基于对角加边模型和最优乘子法的冷热电联供园区微网能量流计算

Energy Flow Calculation of CCHP Campus Micro-grid Based on Block Bordered-diagonal Form Model and Optimal Multiplier Method

由于冷热电联供(combined cooling heating and power,CCHP)园区微网中各个能源网间存在复杂的耦合关系,大大增加了微网能量流计算问题的规模和复杂度。提出了基于对角加边模型(blockbordered-diagonalform,BBDF)和最优乘子法的CCHP园区微网能量流算法。首先对CCHP园区微网进行了详细建模,并针对能源站的不同运行模式建立了相应的输出功率模型,在此基础上建立了计及多种能源网交替耦合的能量流计算模型。通过对统一迭代法的修正方程组进行优化改进,提出了基于BBDF的CCHP园区微网能量流解耦计算方法。在每次迭代中,求出耦合变量的修正量后,再独立求出供冷/热/电网相关变量的修正量。并且应用最优乘子法计算每次迭代的最优修正步长,以减少计算迭代次数,提高收敛性。算例计算结果表明,所提出的算法可明显提高运算效率,改善收敛性,相较于传统的统一迭代算法能减少约60%的计算耗时。

Due to the complex coupling relationship among different energy sub-networks in the combined cooling heating and power(CCHP)campus micro-grid,the scale and complexity of its energy flow calculation are greatly increased.A novel method based on block bordered-diagonal form(BBDF)and optimal multiplier model for the energy flow calculation of CCHP campus micro-grid is proposed.Firstly,the detailed modeling of the CCHP micro-grid is performed and the power output models of the energy station are established according to its different operation states.And the energy flow calculation model is established,which includes the alternating coupling among various energy sub-networks.Secondly,the correction equations of the traditional integrated iterative algorithm are improved,and a new decoupling algorithm based on the BBDF is proposed to solve the energy flow calculation.In each iteration of the proposed algorithm,after the corrections of coupling variables are calculated,the corrections of related variables of cooling/heating/power supply networks can be calculated independently.In addition,the optimal multiplier method is applied to calculate the optimal modified step size of each iteration to reduce the number of iterations and improve the convergence.The calculation results show that the proposed algorithm can significantly improve the efficiency and convergence.Compared with the traditional integrated iterative algorithm,it can reduce the computational time by about 60%.