## 1 Introduction  
In contemporary world, undergoing drastic development of the energy internet and increasing connection of energy sources such as electricity, gas and heat, the clean and efficient use of energy has gradually become the focus of attention [1; 2]. The transformation and upgrading of traditional energy systems are imminent, therefore, the RIES has emerged as the times require [3]. The RIES is a typical energy internet based on a multi-energy complementary structure, which combines various ways of energy supply, such as electric power, photovoltaic energy, wind energy, nature gas and other types of energy to provide users with gas, heat and electricity at a higher overall system energy efficiency [4]. The electricity sectors and heat sectors are interconnected by technologies such as combined heat and power (CHP), the electric heat pump (HP), and electric boiler (EB), and they have been recently recognized as prominent examples for creating add-on values for both sectors [5; 6]. CHP [7] and EB [8] were adopted to solve the problem of wind power consumption and environmental pollution, however, the varieties of energy contained in above studies were limited. The gradually mature power to gas (P2G) technology has enhanced the integration between power and gas networks, providing new ideas for the consumption of wind power and photovoltaic power in the RIES [9]. In [10], a joint schedulingmodel of P2G and thermal-electric decoupling CHP was proposed for the integrated energy microgrid system and the results show that P2G can greatly improve the wind abandonment phenomenon. The Implementation Opinions on Promoting the Construction of Multi-energy Complementary Integration Optimization Demonstration Project issued by the National Energy Administration [11] also pointed out that energy complementarity and coordinated supply should be realized through electric heating triple supply and distributed renewable energy. Therefore, the research on RIES has important practical significance, and the RIES planning is the basis for efficient, economical and reliable operation of the system. The research of RIES planning is mainly divided into two categories [12]: (1) The structure of RIES is known to optimize the capacity or model of the system equipment; (2) optimizing the system structure and capacity or model of the RIES at the same time, that is the initial planning from scratch. The main difficulties in RIES planning are summarized as four parts [13]: Multi-energy coupling modeling, multiple load forecasting, technical economic assessment and planning optimization model solving. Optimal planning of RIES has been previously studied and some attention-grabbing planning models have been proposed. [PERSON], [PERSON] et al. [14] proposed the robust planning method for RIES considering multi-energy load uncertainties. [PERSON], [PERSON] et al. [15] proposed the expansion planning method for RIES considering the uncertainty of wind power. [PERSON], [PERSON] et al. [16] put forward a planning model incorporating demand response and thermo-electrical coupling. Those models are essentially a mixed-integer no-linear programming (MINLP) problem, and the classical convex optimization algorithm is difficult to solve directly. The current solutions are mainly divided into two categories: One is to approximate the optimization model to a linear problem by simplification, which can be solved with optimizer, such as CPLEX [17]; the other is to use intelligent algorithms, such as particle swarm optimization, and genetic algorithms [18]. The energy storage system has played an important role in improving the operation efficiency and economy of RIES, but the study on configuration of the energy storage system is ignored in these papers. Moreover, most of the research on energy storage is based on battery models, while less research involves thermal storage and gas storage equipment [19].