Search results for "Power factor"
showing 8 items of 38 documents
Fast solution of radial distribution networks with automated compensation and reconfiguration
2000
Abstract Optimal operation of radial distribution networks with automated compensation and reconfiguration requires the solution of a combinatorial optimisation problem, since the variables are the on/off status of capacitor banks and the open/close status of tie-switches. The solution approaches recently proposed use iterative algorithms such as genetic algorithms, simulated annealing and tabu search, for which the network needs to be solved in different configurations and at different compensation levels. The aim of this evaluation is that of attributing a quality index to each solution so that all the solutions can be suitably ordered. In an automated network, any configuration can be ob…
Control of ultra-high switching frequency power converters using virtual flux-based direct power control
2017
This paper presents a control technique for ultra-high switching frequency rectifiers known as virtual flux-based direct power control (VF-DPC). This method utilizes AC voltage sensors to provide better power quality at the input and output of power converters. Performance of an ultra-high switching frequency converter using the extended and conventional VF-DPC method is analyzed. The analysis has shown that the extended VF-DPC method can reduce better the total harmonic distortion (THD) of input currents and the ripples of the output DC voltage as compared to conventional VF-DPC. Finally, the effect of switching frequency and inductance size on rectifier operation is investigated in this s…
IEEE Std 1459–2010. IEEE Standard Definitions for the Measurement of Electric Power Quantities under Sinusoidal, Nonsinusoidal, Balanced or Unbalance…
2010
Definitions used for measurement of electric power quantities under sinusoidal, nonsinusoidal, balanced, or unbalanced conditions are provided in this standard. Mathematical expressions that were used in the past, as well as new expressions, are listed, as well as explanations of the features of the new definitions.
Implementation and Experimental Tests of a Management System for MV/LV Distribution Grids
2019
The continuous monitoring of network power flows and the remote control of Distributed Generators and Energy Storage Systems are the essential elements to allow a full exploitation of Renewable Energy Sources and their real integration in distribution networks. Thus in the paper a management system is presented for load flow monitoring in MV/LV distribution network. Moreover, on the basis of calculated power flows, the management system is able to send control commands to DGs and ESSs, to vary their power production or power factor or eventually to disconnect them in order to maintain the network stability. The proposed solution was really implemented in the MV network of Ustica Island, dev…
Thermoelectrics: From history, a window to the future
2019
Thermoelectricity offers a sustainable path to recover and convert waste heat into readily available electric energy, and has been studied for more than two centuries. From the controversy between Galvani and Volta on the Animal Electricity, dating back to the end of the XVIII century and anticipating Seebeck’s observations, the understanding of the physical mechanisms evolved along with the development of the technology. In the XIX century Ørsted clarified some of the earliest observations of the thermoelectric phenomenon and proposed the first thermoelectric pile, while it was only after the studies on thermodynamics by Thomson, and Rayleigh’s suggestion to exploit the Seebeck effect for …
Fuzzy logic controller and game theory based distributed energy resources allocation
2020
Energy management and demand control through conventional energy generation sources are challenging for energy providers. Distributed energy resources (DERs) allocation near load centers may provide a suitable solution. The main contribution of the paper improves the voltage profile and reduce the active and reactive power losses in the distribution network. DERs are integrated with IEEE 33 bus system using fuzzy logic controller (FLC) and game theory for two different cases with unity and 0.9 power factor (PF) and compares with conventional methods of integration (i.e., modified novel method, power loss sensitivity method, voltage sensitivity analysis method). The capacity of DERs is optim…
Current transformers effects on the measurement of harmonic active power in LV and MV networks
2011
The harmonic active power is used to determine the location of polluting loads, the direction of harmonic power flow and to estimate how consequential a certain current harmonic source is. The highest uncertainties, when measuring harmonic active power, are introduced by the current and voltage transducers. This paper presents experimental results which show the impact of current transformers (CTs) on the accuracy of the harmonic power measurements. An expression for the evaluation of the power error in distorted conditions was developed which can be easily utilized in the case of linear current transducers. It is shown how CTs cannot be considered linear transducers and how the higher the …
Electronic Energy Meter Based on a Tunnel Magnetoresistive Effect (TMR) Current Sensor
2017
In the present work, the design and microfabrication of a tunneling magnetoresistance (TMR) electrical current sensor is presented. After its physical and electrical characterization, a wattmeter is developed to determine the active power delivered to a load from the AC 50/60 Hz mains line. Experimental results are shown up to 1000 W of power load. A relative uncertainty of less than 1.5% with resistive load and less than 1% with capacitive load was obtained. The described application is an example of how TMR sensing technology can play a relevant role in the management and control of electrical energy.