Hydro one distribution voltage performance design criteria and power distance test in enabling distributed generation

Constraint models of voltage fluctuation limit on OLTC/SVR caused by DG power fluctuation and generator disconnection to assess their impacts on DG penetration limit

“…This mode enables DG to have more space to satisfy voltage fluctuation constraints. Generally, DG should operate within a reasonable range limit of power factor [22]. According to the relationship between power angle and power factor, there is also a reasonable range limit of power angle.…”

“…However, the voltage fluctuation limit on on-load tap changer (OLTC)/stepvoltage regulator (SVR) resulting from DG power short-term variation, an indirect effect of DG power fluctuation on DG hosting capacity, has been rarely discussed by most DG capacity assessment studies. The propagation of voltage fluctuation resulted from DG power fluctuation could trigger excessive actions of a transformer with OLTC or a feeder SVR [22]. This potential should be avoided because overmuch tap changer hunting will reduce the tap changers' life and increase their maintenance cost [23].…”

“…These two factors are the important practical operating constraints concerned by electrical utility companies [22,24], and the lack of both factors in DG hosting limit assessment could result in oversized DG capacities. Therefore, DNOs established corresponding criteria for DG connection planning to ensure that the normal operation is not affected by these two problems [22,25]. The establishment of these criteria provides foundations for assessing the impact of voltage fluctuation limit on OLTC/SVR and generator disconnection on DG penetration level.…”

“…An analytical method was presented in [22,24] to analyse such impact. However, their determined results are conservative due to the simplicity of the analytical constraint model of voltage fluctuation limit on OLTC/SVR and DG disconnection.…”

“…In this paper, the constraint models of voltage fluctuation limit on OLTC/SVR caused by DG power short-term variation and DG disconnection are proposed, which can be employed to assess their impact on DG penetration limit. According to the practical criteria established by Hydro One Networks of Canada [22], a simply OPF methodology is built and applied to the practical feeder systems, to demonstrate the huge advantages of the proposed models in exploiting the headroom of DG hosting capacity.…”