Basler Electric BE1-11t - Manual (Page 258)

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Default Logic Scheme
All BE1-11t protection systems are delivered with the default logic scheme pre-loaded in memory. If the
function block configuration and output logic of the default logic scheme meets the requirements of your
application, then only the operating settings (power system parameters and threshold settings) need to be
adjusted before placing the BE1-11t in service.
Details of Default Logic Scheme describes the characteristics of the logic scheme and how it combines to
create a protection system for a two-winding transformer. A detailed description of the default scheme is
also provided.
The default logic scheme is designed to accommodate most common transformer protection schemes.
The protection engineer can adapt it by changing the function block operation and settings. This
eliminates the need to create a custom logic scheme.
It should be noted that the default logic scheme also illustrates typical ways of using or controlling various
functions. The user can choose to create a custom logic scheme by mixing the logic from the default
scheme. The flexibility of BESTlogicPlus allows the protection engineer to create a custom scheme that
exactly meets the requirements of the application.
Caution
Always remove the BE1-11t from service prior to changing or
modifying the active logic scheme. Attempting to modify a logic
scheme while the BE1-11t is in service could generate unexpected or
unwanted outputs.
Modifying a logic scheme in BESTCOMSPlus does not automatically
make that scheme active in the BE1-11t. The modified scheme must
be uploaded into the BE1-11t. See the paragraphs on Sending and
Retrieving Logic Schemes.
Operational settings are not included in the default logic scheme. Each
element, target, pickup setting, timing setting, etc. will have to be
enabled and programmed separately using the Settings Explorer in
BESTCOMSPlus.
Overview of Default Logic Scheme
The default logic is shown in Figures 2 through 6 and described in the following paragraphs. The default
logic scheme provides transformer protection. The default logic includes elements and features available
in the base option of the BE1-11t.
Restraint based differential protection (87) is available as well as voltage and current protection elements.
Included protective elements are 24, 27P-1, 59P-1, 81-1, 4, 50-1, 50-2, 50-3, 51-1, 51-2, 51-3, and 87 for
transformer protection functions such as differential protection, short-circuit, ground fault, unbalance,
undervoltage, overvoltage, overexcitation, and overcurrent.
Functions such as breaker failure and virtual breaker control features are not enabled in this scheme.
However, these features can be activated through BESTCOMSPlus.
BESTlogic
™Plus
BE1-11t