## 3 Results
### Discussion  
The study confirmed the effectiveness of the developed algorithm in suppressing interference caused by asynchronous switching of electric heaters maintaining temperature in creep test machines. In the applied solution, buffering of temperature controller outputs has a significant impact on reducing power peaks occurring in the laboratory. In the absence of buffering (the value of \(e_{sp}\) is 1), power peaks reached 20 kW, while the standard deviation was 2.5 kW. Implementing the buffering of energy quanta at a relatively small level of \(e_{sp}=4\) reduces the standard deviation by almost four times, and the power peaks to about 4.2 kW. Raising the buffer level \(e_{sp}\) to 50 improves the characteristic in order to achieve power peaks corresponding to one or two heater activations, i.e., 1.4 or 2.8 kW. Also, small average power changes can be observed on the characteristic in the form of frequency modulation of the rectangular power signal with an amplitude of 1.4 kW, which corresponds to the rated power of a single heater. Increasing the buffer fill level above 100 degrades the power time waveform, and at an \(e_{sp}\) value of 200, the peak power reaches up to 16 kW. A large value of the average buffer fill level results in excessive power averaging, reducing the system's ability to follow the changes in the average power value. This condition also has a negative effect on the temperature stabilisation in the furnaces of the creep test machines, as illustrated in Figure 13. On the basis of the tests carried out, the level \(e_{sp}=50\) was determined, for which the quality of the power characteristics is best and for which the best standard deviation of 0.6 kW was achieved. It was also observed that changes in the buffer level value of the L1 phase between 15 and 85 do not significantly affect either the standard deviation of the system power or the stabilised temperature in the furnaces. Changes to the PI controller parameters also have a fundamental impact on the shape of the power characteristic and the magnitude of the power peaks that occur. The PI controller, working as a low-pass filter, is responsible for following the changes in the average power value of the temperature controllers. Reducing the bandwidth too much causes the system not to follow the changes in the average power, resulting in too fast an emptying of the buffers and the occurrence of momentary oscillations of significant amplitude when the average power changes too much. This phenomenon was observed for very large values of the integral time constant \(T_{i}\) exceeding 800 s. On the other hand, small values of \(T_{i}\) resulted in oscillations in the power characteristics, e.g., for a \(T_{i}\) of 10 s, the peak-to-peak value of the oscillation was approximately 20 kW. These oscillations were caused by the PI controller having too wide a bandwidth, which resulted in insufficiently damped power peaks at its output caused by switching the heaters. The acceptable range of the integral time constant \(T_{i}\) not resulting in power peaks being transferred to the system output was from 50 s to 400 s. A value of \(T_{i}=150\) s was taken as the most suitable. Figure 19: Simulated power waveform for the applied algorithm limiting power peaks with individual selection of parameter \(e_{sp}\) for each phase. The gain \(K\) of the PI controller also affects the characteristics of the low-pass filter. Large gain values result in a direct transfer to the output occurring in the system power peaks. In the analysed system, these changes were observed for \(K\) equal to 0.3. At low values of gain \(K\), the changes occurred at the level of one heater switch-on, while the system was exposed to the possibility of occurrence of momentary destabilisations manifested by the occurrence of single power peaks at the level of several kW. For the system under consideration, the value of gain \(K\) for which single power peaks were observed was 0.0375.