Turbine knowledge, why the main steam pressure rises, the pressure regulating valve is turned up, the valve is turned down, and the electric load and heat load suddenly increase?

This has something to do with the control mode of your turbine. Generally, if the ADS is put into use in a remote mode, the steam turbine side only follows the pressure, that is to say, the function of the tone control is to keep the steam pressure exhausted into the steam turbine at the pressure value you set. Therefore, when the pressure value rises, the main steam regulating valve will open and the pressure will drop.

But this regulation makes it lag, that is to say, at the beginning of regulation, the steam above your set pressure has actually entered the steam turbine and heating system. So your heat load and electricity load will definitely rise in an instant, because the steam parameters have increased.