Worldwide expeditious installation of renewable and distributed energy resources (DERs) is occurring. To achieve faster execution of these projects, most of the existing transmission systems are being upgraded with the addition of various compensating devices such as SVCs, series capacitors, shunt compensators to support wind farms, large PV systems, and other DERs. In this context, the operation of the power grid due to the additional energy resources is posing new challenges in the field of power system protection, monitoring, and control. One of the major issues faced by the utilities with regards to interconnection of DERs into the grid is sub harmonic resonance (SSR) conditions generated due to the interaction of various elements in the power system.
In recent literature, several SSR events have been reported in the existing installations with wind turbine and series compensated systems. Lack of knowledge and availability of suitable protection methodology have led some of these events to damage the hardware components. This presentation describes the use of an industrial sub harmonic protection relay to mitigate SSR conditions associated with the interaction of various power system components such as windfarms, series compensated lines, etc. Results will be presented based on the investigations carried out using hardware-in-the-loop testing of the relay.
Nuwan Perera, Krish Narendra, Nan Zhang ~ ERLPhase Power Technologies Ltd.