Minimum loss operation of distribution networks with photovoltaic generation

The proliferation of photovoltaic generation in distribution networks requires assessing the control schemes that achieve minimum loss operation without requiring excessive switching of conventional equipment, for instance capacitor banks and network reconfiguration devices. Inverters associated with photovoltaic generation are traditionally operated at unity power factor; however, there is a potential to make use of their capacity to supply or absorb reactive power. The control of capacitor banks and line switches which is done on a slow time scale can be coordinated with the fast control of inverters through a multi-period optimal power flow formulation. This study shows that such a formulation can be cast as a mixed-integer linear program, whose minimum energy loss solution is guaranteed to be globally optimal. Numerical results on a distribution network with different variation patterns of load and photovoltaic generation demonstrate that the method is effective in establishing the trade-off between different combinations of minimum energy loss control schemes.