复杂电网下无功及谐波电流检测算法研究

当电网电压不对称、有谐波畸变、频率突变等情况下,传统的基于瞬时无功功率理论的电流检测法检测结果存在较大误差。根据Ip-Iq电流检测理论,提出一种基于复系数滤波正负序解耦网络的电流检测法,对其进行理论分析和数学建模,设计电流检测网络结构。该方法由于锁相环采用了复系数滤波正负序解耦网络,可在复杂电网情况下准确跟踪基波正序分量相序;由于电流滤波也采用了复系数滤波正负序解耦网络,滤波后的电流可以更精确的实现正负序分离。通过在电网电压不对称、有谐波畸变及频率突变三种情况下对所设计的电流检测网络进行仿真验证,结果表明了本方法的可行性和有效性。

Algorithm research of reactive and harmonic current detection under the complex power grid

The detection result of the traditional current detection method based on the instantaneous reactive power theory will produce large error when the power grid voltage is under the conditions of asymmetry , harmonic distortion and frequency discontinuity .According to the I p-I q current detection theory , a current detecting method of the positive and negative sequence decoupling network based on the complex filtering was proposed .The operation principle was analyzed , the mathematical models were built , and the current detecting network structure was designed .Because the proposed PLL used the positive and negative sequence decoupling network based on the complex filtering , this method can track the positive phase sequence of the fundamental wave under the complex power grid conditions .Meanwhile , because the current filtering also used the positive and negative sequence decoupling network that based on the com -plex filtering , the current after filtering can separate the positive and negative sequence more accurately .Simulation is done to validate the current detection network under the conditions that the power grid voltage is asymmetry , harmonic distortion , and frequency discontinuity .The results show the feasibility and effectiveness of this method .