Apparatus Control Function (APC10)

The APC10 Apparatus Control function provides comprehensive control and supervision for up to 10 primary switching devices within a substation bay, including circuit breakers, disconnectors, and earthing switches. It ensures that all switching operations are executed safely, securely, and in accordance with predefined operating conditions.

Before any control command is accepted, APC10 evaluates operating permissions based on information received from multiple protection and control functions, including:

Interlocking logic
Synchrocheck
Operator control location selection
Internal and external blocking conditions

This coordinated decision-making process helps prevent unsafe switching operations while ensuring reliable substation operation.

Key Features

The APC10 function offers a comprehensive set of control and supervisory capabilities, including:

Select-Execute operating principle for enhanced operational reliability
Selection management to prevent simultaneous operation of multiple devices
Operator location selection and supervision for local or remote control authority
Command execution supervision to verify successful operation
Operation blocking and deblocking for maintenance and safety purposes
Blocking or enabling of position indication updates
Substitution of position and quality indications during testing or maintenance
Temporary override of interlocking logic when authorized
Temporary override of synchrocheck for special operating conditions
Operation counter for maintenance and asset management
Mid-position suppression for improved status indication accuracy
Supported Command Modes

APC10 supports two industry-standard control methods to satisfy different security requirements:

Direct Command (Normal Security)

With the Direct Command model, the control command is transmitted directly to the switching device without requiring a prior selection step. The command itself is validated before execution, but the resulting device position is not automatically supervised after operation.

This operating mode is suitable for applications where standard command validation is sufficient.

Select-Before-Operate (SBO) (Enhanced Security)

The Select-Before-Operate (SBO) model provides an additional layer of operational security.

The operating sequence consists of:

Selecting the intended control object.
Verifying successful selection.
Issuing the operate command.
Supervising the resulting device position after operation.

Enhanced security not only validates the command itself but also confirms that the controlled device has reached the expected position. Every SBO command sequence is completed with a CommandTermination service primitive and an associated AddCause status indicating whether the operation was completed successfully or if an error occurred.

Security Levels

The APC10 function supports two configurable security philosophies:

Security Level Description
Normal Security Validates only the control command. Device position after operation is not automatically supervised.
Enhanced Security Validates both the control command and the resulting status of the controlled apparatus, providing confirmation of successful execution and detailed diagnostic feedback.
Local and Remote Operation

Control operations can be performed from the local Human-Machine Interface (HMI) when local authority is enabled. Authority management ensures that only the authorized operator location—local or remote—has control rights, preventing conflicting commands and improving operational safety.

The APC10 Apparatus Control function combines advanced supervision, flexible command handling, and robust security mechanisms to deliver reliable control of primary substation equipment in modern transmission and distribution automation systems.

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