An improved technique and its implementation for control of high power heaters in large autoclaves and similar plants

摘要

This paper presents an improved technique and its implementation for control of high power heaters in large autoclaves and similar plants. These plants are equipped with electrical heaters, which are grouped into number of banks to reduce the quantum of load/power change and improve operability, controllability and reliability. Conventionally, each heater bank is controlled through a power controller (usually Silicon Controlled Rectifier based). The total number of power controllers employed in a system will be equal to the total number of heater banks and they all share a common control signal provided by the temperature controller. While this is an obvious method, it is very expensive and results in decreased power factor and increased harmonic distortions. To overcome the above limitations, this paper explains a better technique; namely, ‘Heater Power Steering Logic (HPSL)’ and its implementation using Analog circuit and also using Programmable Logic Controller.