The author provides a comprehensive review of the basic charge simulation method and its various modified versions reported in the literature. Applications of the charge simulation method, alone as well as in combination with other methods, are considered. Different aspects of this method are critically examined and its potentials and limitations are identified. Possible areas of future research are outlined in order to improve the overall effectiveness of computer-aided analysis and design of high-voltage insulation devices by using the charge simulation method. >

A review of the charge simulation method and its applications

In this paper, the monopolar corona equation is solved using a modified finite element method (FEM) to give the corona current caused by overhea dc transmission lines without using the commonly-used Deutsch's assumption The method is free from empiricism and entails implicitly a decrease of thsurface field intensity of the conductor with the applied voltage in the same manner as observed experimentally. This in itself represents an additional improvement for the analysis of ionized field where the approximation pertinent to the assumption of constant surface field intensity is mitigated. The calculated corona current as well as the current density at the ground plane agreed with those measured experimentally for a laboratory model.

Finite Element Solution of Monopolar Corona Equation

This paper describes a new type of partial discharge (PD) automatic monitor capable of detecting possible troubles caused by PD inside a transformer in the field and preventing the unfavorable phenomenon from expanding.

Partial Discharge Automatic Monitor for Oil-Filled Power Transformer

This paper describes high voltage insulation technology of cryogenic liquids for superconducting power apparatus. The insulation of a superconducting transformer is classified into several insulation components. Moreover, we investigate fundamental insulation characteristics peculiar to the superconducting and cryogenic circumstances: area and volume effects on breakdown strength, V-t characteristics, quench induced dynamic breakdown characteristics and so on. Finally, we systematize the electrical insulation of cryogenic liquids, and propose a flow chart for the practical insulation design of superconducting power apparatus.

High voltage insulation performance of cryogenic liquids for superconducting power apparatus

Research and development results of enhancement techniques of electrical insulation performance for higher electric field application in power transmission/substation equipment, such as transformers, switchgears and cables, are described, especially based on the view point of dielectric materials. Firstly, the electric field analysis, field optimization and field measurement techniques are introduced to discuss higher electric field stress applications in power equipment. Secondly, material types, including gases, liquids, solids, vacuum and their composite systems are discussed to make power equipment with higher insulation performance, lower losses, lower environmental impact and higher reliability. In the process of development, a highly sophisticated new approach to clarify the physical mechanisms of partial discharges was developed and applied. By the introduction and applications of the above mentioned new electrical insulation techniques based on dielectric materials, concepts of future power equipment with higher electric field stress are proposed. This paper is based on the Whitehead Memorial Lecture given at the IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP) 2011 in Cancun, Mexico.

Enhancement of electrical insulation performance in power equipment based on dielectric material properties

Probability distributions of partial discharge (PD) and dielectric breakdown voltage were investigated for the typical components of oil-filled transformer insulation.

PD and BD Probability Distribution and Equi-Probabilistic V-t Characteristics of Oil-Filled Transformer Insulation

The authors have developed a method called "combination method" by which the charge simulation method and finite element method are combined within a domain after being divided into two parts to complete the calculation of the part. The merits of these methods can be effectively used in the combination method, while the inferior part of each method is covered. It can be applied to fields which used to be difficult to analyze with a single method including the field with various mediums in the open space, with space charge, or with leakage resistance, and so forth.

Electric Field Analysis by Combination Method

Through long-term (3 years) partial discharge (PD) tests on some component models for transformer insulation, the authors have revealed that transformer insulation has a threshold voltage, Vol below which no partial discharge will occur regardless of how long the voltage may last The value of VO is more than 625 percent of a 50-percent probability PD inception voltage at one-minute ac test

T. Yanari

Papers

PD and BD Probability Distribution and Equi-Probabilistic V-t Characteristics of Oil-Filled Transformer Insulation

Electric Field Analysis by Combination Method

Problems of Long-Term Reliability for UHV Transformer Insulation

Electric Field Analysis by Combination Method