Posted by Joe Weiss:
Many people feel that green technologies such as wind and solar will minimize the
cyber threat to the grid. I believe they are wrong.
According to an article from the LA Times on the safety of Solar and Wind Power Projects, accidents involving wind turbines have tripled in the last decade, and watchdog groups fear that a surge in wind and solar power projects requiring hiring new and often inexperienced workers could cause such incidents to skyrocket further. Wind turbine accidents involving injuries and equipment damage have surged over the last decade, peaking in 2008 with 128 incidents worldwide. The number of solar incidents is harder to gauge, but most industry workers say it is rising. The solar industry trade group says it is working on its own set of best practices. The organization has offered safety recommendations for an international construction standard being drafted for renewable energy projects. Wind turbines and solar farms use PLCs and SCADA systems. However, neither control systems nor cyber were mentioned in either the wind or solar projects.
Enclosed is a sampling of how control systems are used for wind and solar projects and why they are not different than traditional plants.
- Wind farm networks employ SCADA systems to collect data from wind turbines. A PLC is used for data acquisition and the data is sent via an Ethernet switch. What makes this different than any other plant data acquisition application?
- The Programmable Automation Controller (PAC) has all of the same I/O and communication protocol capabilities as a traditional PLC; however, it also has a real-time operating system and reconfigurable FPGA, enabling advanced control algorithm deployment. In many cases, the PAC acts as the master unit controlling a network of PLCs or other PAC slave devices. The PAC can compute advanced control algorithms and communicate a variety of Ethernet or serial-based protocols (Modbus, OPC, CAN, etc.). Does this look like Boreas or Stuxnet – insecure firmware upgrades?
- Spanish solar energy plants utilize parabolic trough technology combined with thermal storage systems using molten salt batteries to maximize their power-generating capacity. The heat transfer fluid (HTF) piping carries the heat transfer oil between the parabolic mirrors, the steam plant and the power generation circuits. Each site is installing automated actuators and master stations for remote control of the valves. What makes this different than temperature control in any other type of plant?
- The US Iberdrola National Control Center allows generation dispatchers and systems analysts to oversee every turbine at every wind farm (and soon solar and biomass projects) throughout the country. They monitor the performance and efficiency of every turbine and coordinate in real time with the nation's various transmission system operators to insure grid reliability. Isn’t this the same as any other control center?
- Each wind turbine has a control box containing a PLC, power converter, control boards and I/O device. Sensors for wind speed, wind direction, shaft rotation speed and numerous other factors collect and transfer data to the PLC. By detecting the wind's direction, the control system can use a motorized yaw gear to turn the entire wind turbine in the proper wind direction for maximum power generation. The wind turbines are connected to a LAN via a fiber-based, redundant ring connection. Although the turbines are designed to operate autonomously, they also are connected to a remote-control station running the control system that manages and collects data, adjusts turbine settings and provides intelligent alarm, troubleshooting and reporting capabilities via the central data center and control facility. What makes this different than any other plant control system?
- The National Control Center connects via long-haul networks to the plant-based systems and ultimately to the individual turbines, substations, meteorological stations and avian radar surveillance systems. It provides visibility for operators to manage each wind turbine and all the wind farms as a whole. By keeping a record of the activity on a time-interval basis, the SCADA allows the operators to determine what adjustments and corrective actions need to be taken. It records energy output, availability and error signals, and eventually the ability to control power factor, voltage and reactive power production, allowing for the management of wind farms' contributions to network voltage and frequency control. It also gives the operators the capability to manage power output based on real-time grid requirements. What makes this different than dispatching any other fleet of plants?
- Solar power plants using solar trackers typically generate 30% more energy than fixed systems. The function of the PLC is to control the variable-speed drives, which orientate the photovoltaic modules across two axes in order to achieve maximum exposure to the sun throughout the day. The PLC seeks the input from the sun and tracks its pattern along every day of the year. What makes this different than controlling parameters in any other plant?
