Investigation of Factors Affecting Partial Discharges on Epoxy Resin: Simulation, Experiments, and Reference on Electrical Machines

In Power Systems, Synchronous Generators (SGs) are mostly used for generating electricity. Their insulation system, of which epoxy resin is a core component, plays a significant role in reliable operation. Epoxy resin has high mechanical strength, a characteristic that makes it a very good material for reliable SG insulation. Partial Discharges (PDs) are a constant threat to this insulation since they cause deterioration and consequential degradation of the aforementioned material. Therefore, it is very important to detect PDs, as they are both a symptom of insulation deterioration and a means to identify possible faults. Offline and Online PDs Tests are described, and a MATLAB/Simulink model, which simulates the capacitive model of PDs, is presented in this paper. Moreover, experiments are carried out in order to examine how the flashover voltage of epoxy resin samples is affected by different humidity levels. The main purpose of this manuscript is to investigate factors, such as the applied voltage, number, and volume of water droplets and water conductivity, which affect the condition of epoxy resin, and how these are related to PDs and flashover voltages, which may appear also in electrical machines’ insulation. The aforementioned factors may affect the epoxy resin, resulting in an increase in PDs, which in turn increases the overall Electrical Rotating Machines (EMs) risk factor.

Download Full-text

Epoxy resin insulation: The influence of nanoparticles on the flashover voltage and possible alternatives for Electrical Machines Insulation

2016 XXII International Conference on Electrical Machines (ICEM) ◽

10.1109/icelmach.2016.7732748 ◽

2016 ◽

Cited By ~ 2

Author(s):

M. G. Danikas ◽

K. Varsamidou ◽

Y. Cheng ◽

A. D. Karlis

Keyword(s):

Epoxy Resin ◽

Electrical Machines ◽

Flashover Voltage

Download Full-text

A Study of the Behaviour of Water Droplets Under the Influence of Uniform Electric Field in Epoxy Resin Samples

Journal of Electrical Engineering ◽

10.2478/v10187-012-0029-3 ◽

2012 ◽

Vol 63 (3) ◽

pp. 196-200 ◽

Cited By ~ 8

Author(s):

Yonghong Cheng ◽

Xu Zhao ◽

Michael Danikas ◽

Despoina Christantoni ◽

Pavlos Zairis

Keyword(s):

Electric Field ◽

Epoxy Resin ◽

Electric Fields ◽

Uniform Electric Field ◽

Droplet Volume ◽

Water Droplets ◽

Water Conductivity ◽

Volume Number ◽

Flashover Voltage ◽

Droplet Behavior

A Study of the Behaviour of Water Droplets Under the Influence of Uniform Electric Field in Epoxy Resin SamplesWater droplets on the surface of epoxy resin samples were investigated under the influence of uniform electric fields. Several parameters of water droplets were investigatedwrtthe flashover voltage of the epoxy resin samples, such as water conductivity, droplet volume, number of droplets as well as the positioning of the droplets regarding the electrodes. The droplet behavior is affected by the above mentioned parameters. Perhaps the most striking conclusion is that the flashover voltage depends more on the positioning of the dropletswrtthe electrodes than on the droplet volume and/or number of droplets.

Download Full-text

Behaviour of Water Droplets Under the Influence of a Uniform Electric Field in Nanocomposite Samples of Epoxy Resin/TiO2

Engineering, Technology & Applied Science Research ◽

10.48084/etasr.373 ◽

2013 ◽

Vol 3 (5) ◽

pp. 511-515 ◽

Cited By ~ 6

Author(s):

Α. Bairaktari ◽

M. Danikas ◽

X. Zhao ◽

Y. Cheng ◽

Y. Zhang

Keyword(s):

Electric Field ◽

Epoxy Resin ◽

Tio2 Nanoparticles ◽

Water Droplet ◽

Uniform Electric Field ◽

Droplet Volume ◽

Water Droplets ◽

Water Conductivity ◽

Flashover Voltage

In this paper nanocomposite samples of epoxy resin and TiO2 nanoparticles were investigated with water droplets on their surface. A uniform electric field was applied and the behaviour of the water droplets was observed. Parameters that were studied were the water conductivity, the droplet volume, the number of droplets and the droplet positioning with respect to (w.r.t.) the electrodes. All above mentioned parameters influence the flashover voltage of the samples. It is to be noted that – at least in some cases – the water droplet positioning w.r.t. the electrodes was more important in determining the flashover voltage than the droplet volume.

Download Full-text

Voltage Stability of Power Systems with Renewable-Energy Inverter-Based Generators: A Review

Electronics ◽

10.3390/electronics10020115 ◽

2021 ◽

Vol 10 (2) ◽

pp. 115

Author(s):

Nasser Hosseinzadeh ◽

Asma Aziz ◽

Apel Mahmud ◽

Ameen Gargoom ◽

Mahbub Rabbani

Keyword(s):

Renewable Energy ◽

Power Systems ◽

Voltage Stability ◽

Reactive Power ◽

Power Grid ◽

Renewable Energy Sources ◽

Electrical Power ◽

System Stability ◽

Special Issue ◽

Synchronous Generators

The main purpose of developing microgrids (MGs) is to facilitate the integration of renewable energy sources (RESs) into the power grid. RESs are normally connected to the grid via power electronic inverters. As various types of RESs are increasingly being connected to the electrical power grid, power systems of the near future will have more inverter-based generators (IBGs) instead of synchronous machines. Since IBGs have significant differences in their characteristics compared to synchronous generators (SGs), particularly concerning their inertia and capability to provide reactive power, their impacts on the system dynamics are different compared to SGs. In particular, system stability analysis will require new approaches. As such, research is currently being conducted on the stability of power systems with the inclusion of IBGs. This review article is intended to be a preface to the Special Issue on Voltage Stability of Microgrids in Power Systems. It presents a comprehensive review of the literature on voltage stability of power systems with a relatively high percentage of IBGs in the generation mix of the system. As the research is developing rapidly in this field, it is understood that by the time that this article is published, and further in the future, there will be many more new developments in this area. Certainly, other articles in this special issue will highlight some other important aspects of the voltage stability of microgrids.

Download Full-text

Operation Characteristics of Zone 3 Distance Protection in Wind Power Systems with Fixed-Speed Induction Generators

International Journal of Emerging Electric Power Systems ◽

10.2202/1553-779x.2764 ◽

2011 ◽

Vol 12 (4) ◽

Cited By ~ 1

Author(s):

Shenghu Li

Keyword(s):

Power Systems ◽

Wind Power ◽

Reactive Power ◽

Flow Analysis ◽

Load Flow ◽

Synchronous Generators ◽

Induction Generators ◽

Load Flow Analysis ◽

Wind Power Systems ◽

Operation Characteristics

The induction generators (IGs) are basic to wind energy conversion. They produce the active power and consume the reactive power, with the voltage characteristics fragile compared with that of the synchronous generators and doubly-fed IGs. In the stressed system states, they may intensify var imbalance, yielding undesirable operation of zone 3 impedance relays.In this paper, the operation characteristics of the zone 3 relays in the wind power systems is studied. With the theoretical and load flow analysis, it is proved that the equivalent impedance of the IGs lies in the 2nd quadrature, possibly seen as the backward faults by the mho relays, i.e. the apparent impedance enters into the protection region from the left side. The undesirable operation may be caused by more wind power, larger load, less var compensation, and larger torque angle.

Download Full-text