计及主变上层油温约束的受端电网转供优化模型

A Power Transfer Optimization Model of Receiving-End Power Systems Considering Transformer Top-Oil Temperature Constraints

为实现迎峰度夏期间高温、重载主变的主动防护和控制,该文提出一种计及主变上层油温约束的受端电网转供优化模型。首先分析自然天气条件下主变上层油温的等效热模型及热阻参数计算式,在此基础上建立人工降温措施下变压器上层油温的等效热模型,并推导了当前运行点主变油温变化量的线性化方程;再将主变上层油温与负荷的关系曲线分段线性化,构建不同降温措施下主变上层油温的线性化约束;结合主变上层油温、有功功率平衡和电网辐射型结构等约束,以电网运行方式调整的开关动作次数最少为目标,提出计及主变上层油温约束的受端电网转供优化模型。该模型为二次整数规划问题,采用CPLEX工具箱进行求解。最后,通过某实际220k V/110k V受端电网进行仿真分析,验证了文中模型的有效性。

To achieve the active protection and control of transformers under heavy load and high temperature conditions, this paper proposed an optimization model for power transfer of receiving-end power system in consideration of top-oil temperature constraints of transformers. Firstly, the equivalent thermal model and its thermal resistance for the top-oil temperature of transformer in natural conditions were studied. On this basis, the thermal model for the top-oil temperature of transformer in artificial cooling conditions was constructed, and the linearized equation of the variation of top-oil temperature under a certain operation point was derived. The linear constraints of top-oil temperature of transformer under different cooling conditions were developed based on the piecewise linearization for the relationship between top-oil temperature and load of transformer. And then a power transfer optimization model was proposed in the constraints of top-oil temperature, active power balance and radial grid structure, for the objective function of minimum switching number. The model is an integer quartic programming problem, so CPLEX tools were used for solving. Finally, a 220kV/110kV receiving-end power system was used for simulating and verifying that the proposed model was effective.