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When the steam turbine enters normal operation, its power regulation is achieved by changing the opening degree of the control valve GV in order to adjust the steam inlet flow rate. A steam turbine is typically equipped with several control valves for regulating the steam flow rate. There are two common methods for controlling this flow: a) Nozzle regulation: This involves one (or two) control valves corresponding to a set of nozzles downstream of those valves; the control valves are opened in sequence, allowing steam to flow to each group of nozzles one after another, thereby regulating the amount of steam that enters the turbine. This method of regulating steam flow is also known as the sequence valve control method. b. Throttling control: This refers to the situation where all nozzles downstream of the control valve are connected to each other; as the control valve is opened, steam flows through all of these nozzles. The flow rate of steam entering the turbine is regulated by the throttling action of the control valve. This method of regulating steam flow is also known as the single-valve control method, which involves treating multiple control valves as one single valve, opening and closing them all at the same time. The nozzle adjustment mechanism only results in a throttling pressure drop before and after the control valve when the control valve corresponding to a set of nozzles has not been fully opened ； Throttling regulation results in a throttling pressure drop before and after the control valve throughout its entire regulating process. Therefore, nozzle adjustment contributes to improving the efficiency of the turbine at part load. However, the throttle control method facilitates the reduction of the load on the turbine blades throughout the control process, as the steam supply across the entire circumference of the nozzle is beneficial; it also helps to achieve even heating of the turbine during startup. From the relationship curves between flow rate and pressure difference before and after the valves for the two control methods, it can be seen that at low flow rates, when throttling control is used, there is a large pressure difference before and after all control valves ； With the nozzle adjustment method, a pressure difference exists only before and after the control valve, which has not yet been fully opened. For DEH control systems with valve management, it is possible to choose between nozzle regulation or throttling regulation during turbine operation based on the operational requirements, with the valve management function of the DEH enabling switching between these methods. Throttling control is usually employed during the startup of the turbine, especially during cold starts; once approximately 60% of the rated load is reached, nozzle control is used to improve operational efficiency. This advantage **improves operational economy, and is particularly suitable for frequency-regulating units. The nozzle adjustment method also involves the sequence in which the valves are opened, that is, which valve opens first and which one opens later. Due to the partial steam injection, in addition to generating the normal torque on the blades of the control stage that drives the rotor to rotate, the steam flowing through the nozzle also creates an additional force that passes through the center of the rotor. The direction of this force is related to the sequence in which the control valves are opened, and its direction and magnitude change as the degree of partial steam injection varies. It is precisely due to the effect of this additional force that the direction of the load borne by the bearings as well as the load capacity of these bearings change, which can easily lead to instability in the shafting system, resulting in increased bearing temperature or greater vibration. This is an issue that needs to be considered when selecting the valve opening sequence in the nozzle adjustment method.