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Ship motions affect the propulsion system, which causes fluctuations in the power system. Mutually, the power system variations impact the ship velocity by generating speed changes in the propeller. Therefore, interconnecting the ship hydrodynamic and power system has paramount importance in designing and analysing an all‐electric ship (AES). The lack of an integrated model that can be evaluated in various operating conditions, such as manoeuvring, is evident. This paper explores the required perceptions for the power system and hydrodynamic analysis of an AES. Then, an integrated theoretical model comprising both the ship motion and power system is proposed. In addition to providing an accurate model for the ship in varying situations, this study demonstrates that the ship speed estimation during a ship route change differs from when the interconnections are overlooked. In the light of this determination, a straightforward enhancement for the ship speed control system is proposed. The effects of this modification on the ship power system are explored using the proposed model. The developed model is examined in different scenarios, and its advantages are discussed. It is shown that this model is suitable for employing in the model‐based design of AESs. [ABSTRACT FROM AUTHOR]

System instability as a result of high power generation of one of the largest plants of the Iranian electric power grid prevented the plant to be fully utilized. PSSs were installed on the generating units of the power station, to improve its small signal stability, and enhance the stable generation limit. Domain separation and pole assignment techniques were applied for the PSS design. Several field tests were also carried out to verify its effectiveness. This paper presents the PSS tuning procedure, including the design criteria and some of the field test results.

The ability of static VAr compensators (SVC) to reduce the flicker caused by electric arc furnaces and other variable VAr loads depends on their speed, which is limited by delays in reactive power measurement and thyristor ignition. In this paper, a predictive method is proposed to compensate the delay time and, hence, to improve the SVC performance. Previous samples of the load reactive power are used to predict its future values. Predicted VAr is then applied as a reference for reactive power compensation. Index Terms--Electric arc furnace, flicker, prediction, static VAr compensator (SVC), variable reactive power.

This study proposes a modified virtual inertial control (MVIC) scheme for doubly‐fed induction generator (DFIG)‐based wind turbines (WTs), which both improves the frequency response of these renewable resources and enhances the power system oscillation damping capabilities. It is shown that the proposed control structure enables the WT to participate prudentially in system frequency regulation, which means the amount of WT kinetic energy released to the grid and its participation in system frequency support is alleviated as its stored energy decreases. The proposed control strategy is introduced conceptually, and its performance is verified analytically. Effects of wind speed variations on the small‐signal stability of DFIG WTs equipped with the proposed MVIC is investigated, as well. For these purposes, the system characteristic equation and its damping ratio, as well as the transfer function between the wind speed and the wind turbine rotor speed are derived and analysed. Eventually, time‐domain simulation results and modal analysis verify the performance of the proposed method and demonstrate its superiority as compared to the conventional virtual inertial controllers. [ABSTRACT FROM AUTHOR]

Closeness to the nose point of P-V curve, or loadability limit (LL), and voltage instability is one of the main concerns of modern power systems. Hence, online evaluation of LL has attracted the interest of researchers in recent years. This letter introduces a simple local index for online estimation of closeness to LL, using two consecutive scalar local measurements. This index is achieved based on the fact that variation of the load apparent power is zero at LL. The index is suitable for implementation in numerical relays to stimulate local control actions to prevent voltage instability, and in the system control center for system-wide coordinated analysis and control measures. Simulation results on the IEEE 30-bus test system show the suitability of the proposed index. [ABSTRACT FROM AUTHOR]