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Abslroct-Voltage sag tolerance levels were measured for samples of three equipment categories sensitive l o sags: C O I I~~C~O A , PCs and gas discharge lamps. An up-to-date voltage waveform generator was used to produce and repeat the evenu as necessary. Remaining voltage and sag duration were the test variables. For E O O~P C~O~S also the effect of paint-on-wave of sag initiation was studied. The resulu were rather well convergent with earlier studies by other institutes. This justifies more generalized eonclusions on performance of these device categories as well as more statistical approach to the issue. This kind of typical equipment sensitivity data is needed as a library for the future sag assessmu1 methods.

Utilities have traditionally carried out power flow and fault current calculations in their distribution network for monitoring and planning purposes. The network is controlled and operated as a complete system. Network information systems (AMEM-GIS) and different distribution management systems (DMS, SCADA) are the most common software platforms used for completing the task. The calculations are performed in steady state. Solid-state and energy storage based power conditioners, i.e. custom power devices introduce a new generation of active components in the network. To be able to control and operate the network also the new components have to be modeled for steady state simulation and furthermore implemented in the established applications. The models provide the utility software with proper tools for the network power flow, harmonic power flow and energy flow calculations. Also new tools for power quality management can be developed.

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