A coordinated dispatch method with pumped-storage and battery-storage for compensating the variation of wind power

Li et al. Protection and Control of Modern Power Systems (2018) 3:2 DOI 10.1186/s41601-017-0074-9 ORIGINAL RESEARCH Protection and Control of Modern Power Systems Open Access A coordinated dispatch method with pumped-storage and battery-storage for compensating the variation of wind power Jinghua Li*, Sai Wang, Liu Ye and Jiakun Fang Abstract Growing penetration of wind power challenges to power system security, since the conventional generators may not have sufficient capacity to compensate wind power fluctuation plus the reverse peak regulation. In this paper, the high-capacity pumped-storage and fast-response battery-storage are coordinated to compensate the variation of both wind power and load, aiming at shifting peak load, responding to wind power ramping, reducing the curtailment of wind and stabilizing the output of thermal units. A practical framework is designed for optimizing the operation of the hybrid system consisting of the wind, pumped-storage, and battery storage, which can take full advantages of pumped-storage and battery-storage. The detailed mathematical formulations of the pumpedstorage and battery-storage are built. Three cases are studied to demonstrate the advantages of the proposed coordination method. Keywords: Pumped-storage, Battery-storage, Hybrid energy system, Economic dispatch, Renewable energy 1 Introduction With the large-scale wind power grid integration, shifting peak load and responding to the wind power variations become challenging problems. Limited by the adjustable level and ramping rate, the conventional units may not have sufficient capacity to deal with these problems. Storage systems provide an effective way to settle both problems because they can quickly balance the power. However, the utilization of most storage systems is barricaded by the techno-economical feasibilities [1]. For example, compressed-air energy storage [2] and spinning flywheel are considerably complex in practice; the cost of large-scale ultra-capacitors is expensive. Pumped-storage and battery-storage are two most mature and widespread technologies used in practice [3, 4]. Pumped-storage is viewed as the most suitable storage technology to improve the wind power integration for its large capacity [5]. Various techniques have been developed to combine the wind and pumped-storage. Some techniques aim to achieve maximum profit in electrical markets by using pumped-storage as an ancillary service for balancing wind power and consumption * Correspondence: Guangxi University, Nanning, GuangXi, China [6, 7]. Pumped-storage has proved to bring considerable profits as ancillary service in the electrical market. In recent years, with the increasing integration of the renewable sources, pumped-storage plays an important role in keeping the security of power system by balancing the variations of renewable sources. It is used to balance renewable sources variations for islanded grids in [8–10]. The detailed mathematical model combing wind power and pumped-storage has been proposed in [8, 9], and the operation strategy for hybrid wind-pumped storage has been investigated in [10]. [8–10] have provided valuable experiences in wind-pumped coordination in islanded grid. Later, the pumped-storage system is used for a large system in [11]. The effective control methods to accommodate the wind power uncertainty and ensure the system security are investigated in [11]. The Pumped-storage system shows good performances on accommodating the variability of the wind power. Battery-storage is another kind of storage that has been widely used [12, 13]. It can be flexibly installed in every bus of grid and response to power requirement quickly in seconds. Battery-storage is widely used in the load leveling [14], frequency controlling [15], spinning reserves [16], compensating for generation variations [17] and smoothing © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Li et al. Protection and Control of Modern Power Systems (2018) 3:2 the wind power output [18]. These literatures give good examples for applications of battery in micro-grid. Although there exist many methods and technologies for using pumped-storage or battery-storage to accommodate the wind power variability. However, most literatures are the independent studies of pumped-storage [19, 20] or battery-storage [21, 22], the two together are studied less. Reference [23] proposes a new method for weekly scheduling operating patterns of combining pumped-storage and battery-storage. However, the operating characteristics of pumped-storage and batterystorage, nodal power balance, system security are not considered, which will enlarge the deviation between the dispatch schedule and actual operation. This paper investigates the optimal coordination of pumped-storage and battery-storage considering the characteristics of pumped-storage and battery-storage. The proposed method focuses on shaving peak load, reducing the curtailment of the wind power, stabilizing the output of thermal units and responding to the high ramping events of the wind power. The main contributions of this paper are as following:
A practical framework is designed for optimal operation of wind-pumped storage-battery storage hybrid system, which can take advantages of pumped-storage and battery-storage.
The proposed framework can improve the computational efficiency. It’s not easy to solve the dispatch model, because it includes large scale mix variables and nonlinear constraints [24, 25]. This proposed operation framework not only reduces the scale of variables and constraints, but also limits the start-stop times of the thermal units in Intra-Day dispatching.
A security-constrained optimal dispatching problem of a hybrid system of wind, pumped storage, and battery storage is mathematically formulated, with the target of compensating the variation of wind power. The rest of the paper is organized as follows: Section 2 presents the method outline of the proposed approach; Section 3 presents the detailed mathematic formulation; Section 4 analyses the coordinated framework and calculation-benefit of the proposed method; Section 5 applied the proposed method to modified 6-bus system, IEEE 24-bus system, IEEE 118-bus system and concluding remarks are provided in Section 6. 2 Problem of coordinating of pumped-storage and battery-storage 2.1 Issues brought by large-scale wind power penetration The wind power is featured with uncontrollability and unpredictability [26]. Hence, as large-scale wind power Page 2 of 14 increasingly penetrates power systems, many issues ari (...truncated)