"By migrating our design to PACSystems RX7i hot standby CPU redundancy, we achieved a tremendous improvement in system performance," says Stephen Altman, Alstom's control system product engineer. "The improved processing speed translates to tighter regulation of the turbine and greater efficiency. Synchronized data flows much faster, which reduces our cycle times. For the plant, this means a bumpless system, so operations will stay up and the turbine/generator won't trip."
Better Insight for Better Power
To secure consistent, quality electric service in smaller process applications, many users rely on uninterruptible power supplies (UPSs), which are also gaining new monitoring and alert/alarm capabilities via their HMIs or other interfaces.
For example, Captronic Systems Pvt., Ltd. (http://captronicsystems.com) in Bangalore, India, makes automation testing equipment, and it recently needed to build a reliable, flexible, remote-monitoring system to acquire UPSs' electrical power and environmental health monitoring data. Consequently, it implemented National Instruments' NI LabView software, NI PXI real-time platform to serve as a remote terminal unit (RTU), and NI-DAQmx driver software to create a data acquisition (DAQ) system that can continuously monitor and control a UPS station in real time.
"The UPS industry is dramatically changing. Power providers and users concerned about reliability are increasingly focusing on power quality and protection and on power station health. One way to ensure reliability is to remotely monitor UPS power system performance," says Himanshu Goyal of Captronic. "So, we decided to build a system that can address most of the limitations and drawbacks of currently available systems and applications. With our system, users can remotely view real-time data from UPS power station devices and sensors, identify the causes of power system disturbances, and address problems before they cause interruptions. Our system can also integrate with virtually any UPS power station, and remotely monitor and control all UPS power station electrical parameters, including voltage, current, power factor, frequency, and phase angle. We can also remotely control and monitor security devices and sensors, such as humidity and temperature sensors, door open/close contactors, wet floor sensors, smoke sensors, hydrogen cylinder status sensors, and IP surveillance cameras."
Similarly, Arizona Electric Power Cooperative (AEPCO) is a rural generation and transmission cooperative in southeastern Arizona that owns and operates the Apache Power Generating Station in Cochise, Ariz., which serves more than 115,000 homes and businesses. The station has 605 megawatts of combined gross generating capacity, two steam units that can burn coal or natural gas, one natural gas-fired boiler and four gas turbines.
To manage and optimize its power operations, AEPCO's Apache station employs GE Intelligent Platforms' Proficy iFix HMI/SCADA software. The plant has used and upgraded Proficy iFix over many years, and it presently manages coal handling, water treatment, remote wellsites, DCS interface for boiler/turbine control, remote gas turbine control for peaking units and even plant security.
However, when AEPCO evaluated its turbine controls, three of the Apache station's four gas turbines were being controlled with older technology with no or very limited communications. "We wanted remote start and control functions without the added costs of RTU interfaces and configurations," explains John Franklin, AEPCO's logic systems administrator.
As a result, AEPCO used iFix to write its own communication drivers, which allowed hooks to the turbine control systems. This gave AEPCO the remote start and control abilities it was seeking without extra RTU expenses. "If we'd taken the RTU approach, it would have been almost as costly as a $150,000 total system upgrade, and we still would have had to pay for an HMI package." Just right.