At voltage synchronization (mark IV) before line and unit voltages comparison, line voltage (SVL) is modified and corrected by speed (TNH). Does anybody know why this correction should be done?
Synchronization
- Thread starter alizareian67
- Start date
alizareian67,
Synchronization is the same in all Mark IV turbine control panels, regardless of the turbine it is controlling.
I have never noticed the "modification" of SVL by TNH (percent of rated speed) to derive 'Speed Corrected Volts' before (or if I have, I have long since forgotten). I can guess that the designers wanted to make sure the turbine was running before comparing SVL to DV (Driven Volts--the generator terminal voltage; known as "Incoming" voltage in synchronization terms). The product is further modified by the value 1.25B1--which is completely unintelligible to me. The Mark IV uses fixed-point math (as did the Mark V), and the "shifts" and "modifiers" necessary to get things to be in the correct value and units were necessary, if indescribable.
The Mark IV was really the first digital purpose-built turbine control system of its time, and as such the designers took a lot of precautions with things like synchronization--which is SO CRITICAL to be done correctly. This may have just been some kind of "extra" check someone felt was necessary to ensure this critical function was secure
When trying to simulate automatic synchronization off-line (with the generator withdrawn from it's cell ("racked-out" in the TEST/DISConnect position!!!) it is necessary to use a frequency generator connected to the Mark IV. The Mark IV speed matching algorithm looks at TNH and compares it to SFL (Station Frequency-Line) when matching speed (instead of comparing generator frequency directly to line frequency--but since speed and frequency are directly related it's just another method of speed matching).
If you are having problems with auto synchronization, please describe them and we may be able to help you. That algorithm has been used for many, many years and has worked with zero problems. So, although it seems unusual to be modifying voltage with turbine speed it has worked successfully for a long, long time.
Hope this helps! Wish I had a better answer, but, again, if you're having problem(s) this probably isn't the cause.
Synchronization is the same in all Mark IV turbine control panels, regardless of the turbine it is controlling.
I have never noticed the "modification" of SVL by TNH (percent of rated speed) to derive 'Speed Corrected Volts' before (or if I have, I have long since forgotten). I can guess that the designers wanted to make sure the turbine was running before comparing SVL to DV (Driven Volts--the generator terminal voltage; known as "Incoming" voltage in synchronization terms). The product is further modified by the value 1.25B1--which is completely unintelligible to me. The Mark IV uses fixed-point math (as did the Mark V), and the "shifts" and "modifiers" necessary to get things to be in the correct value and units were necessary, if indescribable.
The Mark IV was really the first digital purpose-built turbine control system of its time, and as such the designers took a lot of precautions with things like synchronization--which is SO CRITICAL to be done correctly. This may have just been some kind of "extra" check someone felt was necessary to ensure this critical function was secure
When trying to simulate automatic synchronization off-line (with the generator withdrawn from it's cell ("racked-out" in the TEST/DISConnect position!!!) it is necessary to use a frequency generator connected to the Mark IV. The Mark IV speed matching algorithm looks at TNH and compares it to SFL (Station Frequency-Line) when matching speed (instead of comparing generator frequency directly to line frequency--but since speed and frequency are directly related it's just another method of speed matching).
If you are having problems with auto synchronization, please describe them and we may be able to help you. That algorithm has been used for many, many years and has worked with zero problems. So, although it seems unusual to be modifying voltage with turbine speed it has worked successfully for a long, long time.
Hope this helps! Wish I had a better answer, but, again, if you're having problem(s) this probably isn't the cause.
Thanks CSA,
It's helpful. We want to replace old system with new synchronization relay.
These new relays do all functions automatically, but for substitution. To make a good choice we should recognize all parts of current system.
It's helpful. We want to replace old system with new synchronization relay.
These new relays do all functions automatically, but for substitution. To make a good choice we should recognize all parts of current system.
