Failures of Induction Motors (IMs) can lead to unscheduled downtime and interruption in industry processes. This paper concentrates on the detection of the stator's inter-turn faults which are one of the most frequent causes of failures in IMs. The proposed detection method is based on a similarity index that uses the current waveform. To be more specific, the proposed algorithm presents a full-cycle sliding-window-based index based on cosine similarity that only uses current signals for detection of the stator's inter-turn faults. The proposed index cuts the phase difference before/after the disturbance and, as a result, it only depends on the size variations of the current waveform. The proposed method is technically unaffected by non-fault transient conditions including voltage imbalance, voltage sag, voltage swell, and heavy load changes. The performance of the proposed method is validated with numerous simulated scenarios and has good accuracy and speed of convergence.

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.

Inverter-based generation (IBG) is critical in achieving a dependable and resilient electrical system while meeting the net-zero emission goal. The enormous integration of IBG tends to produce various issues, including reduced rotational inertia and reduced short circuit levels. Several scientific publications agree that the voltage source converters (VSCs) empowered by the so-called grid forming (GFM) control may provide a lasting answer for reaching the future net-zero IBG-dominated power systems. This paper presents a comparative analysis of the dynamic performance between IBR using synchronverter and a traditional synchronous generator (SG), where the specific concern is the transient stability conditions. DIgSILENT PowerFactory has been used for time-domain simulations using a test system, and numerical simulations considering an N-l event prove the significant benefit of GFN converter controls in providing active power during a voltage sag induced by a short circuit condition, allowing the system to endure longer short circuit durations.

The reactive power control mechanisms at the smart inverters will affect the voltage profile, active power losses and the cost of reactive power procurement in a different way. Therefore, this paper presents an assessment of the cost–benefit relationship obtained by enabling nine different reactive power control mechanisms at the smart inverters. The first eight reactive power control mechanisms are available in the literature and include the IEEE 1547−2018 standard requirements. The ninth control mechanism is an optimum reactive power control proposed in this paper. It is formulated to minimise the active power losses of the network and ensure the bus voltages and the reactive power of the smart inverter are within their allowable limits. The Vestfold and Telemark distribution network was implemented in DIgSILENT PowerFactory and used to evaluate the reactive power control mechanisms. The reactive power prices were taken from the default payment rate document of the National Grid. Simulation results demonstrate that the optimal reactive power control mechanism provides the best cost–benefit for the daily steady-state operation of the network.

The transition to a low-carbon society is the driving force pushing the traditional power system to increase the volume of non-synchronous technologies which mainly use power electronic converters (PEC) as an interface to the power network. Today, PEC is found in many applications ranging from generation, transmission, storage, and even active loads and protections. The variety of types, applications is almost unlimited. However, the behaviour of PEC is radically different to the typical devices used in traditional power systems, and its specificity in terms of control, overload characteristics, etc. entails an entirely different approach for modelling and simulation. This chapter presents a general review of the main concepts related to power electronic converters and their implementation in DIgSILNET PowerFactory. The chapter finalises with a discussion about the modern tendencies in power electronic applications in power systems: grid following and grid-forming converters.

Looking to the future, there are several challenges that the electricity networks will face: prosperity, sustainable growth, global, and security. The electricity industry situation is complex because resources across the world are becoming scarce and the need for sustainable growth is increasingly important. The evolution of a decarbonized economy involves three main aspects: developing energy efficiency measures, developing renewable energy capabilities, and dealing with adaptation needs arising due to climate change. However, the massive integration of generation technologies based on power electronic converters (PECs) are producing adverse effects for transmission system operators (TSOs) and distribution network operators (DNOs). The TSOs and DNOs are witnessing this loss of control of their systems and are exploring the possibility of requiring these new generators to adopt a set of functionalities to help mitigate the side effects caused by the converter/renewable generation. The concept of power converter-based microgrids (MGs) provides vast opportunities for many service providers who can help operate the transmission system. The classical concept of an MG defines it as a set of interconnected distributed energy resources (DERs) capable of providing sufficient and continuous energy to a significant portion of internal load demand. The MG concept has been extraordinary explored in the literature, especially with regard to the connection to the traditional alternating current (AC) system. However, the most recent development of grid-friendly or smart-converters allows the PECs to perform additional tasks that could help the TSO with operational problems, such as voltage control, low short-circuit currents, etc. This chapter is dedicated to introducing the concept of grid-friendly or smart-converters and how they can be used to create fully controllable MGs able to provide auxiliaries services to the transmission system: the so-called “transmission system-friendly microgrid.” This is an AC MG fully dominated by power-converter technologies, where the local and wide control is used in the mode of a power converter, which enables novel operational functions, for example, reactive power provision to enable voltage control. This chapter presents the concept of grid-friendly or smart-converters and their main capabilities. Their functions are enhanced by a wide-area control and the concept is a transmission system-friendly MG. The chapter includes numerical results of the proposed control algorithm and its implementation using Python and simulations using DIgSILENT PowerFactory to demonstrate the suitability of the proposed transmission system-friendly MG.