The configuration status of online chemical instruments of 16 ultra supercritical units in 8 power plants which belong to a power generating company was investigated statistically

and the measurement accuracy of these online chemical instruments was detected. According to the inspection results

the error sources and influencing factors of online conductivity analyzer

online p H analyzer

online sodium analyzer

online dissolved oxygen analyzer and online silicon analyzer were analyzed. It proposed that

to improve the accuracy of on-line chemical instrument measurement

the personnel who have obtained the qualification certificate of chemical instrument inspection and calibration in power plant should be employed to carry out regular inspection and calibration by using the mobile on-line chemical instrument inspection device which meets the standard requirements according to the standard regulations of power industry. The ultra-supercritical units have extreme high requirements in each water vapor control index

so the availability rate of the on-line chemical instruments must satisfy the standard

and the on-line chlorine meter should be installed according to the GB/T 12145—2016 standard

to prevent chloride corrosion in thermal equipments and steam turbines.