Introduction to Electromagnetic Compatibility

Particle swarm optimization (PSO) is one of the well-known population-based techniques used in global optimization and many engineering problems. Despite its simplicity and efficiency, the PSO has problems as being trapped in local minima due to premature convergence and weakness of global search capability. To overcome these disadvantages, the PSO is combined with Levy flight in this study. Levy flight is a random walk determining stepsize using Levy distribution. Being used Levy flight, a more efficient search takes place in the search space thanks to the long jumps to be made by the particles. In the proposed method, a limit value is defined for each particle, and if the particles could not improve self-solutions at the end of current iteration, this limit is increased. If the limit value determined is exceeded by a particle, the particle is redistributed in the search space with Levy flight method. To get rid of local minima and improve global search capability are ensured via this distribution in the basic PSO. The performance and accuracy of the proposed method called as Levy flight particle swarm optimization (LFPSO) are examined on well-known unimodal and multimodal benchmark functions. Experimental results show that the LFPSO is clearly seen to be more successful than one of the state-of-the-art PSO (SPSO) and the other PSO variants in terms of solution quality and robustness. The results are also statistically compared, and a significant difference is observed between the SPSO and the LFPSO methods. Furthermore, the results of proposed method are also compared with the results of well-known and recent population-based optimization methods.

A novel particle swarm optimization algorithm with Levy flight

For large photovoltaic power generation plants, number of panels are interconnected in series and parallel to form a photovoltaic (PV) array. In this configuration, partial shade will result in decrease in power output and introduce multiple peaks in the P–V curve. As a consequence, the modules in the array will deliver different row currents. Therefore, to maximize the power extraction from PV array, the panels need to be reconfigured for row current difference minimization. Row current minimization via Su Do Ku game theory do physical relocation of panels may cause laborious work and lengthy interconnecting ties. Hence, in this paper, an alternative to physical relocation based on particle swarm optimization (PSO) connected modules is proposed. In this method, the physical location of the modules remains unchanged, while its electrical connections are altered. Extensive simulations with different shade patterns are carried out and thorough analysis with the help of I–V , P–V curves is carried out to support the usefulness of the proposed method. The effectiveness of proposed PSO technique is evaluated via performance analysis based on energy saving and income generation. Further, a comprehensive comparison of various electrical array reconfiguration based is performed at the last to examine the suitability of proposed array reconfiguration method.

Particle Swarm Optimization Based Solar PV Array Reconfiguration of the Maximum Power Extraction Under Partial Shading Conditions

The amount of literature on partial discharge (PD) and partial discharge induced degradation is vast. In the past 10-20 years significant progress has been made on research within partial discharge induced aging of dielectrics. Researchers now agree on the main mechanisms pertaining to this topic. With the advent of a new generation of dielectrics of which many properties now can be affected by the introduction of small amounts of nano-sized particles it seems to be a good moment to review the progress on the understanding of PD induced aging. Focusing on internal partial discharge in solid polymeric insulation this paper tries to identify achievements and at the same time challenges still to be solved.

/pdf/degradation-of-solid-dielectrics-due-to-internal-partial-p7t3m31s2v.pdf

Degradation of solid dielectrics due to internal partial discharge: some thoughts on progress made and where to go now

Photovoltaic (PV) power system performance depends on local irradiance conditions. PV systems are sometimes subject to partial shading, which may produce a nonideal characteristic curve, presenting true and local power maxima in the P -I curve. Traditional maximum power point tracking (MPPT) algorithms can converge to local maximum, which is not the true MPP. In order to solve the problem, this paper investigates the effects of nonuniform solar irradiance distribution on a PV source. An MPPT algorithm that is able to optimize the source instantaneous operating power under nonuniform irradiance is proposed. The ability of the algorithm and its increased performance with respect to traditional algorithms are evaluated by means of experimental tests performed on a real PV power system.

