The parameters for electrical power quality are specified in the Transmission System Grid Code, particularly in the section relating to planned levels of higher harmonics, flicker, and asymmetry. Emission values are regulated by the Transmission Connection Code. In the development of these latter rules, the transmission system operator in Serbia moved away from the previous practice of setting predefined emission levels, opting instead for the calculation of emission levels at specific connection points in accordance with the IEC 61000 series of standards on electromagnetic compatibility. Since these are complex calculations requiring a thorough understanding of the field, it was concluded that the development of appropriate software is necessary to automate this process. Accordingly, as part of the EU Horizon project R2D2 (Reliability, Resilience, and Defense Technology for the Grid), the PQEL application has been developed using Python to analyze power quality parameters in the transmission grid. The application provides the following features: 1. Calculation of power quality parameters at all nodes in the transmission network, including: Individual harmonic distortion levels, Flicker levels, Voltage unbalance percentage, Equivalent grid impedance, Minimum short-circuit power 2. Calculation of emission limit values for a selected transmission node in accordance with IEC 61000 standards. 3. Monitoring compliance with Grid Connection Code requirements based on measured values of voltage harmonic distortion, flicker, and voltage unbalance. This paper will present a detailed description of each functionality, with results demonstrated using test models in DIgSILENT PowerFactory.