ters
Electrical
- Nov 24, 2004
- 247
Case:
Twenty diesel generators are connected through step up transformers to a common MV bus, off grid. Generators are similar but not exactly the same, with power output ranging 1000 – 1200 kVA. Governors and AVR are also different on some units. All units have PM pilot exciters. After all of them are synchronized they have to deal with picking up some large loads. The largest load is a 5 MW motor driving a pump (load at nominal speed is abut 3.5 MW). How likely is that there could be some severe problems starting the largest motor (direct start, inrush current about 4 In). We are attempting to model this using Cyme, but cannot be sure as we do not have all input information (no data on governors and AVRs, such as time constants, curves, etc) and results are contradictory depending what typical AVR and governor specs are selected. Common sense suggests that a 20 MW plant should be able to deal with a 5 MW motor with ease.
Twenty diesel generators are connected through step up transformers to a common MV bus, off grid. Generators are similar but not exactly the same, with power output ranging 1000 – 1200 kVA. Governors and AVR are also different on some units. All units have PM pilot exciters. After all of them are synchronized they have to deal with picking up some large loads. The largest load is a 5 MW motor driving a pump (load at nominal speed is abut 3.5 MW). How likely is that there could be some severe problems starting the largest motor (direct start, inrush current about 4 In). We are attempting to model this using Cyme, but cannot be sure as we do not have all input information (no data on governors and AVRs, such as time constants, curves, etc) and results are contradictory depending what typical AVR and governor specs are selected. Common sense suggests that a 20 MW plant should be able to deal with a 5 MW motor with ease.