热电阻元件故障原因分析及对策

1前言 天荒坪抽水蓄能电厂采用的热电阻(RTD)均为相应设备的配套元件,由外方提供,投产以来运行情况一直不太稳定,故障率较高.从表1的统计资料表明:自1999年元月至2001年6月,全厂因RTD误动引起机组运行故障(指机组启动失败、跳机、转换失败以及停机失败)达18次,占设备全部故障的2.7%,故障性质恶劣,造成带负荷跳机14次,启停失败4次,给电厂安全生产和设备稳定运行带来了极大的隐患.为此分析RTD故障原因并提出相应的解决办法十分必要.

一种自动测量热电阻时间常数的方法

给出了脉冲宽度调制（ＰＷＭ）恒流源激励的测量热阻动态响应特性和自动给出其时间常数的电路方法。较详细的分析了工作原理和实现电路，并给出了实验结果。

Thermal-hydraulic modeling and analysis of hydraulic system by pseudo-bond graph

To increase the efficiency and reliability of the thermodynamics analysis of the hydraulic system, the method based on pseudo-bond graph is introduced. According to the working mechanism of hydraulic components, they can be separated into two categories: capacitive components and resistive components. Then, the thermal-hydraulic pseudo-bond graphs of capacitive C element and resistance R element were developed, based on the conservation of mass and energy. Subsequently, the connection rule for the pseudo-bond graph elements and the method to construct the complete thermal-hydraulic system model were proposed. On the basis of heat transfer analysis of a typical hydraulic circuit containing a piston pump, the lumped parameter mathematical model of the system was given. The good agreement between the simulation results and experimental data demonstrates the validity of the modeling method.

三线制RTD测量电路及应用中要注意的问题

本文介绍了一种改进的三线制RTD测量电路，以及应用于计算机测温的工业现场中容易发生的问题，并指出了施工接线设计中应改进的地方。