## 1 Introduction  
The world energy demand has been increasing exponentially while conventional energy resources are exhaustible and limited in supply. Therefore, there is an urgent need to conserve the energy resources that are at hand and explore alternative energy resources. Among the various types of renewable energy sources (RESs), solar and wind energies are the most promising sources. Recently, the use of RESs in the form of distributed generators (DGs) and distributed energy systems (DESs) [1] has increased with the aim of an environmentally-friendly society. Moreover, these DGs can supply energy in an isolated situation [2; 3; 4]. However, RESs output is influenced by weather uncertainty, causing voltage deviation, fluctuation and reverse power flow under a high penetration of DGs using RESs [5]. The conventional provisional method for voltage fluctuation is often handled by the use of an on-load tap changer (OLTC) transformer such as the load ratio transformer (LRT) and the step voltage regulator (SVR). This method is only effective for slow changes in voltage by switching the primary and secondary winding ratios of the transformer. Thus, this method cannot maintain the voltage well because steep voltage fluctuations are the nature of the DGs. In addition, voltage regulation by OLTC has not reached a fundamental solution for power quality considering the power factor. As a countermeasure to this problem, the use of reactive power controllers, such as additional static VAR compensators (SVCs) [6; 7; 8; 9; 10; 11] or the reactive power control system by the inclusion of an inverter with distributed generators [12; 13; 14; 15; 16; 17; 18] has been proposed. The literature [19] has discussed rapid and precise tap control online. Another proposed reactive power control improves voltage maintenance and the utilization rate of equipment of the system, which is utilizing the empty area of inverter capacity of an interfaced inverter of an RES generator and battery energy storage system (BESS) [20]. Thus, reactive power compensation methods can be categorized into two types, which are the use of devices at the distribution company (DisCo) side or utilizing the customer side inverter. In particular, using an introduced large capacity BESS at the substation and reactive power output from customer DGs avoids reverse power flow and voltage fluctuation. An increase in demand and a massive installation of RES with uncertainty frequently causes an imbalance in the power system within hours. It is essential to improve forecasting techniques to solve the imbalance of demand and supply, but prediction accuracy cannot always be raised to 100%. Thus, in order to resolve power imbalance with RESs, the BESS has been installed and operated based on optimal scheduling in several areas. Scheduling of the distribution system has been proposed in much of the literature [21; 22; 23; 24]. In addition, power quality such as the power factor has been improved by the reactive power control method using an interfaced inverter of BESS. The BESS can be introduced to the power system to compensate for power quality loss and fluctuations in voltage and frequency [25; 26]. With the increase in the expectation of battery utilization to overcome all variations of RES output, the introduction cost becomes large, and the battery has to be introduced into various places according to DG load points. With the increase of batteries, the cost of the interfaced inverter tends to increase. In this trade-off relationship, it is required to optimize the capacity or capacity reduction of the storage battery. Along with the limitation of control from the upper system, hence, it is proposed to obtain the balance that is controlling and regulating a load demand as the demand response (DR) [27], and the non-cooperative game has been analyzed in the literature [28].