In the actual operation of pumps, regulating the rotating speed of the pump based on the affinity law through variable speed drives is deemed as a prudent and convenient approach to mitigate energy loss. However, the multistage side channel pump is composed of one centrifugal impeller at the first stage and one or more side channel structures, the applicability of affinity law to this composite structure has not been confirmed. Three schemes with different suction angles of single-stage and one multistage side channel pump were investigated under different rotating speeds through numerical and experimental analysis. The findings elucidated that the single-stage side channel pumps exhibit a proportionate relationship to the affinity law, regardless of how the geometry varies. The numerical work was validated by the comparison between the simulated result and the tested result of the multistage side channel pump under two rotating speeds. Noticeably, the entire performance of the multistage side channel pump conforms to the affinity law, which has the same phenomenon as the single-stage side channel pump. The entropy production causing dissipation of turbulence flows in each stage exhibits a similar tendency as the overall head. As a result, the vortex distribution in average time and transient moment are almost analogous in the impeller of each stage under corresponding flow points. This briefly explains composite structures could be considered as pumps in series regardless of their composition. The outcome of this research could offer a theoretical basis for energy-saving methods of side channel pumps.

Renewable sources with numerous converter-control operations introduce dynamic fault signatures in the network. Such nonhomogeneous situations result in maloperation of available phase selection methods at times, which may further lead to incorrect protection decisions and affect system resilience. In this paper, an adaptive phase selection method is proposed for lines connecting converter-based sources. Phase selection zones are formed based on the relations between faulted path sequence currents, which are unique to each fault type and remain independent of system conditions. The method uses local voltage and current data to compute an adaptive phase shift for selection zones and calculate an index based on signal availability for deriving decisions. Performance of the proposed method is evaluated on a renewable integrated 9-bus system using PSCAD/EMTDC simulation and found to be accurate and independent of converter-control operations, source types, and system conditions.

This paper presents a Digital Twin (DT)-based methodology for real-time assessment of microgrid resilience. Unlike conventional assessment methods, the proposed approach makes use of live system data via the DT of a microgrid; considers not only the steady-state power/energy balancing, but also the dynamic system security constraints under adverse operational conditions associated with line or generator outages. A real-time model based on the future anticipated microgrid at the University of Strathclyde campus has been developed in the RTDS simulator, and a prototype DT of the microgrid and the proposed DT-based resilience assessment have been implemented on a hardware platform, which is interfaced with the RTDS via communication links for realistic demonstration. Preliminary results are generated to illustrate the fundamental concepts of the approach, where N-1 tests and a large sample size are used to generate visualisations of system risk and impact of different events to identify high risk components and compute performance metrics e.g. loss of load probability. This work is intended to be continued on larger networks with more complex systems to demonstrate the value of fast-acting resilience quantification.