To maintain the current safety standards expected within power grids whilst incorporating new functionalities, such as distributed power generation, an increase in the precision of control and sensing devices is needed. A critical element for achieving this goal is the incorporation of phasor measurement units (PMUs) across the grid. However, the greater precision offered by PMUs is dependent on all them being synchronised to the same time source. This could be achieve through civilian GNSS time signals, however these are easily jammed. An adversary could exploit this vulnerability to manipulate or delay PMU measurements that are used in state estimation (SE) calculations, which estimate the current state of the power grid. The consequence of injecting malicious data in the SE calculation have been studied in depth, but less attention has been given to the attack vectors that could be used for their introduction. There has been some attention paid to how the manipulation of an individual PMU’s data can be used to facilitate a SE attack, but none has be given to the phasor data concentrators (PDC), the intermediate device which aggregates the PMU measurements before they are used in SE calculations. This paper presents an initial result that shows how a PDC can be utilised to lessen the chances that an adversary can successfully implement a SE attack, through the proposal of a PDC re-transmission algorithm. The proposal shows how a PDC can integrate the retransmission of data that it has discerned as corrupted or maliciously delayed. The proposal is formalised in applied \(\pi \) -calculus.