A new polyvinyl chloride (PVC) cable insulation using micro-filler material

In the recent years natural rubber has been completely replaced by synthetic rubbers and plastics as cable insulation. The physical properties required for wire and cable insulation depend on the type of application. It should have good elongation and tensile strength and toughness, so that it will withstand handling during installation and service. It should also have low dielectric constant and power factor but high dielectric strength and insulation resistance. Also, during operation, because of overloading, the insulation may be exposed to high temperatures for long periods. This necessitates the insulation to have excellent resistance to ageing at high temperatures [1]. The main types of insulation used in the cable industries are paper, rubber, plastics and compressed gas. Paper insulated lead sheathed cables are still used because of their reliability, high dielectric strength, low dielectric loss, and long life [2]. The most commonly used insulating materials for low and medium voltage (up to 3.3 kV) cables are polyvinyl chloride (PVC). PVC is not suitable for high voltage applications because of its high dielectric constant and high loss. The polyvinyl chloride (PVC) has played an important role in electrical insulation in electrical components and equipment. Sometimes, in the manufacture of PVC cables jacketing, the additives for the formation and their compatibility may affect on the electrical properties of the cable. Therefore, the response of dielectric properties of PVC to imposed alternating electric field (AC) of various strengths and frequencies become point of interest [3]. The additives used in PVC formulations are mainly plasticizers, stabilizers, lubricants and fillers. Fillers have important roles in modifying the properties of various polymers and lowering the cost of their composites. The effect of fillers on properties of composites depends on their level of loading, shape and particle size, aggregate size, surface characteristics and degree of dispersion [4]. UEKI showed that the filler dispersion is one of the factors that have an influence in the electrical strength on composite [5]. Low electrical strength could lead to failure of cable due to overvoltage

The behaviour and performance of metal oxide varistor under the application of multiple lightning impulses

The behaviour and performance of lightning protective devices such as the metal oxide varistor (MOV) under the application of multiple lightning impulse are different from that of the standard single stroke test. Since the MOV is the most common, economical and reliable device for low voltage and telecommunication systems lightning protection, a precise method of testing has to be adopted based on natural characteristics of lightning to accurately determine its performance and capability. In this work, a Multiple Lightning Impulse Generator (MIGe) with new electronic delay triggering technique with a voltage capability of 5 kV and a current capability of 1 kA has been designed, constructed and developed in the laboratory to conduct impulse testing based on natural lightning parameters. The generator can produce up to five sequences of impulse voltage and current with variable characteristics such as impulse waveshapes and time interval between impulses. This system also incorporates an electronic triggering and delay circuit to initiate and delay the breakdown process of the sphere gaps. Laboratory studies are then being carried out on 2 kV and 5 kV voltage and 1 kA current ratings metal oxide varistors. The electrical and thermal responses of the device are then being analyzed to determine the effect on the varistor characteristics. From the results it has been found that material degradation has occurred on the MOV test samples when multiple lightning impulse are being subjected as compared to the standard testing procedures. The degradation is shown by reduction in the electrical characteristics where the DC voltage at 1 mA current value reduces more than the tolerable limits of ±10%. The other parameters being studied which are the temperature, insulation resistance, capacitance and partial discharge also showed a considerable effect whereby the percentage change is significant when the multiple impulse is applied

Dielectric property of waste tire dust-polypropylene (WTD-PP) composite for high voltage outdoor insulation application

High voltage insulation technology is still undergoing continuous development and improvement from time to time, from conventional ceramic type since to newly polymeric composite insulation material. This includes the development of new composite materials. This paper focused on the possibility of using Waste Tire Dust-Polypropelene (WTD-PP) composite with Alumina Trihydrate (ATH) as the main reinforcement filler for high voltage insulation material. Compound of WTD-PP without and with ATH were prepared with different compositions of WTD-PP content and different amount of ATH filler. A step of processes to produce this newly polymeric composite is presented in this paper. The basic requirement to determine and evaluate the performance of the selected materials as high voltage outdoor application shall comply to the international standard, BS EN 62039:2007. This standard lists several requirements of electrical and mechanical properties that must be fulfilled for materials to be used for high voltage outdoor application. Experimental work has been conducted on the dielectric strength of WTD-PP composite. Breakdown test complying with BS EN 60243-1:1998 is adopted to examine the breakdown strength of this newly polymeric composite. It was found that the breakdown strength of these composites is less than 10kV/mm due to it carbon black content but can be used for lower voltage insulation application

Dielectric strength of waste tyre dust-polypropylene (WTD-PP) for high voltage application

