LOST OF SENSING ISSUE DECS-200
LOST OF SENSING ISSUE DECS-200
(OP)
HI THERE, OUR BEST REGARD;
FIRST, SORRY FOR OUR BAD ENGLISH, WE ARE A TROUBLE WITH OUR DECS-200. WE HAVE A 4.6 MW GENERATOR, WHEN WE GIVE THE STOP COMMAND, 3 SECONDS LATER OPENS THE GENERATOR'S SWITCH THEN APPEAR ON SCREEN VOLTAGE MATCHING,OF COURSE, THE GENERATOR VOLTAGE DECREASE AND 2 SECONDS LATER APPEAR "LOST VOLTAGE SENSING" ALARM AND TRIP 86E TROUGH RELAY 3 BECAUSE WE SET SO. OUR QUESTION IS WHY APPEAR THAT ALARM WHILE GENERATOR IS STOPPING, AS SOON AS STOP, WE RESET AND EVERYTHING TURN INTO NORMAL, IN NORMAL OPERATION THE DECS-200 WORKS ON PF CONTROL AND DOESNT TURN TO FCR IF LOST OF SENSIG OCURRS. PLEASE HELP US
FIRST, SORRY FOR OUR BAD ENGLISH, WE ARE A TROUBLE WITH OUR DECS-200. WE HAVE A 4.6 MW GENERATOR, WHEN WE GIVE THE STOP COMMAND, 3 SECONDS LATER OPENS THE GENERATOR'S SWITCH THEN APPEAR ON SCREEN VOLTAGE MATCHING,OF COURSE, THE GENERATOR VOLTAGE DECREASE AND 2 SECONDS LATER APPEAR "LOST VOLTAGE SENSING" ALARM AND TRIP 86E TROUGH RELAY 3 BECAUSE WE SET SO. OUR QUESTION IS WHY APPEAR THAT ALARM WHILE GENERATOR IS STOPPING, AS SOON AS STOP, WE RESET AND EVERYTHING TURN INTO NORMAL, IN NORMAL OPERATION THE DECS-200 WORKS ON PF CONTROL AND DOESNT TURN TO FCR IF LOST OF SENSIG OCURRS. PLEASE HELP US





RE: LOST OF SENSING ISSUE DECS-200
Probably your best bet is to setup your datalog to watch the control inputs, and then review it to see what is coming back in. The DECS is a very capable regulator, but with all of its features, sometimes is hard to get it setup to meet your needs.
Is this a new unit startup? Or an existing unit that worked ok before and now appears to have a problem?
Hope that helps, Mike L.
RE: LOST OF SENSING ISSUE DECS-200
RE: LOST OF SENSING ISSUE DECS-200
RE: LOST OF SENSING ISSUE DECS-200
On many units I work on, we only issue a stop command to the DECS when we have a fault, usually tied to the 86 lockout. This is mainly on smaller (1-2MW) standby units and we don't program the DECS to do any protection, we let the protective relaying handle it. Otherwise it stays in START all the time and when unit speed gets above the cutoff frequency it ramps to rated and builds voltage quickly. You may or may not consider this depending on how well your protective relaying is setup.
Hope that helps, Mike L.
RE: LOST OF SENSING ISSUE DECS-200
We have a policy to run the generator into reverse power mode and trip on our protection relay which is set at 2%. This ensures that the reverse power is operational and opens the contacts at minimal current. This would disable the alternator in line with your protection policy.
I am assuming you are refering to the DECS 200 from Basler.I agree with the above comments that it is a very good and veritile unit. There are two sets of contacts; A33 and A34 (Parallel) and A35 and A36 (VAR)
Using combinations you can get different control modes.
In my manual it is on page 5-31.
If you are running with other generator you should be in droop mode. 52L/M open and 52J/K closed. If you are running with the utility, 52L/M open and 52J/K open. If you are running as a single unit, 52 L/M Closed and 52J/K closed. The status comes from the breaker auxilieries and feed into the contacts.
Your 86E is a lock out which should have a requirement for human intervention to reset.
Good luck
RE: LOST OF SENSING ISSUE DECS-200
I really appreaciatte your help, you gave me tons of ideas of what the problem could be, let me tell you that i got it fixed, the DECS it was not receiving stop command trough a N.C. contact when we were stopping, a contact that is supposed to close when the main switch is oppened it was not doing so, the contacts A23 and A24 (STOP) kept opened, we cleaned the contacts, test and since now on, everything turned to normal.