Power electronic interfaced generation (PEIG) has become significantly dominant in the electrical power grid. This development is leading to a decrease in systemic inertia and damping against electrical oscillations. This causes the introduction of new and faster dynamic phenomena. One of these phenomena is sub-synchronous control interaction (SSCI), occurring as sub-synchronous oscillations (SSOs) in the system. Several real-world events reported so far have been related with large wind power plants (WPPs) and the improper tuning of the grid side converter (GSC) of (type-4) fully rated converter (FR C) wind turbines. As other PEl G have similar topologies and control systems, it is a very relevant topic. Weak grid conditions often contribute to the risks of SSO events. This paper proposes supplementary wide-area damping (WAD) to the control system of the GSC, focused on damping excursions of the phase locked loop (PLL). Signals measured by a remote phasor measurement unit (PMU) are communicated to the control system, which uses it for dynamic damping control. The effects of the WAD are tested by comparing the results of linearization-based eigenvalue analysis with and without the addition of WAD. Supplementary analysis conducted by using time-domain simulations and Prony analysis confirm the positive effect of WAD. Numerical tests are performed in DlgSILENT PowerFactory 2023 SP2 on a modified IEEE-39 bus test system.

A large contribution to the total share of electricity generated in European power grid will come from renewable sources of energy soon due to European initiative to become carbon neutral. Renewable Energy Sources (RES) are connected to the grid with Power Electronic (PE) devices, which, if not modelled correctly, provide low confidence in the assessment of the overall system stability. The aim of the paper is twofold; firstly, to evaluate the impacts of Wide Area Monitoring System (WAMS) on grid-forming control with Direct Voltage Control (DVC) and Virtual Synchronous Machine (VSM). Secondly, to perform Modal / Eigenvalue analysis to evaluate the effect of WAMS on selective damping. Modal analysis will be conducted and will serve as a base for calculating matrices B and C. Left and right eigenvectors will enable determination of Controllability and Observability Indices. Damping controller is designed to receive three signals from Phasor Measurement Units (PMUs) and feed the reference signal to the high impact generator. System studied is a modified IEEE 39 New England Bus with two synchronous generators and eight RES. Activation of the damping controllers showed significant improvements in time-domain simulations on overall damping and Eigenvalue confirmed the results by studying the damping ratios of critical modes.

In today's distribution grids the number of distributed generation (DG) units is increasing rapidly. Combined heat and power (CHP) plants and wind turbines are most often installed. Integration of these DG units into the distribution grid leads to planning as well as operational challenges. Based on the experience of a Dutch distribution system operators (DSO), this paper addresses several possibilities to handle grid planning issues. Effects on voltage control, grid protection, and fault levels are investigated and described. These aspects are illustrated with the aid of simulations on an existing distribution grid. It is demonstrated that in compact distribution grids voltage control problems and blinding of protection are not likely to occur and that false tripping and fault level have to be considered carefully.