**4.3 Main features of the human machine interface for trainees**

The better option for the operator console is to emulate via software the consoles of the actual plant, this represent the less cost option compared with the acquisition of such consoles, in this way a graphic imitation of the actual HMI provides a suitable operation interface. This HMI is a graphical application based on a multi-window environment with interactive process diagrams, these diagrams are organized in hierarchical levels following the organization of the power plant systems, i.e. boiler, turbine, etc. There are two main types of diagrams: information diagrams and operation diagrams. The first type shows values of selected variables. The values are presented as bar or trend graphs. The trainee

Fossil Fuel Power Plant Simulators for Operator Training 109

there is a chronologic list of the alarms fired during the simulation, in this way the trainee is always notified of the occurred events. This list must be according to the alarms of the

The main challenge for the simulator users (operators) is the cultural change, because now operators have to utilize a modern tool like a PC instead of a control boards, therefore the operators must forget their former operation habits and adopt novel operation techniques

Usually the fidelity of a simulator is mainly based on the behaviour of a group of variables called critical parameters. These parameters are related with conservation principles of mass and energy of the power plant and they will be selected only if they can be accurately measured. Any other variable not selected as critical parameter and which is observable in

According to the previous classification, the criteria to assess the performance of the

 In steady state, the maximum variation of the critical parameters is ± 2% and for no critical parameters is ±10%. The value of these parameters must be consistent regarding the information of the reference plant. All of this is only valid for generation states greater than 25% of rated load. Another operation states, for instance, "cold iron" can be verified to assure that all simulator parameters, e.g. temperatures, correspond with the

 During transients conditions, due to malfunctions or abnormal operations, the simulator must have the same trend as the one reported in the actual plant, under the same operating conditions. Regarding the permitted duration of these transients, it is suggested a maximum time variation of ± 20% between simulation and actual data. In the absence of information, the trends and duration of the transients must be according

In any state, the simulator will not violate any physical or conservation law and its real-

The acceptance procedures define the required tests to carry out before a simulator can be ready to use it as a part of the training programmes for operators, the execution of these procedures is also a way of verifying if the simulator meets with its specification and scope. These procedures include exhaustive tests of all the hardware and software involved, the

actual power plant.

Feedwater flow.

Fuel flow.

Main condenser pressure.

 Combustion air flow. Generated electric power.

for a fluent and safe navigation in a new HMI.

**4.4 Performance criteria and acceptance procedures** 

 Flow, pressure and temperature of main steam. Flow, pressure and temperature of reheat steam.

simulator can be summarized in the following three points:

to the expected behaviour of the existing physical phenomena.

room temperature of the simulation.

time operation will be assured.

required tests can be summarized as:

the operator HMI is called no critical. Typical critical parameters are:

uses the operation diagrams to control and monitor the whole process, with them he operates pumps, fans valves, and also he can modify set points of automatic controls and carry out any feasible operation in a similar way as he would do in the actual power plant. When the trainee needs to perform an action, he selects the suitable pictogram with the cursor, and then a pop-up window appears with the corresponding operation buttons. At any time the trainee can open all the pictograms he wants, and can do this in any operation console. The operation diagrams also have value windows; they show a pop-up window with the value of one variable (e.g., boiler drum level, turbine speed, etc.) and its operation range. The trainee easily visualizes the off-service equipment because it is shown in white and the equipment on-service has a specific colour depending on its working fluid. To this end, green equipment handles water, blue equipment handles air, red equipment handles steam, and so on. Figure 12 shows the operation diagram of combustion gas, where it is open a pop-up window to start a motor.

Fig. 12. Interactive process diagram

One important improvement of this kind of HMI is its capacity to show to trainee more information (temperatures, pressures, flow rates, etc.) compared to former control board simulators so it is expected that this kind of features help the operator to analyze in a better way a particular phenomena. In the bottom of the diagram displayed in Figure 12 there is a chronologic list of the alarms fired during the simulation, in this way the trainee is always notified of the occurred events. This list must be according to the alarms of the actual power plant.

The main challenge for the simulator users (operators) is the cultural change, because now operators have to utilize a modern tool like a PC instead of a control boards, therefore the operators must forget their former operation habits and adopt novel operation techniques for a fluent and safe navigation in a new HMI.
