Steam drum level control system, computer program product and related methods

A system comprising:

• a steam turbine (ST);
• a gas turbine (GT);
• a heat recovery steam generator (HRSG) having a steam drum and being fluidly connected with the ST and the GT;
• and
• a control system coupled with the ST, the GT and the HRSG, the control system configured to control a flow of steam through the steam drum by performing actions including:
• measuring:
• a steam pressure within the steam drum, a load on the GT, a position of a bypass valve bypassing the HRSG, and a steam flow rate through the steam drum;
• defining a threshold range for each of:
• a steam pressure within the steam drum, a load on the GT, a position of the bypass valve bypassing the HRSG and a steam flow rate through the steam drum based upon the measured data and a target steam level;
• and
• adjusting a drum level setpoint of the steam drum in response to at least one of the steam pressure within the steam drum, the load on the GT, the position of the bypass valve bypassing the HRSG or the steam flow rate through the steam drum deviating from the corresponding threshold range,
• wherein the drum level setpoint accounts for a minimum water inventory required in the steam drum to prevent a low-level trip event, and wherein the drum level setpoint is defined by the following equation:
• Level set point =F(W1 ×Steam Pressure, W2 ×Load on GT, W3 ×Position Of Bypass Valve, W4 ×Steam Flow Rate), where F includes a form or function defining the relationship between each of the measured steam pressure within the steam drum, load on the GT, position of the bypass valve bypassing the HRSG, and steam flow rate through the steam drum, and the target steam level.

A computer program product comprising program code stored on a non-transitory computer-readable medium, which when executed by at least one computing device, causes the at least one computing device to control a power plant system including a steam turbine (ST), a gas turbine (GT), and a heat recovery steam generator (HRSG) having a steam drum fluidly connected with the ST and the GT, by performing actions including:

• measuring:
• a steam pressure within the steam drum, a load on the GT, a position of a bypass valve bypassing the HRSG, and a steam flow rate through the steam drum;
• defining a threshold range for each of:
• a steam pressure within the steam drum, a load on the GT, a position of the bypass valve bypassing the HRSG and a steam flow rate through the steam drum based upon the measured data and a target steam level;
• and
• adjusting a drum level setpoint of the steam drum in response to at least one of the steam pressure within the steam drum, the load on the GT, the position of the bypass valve bypassing the HRSG or the steam flow rate through the steam drum deviating from the corresponding threshold range,
• wherein the drum level setpoint is defined by the following equation:
• Level set point =F(W1 ×Steam Pressure, W2 ×Load on GT, W3 ×Position Of Bypass Valve, W4 ×Steam Flow Rate), where F includes a form or function defining the relationship between each of the measured steam pressure within the steam drum, load on the GT, position of the bypass valve bypassing the HRSG, and steam flow rate through the steam drum, and the target steam level.