| Abstract [eng] |
The replacement of synchronous generators with inverter-based renewable energy generation reduces the inertia of the power system, thereby deteriorating system stability following disturbances. This work quantitatively evaluates the impact of renewable generation and a battery energy storage system on the frequency and voltage stability of the power system. The study was conducted on a modified IEEE 9-bus system, modelled using Siemens PTI PSSE 36 software. A matrix of 15 scenarios was formulated, comprising different percentage shares of renewable generation in the system, battery energy storage system capacities, and control strategies. A uniform disturbance — a reduction in the system's generated active power by 30 MW — was applied to all scenarios. The following stability indicators were evaluated: rate of change of frequency, post-disturbance frequency minimum, steady state frequency, integral absolute error, voltage minimum, voltage dip magnitude, and recovery time. It was established that at a high share of renewable generation without a battery energy storage system, the rate of change of frequency increases fivefold compared to the baseline scenario. The droop of the battery energy storage system was identified as the parameter most significantly affecting the quality of the system response. The capacity of the battery energy storage system results in a negligible change in the indicators, demonstrating that, under the selected disturbance scenario, the nominal capacity of the battery energy storage system is not a limiting factor. It is concluded that at a low share of renewable generation, a battery energy storage system is not necessary to ensure frequency stability, whereas at a high share of renewable generation, the droop control strategy is insufficient to significantly improve stability. |
