Selecting a critical power monitoring and control technology
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.
A BMS controls, monitors, optimizes, and reports on mechanical and electrical equipment such as air handling and cooling, lighting, power, fire, and security systems. BMS comprises software and hardware similar to that of SCADA. Software can be either proprietary, using protocols such as C-bus or Profibus, or open architecture that integrates Internet protocols and open standards such as XML, BACnet, LonWorks, and Modbus. Basic controls include manual switching, time clocks, or temperature switches that provide the on and off signals for enabling pumps, fans, or valves.
Unlike other monitoring and controls systems, BMS enables two-way communication between building and property managers and their employees, tenants, or residents. This two-way communication feature is a valued capability for hospitals and office buildings because both types of facilities must maintain a comfortable environment, and in the process, save energy. Systems linked to a BMS typically represent 70% of a building’s energy usage, including lighting. The BMS also track and schedule building maintenance. For example, the Bryan Medical Center East Campus in Lincoln, Neb., uses a BMS to maintain temperature and other environmental conditions for patients, visitors, and staff.
A BMS can also play a role in protecting the critical power system. Geisinger Medical Center in Danville, Pa., monitors crucial power generators through both its BMS and its security system. “We are monitoring emergency power at both locations 24 hr daily,” said Al Neuner, Geisinger’s vice president of facilities operations. “So, if one misses the alarm, the other location will catch it before we experience power problems.”
However, some say the functionality offered by a legacy BMS does not include the software tools needed to manage mission critical operations and processes. More than basic alarm and control notification are required. In addition, a BMS may not distinguish between critical and noncritical monitoring. The same technology manages temperatures of offices as well as data center hot aisles.
Also, data transfer between critical power equipment occurs at speeds and bandwidths that could incapacitate most BMSs. Power quality data, such as waveform capture and transient harmonic displays, are cases in point.
A BMS needs to be sophisticated enough to import crucial operational data from power controls. “The building automation system should allow a one-line diagram of the emergency backup power system,” said Robert McCarthy, senior associate with Environmental Systems Design.
Technology research firm Gartner defines data center infrastructure management (DCIM) as "tools that monitor, measure, manage, and/or control data center use and energy consumption of all IT-related equipment (such as servers, storage, and network switches), and facilities infrastructure components (such as power distribution units and computer room air conditioners)." Said another way, it manages energy, assets, availability, risk, services, the supply chain, and IT automation by acquiring data using simple network management protocol, BACnet, or Modbus.
As the relatively new monitoring and control technology continues evolving, it seems the larger the data center, the greater the need for DCIM. Well-known Internet service providers, search engine entities, and upcoming enterprise computing centers have particular need for the specialized capabilities of DCIMs. As a system, DCIM can encompass specialized 3-D visualization software, hardware, and sensors to monitor and control all IT and facility infrastructure equipment in real time. It automates three primary functions: data collection, infrastructure modeling, and analytical reporting.
The primary DCIM drivers are:
- Greater power and heat densities
- Growing virtualization and cloud computing
- Increasing dependence on critical IT systems
- Increasing demand for energy efficiency
- Pursuit of green IT initiatives.
At its best, DCIM produces improved uptime, efficient capacity planning and management, valuable business analytics, and deeper process and change management. However, the relationship between IT and facility infrastructure management, and the equipment they manage, must continue evolving to realize its promise.
As with BMS, DCIM systems need to be sophisticated enough to import crucial operational data from power controls to effectively monitor and control critical power systems.
According to 451 Research, “DCIM systems today mostly look at the present status of the data center for the purpose of improving operational efficiency and availability. But data center managers must also look forward—some of their biggest challenges are in avoiding huge cost overruns by over-provisioning and avoiding becoming constrained operationally by a shortage of power, cooling, or space.”
Compared to legacy SCADA and BMS, and emerging DCIM, monitoring and control capabilities of CPMSs are apples to their oranges. Rather than being all things to all infrastructure systems, CPMS monitoring and controls are dedicated to managing critical power generation and distribution. These high-end power controls are proprietary or semiproprietary solutions, running on either a shared or a dedicated backbone.
They typically work in tandem with a SCADA, BMS, or DCIM, providing the needed sophistication, speed, and analytics specific to power generation and distribution. Bryan Medical Center depends on the seamless exchange of information between its CPMS and BMS.
CPMSs typically oversee gensets, circuit breakers, transfer switches, bus bar, paralleling control switchgear, UPSs, and other critical power distribution equipment. They watch normal and emergency voltages and frequency, and indicate transfer switch position, source availability, normal and emergency voltage and frequency, current, power, and power factor. They also display transfer switch event logs, time-delay settings, rating, and identification. They facilitate critical power system load management, bus bar optimization, testing, maintenance, reporting, trending, and analytics. They ensure power reliability during surges, sags, and outages.
CPMS reporting capabilities help health care facilities comply with NFPA 70, NFPA 99, and NFPA 110 requirements for hospitals, as well as joint commission reporting requirements for maintaining accreditation. A dedicated and fully integrated power monitoring system helps data centers and telecommunications sites satisfy National Electrical Code requirements and EN50160 Power Quality Compliance.
Sophisticated power controls operate at extremely high speed (in milliseconds) and cache or share voluminous data from one device to the next without disrupting other building functions (see Figure 2).
“When you are doing forensics, you need fast and accurate time marks to track down where things went wrong,” said Morris Toporek, senior vice president for Environmental Systems Design.
Northwestern Memorial Hospital’s Prentice Women’s Hospital in Chicago accomplishes data transfer with a self-sustaining, isolated network that includes a self-healing Ethernet dual fiber optic ring. “Self-healing means that communication happens both ways on both rings,” said Junnaid Malik, electrical engineer with Cosentini Associates mission critical group. “One ring could be physically cut and the system could still communicate.”
Power quality analysis is the leading edge of power control technology (see Figure 3). It is very different from traditional monitoring. Analytics look at power harmonics and high-speed transients, and can be used for trending and predicting growth.
In terms of security, some CPMSs are protected with the same 128-bit encryption technology used by NASA.
Deciding which of these monitoring and control technologies is optimal depends on the application for which it is intended. The decision should be based on the importance of power reliability for a given set of operations or processes. If reliable power isn’t absolutely critical, a SCADA system or BMS might be appropriate. If a holistic view of a data center’s IT and facility infrastructure is a high priority, DCIM might be the logical choice. However, when the stakes are high for maintaining critical power, consider the specialized capabilities of CPMS monitoring and control that can also work alongside the other monitoring and control technologies.
Bhavesh Patel is director of marketing and customer support at ASCO Power Technologies, a business unit of Emerson Network Power. He is an accomplished public speaker with expertise in power system markets and has delivered presentations at NFMT, PowerGen, and ASHE. He has written many articles about power reliability and quality, and has hosted roundtable discussions of industry stakeholders to continue surfacing issues that help to improve power reliability.