Research On Three-phase Unbalance Contro Method Of Rural Power Network

With the continuous development of the economy,intelligent electronic devices have become popular.These electrical devices have brought convenience to social production and have also triggered a series of power quality problems.Among many power quality problems,three-phase unbalance is the focus of power system analysis.A severe three-phase imbalance can result in damage to electrical equipment and increased system losses.Therefore,reducing the three-phase imbalance is particularly important for improving the stability of the power system.The most common method for reducing the three-phase imbalance of the system is the commutation technique.Traditional commutation techniques mainly include genetic algorithms and particle swarm optimization algorithms,but these two methods have certain complexity and locality.Therefore,this thesis proposes a three-phase unbalance control strategy to reduce the three-phase imbalance of the rural network.The method mainly adjusts the power load to ensure that the user load is evenly distributed among the three phases A,B and C.Finally,the effectiveness of the method is verified by a case study.The main work of the thesis is summarized as follows:(1)The rural network commutation device was designed to reduce the three-phase unbalance of the system.According to the three-phase current unbalance degree,the discriminating condition of the three-phase power imbalance is derived,and the switching mode of the commutating switch between the three phases is controlled by the final commutation command of the three-phase control strategy,thereby suppressing the three-phase unbalance,in line with the corresponding national standards.(2)A three-phase unbalance strategy based on load forecasting is proposed to reduce the three-phase unbalance in the rural network.First,the method combines the multi-objective function with the control strategy to obtain the optimal solution of the function.Secondly,the overall and local control methods are used to reduce the three-phase unbalance of the system.Finally,an example analysis shows that the control strategy can effectively reduce the three-phase unbalance of the rural network.