controller is designed through...
The use of distributed generation and demand response programs in smart grids implies management and integration of these resources when they are interconnected with the main power system. In the present paper, it is defined a methodology that can be used by the Virtual Power Player in order to aggregate and schedule the resources. The aggregated producers and consumers are optimally managed, making...
The principal manifestations, causes and harms of automatic voltage control (AVC) mismatch in hierarchical and regional large-scale power systems are summarized. Based on the analysis of the essence of AVC mismatch, a game model of volt/var control is presented. The payoff function which consists of the relevant operation indices in a certain control mechanism and includes the control avails and costs...
The impact of the increasing connection of distributed generation to medium voltage (MV) distribution feeders, with particular reference to photovoltaic (PV) units, justifies the application of an adaptive control of voltages and reactive power flows. This paper describes the analysis of a voltage/var control (VVC) structure that includes the cooperative control of the reactive power regulators of...
As the penetration level of embedded generation in the electricity distribution network rises, network operators' need for real time and geographically accurate information about the Low Voltage (LV) network increases. Smart meters and network monitors are the main providers of Smart data to the network operators. However, the Smart data need to be presented to the users in meaningful ways, that are...
Demand aggregators are new market players that represent a group of consumers in the electricity market. This paper proposes an aggregator model responsible for gathering residential and commercial consumers, which has the role of managing their flexible consumption in the day-ahead electricity market. A methodology to optimize the aggregator's bids is also presented. It optimizes the scheduling of...
This paper discusses the use of primary frequency response metrics to assess the dynamics of frequency disturbance data with the presence of high system non synchronous penetration (SNSP) and system inertia variation. The Irish power system has been chosen as a study case as it experiences a significant level of SNSP from wind turbine generation and imported active power from HVDC interconnectors...
A predictive decision support algorithm for power systems with a high share of renewable generation is presented. We consider a scenario where, e.g. within 1 hour, the renewable share is first gradually increased and compensated by secondary reserve. Then, a sudden disconnection of one or several wind farms occurs, e.g., because of violated fault ride through requirements. This disconnection has to...
Among the power system corrective controls, defensive islanding is considered as the last resort to secure the system from severe cascading contingencies. The objective is to maintain the stability of the resulting subsystems and to reduce the total loss of load in the system. The slow coherency based islanding can successfully be applied for the defensive islanding. In this paper, two new partitioning...
Off-grid solutions based on PV-diesel hybrid systems with battery backup during night are operationally ready to provide communities with electricity services, particularly in rural areas. However, lack of efficient energy management strategies to balance supply and demand results in frequent outages especially during night and increase the diesel fuel consumption, thus leading to a fiasco. This paper...
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