Implementation of a centralised voltage control experiment in presence of distributed generation in ERDF's MV network

SUMMARY The penetration of distributed generation (DG) in t he French electric system has widely increased in the last years, with PV panels and wind farms conne ctions to the Medium and Low voltage networks, either on dedicated MV feeders or to the existing n etwork (MV and LV feeders with a mix of both load and generation). In the latter case, the volta ge profiles along feeders are impacted leading to voltage rise issues, mainly in rural networks domin ated by long overhead lines with a low consumption level. To be able to face these impacts , ERDF (French Distribution Network Operator) envisages to implement a centralized Voltage Control Function (VCF) which adjusts the voltage profiles in real-time. As described in the paper, t he experimentation of such control function in a zo ne of ERDF’s network is a first step before its deploy ment. The centralized control function requires a cost ef ficient instrumentation of the MV network which enables an assessment in near to real time of the v oltage profiles along MV feeders. The accuracy of instrumentation is critical for the efficiency of t he voltage control algorithms, while synchronizatio n of the measurements retrieval is compulsory for the “n ear to real time” state estimation on which the voltage algorithms rely. The distribution network s tate estimation function and the voltage control functions will be implemented in the control center tools of ERDF. The voltage management approach determines a voltage control set point at the MV busbar of HV/MV substations in order to keep all voltages in the MV and LV networks within statutory limits: such control signal is sent from the SCADA system to HV/MV substation RTUs. This control can be considered as a secondary voltage control. The auto matic mode of HV/MV transformers’ on-load tap changers will then keep the MV busbar voltage near this voltage reference: this local control can be considered as a primary voltage control. This paper describes centralized voltage control solution which will be experimented in ERDF’s MV network. The different equipments’ requirements for the implementation of this centralized control function are discussed: • Sensor’s number and position in the network, sensor s’ accuracy • RTUs’ functionalities • Communication requirements Then, the paper illustrates how the function is pla nned to be integrated with the existing SCADA system of ERDF distribution control centers. Such a rchitecture shall be flexible enough to enable efficient functional evolutions management on both sides (SCADA & VCF). Moreover the VCF design shall allow its operation in different Contr ol system modes (real time operation, simulation, etc).