Inverter based generation (IBG) is a necessary technology in the energy transition and reaching ambitious objectives of zero-net emission. However, the colossal penetration of IBG may create several issues. Using Voltage source converters (VSCs) equipped with the so-called grid forming control is thought of as a long-term solution of IBG-dominated power systems. This paper shows a glance of the dynamic performance during a system frequency event (SFE) considering three of the most common grid forming controller types used to emulate synchronous generation operation: Virtual Synchronous Machine (VSM), the Synchronverter and grid forming droop control; and compared with a classic synchronous generator (SG). Numerical results of time-domain simulations of a tests system show the enormous advantage of the grid-forming converters controls to provide an extremely fast frequency response when compared to the case of the traditional SG.@en

Electrical power systems are continuously upgrading into networks with a higher degree of automation capable of identifying and reacting to different events that may trigger undesirable situations. In power systems with decreasing inertia and damping levels, poorly damped oscillations with sustained or growing amplitudes following a disturbance may eventually lead to instability and provoke a major event such as a blackout. Additionally, with the increasing and considerable share of renewable power generation, unprecedented operational challenges shall be considered when proposing protection schemes against unstable electro-mechanical (e.g. ringdown) oscillations. In an emergency situation, islanding operations enable splitting a power network into separate smaller networks to prevent a total blackout. Due to such changes, identifying the underlying types of oscillatory coherency and the islanding protocols are necessary for a continuously updating process to be incorporated into the existing power system monitoring and control tasks. This paper examines the existing evaluation methods and the islanding protocols as well as proposes an updated operational guideline based on the latest data-analytic technologies.@en

Utilizing superconducting technology in fault current limiters for power grid applications is a practical solution to achieve a more modern and efficient power system. This is due to their low-loss profile, high efficiency, and ability to transmit about 5x more power in the same footprint compared to conventional counterparts. In addition, the integration of renewable energy resources into power grids makes the use of fast circuit breakers essential. However, the Transient Recovery Voltage (TRV) of fast mechanical circuit breakers stays a concern. This paper studies the TRV of a fast circuit breaker during a fault condition. Then the effect of a solid-state superconducting series reactor (SSSR) on the TRV of the circuit breaker is investigated and compared using an analytical model, simulation studies, and experimental testing. The results prove that an SSSR significantly diminishes the TRV of the fast breaker and offers an effective superconducting solution for modern power grids.@en

Fast internal detection and location in Shunt Ca-pacitor Banks (SCBs) can lead to the prevention of damages to other SCBs' elements and consequently avoid undesirable performance and effects in power system operation. This paper targets the performance of phasor-based algorithms of failure detection and fault location of SCBs. Being dependent on the fundamental phasor components which usually are calculated based on the Discrete Fourier Transform (DFT), the failure detection and fault location algorithms suffer from almost one-cycle delay. This paper provides sub-cycle phasor estimation based on the least-square technique. The proposed algorithm is evaluated for different configurations of SCBs considering different fuse protection designs. The proposed method provides a criterion for relay decision-making in the case of multiple faulty phases condition. The proposed method is designed to monitor and detect consecutive failures based on the existing data of commercial relays. Performance evaluations are conducted under different circumstances namely voltage unbalance conditions and multiple internal fault locations.@en

Rapid protection of modern electric networks using fault current limiters (FCLs) is often delayed and limited by the inherent controller, sensor, and power electronic unit delays. This article proposes a novel self-activated FCL (SAFCL), comprising a dc saturation winding, series ac limiter windings, and ac parallel reactor, which limits the fault current in less than 0.4 ms. Furthermore, the advantage of this SAFCL, when compared to a traditional saturated core FCL (SCFCL), is that it does not rely on any external controller, sensor, controllable solid-state switch, and battery. In the normal state, the SAFCL behaves like a saturated reactor with a very low impedance and in the fault state, cores are entered to the unsaturation region without relying on an external controller which imposes a high impedance to limit the fault, rapidly. The performance of the SAFCL is evaluated through off-line MATLAB and Maxwell ANSYS FEM simulations, and is also validated by experimental studies conducted on a scaled-down prototype. @en