after the main steam pressure increases, the total useful enthalpy drop increases, increasing the power capability of steam, so if keeping the original load constant steam flow can be reduced it is advantageous to the economic operation of the unit. But the last few steam humidity level will increase, especially in the work of the last stage blades disadvantage. For adjusting the level, the most dangerous working condition is at the time of the first regulating valve fully open, the beginning of this time pressure, enthalpy drop and adjust the level of traffic increased, disadvantage for the adjusments, but at rated load, regulating stage enthalpy drop is not at the maximum, generally not very dangerous. Main steam pressure rises and there is no overrun, the unit runs at rated load, as long as the final stage exhaust humidity does not exceed the allowable range, adjust the level can be consider not dangerous, but the main steam pressure is not free to rise. Main steam pressure is too high, adjust the level enthalpy drop is too large, a long time will damage the nozzles and blades, in addition to the main steam pressure gauge rises, steam humidity of last few levels blade greatly increased, blade suffer erosion. The new steam pressure rises too much, also lead to increased steam conduit, steam room, valve and other parts bearing stress, bring some threats for the safe operation of the unitbring.