Erratum: Rodrigo-Mor et al. Principles of Charge Estimation Methods Using High-Frequency Current Transformer Sensors in Partial Discharge Measurements. Sensors 2020, 20, 2520

The authors wish to make the following erratum to this paper [...]

Simulation And Development Of Electronic Ballast for High Pressure Discharge Lamps

The advantages and disadvantages of using electromagnetic ballasts for power supply of high pressuredischarge lamps (HPDL) are considered. The advantages of using electronic ballasts for supplying HPDL are shown. The analysis is fulfilled of the operation of the HPDL when powered by a high-frequency current, in particular, high-pressure sodium lamps (HPSL). It is indicated that when high-pressure discharge lamps are supplied with a high-frequency current, acoustic resonance may appear. The basic requirements to be met by electronic ballasts for HPSL have been determined. The topology of construction of electronic ballasts for supplying HPDL with a capacity of up to 1 kW has been selected. It has been established that half-bridge converters with inductive ballast and active power factor corrector (PFC) allow maintaining a stable power on the lamp while changing its parameters and efficiency. Mathematical modelling of the electronic ballast based on a half-bridge converter and an ignition device for the sodium discharge lamps DNaT type has been carried out. According to the proposed topology, the electronic ballast was developed for a DNaT 600 lamp powered from the 380 V network. Test operation of the lamps confirmed the reliability of the proposed electronic ballast topology.

Study of properties of acrylic, epoxy and epoxy acrylic compositions structured by the methods of convection heating and heating in the field of high-frequency current

This work is devoted to the development and study of the processes of accelerated structuring of polymer composite materials in the field of high-frequency current (microwave field) which are used in the electronic and instrument-making industries, etc. The complex of properties and the features of structuring of epoxy, acrylic and epoxy acrylic polymer composite materials in the microwave field are investigated. In comparison with the traditional method of structuring and polymerization (convection heating), the structuring in the microwave field equally affects the properties of the studied polymer composite materials, regardless of the chemical nature of the oligomer. The action of the microwave field for all studied polymer composite materials causes an increase in the degree of conversion of binders and a decrease in the content of residual monomer (methyl methacrylate) in thermoplastic acrylic polymer composite materials. In addition, the microwave treatment provides the completeness of chemical and physicochemical processes of the formation of rational structure of polymer composite materials with stable properties. The conducted research allows recommending various regimes of the structuring of the studied polymer composite materials taking into account operating conditions. These regimes ensure the reduction of structuring duration and provide a high level of mechanical and operational properties.

Pengukuran dan Analisis High Frequency Current Transformer Pendeteksi Partial Discharge

The lifetime of high voltage equipment is very dependent on the condition of insulation, poor insulation means the life span of high voltage equipment is getting shorter. Partial Discharge is one of the causes of deterioration of high voltage equipment insulation. The ability to know the phenomenon of partial discharge in equipment becomes very important and adds value to the maintenance of high voltage equipment. Many explanations regarding partial discharge, partial discharge is the lack of uniformity of the electric field in the isolation or dielectric media which will result in the phenomenon of Partial Discharge where this will lead to the failure of the isolation media. Partial Discharge that occurs continuously can cause damage (breakdown) on a high voltage equipment. Therefore, before a high voltage device is used, Partial Discharge detection is necessary. Partial Discharge Detection can use the Partial Discharge measurement circuit. In testing partial discharges can be tested using a sensor with various circuits including High Frequency Current Transformers (HFCT) so that this research will discuss one part of the Partial Discharge measurement circuit, the HFCT detector. Hopefully, the HFCT detector can be further developed and can be used for better partial discharge detection.