Synchronization & Start Up
Synchronization & Start Up
(OP)
I would like to know any experiences that people might have had when starting up gas turbines in an industrial facility that had steam generators already supplying power.
I had some experiences in the past were during initial start up the bringing up some steam turbine generators to synchronize for first time caused the tripping of some gas turbines. Some of the reasons I rememeber hearing during the course of several meetings were items such as:
1.- Gas Turbines will pick up load faster than the steam turbines , therefore overloading themselves.
2.- Load sharing was not properly set up ( droop resistance,incorrect value).
3.- Operators were not properly monitoring situation.
What is the group experince in this ares, and can someone explain item #2
I had some experiences in the past were during initial start up the bringing up some steam turbine generators to synchronize for first time caused the tripping of some gas turbines. Some of the reasons I rememeber hearing during the course of several meetings were items such as:
1.- Gas Turbines will pick up load faster than the steam turbines , therefore overloading themselves.
2.- Load sharing was not properly set up ( droop resistance,incorrect value).
3.- Operators were not properly monitoring situation.
What is the group experince in this ares, and can someone explain item #2






RE: Synchronization & Start Up
Sharing of real power (kW) is a function of the governors and their settings. The simplest approach is to set all governors for simple droop control when operating in parallel. The droop settings must be similar to permit equal load sharing, within the capabilities of the generators. There are other, more complicated options, depending on the overall electrical system and your requirements. But the governor instruction manuals should have a section dealing with load sharing.
Sharing of reactive power (kVAR) is a function of the voltage regulator settings and configuration. These can be set up to operate in a droop mode, similar to the governors with all units sharing roughly equally in the production of vars. Again, your AVR manuals should provide some guidelines for your particular regulators.
If your units are tripping on reverse power, or over/underspeed, the problem may be with the load sharing amongst the governors. If they are tripping due to over/undervoltage or similar, the problem may be with the reactive power sharing settings in the regulators.
RE: Synchronization & Start Up
a) System Studies
b) Start Up verifications.
I saw that some of the traditional studies were issued by the Engineering firm ( fault study, power flow), but I really did not see anything else. Equipment suppliers have stated that the droop values should set up by customer or whoever is handling the overall "master plan".
For example what should I look for during design and previous to start up in the form of documentation. Should we have an integration document with all type of droop settings for the regulators before and after the generator expansion.
RE: Synchronization & Start Up
During commissioning, there should be been some tuning of the governor and VR response characteristics.
But the design documents should cover how the units were intended to operate in parallel mode, and someone should calculated at least a starting point for the droop settings.
What is causing the units to trip?
RE: Synchronization & Start Up
RE: Synchronization & Start Up
The tasks of 'startup verifications' are mentioned. If thorough commissioning tests have not been documented, it's rather difficult to speculate on the actual cause, and may turn into a very expensive omission.
RE: Synchronization & Start Up