Worldwide, mobility electric has represented a tendency to achieve environmental goals. However, the expansion of charging Electric Vehicles (EVs) on power distribution networks could cause problems related to energy quality and reliability. Battery Energy Storage Systems (BESS) associated with Photovoltaics (PV) systems are a promising solution for supporting the EVs charging infrastructure and reduce negative impacts on the electric grid. In this context, this paper proposes an on-grid PV-BESS for fast charging EVs in Campinas, Brazil. The objective is to analyse and provide a technical-economic and viable option for the charging stations in Brazil. The proposed system is formulated, optimized, and evaluated using the Homer Grid software. The results show the optimum technical-economic system composed of 100 kW/200 kWh BESS, 45 kWp PV system, and two fast stations.

A disconnector failure can lead to significant problems in a distribution system. For instance, two large blackouts in Sweden were partially caused by disconnector faults. One way of preventing future failures is condition monitoring. There is however a lack of previous research focusing on condition monitoring of disconnectors. In fact, most previous research on condition monitoring for switch gear focuses on circuit breakers, and the research focusing on disconnectors mainly study faults related to electrical breakdown. This study examines the possibility to predict mechanical failures of disconnectors using manoeuvre times recorded in SCADA. It studies the effects of external factors on manoeuvre time as well as the behaviour characteristics of four types of disconnectors.

For decades, high-voltage (HV) fuses have provided economical and most reliable protection of electrical applications standardized by IEC60282-1[1]. They fulfil both either the protection of the circuit components or the energy limitation, fast disconnection to limit negative effects to the corresponding network. They are often used in combination with a second switching-device of limited switching capacity. Typically, such kind of medium-voltage switching - or control-gears handle the switching tasks of the pure operating current of the application up to a certain, but limited level of short-circuit current. In the event of a high-current fault, occurring either on the grid or in one of the components, failure currents may arise which exceed the breaking capacity of this switching device. This is where the “high-voltage high-breaking- capacity fuses” – or HV fuses for short – step in. The development of more compact and economical switchgear solutions requires HV fuses with a reduced power dissipation are still able to handle higher transformer capacities. These now available so-called “Low Loss” fuses [2] provide the well-known protection of transformer circuits even in case of higher transformer capacities up to 3.000 kVA in combination with encapsulated switchgears subjected to IEC 62271–105 [3] as applied in actual renewable applications like wind or solar farms of a higher power level. However, before the “Low-loss” fuses were available HV fuses were also used inside renewable energy systems of a reduced power level. After some years of operational experiences, it became obvious that special attention has to be paid to the additional issue of cyclic stability due to current fluctuations given by nature in case of such renewable energy systems. SIBA decided to take care of this matter by developing a corresponding melting-element system and fuse series with an enhanced cyclic stability called ICS. This new fuse series can be seen as a second step and further development of the known “Low-loss” type. In addition to the improved power loss and thermal situation, this new type is providing an enhanced mechanical cyclic stability in case of current fluctuations inside renewable energy systems.

Many electrical substations are going through digital transformation that will, sooner or later, enable some of the activities currently performed by human (i.e. control, monitoring, repair and maintenance) to be performed without the presence of personnel in the substation. In order to create a structured approach and unified view on the journey towards full substation autonomy, this paper introduces definition of substation autonomy levels. Such definitions help end users in setting their road maps in reaching various substation autonomy levels.

Safety related to internal arc in a switchgear is a major concern. The switchgear designers have used different methods over the years to calculate important variables (pressure etc.) for internal arc design. In the beginning, considering the outflow of gases due to volumetric heating by arc energy, pressure rise was calculated. Afterwards CFD (computational fluid dynamics) was introduced to model in detail the flow and energy balance. In all of the above models, there are lot of fit parameters to begin the calculation and they only provide approximate pressure rise. All these methods need input in the form of electrical energy (fault current and arc voltage). Fault current is defined by standards, but arc voltage is an unknown input. In addition, these methods don't tell about the arc propagation, which can be useful to avoid the burn-through. In order to overcome the above-mentioned limitation, for the first time, the modelling of free burning arc in large switchgear volume was performed. The advantage of such a method is that the arc voltage and the heat transfer are calculated from first principle and assumptions are not used for the input parameters. The movement of arc also shows the location where designers can introduce extra protection to avoid burnthrough