This paper examines the performance of Waste Tyre Dust-Polypropelene (WTD-PP) composite with Alumina Trihydrate (ATH) as the main reinforcement filler for high voltage outdoor insulation material. Compounds of WTD-PP without and with ATH were prepared with different compositions of WTD-PP content (20/80, 40/60,60/40,80/20wt%) and different amount of ATH filler (0,50,100,150pph). The parameter studied is dielectric strength of WTD-PP composite and BS EN 60243-1 was complied. It was found that the performance of these compounds as outdoor high voltage insulation application. The volume resistivity as well as dielectric strength of the compounds was reduced due to high content of carbon black into the waste tyre. It also shows the effects of ATH into the compounds and the optimum value the ATH is 100pph

Study on the early streamer emission mechanisms aided by laser ionization process

Lightning, considered as a spectacular meteorological phenomenon, is one of the most fascinating events in the world. The preliminary scientific and systematic understanding of lightning phenomenon was first constituted by Benjamin Franklin in 1752 that used a kite in order to verify that lightning is really a stream of electrified air. Interestingly when Benjamin Franklin experimented with the electric kite, there were no very tall structures and high rise buildings like we observed today. However till today over more than 200 years the Benjamins lightning rod is still the most internationally accepted LAT. Many standards of LPSs have been published. Among which are the following standards: BS 6651 (British), NFPA 780(American), IEC 61024-1-2. These standards discuss and outline all important aspect of LPSs including design and methods for installing lightning terminal,bonding, and zone of protection calculation. However, these standards utilize Franklin rod concept for their lightning terminals. Even though these standards give some guidance and recommendations for installation of lightning protection, the standard can not assure the systems can provide 100% protection because there are evidences showing these systems can experience malfunctioning. A LAT tip can be damage by harsh environmental condition for instance due to acid rain that will affect on corona emission pattern. Corona developed on a tip of LAT have affect on the performance of the LAT. To study corona on the damage conventional lightning air terminal a new testing set-up was introduced. This testing set-up was completed with humidifier system, temperature control room and adjustable in high of cloud simulation disk. Indigenous Electric Field Mill system was developed. It was completed with a terminal to ADC before a PC (for display, analysis, and data collecting), a personal warning system, and an infra red unit (to initiate laser unit in LPS). The corona emission patterns on the damage convention LATs were acquired from the corona study. Further an empirical model by using dimension analysis was acquired. From this series of works an intensive reviewed published literature on lightning air terminal and lightning protection system was accomplished. A new model of LAT which is still conventional completed with free charge generator and laser unit was introduced

Ann expert system for diagnosing faults and assessing the quality insulation oil of power transformer depending on the DGA method

Dissolved gas analysis is a common method for diagnosing faults in electrical transformers and determining the type of faults early on, depending on the specific standards used. Applying dissolved gas analysis methods can be used in diagnosis and in the evaluation process. There are many methods used in the diagnosis of faults in power transformers, including traditional and intelligent.The use of an intelligent expert system relies on dissolved gas analysis using artificial neural networks, and it gives excellent results in diagnosing faults and assessing the quality of insulating oil during service and the application of appropriate treatment

Dieletric Strength of Waste Tyre-Dust-Polypropylene (WTD-PP) for High oltage Application

Abstract: This paper examines the performance of Waste Tyre Dust-Polypropelene (WTD-PP) composite with Alumina Trihydrate (ATH) as the main reinforcement filler for high voltage outdoor insulation material. Compounds of WTD-PP without and with ATH were prepared with different compositions of WTD-PP content (20/80, 40/60,60/40,80/20wt%) and different amount of ATH filler (0,50,100,150pph). The parameter studied is dielectric strength of WTD-PP composite and BS EN 60243-1 was complied. It was found that the performance of these compounds as outdoor high voltage insulation application. The volume resistivity as well as dielectric strength of the compounds was reduced due to high content of carbon black into the waste tyre. It also shows the effects of ATH into the compounds and the optimum value the ATH is 100pph

Detection and wavelet analysis of acoustic emission signal from partial discharge captured by multimode optical fiber and piezoelectric sensors in insulation oil

High-voltage transformer is the most critical and expensive component in a power system network in order to ensure the stability of the system. Partial discharge (PD) detection is a technique widely used for high voltage equipment insulation condition monitoring and assessment. In this paper, the characteristics of two acoustic sensors multimode fiber optical (FO) and piezoelectric (PZT) sensor have been successfully explored and monitor the condition of high voltage equipment insulation. Both the sensors were placed in an oil tank in which optical breakdown was produced by neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (1064 nm) device. The optical signal of light source was linked by a photodetector which was also connected with multimode fiber (MMF) by means of a fiber optical adapter. The data obtained by both sensors were then analyzed in time and frequency domain