基于去中心化交易模式的充电站日前购电策略

电动汽车充电站大规模建设下,协调充电站的充电功率对配电网的安全经济运行具有十分重要的意义。受制于不同充电站之间的利益冲突以及实时控制技术的瓶颈,电网公司难以对充电站实行集中管理。文中基于去中心化交易模式,提出了充电站参与日前电力市场的购电策略。首先,借助区块链存储技术,设计了适用于充电站日前购电协议的智能合约。然后,采用二阶锥规划求解交流最优潮流模型得到不同时间配电网各节点用电的边际成本,并以此为潮流运行点构建线性化阻塞管理模型,从而得到配电网节点边际电价。最后,考虑电动汽车的停泊特性,以购电成本最小为目标建立了充电站分散式优化调度模型并根据价格信号分散求解。在IEEE 33节点配电网系统中进行了充电站购电策略仿真,仿真结果表明,所提出的充电站日前购电策略能实现分散式调度,改善了配电网的潮流分布;同时,节点边际电价能够作为公平的价格信号引导充电站有序充电,在保证配电网安全经济运行的同时降低充电站的购电成本,提高充电机的利用率。

Day-ahead Electricity Purchasing Strategy of Charging Station Based on Decentralized Trading Mode

It is very important to coordinate charging power of charging station(CS)for safe and economic operation of distribution network with large-scale construction of CSs. Restricted by the conflict of interests between different CSs and the bottleneck of real-time control technology, it is difficult for power grid companies to centralize the management of CSs. In this paper, a strategy for CSs to participate in the electricity market is proposed based on the decentralized trading mode. Firstly, according to the storage technology of blockchain, an intelligent contract is designed for pre-purchase protocol of CS. Then, the AC optimal power flow model is solved by second-order cone programming to obtain the marginal cost of power consumption at each bus of distribution network at different time. Based on the solution, a linearized congestion management model is established to calculate the distribution locational marginal price(DLMP). Finally, considering the parking characteristics of electric vehicles, in order to minimize the cost of electricity purchasing, a decentralized optimal dispatching model of CS is proposed and dispersedly solved according to the price signal. The simulation of power purchase strategy for CS on IEEE 33-bus distribution network system shows that the proposed strategy can achieve decentralized dispatching and optimize the power flow of the distribution network. Meanwhile, as a fair price signal, DLMP can guide CSs to charge orderly, which is able to reduce the cost of CSs and improve the utilization rate of chargers under conditions of safe and economic operation.