Selecting a critical power monitoring and control technology
Choosing a monitoring and control technology should be based on the power reliability requirements for the application.
A funny thing happened on the way to the forum for better power reliability: monitoring and controlling that power started taking center stage.
Reliability-based design, reliability-centered maintenance, and failure prevention depend on gathering, analyzing, and acting on data from critical power generation and distribution components and systems. Everyone involved in designing, constructing, commissioning, and maintaining a building—consulting engineers, contractors, and building owners/managers—has a stake in optimizing power system monitoring and control. They all win when it works; they all lose when it doesn't.
Data center and health care facility executives, especially, crave more power control information. One reason is that power systems are more complex and sophisticated than ever, and could mean the difference between life and death to an organization's operations. For example, data center downtime costs business more than $5,000/min, according to a 2011 Ponemon Institute study of U.S.-based data centers. With an average reported incident length of 90 min, that's nearly $500,000 on the line—or off the bottom line.
Complex power systems are vulnerable to problems that can undermine the very power reliability they're designed to provide. Sophisticated power monitoring and control technologies help ferret out potential problems and provide a raft of benefits that can extend throughout an organization (see Figure 1). The starting point for evaluating and selecting power monitoring and control technologies is for the facility executive to pinpoint information needs and thoroughly understand the business’s operational processes.
The monitoring and control technologies that are usually considered are legacy supervisory control and data acquisition (SCADA) systems and building management systems (BMS). The two new technologies are data center infrastructure management (DCIM) systems and critical power management systems (CPMS). The first three are overarching technologies. They aim to monitor and control an entire facility or campus, including critical power. The fourth dedicates itself to controlling only critical power generation and distribution systems.
These four technologies have similarities and differences that are important to consulting engineers, contractors, building owners, and facility executives (see “Power system management monitoring and control technology comparison”). This article describes each technology, highlights its capabilities and limitations, and suggests which system may be best suited for a given application.
Technically, all systems designed to monitor and control business operations and processes are SCADA systems. This article addresses legacy SCADA systems meant for a variety of industrial, commercial, and institutional applications. Telecommunications, power utilities, water and waste control, energy, oil and gas refining, and transportation have historically applied SCADA.
SCADA systems help improve efficiency and operational reliability, and lower costs, thus increasing profitability of operations and processes and enhancing worker safety. Best-in-class SCADA provides alarm handling, trending, diagnostics, maintenance scheduling, logistics, and other benefits. For alarm handling, though, a cascade of quick alarm events could mask the underlying causes of trouble.
Third-generation SCADA systems include a computer and open, or off-the-shelf, system architecture that acquires data from and sends commands to monitored equipment, a human-machine interface (usually a computer monitor screen), a networked communication infrastructure, sensors and control relays, remote terminals units (RTUs), and programmable logic controllers (PLCs). Note that the range of available RTUs and PLCs require careful consideration to ensure the classes of equipment selected will provide needed scalability, optimize functionality, and prove most cost effective for a given SCADA application.
Standard protocols and Internet accessibility of networked SCADA systems make the systems susceptible to remote attack. In April 2008, the Commission to Assess the Threat to the United States from Electromagnetic Pulse [EMP] Attack issued a Critical Infrastructures Report that concluded: "SCADA systems are vulnerable to EMP insult. The large numbers and widespread reliance on such systems by all of the Nation’s critical infrastructures represent a systemic threat to their continued operation following an EMP event. Additionally, the necessity to reboot, repair, or replace large numbers of geographically widely dispersed systems will considerably impede the Nation’s recovery from such an assault."
Additionally, in June 2010, an antivirus security company reported the first detection of the Stuxnet malware, which attacks SCADA systems running on Windows operating systems. SCADA and control product vendors have developed specialized industrial firewalls and virtual private network products for TCP/IP-based SCADA networks.