Process Control Systems Overview
Process control systems are the backbone of energy operations, monitoring and controlling physical processes in power generation, transmission, and distribution facilities. Understanding these systems is essential for implementing ISO 27019 security controls.
Components of Process Control Systems
SCADA Systems
Supervisory Control and Data Acquisition systems provide centralized monitoring and control:
- Monitor real-time data from remote sites
- Control equipment from central locations
- Display system-wide status and alarms
- Log historical data for analysis
- Example: Grid operator monitoring substations across a region
Distributed Control Systems (DCS)
Process-centric control systems commonly used in power plants:
- Modular, distributed architecture
- Real-time control of generation processes
- Coordinated control loops
- High reliability and redundancy
- Example: Boiler and turbine control in a coal plant
Programmable Logic Controllers (PLCs)
Ruggedized computers for industrial automation:
- Control individual processes or equipment
- Execute ladder logic or function blocks
- Interface with sensors and actuators
- Common in substations and distribution
- Example: Circuit breaker control in substations
Remote Terminal Units (RTUs)
Telemetry devices for remote monitoring:
- Deployed at remote unmanned sites
- Collect data from sensors
- Execute basic control functions
- Communicate with SCADA master
- Example: Pipeline pressure monitoring stations
Energy Sector Architecture
Purdue Model for Energy
The standard reference architecture for industrial control systems:
| Level | Name | Energy Examples |
|---|---|---|
| 3-4 | Enterprise Network | Corporate IT, business systems |
| 2-3 | Site Operations | Historian, HMI, engineering workstations |
| 1-2 | Control Systems | SCADA servers, DCS controllers |
| 0-1 | Field Devices | PLCs, RTUs, IEDs, sensors |
Communication Protocols
IT Protocols
Standard networking used in upper levels:
- TCP/IP, HTTP/HTTPS
- Database connections (SQL)
- File transfers (FTP, SFTP)
OT Protocols
Specialized protocols for process control:
- DNP3: Distribution automation (SCADA to RTUs)
- Modbus: Device communication (legacy, widely used)
- IEC 61850: Substation automation standard
- OPC UA: Modern industrial interoperability
- IEC 60870-5-104: European telecontrol standard
Security Characteristics
Availability is Critical
Unlike IT systems where confidentiality often comes first:
- Process continuity is paramount
- Downtime can cause cascading failures
- Safety systems must remain operational
- Recovery time measured in seconds/minutes
Long System Lifecycles
Energy infrastructure operates for decades:
- 20-40 year equipment lifespans
- Legacy systems still in production
- Difficult to patch or upgrade
- Windows XP/2000 still common
Physical Consequences
Cyber actions have physical impacts:
- Circuit breaker operations
- Generator trip events
- Load shedding
- Equipment damage
- Personnel safety risks
Smart Grid Components
Advanced Metering Infrastructure (AMI)
Millions of smart meters creating new attack surfaces:
- Two-way communication with utilities
- Remote disconnect capabilities
- Detailed consumption data
- Firmware update mechanisms
Distributed Energy Resources (DER)
Renewable energy and storage integration:
- Solar inverter control
- Battery energy storage systems
- Electric vehicle charging infrastructure
- Demand response systems
Grid Management Systems
Modern systems for grid optimization:
- Energy management systems (EMS)
- Distribution management systems (DMS)
- Outage management systems (OMS)
- Advanced distribution management (ADMS)
ISO 27019 Relevance
ISO 27019 addresses security for ALL these components:
- Controls for legacy and modern systems
- Guidance for protocol security
- Network segmentation strategies
- Safe patching procedures
- Incident response for OT
Next Lesson: Understanding the crucial differences between OT and IT security approaches.