Application of single-phase three-wire transformer model in distribution network with solar home system

As solar home systems are concentrated in distribution network in residential areas, the voltage of connection points rises according to the reverse power flow when the demand of load is less than power generation out-put. When single- phase three-wire power distribution transformer (method) is applied to low-voltage distribution network, power flow calculation becomes the major approach to perform quantitative analysis. We looked for a method of analysis in which the high-voltage systems and the low-voltage single-phase three-wire systems are unified for calculating power flow. The first step is setting up a single-phase three-wire transformer model. This paper presents a new model of single-phase three-wire transformer using the indication method between nodes. Meanwhile this paper also gives the model´s nodal transform matrix for calculating power flow. Using this model we can solve the problem of power flow calculation by using conventional power- flow-calculation methods when high-voltage and low-voltage with single-phase three-wire distribution systems are intermingled. The results also can reflect the voltage characteristics of connection points when injecting effective power into node from solar home systems. Using this new model we computed an example and analyzed the result. When solar home systems are connected in single-phase three-wire low-voltage distribution network, changing the power generation out-put, the voltage characteristics of connection points are consistent with theoretical analyses. The example shows that the model is feasible for calculating power flow of low-voltage single-phase three-wire systems with solar home system.