Proposal of fault prediction system for underground installations

The absence of intelligent systems for fault prediction in components and equipment in underground installations does not allow a correct structure for maintenance programs to reduce intervening maintenance actions. Thus, it is necessary to devise a computer system that can conjugate potential causes and factors of failure as input data that can correctly inform output data, which represents a component or equipment failure prediction. The aim of this paper is to present a proposal system to support maintenance analyses, where sensors of temperature, water level and vibration, can provide real time data to analyze the isolation condition of transformers and switches within underground chambers. The paper also presents a new use of a neural network to alarm partial discharges (PD) activities. A case is presented where hardware and software are developed and an underground chamber is used as a real test case. In this research, cost, performance, environmental hostility, and the availability of installed equipment in the Brazilian market were considered. After the methodology was verified, the cost was compared with imported equipment, and the result was approximately a 50% cost reduction. Issues of telemetry, hub specification, and sensor installation were also evaluated.     

Methods for prolonging the service lives of expensive installations

Theoretical and practical methods for prolonging the service lives of expensive installations in special-purpose machine building are considered. Design and analytical expressions for determining the probability of survival on the basis of safety margins with respect to the strength, wear resistance, corrosion resistance, and other criteria are obtained. Experimental techniques of the extension of the service life from the results of tests and flaw detection for nodes, mechanisms, and assembly units are described. A probabilistic method for computing the serviceability of the article in the course of the extended lifetime starting from the actual operating conditions for the element base is presented.     

A modular bipolar power supply for high-power ion-plasma installations

The circuitry solutions, design, and main parameters of a modular pulse bipolar power-supply unit for high-power ion-plasma facilities are described. The modular principle of designing power supplies provided their application in various processes. The results of tests of the developed device as the power supply of a magnetron sputtering system with a power of 60 kW and a high-voltage power supply of the substrate bias voltage with a power of up to 40 kW are presented. The efficiency of applying bipolar pulses for preventing arcing at the magnetron cathode is experimentally demonstrated.     

Pressure-jump apparatus suitable for repetitive experiments

A repetitive pressure-jump apparatus has been devised and used for the measurement of a small relaxation effect in solution. Although the pressure rise time of the apparatus is inferior to the usual method, signal averaging has enhanced signal-to-noise ratio of the relaxation spectrum.     

继电保护系统在不同技术领域的适用度研究

继电保护原理主要是伴随着电力输电系统的发展而不断发展的,这一原理已被广泛应用于各个相关领域,其作用就是在必要时刻控制电路的通断,以达到保护整个电路或电气设备的作用.然而,每个应用领域的技术要求不同,保护的设备、方式也各有特点,故笔者认为有必要对继电保护系统在不同技术领域的适用度做相关讨论.