In order to mitigate the voltage violation problems in low-voltage distribution network with large penetration of photovoltaic

a multi-mode control strategy of photovoltaic inverter is developed to optimize reactive power of photovoltaic inverter

based on which more photovoltaic generation can be accommodated. Node virtual injection of active power(NVIP)is defined through the voltage sensitivity theory

while the conversion between active and reactive power can be realized by means of voltage regulation. The operation modes of photovoltaics are divided into three kinds according to the NVIP

including overvoltage suppression

undervoltage suppression

power loss and power factor optimization. If the NVIP causes the network overvoltage(undervoltage)operational risk

risk suppression will be taken as the target to regulate the inverter reactive power; whereas

the optimization of power loss and power factor will be taken as the target. Meanwhile

in order to realize on-the-spot coordinated control

coordinated control parameters are obtained from the optimization model through voltage sensitivity matrix. The efficiency and flexibility of the proposed method are verified by the low-voltage distribution network with high density residential photovoltaics

the network power loss and power factor are also optimized.