【作者】 张晓慧；

【导师】 张化光；

【作者基本信息】 东北大学 ， 电力电子与电力传动， 2009， 硕士

【摘要】 电网无功优化可以有效地降低电能在电网中传输和分配过程中能量损耗,明显改善电压质量,提高系统稳定性,节约能源。因此,研究地区电网无功优化问题具有十分重要的意义。潮流计算是电力系统规划设计与运行分析的基本工具,是无功优化最基础的计算工具,本文的任务就是研究适用于地区电网无功优化的潮流算法。地区电网包含了高压的输电网和中低压的配电网,网络结构由环状和辐射树形网络共同构成。这种电力网络用单一的潮流算法是无法实现准确求解的,本论文就是根据地区电网的一主多从的网络结构特点,提出用交替迭代的综合计算方法求解全网的潮流,在环状输电网络中以牛顿-拉弗逊方法求解潮流分布,在辐射状配电网中用前推回代方法求解潮流分布,两种算法通过主网和从网的边界条件交换计算数据。综合算法将规模庞大的全局潮流问题分解成发输电潮流和一系列小规模的配电子网潮流问题,降低了计算规模,保证潮流计算的准确性和收敛精度,实现了全网确定值潮流问题的准确求解。为了更加准确地模拟电网的各种不确定运行状态,满足动态调节负荷和发电的要求,本文采用了负荷增量调整自适应的计算方法求解潮流对应的变化范围,该算法考虑当发电和负荷发生功率不平衡时,不是仅由平衡节点进行功率调整,而是由各发电机的联合调整,并根据已计算的定截面潮流结果,叠加由于功率不平衡而产生的电压和功率差值,提高了潮流计算软件的易用性和计算效率。本文提出的交替迭代全局综合算法和负荷增量调整自适应算法,解决了多层结构的电力网络的全局求解问题,计算结果准确地模拟的实际电力系统的运行状态,满足了无功优化对潮流计算的要求,是分析电网运行方式的理想工具。更多还原

【Abstract】 Reactive Power Optimization (RPO) of power system can effectively reduce the energy losses caused by power transmission and distribution,which can not only improve voltage quality and power system stability obviously, but also economize energy. Therefore, the study of RPO of local power network is of great significance. Power flow calculation is the most fundamental tool for the planning and analysis of power system, and for RPO as well. The thesis proposes power flow calculation which is suited to RPO of local power network.Regional power network is consisted of high-voltage transmission network and middle and low-voltage distribution network, the structure of which constitutes of the transmission network in form of rings and the distribution network in form of trees. The complex network structure cannot be calculated accurately with this single flow algorithm. With regard to the master and slaves network structure, the thesis proposes the comprehensive method of alternative and iterative algorithm to calculate power flow of the whole network. That is, Newton-Raphson algorithm is used to calculate the transmission network power flow, and forward/back sweep method is used to calculate the subordinate power flow in the distribution network. The two algorithms exchange data through the boundary conditions between the principal and subordinate networks. The large-scale problem of GPFC is divided into a transmission power flow and a series of small-scale distribution network power flows with the application of the alternative and iterative algorithm in calculation. Hence the calculation scale can be reduced, and the accuracy and convergence precision can be guaranteed, and the accurate calculation of the fixed flow of global network can be achieved.In order to simulate the unsure operation status of the true network exactly and to meet the requirement of load regulation and power dynamically, the thesis adopts the auto adaptive method of load increment adjustment to obtain the varying range in accordance with the power flow, the method demonstrate that imbalance power was adjusted by all generator of power net, and was not only balanced by balance node, which add the mismatch value of voltage and power owing to imbalance power on fixed calculation result, therefore the method increases the efficiency and convenience of the calculation software.As mentioned above, the methods of both alternative and iterative algorithm and the auto adaptive load increment adjustment solve the overall problem of the multi-storey power network flow, and the calculation results accurately simulate the operation situation of the realistic power system and meet the requirement of RPO as well. Therefore, the two methods are the ideal tools to analyse the operation mode of power networks.更多还原