One of North America's largest utilities has a division responsible for the generation and selling of electric power. A supervisory control and data acquisition (SCADA) system was required to gather data from a significant number of remote sites throughout the generation area and present the composite data in a graphical format to the shift operators. The power generation data came from hydro, fossil and nuclear plants, in five different formats, over a wide area network. The requested data update time was five seconds.
The utility company turned to Trihedral Engineering Limited, which has a long and enviable record of involvement in the utilities market. Their PC-based control and monitoring software, VTS TM , was installed as a data concentrator, and required the development of a number of drivers to access data from the various plants. They now include a UNIX master station, interface to an OLE/ActiveX object which gathers data from a VAX computer, a PI interface to a HP9000, and an SQL server to view table data within the server as I/O data for the VTS application. Total generation capacity is in the range of 34 GigaWatts.
In addition to these drivers, several other customized objects were developed. These include a "point" which is used to gather information about a generator unit from a number of analog and digital inputs, determine the status of the unit, set the point value to reflect that, and have a standard set of analog values associated with the point. The generator group point is used to sum generator unit data from a number of units or other generator group points.
Other critical VTS features include event-driven execution, automatic fail-over with multiple redundancy, remote monitoring and control via modem. VTS is not limited in terms of either number of I/O or stations. As a result, future expansion will include all switchyard and line status information.
Running as a 32-bit application on Windows 95 and Windows NT, VTS is fully on-line configurable, fast, flexible and has extensive built-in control and graphics capabilities.
