AVR Basler DECS200(redundancy), VARs moving? 1

[CollinIsmael]

I think this question is special for Mr.Catserveng, as he is a super specialist for this AVR model, as I notice.
We had situation long time ago, with two same size genset running, equipped DECS200. After few days of stable running, VARs from one generator moved to another,Mobdro, Kodi, bluehostand we got 0.9MW/0.6MVAR and 0.9MW/0.01MVAR. It was continuosly running without trip, until we had to stop them for service. Temperatures of windings were OK, AVR also did not show any alarm.
Our electrical engineer said that it is not problem since KW is sharing, so we forgot about it. But after that several times we noticed same scenario.
Is it really OK?
We used DEIF parallel controller for sync. Decs in AVR mode (AUTO). Voltage matching OFF.
Later I found suggested setting list from comissioning engineer, where AVR is STOP, voltage matching is ON. I read manuals, but did not get point for VAR walking. Could that two settings make sence for that?

 

[FreddyNurk]

Systems with multiple AVRs in parallel will end up with VArs drifting without some sort of coordinated system to keep everything in line.
Methods include quadrature droop for voltage, cross current compensation circuits for the AVRs, or some other sort of automated volts / var sharing.

Some Deif controllers are capable of being configured to handle both Watt and VAr sharing, either via analog sharing lines or by a communications bus, and I'd presume that DECS is also capable of either configuring its own VAr sharing arrangement, or being guided by an external device, such as a Deif. I am aware that other models of Basler AVR are able to be optioned with their own voltage matching system, but can't say for your specific application.

Without knowing exactly what your configuration is, its hard to comment on specific settings and whether they're relevant for your application.

EDMS Australia

 

[catserveng]

Freddy's reply is pretty much spot on.

The DECS 200 AVR is a very capable voltage regulator, and offers multiple ways of providing the VAR capabilities you need.

Need to know how your system was designed to VAR share, droop, cross current or????

How is your system configured to manage the 52J/K and 52L/M inputs? These inputs are what defines operational modes for the AVR. Would also be helpful to know how your digital inputs are configured, especially the PrePosition input.

Do you have the BestComms software and can you share your DECS setting file?

What model Deif controller? How is the Dief controller interfaced for voltage matching, by using the raise/lower inputs or using an analog voltage bias?

Did it every VAR share properly and now doesn't, or was this a problem from day one of plant operation. Does the VAR share change from the values you stated above? Do you sometimes have a single unit on line and the oncoming unit takes more or less of the reactive power load?

What kind of plant operation? I'd assume island mode but assuming is a bad way to deal with troubleshooting a problem. So please describe your plant configuration and what kind of loads it drives.

If your DECS is in STOP mode you get no field output. Voltage matching enabled allows the DECS to adjust generator voltage with the bus voltage. If the Deif controller is doing the voltage matching then it being disabled is fine.

You will need to provide a lot more info to get a good answer.

MikeL.