三相异步发电独立电力系统不对称稳态运行分析

Steady-state analysis for isolated three-phase induction generator system with asymmetric loads

建立了三角形接法鼠笼式异步发电机三相负载不对称时独立系统的数学模型,对该独立系统中各电量之间的关系进行分析,计算发电机三相输出电压及绕组电流大小。基于对称分量法,推导出发电机侧正序和负序等效电路,并求出三角形连接的负载侧序电压与序电流之间的关系,进而得出满足发电机稳态运行要求的目标函数,省去了复杂的电路分析。针对稳态运行方程的非线性及复杂性,采用优化算法求解出系统的频率和正序电抗,并以此为基础计算系统的稳态电压值。计算值与实测值吻合度较高,表明所提目标函数的正确性以及所采用优化算法的准确性和有效性。

A mathematical model is established for an isolated system of delta-connected squirrel-cage induction generator with three-phase asymmetric loads,the relationship among its electric variables is analyzed and its three-phase output voltages and winding currents are calculated. The generator-side positiveand negative-sequence equivalent circuits are derived based on the symmetrical component method,the relationship between the sequence voltage and sequence current of delta-connected load side is built and the objective function for satisfying the steady-state operation of generator is derived without complex circuitry analysis. Aiming at the nonlinearity and complexity of the steady-state operation equations,an optimization algorithm is applied to solve the frequency and positive-sequence reactance of system,based on which the steady-state voltage of system is calculated. The better conformity between calculative and measured data verifies the validity and accuracy of the proposed objective function and the applied optimization algorithm.