• Select-Execute principle to give high reliability
• Selection function to prevent simultaneous operation
• Selection and supervision of operator place
• Command supervision
• Block/deblock of operation
• Block/deblock of updating of position indications
• Substitution of position and quality indications
• Overriding of interlocking functions
• Overriding of synchrocheck
• Operation counter
• Suppression of mid position
Two types of command models can be used:
• Direct with normal security
• SBO (Select-Before-Operate) with enhanced security
Normal security means that only the command is evaluated and the resulting position is not
supervised. Enhanced security means that the command is evaluated with an additional
supervision of the status value of the control object. The command sequence with enhanced
security is always terminated by a CommandTermination service primitive and an AddCause
telling if the command was successful or if something went wrong.
Control operation can be performed from the local HMI with authority control if so defined.
14.3.2 Operation principle
M13423-4 v7
A bay can handle, for example a power line, a transformer, a reactor, or a capacitor bank. The
different primary apparatuses within the bay can be controlled via the apparatus control functions
directly by the operator or indirectly by automatic sequences.
Because a primary apparatus can be allocated to many functions within a Substation Automation
system, the object-oriented approach with a function block that handles the interaction and
status of each process object ensures consistency in the process information used by higher-level
control functions.
Primary apparatuses such as breakers and disconnectors are controlled and supervised by one
function block (SCSWI) each. Because the number and type of signals used for the control of a
breaker respectively a disconnector are almost the same, the same function block type is used to
handle these two types of apparatuses.
The SCSWI function block is connected either to an SXCBR function block (for circuit breakers) or
to an SXSWI function block (for disconnectors and grounding switches). The physical process in
the switchyard is connected to these two function blocks via binary inputs and outputs.
Four types of function blocks are available to cover most of the control and supervision within the
bay. These function blocks are interconnected to form a control function reflecting the switchyard
configuration. The total number used depends on the switchyard configuration. These four types
are:
• Bay control QCBAY
• Switch controller SCSWI
• Circuit breaker SXCBR
• Circuit switch SXSWI
Section 14 1MRK 502 066-UUS B
Control
826
Technical manual
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