# Parameterized Modeling and Planning of Distributed Energy Storage in Active Distribution Networks
## 1 Introduction
For instance, low cycle efficiency will increase the cost of effective output power; and a low cycle life adds to the total cost owing to high-frequency equipment updates. A single type of energy storage device has its unique advantages, but it is difficult to incorporate high efficiency, long life, and many other requirements in one device. Therefore, coordinated planning of multiple types of energy storage systems can adequately cover the potential technical advantages of various DES, and meet the demand for energy storage performance in distribution networks. On the other hand, with the development of DES, the cost of energy storage systems will be significantly reduced, and the economic benefits in distribution networks will become more promising. For the reason that the cost of different DES types varies enormously, it is necessary to compare the costs of different types of energy storage in different scenarios and choose the optimal DES selection to maximize economic benefits. However, the quantization parameters of DES are complicated and challenging to parameterize, and it will increase the difficulty of the calculation due to the parameter multiplication of various DES types. In summary, there is a need to propose a parameterized model, which can transform the efficiency, life cycle, and other characteristics of multiple DES types into parameterized representation. The parameterized model will provide a quantitative description for different typed of DES, making it possible to scientifically and comprehensively consider the specific characteristics of different DES types in optimal planning. This paper proposes a parameterized model for optimal DES planning in ADNs. The main contributions are summarized as follows:  
1. The economic and technical characteristics of DES are comprehensively categorized and analyzed. Then, the influences of DES characteristics on the operation and planning are also considered to provide a parameterized modeling for DES planning in ADNs. 2. An optimal planning model of DES considering parameterized characteristics of DES is proposed in this paper. The proposed model considers multiple types of DES, which can solve the problem with coordinated planning. By applying the convex relaxation technique and introducingthe relevant auxiliary variables, the proposed model is transformed into an effectively solved mixed-integer second-order cone programming (MISOCP) model. The remainder of this paper is organized as follows. In Section 2, a set of parameterized data is defined to apply in DES planning in ADNs. In Section 3, considering two different application scenarios for DES, the parameterized modeling of DES planning in ADNs is proposed. Section 4 proposes the method that transforms the original model into an effectively solved mixed-integer second-order cone programming (MISOCP) model. In Section 5, numerical results on the modified IEEE 33-node system and modified IEEE 123-node system demonstrate the effectiveness of the proposed method, and the effects of DES are evaluated by two evaluation indexes. Finally, conclusions are drawn in Section 6.