Droop Mode and MW Mode Selection

GA as usually msamad with generator setup reference, couldn't help with my "check the fuel filters" advice for load sharing problems with this . Much too complex to try "detrail method" for anyone as some have tried, point them in the right direction is the best. The woodward book is great.

Stay dry today,

I'm off soon to replace a bunch of GE GEM analog speed/voltage controls with new GE EGR digital control units. I bet you work with MUCH bigger stuff than this.

Yes, it is usual for Grid Codes to require a droop governor on units above a certain size. But electricity is sold on the basis of a unit declared megawatt, because the loads are megawatts and take no regard to generator capacity variation with ambient! Declared capacity may be varied "day to day" for gas turbines. The governor always operates in droop, the plant control has a slower-acting megawatt control loop, which adjusts the governor speed setting as a "robot operator" to keep the MW at target for the "run", despite frequency variations typically +/- 0.2% in UK. A GT governor will respond to frequency change with a "simple lag" response of about a second or so (depends on size and type); whilst "MW loop" would take 30s or more to correct effect of 0.2% frequency change on MW output. Consequently, governor contributes to frequency control in short term, though longer term regulation is a management operation.

You may find it useful to look at http://www.nationalgrid.com/uk/Electricity/Codes/gridcode/ where you can the United Kingdom Grid Code for generating plant 50MW or greater. There are also commercial rules for bidding and supply of electricity.