Abstract-During a change in operating condition, oscillations of small magnitude and low frequency often persist for long periods of time and in some cases even present limitations on power transfer capability. Generators in power systems are equipped with automatic voltage regulator (AVR) to control terminal voltage. It is known that AVR has a detrimental impact upon the dynamic stability of the power system. Power system stabilizers (PSS) are widely used to generate supplementary control signals for the excitation system in order to damp out low-frequency oscillations (LFOs). In this paper proportionalderivative power system stabilizer (PD-PSS) used to damping LFO after tuning the gains of the PSS by using PSO. The damping boundary condition of PSO technique is modified to improve its performance in the tuning and optimization process. Simulation studies performed on a typical single-machine infinite-bus (SMIB) system used in MATLAB Simulink program. Assessing the performance of the proposed modified PSO based PD-PSS with Speed deviation (∆ω) as an input signal using eigenvalue analysis. The proposed PSO based PD-PSS is evaluated and examined under different operating conditions and inertia constant each one of them applied with two test cases small disturbance and short circuit. A comparative study between the proposed PSO based PD-PSS, original PSO based PD-PSS, and lead-lag PSS is done in this work. The results ensure the superiority, the effectiveness, and the robustness of the proposed PSS over the other techniques.

Climate change, environmental impact and the limited natural resources urge scientific research and novel technical solutions. The monograph series Green Energy and Technology serves as a publishing platform for scientific and technological approaches to "green"-i.e. environmentally friendly and sustainable-technologies. While a focus lies on energy and power supply, it also covers "green" solutions in industrial engineering and engineering design. Green Energy and Technology addresses researchers, advanced students, technical consultants as well as decision makers in industries and politics. Hence, the level of presentation spans from instructional to highly technical. **Indexed in Scopus**. **Indexed in Ei Compendex**.More information about this series at https://link.springer.com/bookseries/8059

was published, studies had "not provided compelling evidence" for IV B (Henry and Dutrow 1996, p. 504). Of great signiÞ cance are the implications for understanding why some tourmalines incorporate IV B and others do not. In this work, we provide detailed models with short-range orders to explain the relationship between the occupancy at the Y site and the T site.These short-range orders imply also that an oft-used calculation of the Li content by difference on the Y site may be problematic for Al-rich tourmalines (olenite, elbaite, rossmanite) because these tourmalines can contain vacancies at this site. It can also be problematic to normalize such tourmalines to 6.00 Si apfu by ignoring B non-stoichimetry, especially when they contain only low amounts of Fe, Mn, and the Al content at the Y site exceeds 1.3 apfu.Tourmalines that contain IV B were described recently from several localities. From a pegmatite near Stoffhütte, Koralpe, Styria, Austria, olenite samples with up to ~1 apfu IV B were described (

The optimal-linear-regulator theory is used to optimise an amplidyne speed control system subjected to a constant load disturbance. As such a regulatory system tends to a steady state in response to a step disturbance. To be able to use a quadratic performance index as an optimisation criterion, three different techniques of variable transformation which moved the steady state to the origin of co-ordinates were employed. The first modification technique yielded an optimal control proportional to the state and to the load disturbance, ie, Feedforward Control. The second method led to an optimal control proportional to the state and the time-integral of the speed error, ie, Integral Feedback Control, while the third resulted in an optimal control proportional to the state and to both the load disturbance and to the time-integral of the speed error. This third control may be described as Integral Feedback/Feedforward Control. The transient responses of the system in the three cases to a step load disturbance were calculated, and the Integral Feedback/Feedforward Control gave the best results.

In this paper the proportional integral derivative (PID) controller is designed and used to control the DC servo motor. The PID parameters are optimized by the trial and error method. The controller is verified on the loaded DC servo motor by SIMULINK program. The controller SIMULINK model is verified experimentally. Acceptable agreement is obtained between theoretical and experimental results. Simulation and experimental results verify the effectiveness of the PID controller of the DC servo motor.