Combined heat and power generating station - has automatic control to vary ratio of outputs at constant steam input

摘要

A two stage turbine (18, 19) drives an electrical generator. Steam is bled (20) from the discharge of the high pressure stage to supply a district heating or process steam system. Transducers produce signals proportional to frequency (1), inlet steam flow (3) bleed steam flow (2) and bleed steam pressure (4). These signals are fed to a computer unit which determines the maximum permissible change in turbine load at the existing steam conditions. The output of the computer unit is amplified (5, 6) and used to control the intermediate pressure inlet valve (23) to the low pressure stage and the bleed steam valve (22). They are operated to keep the inlet steam flow constant.