## Low Voltage Control Tool  
### Proposed Framework  
The LVC tool performs the active management of an LV network recurring to two main resource types:  
* DSO-owned resources, such as OLTC transformers and energy storage devices, and
* Privately-owned resources, in this case private consumers willing to participate in grid operation through demand response schemes.  
It is assumed that the private consumers willing to participate in grid operation have installed a HEMS [25]. The HEMS is a local controller, installed at the private consumer household, that is simultaneously responsible for the optimization of the consumption of the household itself, and the calculation of the flexibility available for the different periods of the day, that can be exploited by the DSO to perform the active management of the LV network. Therefore, the HEMS acts as an interface between the LVC tool and the consumer's appliances, communicating to the DSO the flexibility available in the household for a certain period ahead, and receiving eventual consumption change set-points that might be requested by the DSO. The interaction between the DSO and the private consumers willing participate into grid operation is performed through a type of neutral access platform, called grid and market hub (GM-Hub), responsible for collecting all the flexibility offers from the consumers and making them available to the DSO [26]. Furthermore, the GM-Hub is also responsible for receiving the control actions from the DSO (flexibility activation requests), and communicating them to the private consumers.  
The LVC tool operates in two main timescales:  
* Preventive scale (typically one day ahead), and
* Quasi-real-time scale (typically 15 min ahead).  
In the preventive stage, the algorithm requires forecasts of generation, load and flexibility available provided by the private consumers in order to determine a preventive control action to apply to the LV network controllable resources [27; 28]. The control actions produced by the preventive control module are communicated to the DSO, for validation purposes that then can accept or perform changes to the control action determined by the LVC algorithm. In real-time the algorithm uses a state estimation algorithm, the Low Voltage State Estimator (LVSE), to obtain a snapshot of the network in real-time recurring to a subset of the smart meters measurements available in the network [29; 30]. It is important to highlight the requirement for the usage of a LVSE algorithm for the operationalization of the proposed management scheme, since current AMI solutions are unable to provide accurate synchronized real-time measurements in useful time in order to enable the management of the LV network in real-time. The main objective of the real-time control module is to assess the actual network conditions registered in real-time, and compare them to the conditions that were forecasted in the preventive stage. If these significantly differ, the control action is updated accordingly, and the new set-points (control action) are generated and submitted to the validation platform. Therefore, the real-time control module of the LVC tool has a corrective character, acting solely if the network conditions significantly differ from what was forecasted. A simplified schematic of the proposed framework is shown in Figure 1.  
Figure 1: Proposed framework for the Low Voltage Control (LVC).