Spinning reserve


Thread Starter


Hi, Dear all
I m really enjoying reading threads on this platform.
i wanted to know about spinning reserves.

1) What is spinning reserve? Is it MW output of turbine at the time immediate after synchronisation with infinite grid?

2) Up to what extent we can reduce the spinning reserve and what are the implications of changing the spinning reserves while we are connected with grid?
Technically, 'spinning reserve' used to refer to excess capacity connected to an infinite grid. For example, if the current load on the grid was 10000 MW and the sum of the capacity of all the generators connected to the grid was 11000 MW, then there would effectively be 10% available capacity for an increase in load that was running ("spinning"). This would mean that some of the generators were not operating at their rated output and their difference in output was available "in reserve".

GE has co-opted the term to refer to the load which one of their heavy duty gas turbine-generator units automatically loads up to immediately after an automatic synchronization if no other load command was enabled (such as Pre-selected Load or Base Load) when the automatic synchronization was initiated.

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A Google search yielded this document and several other definitions of spinning reserve:

http://www.eee.manchester.ac.uk/res...tstheses/aoe/rebours et al_tech rep_2005A.pdf

This document has one of the best definitions of some terms those of us in the power generation industry are becoming painfully familiar with: Primary-, Secondary- and Tertiary Frequency Control, along with an excellent description in Fig. 2.2.

But, the point was an Internet search engine can be used for the legacy definition, and some really good related information in terms of some of the modern usages and new conventions.
Thanx CSA & Corso for the valuable information. but i had one more query in my mind on spinning reserve.
Can we change spinning reserve setting(we have GE M/C)as per our requirement so that the machine does not trip on Low forward power (32L)immediately after synchronisation? What does the grid demands from an individual plant as far as spinning reserves are concerned?
I believe it could be done. My best guess would be to look into the control constants. Normally the load after synchronizing is about 3-5MW depending on plant requirement.

As for the grid demand, it totally viewing from different perspective as it involves on how the load factor for the grid is managed. Most grid operators would put about 15-20% load on spinning reserve just because anything more than that would be simply wasting energy on transmission and ultimately = money.

Hence a plant operation does not reflect on the spinning reserve of the grid as only the grid operator has the control and wisdom on how to maintain the grid reliability (although nowadays this is done using complex power flow softwares and the grid operator just sit back and watch TV ;) )

If you have a Speedtronic Mark IV or Mark V or Mark VI, the spinning reserve load setpoint is adjustable.

You need to examine the sequencing for your particular unit, but the typical name of the setpoint is Control Constant LK90SPIN. But check your sequencing to be sure.

I fear, though, that if the unit doesn't load fast enough that it might still trip on low forward power. The loading rate for loading to Spinning Reserve is usually the "Auto" loading rate, and that's usually a moderate rate (less than the "manual" loading rate which is used when clicking or RAISE SPD/LOAD or twisting the RAISE SPD/LOAD switch).

The "grid" has no demands on a unit operating in droop speed control. If by "grid" you are referring to the regulatory agency that controls the grid and sets the rules for connection, that would depend on what the rules and regulations are in your country.