Experimental Performance of MPPT Algorithm for Photovoltaic Sources Subject to Inhomogeneous Insolation

In this paper, a new low-cost device is proposed for fault location in power distribution system. The device is part of a system that should include several units installed in couples at the two ends of medium voltage (MV) cable lines. Their low cost justifies a widespread installation of these devices, moreover other functionalities could be considered so as to enrich the potential of the system for MV cables monitoring and asset management. The system exploits a two-end traveling wave technique, low complexity, and low-cost solutions both for the analog front end as well as for the communication infrastructure. A LoRa network is indeed considered as wireless modulation technique perfectly suited when communication links with three characteristics are needed: low power, low bit rate, and long range. This paper shows the device that has been set up in Prysmian Electronics with some experimental phases showing the effectiveness of the proposed solution and the further developments expected.

A Two-End Traveling Wave Fault Location System for MV Cables

In this paper a novel high voltage (HV) system for testing five specimens in parallel under different combinations of voltage and temperature is presented. When partial discharges (PD) are present, the system allows under a computer supervision the cyclic acquisition of PD signals coming out from each specimen by mean of a new partial discharge phase resolved analyser (PDPRA) built in our laboratory. Each specimen is provided by a suitable circuit breaker, ad hoc designed, that disconnects the high voltage (HV) side of the broken-down specimen, without the central HV supply is interested. The specimen temperature regulation (up to 100/spl deg/C) is performed by a pt100 thermo regulator in a silicon oil bath. Finally, some tests have been performed to check the absence of any mutual PD interference between the specimens.

http://ieeexplore.ieee.org/iel5/7083/19093/00884062.pdf

A novel HV system for multi specimens aging tests under partial discharges and temperature

A partial discharge acquisition system (500) comprising: - a synchronization signal sensor device (200) comprising: a sensor module (202) structured to remotely detect a first synchronization electromagnetic signal (S ES1 ) generated by an alternate current electrical voltage associated with the operation of an electrical object (101) and provide a corresponding first detected electrical signal (S syn1 ); a transmitting device (203, 204) structured to irradiate a second synchronization electromagnetic signal (SEs2) related with said first detected electrical signal (S syn1 ); - a partial discharge detection apparatus (400) comprising: a receiving device (700) structured to receive said second synchronization electromagnetic signal (S ES2 ) and generate a corresponding received electrical signal (S synw3 ) representing at least a timing parameter of said alternate current electrical voltage; the receiving device (700) and the transmitting device (203, 204) being configured to establish a wireless communication link defining a deterministic transmission delay.

Partial discharge detection system and method with synchronization

The aim of the present work is to recognize the type of defect in insulating materials employed in DC electrical systems. This analysis, under AC stress, is carried out by using the Phase Resolved method (PRPD). While, under constant voltage stress this method cannot be performed and measurements show complexities. In order to overcome these problems, a new technique is proposed, based on the application of a periodic continuous waveform. Simulation results, carried out by using a model based on a time-variable conductance of an air void defect, showed the PRPD pattern that can be obtain. Furthermore, compared to the constant DC stress, the measurement duration became lower and the discharges repetition rate greater. Finally, experimental tests have been made in order to validate simulation results.

A new technique for partial discharges measurement under DC periodic stress

A partial discharge detection system including a partial discharge acquisition and processing device includes: a partial discharge detection device configured to provide a detected partial discharge electrical signal from partial discharge pulse generated by a first electrical object; and a first communication module configured to receive a detected synchronization signal carrying detected synchronization phase values and corresponding reference time values associated with an electrical supplying voltage of a second electrical object. The partial discharge detection system further includes: a phase value generator configured to produce synthetized phase values representing a synthetized synchronization signal, the phase value generator being adjustable according to phase errors; and an error computing module configured to compute said phase errors from the synthetized phase values, the detected synchronization phase values and the corresponding reference time values.

Roberto Candela

Papers

A Two-End Traveling Wave Fault Location System for MV Cables

A novel HV system for multi specimens aging tests under partial discharges and temperature

Partial discharge detection system and method with synchronization

A new technique for partial discharges measurement under DC periodic stress

Partial discharge detection system and method employing a synthetized synchronization signal