Distributed photovoltaic research on distribution network protection mechanism

( A) The short circuit current calculation methods in the traditional distribution network, the calculation of short-circuit current method has four kinds: equivalent voltage source algorithm, superposition algorithm, the phase zero loop current method, the transient simulation algorithm. Before the three used to calculate the steady-state fault current, four to

( A) The short circuit current calculation methods in the traditional distribution network, the calculation of short-circuit current method has four kinds: equivalent voltage source algorithm, superposition algorithm, phase zero loop current algorithm and transient simulation algorithm. The first three are used to calculate the steady-state fault current, four are used to calculate the transient fault current. Distributed photovoltaic power distribution network, a great influence on the traditional distribution network: the power distribution system with multiple power supply, wires of the number of active power and reactive power and direction change. Put forward the new requirements, therefore, the protection of distribution network, at the same time in the study of distribution system protection, should be to develop a new method for short-circuit current calculation. New short-circuit current calculation method can be improved on the basis of the traditional method, and combined with the characteristics of distributed photovoltaic power generation. ( 2) Set up and configure protection principle when distributed photovoltaic power distribution network, feeder protection can be divided into the upper main feeder protection, branch feeder protection upstream and downstream of the main feeder protection and downstream branch feeder protection. Different position of feeder protection has the different effect of distributed photovoltaic power plant capacity. When a failure occurs, the failure occurred in the upstream of protection, within the scope of protection and protection of the downstream, have different impact on distribution network protection. Concrete should be according to the exact location of the fault can be implemented. In recent years, distributed photovoltaic power generation has developed rapidly. Distributed solar energy photovoltaic solar power dependence, belong to the renewable energy. The distributed power distribution network has a certain impact to the traditional distribution network protection, mainly on the reliability, sensitivity and selectivity. In order to better achieve the protection of distribution network, studied a new kind of distribution network protection mechanism, in order to ensure the normal operation of power transmission.