锅炉汽包水位监视基准表和保护仪表选型

Type selection of monitoring standard meter and protective meter of boiler drum water level

分析差压水位计环境温度修正难点、测量附加差压的不确定性和随机性、实测不稳定、易大幅度漂移、0位必须频繁核对等问题。差压水位计的测量不稳定性影响保护全过程投入,保护实际传动校验问题多。通过差压水位计和新型电接点水位计的性能比较,指出监视基准表、主表和保护仪表不宜选用差压水位计,而应选用电接点水位计。提出保护与自调“合用”差压式信号的“危险集中”问题,并提供“危险分散”设计实例供借鉴。

The correction difficulty of environmental temperature, uncertainty and randomness of additional differential pressure of measurement, unstability of actual measurement, easy to drift by big margin and frequent check of zero position etc. problems of differential pressure water level gauge were analyzed. The unstability of differential pressure water level gauge affects the full-process commissioning of protection with more problems in actual drive check of protection.Through the comparison of performance between differential pressure water level gauge and new type electric contact water level gauge,it is indicated that differential pressure water level gauge is inadvisable, while electric contact water level gauge is advisable to be selected as monitoring standard meter, main gauge and protective meter. The paper brings forward also the 'concentration of risk' problem of protection and automatic regulation'sharing'differential pressure signals and provides a design example of 'scattering of risk' for reference.