Analysis of synchronous condenser capability of active generator sets in the non-frequency based ancillary markets

Abstract

The global power system is undergoing a significant evolution driven by the green energy transition, decentralization, and load-side dynamics. While this transition enables an enhanced resilience and greater energy flexibility, it also introduces significant technical and operational challenges on grid stability issues, system strength, and power quality. To ensure a reliable and secure operation amidst these challenges, system operators must maintain an adequate supply of ancillary services. Among the grid-connected devices capable of delivering such services, synchronous condensers have gained renewed interest due to their ability to pro-vide reactive power, inertia, short circuit strength, and fault ride-through capabil-ity.

This thesis studies the prevailing stability challenges in the power system, existing and future non frequency based ancillary markets, and renewed interest on syn-chronous condensers as a grid connected device to provide non frequency ancil-lary services, through a detailed literature study The thesis conducts a compre-hensive scenario-based simulation analysis on Wärtsilä 20V31SG gas turbine gen-erator sets to quantify its synchronous condenser capability to provide non fre-quency ancillary services in supporting grid stability under increasing inverter-based resource (IBR) penetration, as its main objective. Analysing the impact of deploying the conventional synchronous machines as synchronous condensers instead of merit order curtailments in high renewable energy injection was also an objective of the thesis.

The analysis is conducted through time domain simulations using DIgSILENT PowerFactory, based on an IEEE 14-bus system scaled to represent a large power network. A base case with 30% IBR penetration was developed and extended to configurations with 50%, 75%, and 96% IBR shares. For each case, dynamic simu-lations were conducted to assess the performance of the Wärtsilä gensets under different operating modes and disturbance events.