Series Resistance Microammeter: High d.c. voltages are usually measured by connecting a very high resistance (few hundreds of megaohms) in Series Resistance Microammeter as shown in Fig. 7.1. Only the current I flowing through the large calibrated resistance R is measured by the moving coil microammeter. The voltage of the source is given by The …
Surge Voltage and its Distribution and Control: The design of power apparatus particularly at high voltages is governed by their transient behavior. The transient high voltages or surge voltages originate in power systems due to lightning and switching operations. The effect of the surge voltage is severe in all power apparatuses. The response of a …
Advantages and Disadvantages of Various Numerical Methods: For computing the electric fields, various methods have been used, viz. Finite Difference Method, Finite Element Method, Charge Simulation Method and Boundary Element Method. Each of these methods has its own advantages for solving a particular problem. With the FDM, the numerical evaluation of the difference equation is …
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Boundary Element Method (BEM) in Electric Field: Though the charge simulation method is known for its accuracy and speed, it is not very efficient in case of multi-dielectric problems and very thin electrodes, which are often used to control and get the electric field strength in condenser bushings, transformers, etc. Such problems can be solved …
Charge Simulation Method for Electric Field: Charge Simulation Method (CSM) belongs to the family of integral methods for calculation of electric fields. There are two variations of this method: CSM with discrete charges and CSM with area charges. Charge Simulation Method with discrete charges is based on the principle that the real surface charges on …
Electric Field Equation: Electric Field Equation – In recent years, several numerical methods for solving partial differential equations which include Laplace’s and Poisson’s equations have become available. There are inherent difficulties in solving these equations for two or three dimensional fields with complex boundary conditions, or for insulating materials with different permittivities and/or conductivities. Proper …
Electric Stress Control: The Electric Stress Control distribution is usually governed by the Poisson’s equation: where φ is the potential at a given point, ρ is the space charge density in the region, and ε0 is the electric permittivity of free space (vacuum). However, in most of the high voltage apparatus, space charges are not normally …
Solid Dielectric Materials and Composites Materials: A good solid dielectric should have some of the properties mentioned earlier for gases and liquids and it should also possess good mechanical and bonding strengths. Many organic and inorganic materials are used for high voltage insulation purposes. Widely used inorganic materials are ceramics and glass. The most widely …
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Breakdown in Liquid Dielectrics: Liquid are used in high voltage equipment to serve the dual purpose of insulation and heat condition. They have the advantage that a puncture path is self-healing. Temporary failures due to overvoltage are reinsulated quickly by liquid flow to the attacked area. However, the products of the discharges may deposit on …
Electric Field Stress: Electric Field Stress – In modern times, high voltages are used for a wide variety of applications covering the power systems, industry, and research laboratories. Such applications have become essential to sustain modern civilization. High voltages at applied in laboratories in nuclear research, in particle accelerators, and Van de Graaff generators. For …