Distribution grids are subject to a drastic evolution in their operating conditions due to the high integration of renewable energy resources (RES) and their ability to regulate voltage. To cope with this issue, modern solar photovoltaic (PV) systems are equipped with smart inverters enabled with communication capabilities that allow the coordinated operation to offer services such as controlling voltage by appropriately setting the reactive power production. This paper proposes a co-simulation framework for smart converter reactive power control in active distribution grids. The proposed framework is used to appropriately control smart inverters installed in PV systems to inject/withdrew reactive power ensuring voltage control at the time that minimises active power losses of the active distribution grid (ADG). The proposed approach has been tested in a modified version of the Kumamoto distribution system. The suitability of the proposed framework has been demonstrated. ... Read more

Reaching net-zero emissions within the proposed time requires an enormous effort from the energy sector, and it is even more challenging for the electricity infrastructure. This article offers a modified version of the IEEE 39-bus system specifically created to allow zonal day-ahead market (ZDAM) simulations. The system representation is based on the original version of the IEEE 39-bus system but considers the integration of renewable energy resources (RES) in the generation mix: solar and wind. Hourly time series are used to define load profiles and wind and solar power generation. The zonal dayahead energy market information has been created by solving the optimisation problem. Numerical results of the proposed power test system are provided for the yearly ZDAM and steady-state performance, in N and N-l conditions, respectively, through Pyomo and DIgSILENT PowerFactory features. ... Read more

The operation schedule of the power generation units in electrical power systems is determined by the optimisation problem known as unit commitment (UC), aiming at minimising the total cost considering the generation constraints. To obtain a feasible solution from the network perspective, the security-constrained UC (SCUC) problem has been defined to embed the network constraints in the optimisation problem as well. Also, the higher penetration of renewable energy sources (RES) has increased the difficulty of UC problem, mainly due to the uncertainty and the high variability of RES. This paper proposed a SCUC with economic dispatch (SCUCED) optimisation developed in two stages. The first one is the solution of a merit-order based zonal day-ahead market (ZDAM) optimisation to define a preliminary generation schedule. In the second stage, the SCUCED is solved based on AC load flow routines and sensitivity factors to embed the full network representation. The approach is applied to a modified version of the IEEE 39-bus test system. ... Read more

The increasing penetration of renewable energy resources (RES) in transmission system operating conditions require a suitable test system and a dataset to cope with current issues. RES penetration remarkably affects day-ahead market outcomes regarding zonal prices and dispatched generation levels. For this purpose, zonal day-ahead energy market models in the presence of RES in the generation mix need to be implemented. In this paper, the IEEE 39-bus system has been suitably modified to include solar and wind generation in the traditional generation mix. Hourly time series are used to define load profiles and wind and solar power generation. The zonal day-ahead market (ZDAM) resolution is simulated by solving a Linear Programming optimization problem employing Pyomo. Furthermore, steady-state nodal analysis is carried out using DIgSILENT PowerFactory, performed over a year horizon. ... Read more

The dispatch schedule of the electrical power plant units is the result of the solution to the unit commitment optimisation problem, and it minimises the cost of production considering pre-defined technical limits. The security-constrained unit commitment problem has been defined as including the network constraints in the previously mentioned optimisation problem to obtain a feasible power system solution. The traditional security-constrained unit commitment methods are based on the DC-power flow model, where the network losses and voltage magnitudes are neglected in the problem formulation. This paper proposed a bi-stage security-constrained unit commitment with an economic dispatch (SCUCED) optimisation problem. A merit-order-based zonal day-ahead market problem is solved in the first stage to define a preliminary generation commitment. In the second stage, the SCUCED is solved based on the AC-power flow model and sensitivity factors to embed the full network representation in the optimisation problem. In this paper, the proposed method is illustrated by an application to a modified version of the IEEE 39-bus test system. ... Read more