Modeling and control of advanced pumped storage hydropower for power system resiliency enhancement.


With the gradual increase in renewable penetration, system operators are searching for flexible resource that can help mitigate problems of future low-inertia power systems. To analyze the benefit of advanced pumped storage hydro (PSH) configurations as flexible resources, the mathematical models and controls for each configuration are required but are not available with academic or commercial software platforms. Thus, effort is dedicated to the development of these models and displaying that they can be integrated with test systems for power system studies in MATLAB/Simulink. First, a governor model is constructed for pump and generator modes separately for the adjustable speed PSH (ASPSH). Second, a governor model is constructed for ternary PSH (TPSH). Finally, a governor model for Quaternary PSH (QPSH) was constructed. For ASPSH and TPSH configurations, governor models and inverter controls were formulated and a single-machine-infinite-bus (SMIB) integration and a 9- bus system integration tests were performed. The ASPSH model was able to regulate the speed of the turbine successfully and hence maintain the high efficiency, while tracking real power references in both generation and pump modes. Also, through the integration tests in the 9-bus test system it has been demonstrated that, the governor structure can provide primary frequency regulation in both pump and generation modes. Further, an adaptive droop (AD) system was designed for the ASPSH system which showed that the AD algorithm in-hand with the converter control could provide enhanced primary regulation for the system. For the TPSH configuration, the SMIB integration results demonstrate that the governor model can track power references accurately in the pump mode and that, the model can demonstrate the mode change pump to generator and vice-versa without the loss of synchronism. Simultaneously, the 9-bus test system integration displayed that the pump mode reference tracking could be of great benefit for the network, but the mode change capability is an important emergency response tool for the system operators. The QPSH system with the converter-based pump model was constructed and integration studies in the western interconnection system for different renewable penetrations showed that QPSH could support greater penetrations of renewable energy in the same network. Finally, the revenue earning potential of the PSH configurations was evaluated, which concluded that TPSH could earn higher revenue even while considering wind penetration and seasonal variation of load and wind profiles.

Power system. Energy storage. Integration studies. Pumped hydro.