The relationship between regulating valve configuration mode and inlet steam pressure of the turbine was discussed.Taking a supercritical and a subcritical 600 MW unit as the examples

the operation efficiencies of the two units under different regulating valve configuration modes were calculated in detail.The difference of heat rate changing rule between the above two units in constant pressure operation mode and sliding pressure operation mode of the sequence valve was pointed out.Moreover

with different numbers of the regulating stage nozzle controlled by each high pressure valve

the variation rule of heat rate in different regulating value configuration modes and the configuration principle were put forward.Also

the effect of overlap degree was quantitatively analyzed.The results show that

configuration mode of the regulating valve has significant influence on the unit's efficiency.For the unit with four high pressure regulating valves

if the regulating valve was opened early

with every 2%increase in the pressure loss

the unit heat rate increases by about 13kJ/(kW·h)to 15kJ/(kW·h)in two-valve-point

only about 5kJ/(kW·h)to6kJ/(kW·h)in three-valve-point and a slight little in-less-than-two-valve-point.