An analytical tool to check for static grid code compliance of generating sets

With the recent introduction of more stringent grid codes, genset manufacturers have needed to reexamine the true stability limits for their products. This paper compares an approximate analytical method developed by Walker ^[1] with Finite Element and direct measurement of the reluctance variation for a commercial synchronous generator. The tool described in the paper operates the synchronous generator upto and past the machine's stability limit and compares practical results with theoretical expectations. Grid codes ^[2] are regulations imposed by the Transmission and Distribution system operators that define the steady state and transient conditions a generating set might face while connected to the grid. Static grid codes discuss steady state conditions which include voltage and frequency variations and the power factor at the point of common coupling (PCC). In order to analyze the compliance of a generating set with these requirements, the authors have developed a tool using Microsoft Excel to understand the implications of the static codes. The input is the alternator specifications - power, voltage and frequency ratings, the d and q axis reactances and the voltage and power condition dictated by the grid code. The tool minimizes the time and effort that needs to be put in to evaluating grid code compliance. Once the inputs have been fed into the tool, it verifies if the alternator is stable during a particular steady state condition and also suggests new ratings for the alternator that would make it comply with the static grid code.