Coordinated Measurements for governor operations in the Southern Indian Grid

摘要

The Southern grid of the Indian power system is a network with an installed capacity of about 37000 MW. It comprises of several thermal and hydel units. The network allows the operating frequency to vary over a band from + 0.5 Hz to -1.0 Hz from the nominal 50 Hz. This is due to the historical chronic shortage of power in the network. Since 2004 about 460 special energy meters with 0.2 class accuracy have been erected across the network. Normally despatch is done every 15 minutes with set point control. On one occasion an experiment involving governor operation across all hydro units and thermal units in excess of 200 MW was carried out for a period of three hours. Records of frequency profile, state generation, interregional flows etc., are available at sampling of 1 minute over six hours. We have analyzed the performance of the free governor mode operation (FGMO) based on site data. It is shown that the response for the hydro units swamped those of the thermal units in the three hour duration. Operation under governor control of all units could not be sustained for more than fifteen minutes. Several hydro units tripped during the experiment. A simulation model with a 2 unit system shows that smaller machines tend to move out of synchronism for load variations close to their capacity. One machine in the network shows this classic behaviour.