## 1 Introduction  
Electrical energy in Puerto Rico has been mainly produced using imported fossil fuels. For the fiscal year of 2020, petroleum-based power plants supplied almost half of the total power generation, while coal-based power plants supplied 29%, and renewable energies only supplied 2.5% [1]. The Puerto Rico Electric Power Authority (PREPA) is aimed to increase renewable energy penetration to 40% by 2025, 60% by 2040, and 100% by 2050 [2]. Particularly, solar energy is the renewable resource that has grown the most with an increase in supply from 0.3% in 2015 to 1.4% in 2020 [3]. Additionally, PREPA is aimed to add up 2740 MW and 1440 MW in solar power and batteries, respectively in the following years [4]. Due to the inherent stochastic nature of solar irradiance, factors such as frequency and voltage stability of a converter-dominated power system (CDPS) may be critically affected on cloudy days. To overcome this issue, some local power authorities across the world have imposed solar power plants to include power ramp-rate control (PRRC) methods in their power injection controllers. A maximum power ramp-rate (PRR) of 10% of the contracted power capacity per minute is allowed in Germany, whereas Hawaii, Ireland, and Denmark allow a maximum PRR of 2 MW/min, 30 MW/min, and 100 kW/s respectively [5, 6]. The Puerto Rico Energy Bureau (PREB) has developed a regulation on renewable energy development--including its registration and operation--as a strategy for rebuildingand strengthening the electric power system. The Bureau's purpose is to increase the local renewable energy generation and provide a regulatory framework for the implementation of renewable energy across the island. One of the most important requirements described in the regulation is the Power Purchase and Operation Agreement (PPOA) or electric power contract. The PPOA is a document that establishes an energy contract between two parties (the seller and the buyer). This contract contains mutual obligations between the parts involved in the power sale, that governs the rights and duties of the parties [7]. One of the most important requirements for third-party photovoltaic (PV) power plants stipulated in the PPOA is the Minimum Technical Requirements for the Interconnection of Photovoltaic Installations (MTR). MTRs are mandatory requirements that the third-party seller must meet to help the main grid in case of contingencies. In the MTR, the ramp rate requirement is addressed, which sets the maximum rate of change for the system's output power. This maximum rate applies for both, increasing and decreasing the output power with a requirement of 10% of the contracted capacity. Additionally, the current MTR requires the third-party systems to be able to deliver 30% of their measured AC capacity for at least 25 min using their storage units [8]. To fulfill PRR requirements and smooth power fluctuations, large-scale solar power plants (LSSPP) rely on the use of energy storage systems (ESS). The state-of-charge (SOC), the output power Pout, and the depth-of-discharge (DoD) of the ESS through a day may vary drastically depending on the PRRC method and the type of battery used. These factors directly impact battery degradation and the levelized cost of storage (LCOS) [9; 10; 11]. Thus, LSSPP may incur extra costs in ESS depending on the implemented PRRC method. The ramp-saturation (RS) is the simplest PRRC method [12; 13]. In this method, the battery absorbs or injects power when the PRR at the point of interconnection (POI) exceeds the requirement. The Simple Moving Average (SMA) and the Exponential Moving Average (EMA) are also two popular methods due to their low computational cost and ease of implementation [14; 15; 16; 17]. However, the RS, MA, and EMA methods require a large ESS storage capacity [13; 18; 19]. This implies an increase in costs and battery degradation.