# Application of the Residue Method in Steam Superheater Fault Detection
## 4 Experimental Results and Discussions  
The final tests on the voltages at various points of the electronic circuit were conducted on the simulator, corresponding to the temperatures at a scale of 1/100 of the real steam superheater assembly at the Isalnita Thermal Power Plant boilers. These tests were run in parallel with the simulations carried out during the design and construction phase of the circuit. The simulations were conducted in a stationary mode. For the tests on the mock-up, a DC voltage stabilizing source was utilized, with V1 at 10 V for the live steam + gas input (green connector), V2 at 12 V for the operational amplifier supply (red connector), and V3 at 5 V for the \(W_{inj1}\) and \(W_{inj2}\) injectors input. Figure 11 is a visual depiction of the steam temperature control framework within the simulated superheater utilizing BORIS software (the basic module of WinFACT 10). BORIS is a program that facilitates dynamic system simulation through directed blocks. One of the principal benefits of BORIS is its extensive library, which allows for the simulation of nearly any type of dynamic system. Furthermore, BORIS can utilize a vast number of blocks, limited only by the computer's memory and the optimal arrangement of the block structure. The simulator shown in Figure 7 has been predicted to have potential malfunctions. These malfunctions include a \(W_{inj2}\) actuator fault that can be simulated by substituting the control signal from the temperature regulator Ta3 with a constant voltage supplied from the supply voltage source adjustable via potentiometer P3. It is also possible to simulate a change in steam temperature at the entry to the superheater, corresponding to a fault in the steam system, by using switch \(K1\). Finally, it is possible to simulate a change in flue gas temperature in the entry zone of the superheater, corresponding to a fault in the combustion zone, using switch \(K2\). As previously stated, this paper chose to focus on experiments where actuator faults are present. The next step was to collect information from the electronic simulator. This step was performed by connecting the simulator to an acquisition board. For these experiments there were used the data acquisition board dSpace, the data acquisition board Cassy lab, an electronic simulator for the three superheaters, and MATLAB/Simulink. Figure 10: The diagram of the fault detection model. The next step will utilize the electrical diagram of the electronic simulator shown in Figure 12 and the data acquisition board dSpace to perform the simulation. The steam temperatures \(T_{a2}\) and \(T_{a3}\) are connected to the input of the data acquisition board dSpace ADC5 and ADC6, respectively. On the other hand, the injection flow Winj1 and Winj2 are connected to the output of the data acquisition board dSpace DAC1 and DAC2, respectively. If you are using the dSPACE 1104 system, MATLAB Simulink can be used to implement the block diagram from Figure 13 which utilizes a PI control law. The scheme consists of two signal generators that have adjustable frequency and amplitude, two input constants (T*\({}_{a2}\) = 4.53 and T*\({}_{a3}\) = 5.5), two input channels of the dSPACE board (ADC5, ADC6), and two output channels of the dSPACE board (DAC1, DAC2). Once you have made the appropriate settings for the dSPACE 1104 system, you can proceed with your simulation. Figure 11: Steam superheater: (a) simulator; (b) temperature control structure. Figure 12: Electrical diagram of the electronic simulator and the data acquisition board dSpace. After experimenting, some interesting results were obtained. In one scenario, a fault in the actuator was simulated that affected the temperature T\({}_{a3}\). To ensure accuracy, elements were introduced in the electronic scheme to simulate response delay. After that, the system was allowed to reach a steady state before applying the fault via switch K3, which was locked to simulate a temperature drop. Once the fault appeared, it was detected using a residual generator for the system.