Series Capacitor Bank Command Verification Against Grid State

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Solution Overview

Problem

Existing power systems are vulnerable to malicious control of series capacitor banks (SCBs) by attackers who can manipulate control commands, leading to issues like overloading, voltage violations, and reduced stability, which current security measures fail to adequately address.

Innovation Solution

Implement a protection layer in the SCB controller that intercepts remote control signals, assesses their consistency with the power system's physical state using line fault detection, system disturbance detection, and interlocking schemes, and blocks or allows commands based on this assessment, including checks for line faults, system disturbances, and load conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If SCB control commands are transmitted remotely without verification, then system operation flexibility is improved, but system security deteriorates due to vulnerability to malicious control

Engineering Contradiction:
Improveremote control flexibilityVSAvoidsystem security
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces an intermediary verification mechanism that sits between the remote control system and the SCB execution system. This intermediary assesses whether control commands are consistent with the actual physical state of the power system by comparing command intentions with sensor data from the field, thereby preventing malicious commands from executing while still allowing legitimate remote control operations to proceed.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements a feedback loop where the actual physical state of the power system (measured by sensors monitoring voltage, current, power flow, etc.) is continuously fed back to the control system. This feedback enables the verification mechanism to assess whether received control commands are consistent with the current system state, creating a closed-loop control system that enhances security while maintaining operational flexibility.

Inventive Principle:
Principle #23Feedback

2Reliability

If all remote control commands are blocked for security, then system security is improved, but system productivity deteriorates due to inability to respond to emergencies

Engineering Contradiction:
Improvesystem securityVSAvoidemergency response capability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary verification of control commands against the actual physical state before execution. By assessing command consistency with sensor data in advance, the system can quickly identify and block malicious commands while allowing pre-verified legitimate commands (including emergency responses) to execute without delay, thus maintaining both security and productivity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control system dynamically adjusts its response based on the assessed consistency of commands with the actual system state. When commands are verified as consistent with physical conditions, they are allowed to execute immediately. When inconsistencies are detected, commands are blocked. This dynamic approach ensures that security measures do not unduly hinder legitimate emergency responses while effectively blocking malicious control attempts.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If SCB position is manipulated under normal conditions, then attacker control capability is improved, but system stability deteriorates due to unauthorized position changes

Engineering Contradiction:
Improveattacker control capabilityVSAvoidsystem stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The system implements preliminary anti-action by proactively verifying the consistency of control commands with the actual physical state before execution. This preventive measure counteracts potential malicious manipulation attempts by blocking commands that do not align with the true system state, thereby protecting system stability before attackers can exploit unauthorized position changes.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The system converts the potential harm of remote command transmission into a benefit by using the command verification process. The same communication channel that attackers might exploit is also used to transmit legitimate control commands, which are then verified against sensor data. This transforms the vulnerability into an opportunity for enhanced security through consistency checking, where the control system benefits from having multiple data points (commands and sensor readings) to verify system state.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Reliability

If command verification based on physical state is implemented, then system security is improved, but device complexity increases due to additional assessment mechanisms

Engineering Contradiction:
Improvecommand verification securityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control system is designed with multi-functionality, where the same hardware processors and communication infrastructure serve both normal control operations and security verification functions. By making the verification mechanism universal rather than separate, the system achieves enhanced security without proportionally increasing device complexity, as existing resources are utilized for dual purposes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the control command processing function with the security verification function into a unified control system. Instead of having separate verification hardware and software layers, the assessment of command consistency with physical state is integrated into the existing control logic, combining multiple functions into a single cohesive system that reduces overall complexity while maintaining security enhancements.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4333235B1Methods for secured capacitor bank control of series-compensated transmission line
Publication Date: 2025.11.05 HITACHI ENERGY USA INC
  • EP4333235B1 patent drawingFigure 1
  • EP4333235B1 patent drawingFigure 2
  • EP4333235B1 patent drawingFigure 3

AI summary

Power systems, such as transmission systems, may comprise a series capacitor bank (SCB) to provide series compensation on a power line. The SCB may be electrically inserted into the power line or bypassed according to commands sent by remote systems. Such commands may be compromised in a cyberattack to cause deteriorated conditions and instability in the power system. Thus, according to an embodiment, a protection layer is provided in an SCB station to intercept commands prior to execution, assess the consistency of the commands with a physical state of the power system, and either allow or block the commands based on the assessment, to thereby protect the SCB from cyberattacks.