摘要
随着负荷日渐增加和新能源大量并网,柔性直流互联系统被广泛应用于实际工程。基于下垂控制策略的柔性直流互联系统能按下垂特性实现系统功率和电压的自动调节,但系统的传输容量受到换流站容量和电压质量要求的约束而难以充分利用。为此,文中提出一种基于柔性直流互联系统容量优化的自适应下垂控制策略。该策略首先增加了下垂系数修正环,在电压或功率即将越限时逐渐调节相应换流站的下垂系数,在不过容或不越限的前提下增大传输功率。此外,为了削弱下垂系数改变对原有控制造成的影响并优化系统能源消耗特性,以系统对接源储荷潮流调整率最小、发电能源耗量最少为目标建立数学模型。通过非支配排序遗传算法(non-dominated sorting in genetic algorithm, NSGA-Ⅱ)求解模型,得出各换流站的最优修正梯度。最后,使用PLECS搭建四端柔性直流互联模型,仿真验证所提策略的有效性和可行性。
With the increasing load and a large number of new energies connected to the grid,the flexible DC interconnection system is widely used.The flexible DC interconnection system based on sagging control strategy can realize automatic regulation of power and voltage according to sagging characteristics,but the transmission capacity of the system is limited by the capacities of different converter stations and requirement of voltage quality.So it is difficult to make full use of the transmission capacity of the system.An adaptive sagging control strategy for capacity optimization of flexible DC.interconnection systems is proposed in this paper.By the proposed strategy,a sagging coefficient correction loop is added to gradually adjust the sagging coefficient of the corresponding converter station when the voltage or power is close to the limit.By the correction loop,the power can continue to increase without exceeding the limit.In addition,in order to reduce the influence of droop coefficient change on the traditional control and optimize the energy consumption characteristics of the system,a mathematical model is established with the goal of minimizing the adjustment rate of the power flow and the energy consumption of the power generation of the system.Then the non-dominated sorting in genetic algorithm(NSGA-Ⅱ)is used to solve the model and the optimal correction gradient of each converter station can be obtained.Finally,PLECS is used to build a four-terminal flexible direct interconnection model which verifies the effectiveness and feasibility of the proposed strategy.
作者
张秋玥
王楚扬
张犁
ZHANG Qiuyue;WANG Chuyang;ZHANG Li(School of Electrical and Power Engineering,Hohai University,Nanjing 211100,China)
出处
《电力工程技术》
北大核心
2025年第4期90-99,共10页
Electric Power Engineering Technology
基金
国家自然科学基金资助项目(52007052)。
关键词
柔性直流互联系统
下垂控制
换流站容量
电压质量
传输容量
最优修正梯度
flexible DC interconnection system
sagging control
converter station capacity
voltage quality
power transmission capacity
optimal correction gradient