Maximizing the utilization of grid components in operation is a major challenge for distribution system operators. In order to achieve this, assessment of the technical conditions of the equipment is required. The dielectric performance of insulation systems can be evaluated by the interpretation of Partial Discharge (PD) signals. Evaluation of the characteristics of these time-resolved signals is of highest importance. Conventional methods have several drawbacks, such as the complexity of the test setup and the settings as well as costs of the systems. Available PD measuring systems are not designed to face future challenges arising from Direct Current (DC)-infrastructure for energy distribution. To apply machine learning (ML) algorithms, typically the complete time signals have to be provided in order to extract features. In the present study, to allow a real-time processing at high signal resolutions, an automatically initializing algorithm was developed to separate noise and deterministic signals from each other. The PD or interference signals are available for extended signal processing such as clustering or classification. The implementation of this technology for Alternating Current (AC) and DC voltage applications was evaluated under practical conditions. Finally, an outlook on future applications and options using algorithms of ML in combination with the presented technology is given.

We present here the development of a self-healing dielectric fluid (SHF) for leaking fluid filled cables (FFCs). Within the UK alone it is known that ∼400,000L of fluid is lost from these assets per annum, with consequential financial, environmental, and reputational costs for the operator. Although significant effort is taken in locating and repairing these leaks, most FFCs are either underground or otherwise inaccessible, resulting in significant time, labour, and disruption being incurred during remediation.

The development of SHFs provides an alternative solution. Under normal operation, SHFs provide the same function as a dielectric fluid (and can be handled and deployed in the same manner), but upon the formation of a leak the fluid will autonomously gelate in the affected area, resulting in the significant reduction or cessation of the leak. The effect is enhanced further by the presence of backfill, resulting in the formation of a hardened, oil-proof barrier that restricts the spread of cable oil and reduces the overall environmental impact.

This paper covers the SHF development pathway, provides results obtained from laboratory test rig and decommissioned circuit trials, and provides a view of further work required to allow this technology platform to transition to Business as Usual.

Existing MV/LV substations have been designed according to the applicable standards of the past. Since then, however, standards on internal arc resistance of substations have become stricter and safety awareness among grid operators has also increased. The replacement of electrical components in existing MV/LV substations, particularly exchanging the MV switchgear, can be a natural opportunity to assess and, if needed, upgrade the substation's internal arc resistance. In an attempt to avoid the assessment of each substation individually, this study investigates in general the need to upgrade internal arc resistance of MV/LV substations, based on worst-case situations. It appeared that in all considered cases a simple and affordable pressure relief hatch can solve any overpressure problems. Therefore, in case of replacement of the MV switchgear, this hatch can now be applied as a standard to ensure the internal arc resistance of the substation.

Arc extinguish grids are used to increase the arc voltage at fault current interruption for load-break switches and/or molded case circuit breakers (MCCB). The extinction grids are often made of iron. The surfaces of the iron grids melt after current interruptions. This is because the arc is driven to the grids surfaces by magnetic forces. When the grids were laminated by thin iron sheets same as the transformer core, the arc voltage was smaller than that of normal grids. Therefore, we consider the magnetic force due to the eddy currents generated inside the grids drives the arc. It is known that the relative permeability of iron after heated above Curie temperature decreased. After current interruptions with many times, the melted are of the grids surface is increased and the relative permeability of the iron grid is decreased. Then the magnetic force driven the arc to the grid becomes small and the interrupting performance for the MCCB will be degraded.

In this paper, optimization of battery energy storage for e-mobility unpredictable loads is presented. The analysis of interaction between group of electric chargers connected to the network and the battery energy storage system has been performed by means of artificial intelligence tools. In order to deal with optimization of the capacity of the battery energy storage, the electrical vehicle load profiles are studied. The solution provides an optimal capacity of the battery energy storage to be installed based on predictions obtained from historical data. Analysed installation is based on Li-Ion batteries with limited lifetime which is non-fixed and related not only to battery chemical characteristic and specifications but also to operation and storage conditions.