# Dispatchable Substation for Operation and Control of Renewable Energy Resources  
[PERSON]  
1 School of Electrical Engineering, Korea University, 145 Anam-ro, Songbuk-gu, Seoul 02841, Korea; [EMAIL_ADDRESS] (Y.Y. ); [EMAIL_ADDRESS] (S.K. ); [EMAIL_ADDRESS] (J.L. ); [EMAIL_ADDRESS] (C.H.) [PERSON]  
2 School of Electrical Engineering, Hanbat National University, Dongseo-daero, Yuseong-gu, Daejeon 34158, Korea; [EMAIL_ADDRESS] 2  
[PERSON]  
1 School of Electrical Engineering, Korea University, 145 Anam-ro, Songbuk-gu, Seoul 02841, Korea; [EMAIL_ADDRESS] (Y.Y. ); [EMAIL_ADDRESS] (S.K. ); [EMAIL_ADDRESS] (J.L. ); [EMAIL_ADDRESS] (C.H.) [PERSON]  
1 School of Electrical Engineering, Korea University, 145 Anam-ro, Songbuk-gu, Seoul 02841, Korea; [EMAIL_ADDRESS] (Y.Y. ); kswvoice@korea. inherently contribute to the stability of the network. Numerous studies have been conducted and countermeasures have been adopted for the stable operation of a power system with high levels of renewable energy penetration. The most reliable and fundamental solution for this problem is to increase the proportion of synchronous generators or other devices that can suitably replace synchronous generators. Energy storage systems (ESSs), or synchronous condensers, are considered to be good alternatives for synchronous generators. Pumped storage hydroelectricity generators or batteries can absorb or supply active power to the network, while synchronous condensers can increase the overall inertia of the network and enhance the voltage stability. The response of a battery energy storage system is sufficiently fast to support the frequency response of a network with properly designed controllers. However, the capital costs of these devices hinder the realization of the required capacity for a power system. In a case where countermeasures are insufficient, a grid operator needs to limit or curtail generation from renewable generators directly. As the cost of renewable generation continues to decrease and with the increase in penetration, several TSOs have started adopting constraints or curtailment of renewable generation at a daily or hourly basis. In previous research, ref [4] proved that forecast information can be utilized to make renewable generators dispatchable, similar to conventional generators. The Midcontinent Independent System Operator (MISO) uses an interconnection tool to operate PV and wind turbines as dispatchable intermittent resources (DIRs) based on the forecast information obtained every 5 min. It is expected that more TSOs or power systems will consider renewable sources as DIRs, as their penetration into their network continues to increase. To realize the dispatchability of intermittent resources, the forecast information must be accurate. Depending on the reliability of the forecast information, the addition of ESSs is feasible if the amount of erroneous forecast becomes significant. Typically, TSOs design an appropriate range of do-not-exceed (DNE) limits of DIR to improve the accuracy of the forecast information. The DNE limits and dispatch signal can be applied to individual renewable energy source (RES) units or managed centrally at the plant level in case of large wind farms. Hierarchically managing the unpredictability of RES can be beneficial for both TSOs and renewable generators, because fluctuations caused by a large group of renewable generators would be more stable than a single unit's output [5]. Dispatching of DIRs can, therefore, be more efficient if multiple wind or PV farms are clustered together and made to work as a single generator unit. This can be accomplished at the substation level by adding ESSs and other auxiliary devices for more grid-supporting features. In the cases of small distributed renewable sources, such as rooftop solar panels, these requirements such as DNE or curtailment order by TSOs are difficult to realize and may not be obligated in order to promote installation of distributed renewable sources by government policies.